With the rapid development of optical display technology, UV curing adhesives are increasingly used in the field of optical films, especially in liquid crystal displays (LCDs), flexible screens and touch panels, where their high transparency, fast curing and low shrinkage characteristics have made them key materials. This article focuses on the technical characteristics of low refractive index UV adhesives, and combines the LM-301 series products of Shenzhen U-Sunny to analyze how they meet the manufacturing needs of precision optical films.
Core technical characteristics of low-refractive index UV glue
Low-refractive index UV glue (refractive index ≤ 1.45) is mainly used for interlayer bonding of optical films, such as the composite of polarizers, diffusion films and brightness enhancement films. Taking Shenzhen Youyang's LM-301 series as an example, it is based on modified polyurethane acrylate technology, and the refractive index can be as low as 1.40 after curing, which significantly reduces the interface reflection loss in the optical path and improves the display brightness and uniformity. In addition, the product only requires 5000mJ/cm² of curing energy at 365nm band, and the curing depth reaches 15mm. Combined with a linear shrinkage rate of 1.2%, it ensures that there are no bubbles and residual stress in the bonding layer, which is suitable for precise bonding of ultra-thin flexible substrates.
In terms of physical properties, the hardness of LM-301 after curing reaches A80 level, the tensile strength is as high as 240MPa, and the boiling water absorption rate is only 0.3%. It still maintains stable bonding strength under high temperature and high humidity environment. Its low glass transition temperature (15°C) and high flexibility design can effectively alleviate the risk of stress cracking caused by differences in thermal expansion coefficients, and is especially suitable for long-term use of thermoplastic substrates such as PET and PC.
Shenzhen Youyang's LM-301 innovative advantages
Shenzhen Youyang's LM-301 series further optimizes the scratch resistance and light transmittance of optical films by introducing fluorinated monomers and silicone modification technology. Compared with traditional high-refractive index adhesives (such as G-UV4003T5 with a refractive index of 1.62), the low refractive index of LM-301 can reduce light scattering, and at the same time, the nano-filler composite technology balances hardness and elasticity to meet the bending resistance requirements of flexible folding screens.
In terms of process adaptability, LM-301 supports single-component operation, does not require premixing, and can accurately control the amount of glue with an opaque dispensing needle. For temperature-sensitive substrates (such as EVA films), the curing process does not require high-temperature heating, which reduces energy consumption and avoids deformation of the substrate. In addition, the product can be used stably within 7 days after opening, reducing material waste.