May 22, 2022 Longchang Chemical

5 types of UV light-curing adhesives

UV adhesives can be broadly divided into 2 categories with substrates (tape, double-sided adhesive), and without substrates (liquid glue), the latter used when UV light irradiation curing, the former UV light irradiation can increase or reduce the bonding, UV reduction adhesive tape as temporary protection or temporary positioning, in microelectronics, optoelectronic devices, such as wafers, touch screen glass processing industry has a great demand.
UV pressure-sensitive adhesive (PSA)
PSA is currently made by solution coating, drying and chemical reaction, more than 60% of the solvent to be volatilized and burned off, high emissions, long production process, low efficiency, the product may also be residual solvents and other harmful chemicals. Production of PSA by UV curing, the solvent-free liquid components coated on the substrate after the UV light irradiation for photopolymerization is made, without the need for a hot baking channel, the production line is simplified, the production process is environmentally friendly, almost zero emissions, and production efficiency is greatly improved.
PSA is available in various forms, from decorative films, various protective films to engineering structural tapes, and is very versatile, being used in advertising panels, electronic products to high-end packaging boxes.
UV laminating adhesive
Food, beverage and some biomedical products need high barrier flexible packaging, the barrier properties of the packaging material determines and affects the time of edible. High-barrier packaging materials made of plastic film and paper, metal film composite, with high strength, good oxygen and water barrier, safety and health, non-toxic, adaptable to the characteristics of printing, freeze-resistant and 120 ℃ high temperature resistance. At present, almost all of the composite adhesive in the flexible packaging industry is solvent-based adhesive, the quality of the solvent > 70%, the composite process through the coating, solvent evaporation, compounding, storage and ripening process steps, in addition to flammable, explosive, high emissions, long production process, low efficiency, the composite film also residual solvent. Whenever the demand for fine packaging is high and delivery is urgent during the holiday season, many composite packaging films are delivered without fully reacting and thoroughly evaporating clean solvents. Residual solvents and incomplete reaction chemicals may penetrate and contaminate food, which is a major reason why there are still many pharmaceutical and food packaging products that do not meet the health indicators. Although water-based adhesives are solvent-free, they are slow to dry, inefficient in production, and have unsatisfactory bonding properties to plastics. Replacing solvent-based adhesive with UV adhesive, not only the production efficiency of composite film will be greatly improved, from the original production process of several hours to a minute can be completed; UV adhesive does not contain solvents, no volatilization, no harmful residues, more can ensure that the composite film to meet the health and hygiene requirements of food, pharmaceutical and other packaging materials. If the solvent evaporates for several hours or even dozens of hours, the construction site can not be used during this period, if the use of light-curing adhesive is not such a problem, you can first light-curing adhesive coating on the ground, self-leveling after the UV light to make it cured, the surface has a sticky, and then the PVC floor can be laid on the immediate use, not only greatly shortened the construction cycle, and the entire production process without solvent evaporation, no pollution Indoor air.
UV construction adhesive
Safety glass mainly adopts polyvinyl butyral film as the bonding material, and the glass pieces are bonded through the process of vacuum degassing and hot pressing, and the total production time takes about ten hours. The production of laminated safety glass using liquid bonding method of sealing, glue filling and storage in natural light for tens of minutes to complete the light polymerization has also been a longer time, but is still a non-mainstream product, mainly used in the low-end safety glass market. The liquid bonding method is not widely accepted mainly because the performance of UV adhesive is still insufficient and the safety lacks trustworthy data. UV adhesive is growing well in the construction sector, with store kitchen windows and decoration, stained glass are using UV adhesive. With the improvement of performance, UV construction adhesive will have great development.
In recent years the application of PVC stone plastic flooring in the rapid development in the country, construction method is first scraping a layer of adhesive on the construction ground, and then the PVC floor bonding up. pvc plastic flooring adhesive can be mainly divided into water-emulsion, solvent-based, reactive 3 major categories. Water emulsion type adhesive with water as the dispersion medium, the product is non-toxic, low cost. But poor water resistance, generally by water immersion, the adhesion force dropped significantly, such as water-based acrylate. Solvent-based adhesives are mainly polyvinyl acetate and neoprene adhesives. Reactive type is polyurethane series adhesive. These types of adhesives are needed after construction.
UV electronic adhesive
The field of electronic products has been a large number of use of UV adhesive, including the positioning of the line, pin sealing, LCD panel preparation, cell phone keys, etc., UV curing bonding is a must-use technology means in the manufacture of electronic products. With the thin layer of electronic products and the emergence of organic optoelectronic devices, flexible bendable display devices, to adapt to the roll-to-roll process of UV adhesives have a huge demand. UV curing of efficient, fast, timely, controllable characteristics will be fully revealed.
UV optical adhesives
Touch screens are currently the single largest application for UV optical adhesives. UV optical adhesives in touchscreens have 3 functions: bonding, increasing light transmission and improving impact resistance, and need to meet stringent performance requirements, including color, weathering and environmental stability, electrical properties, optical properties, etc. Touch screen lamination involves bonding materials are: glass, ITO conductive layer, PET, PMMA, PC, etc.. When the touch screen with sapphire, in order to improve light transmission will require a higher refractive index of UV adhesive. Currently used for touch screen with liquid (LOCA) and solid (OCA) optical adhesive, the former with program-controlled dispensing machine dispensing, cover the glass cover, leveling and filled through the cover curing, with the advantages of good filler, easy to apply glue, but the need to do overflow glue cleanup; OCA is a double-sided PSA without substrate, the upper and lower are release film, use first remove the light release film for lamination, and then remove Heavy release film and then laminated with another adhesive surface. Earlier touch screen using liquid adhesive is heat curing, the production process is long and inefficient, and now has all changed to UV curing adhesive. The current OCA is still using the traditional solvent-based adhesive after coating, drying, thermal cross-linking process production, long baking channel, dust and other defects caused by more. Changing to UV curing process will greatly improve production efficiency, reduce equipment input and production costs.
UV medical adhesive
UV adhesive in the medical field has great room for growth, such as medical pressure-sensitive adhesive or tape to UV curing preparation, can form a series of products.

Contact US