Since 1960, foreign countries have reported extensive research on UV light curing adhesives. And has made remarkable achievements. Nowadays, UV adhesives have been successfully applied in many industrial assembly fields, especially high-tech industries that require rapid assembly, such as LCD manufacturing, camera and other optical product manufacturing, optical disc manufacturing (CD, VCD, DVD, DVD-R), Manufacturing of electronic components in the optoelectronic information industry, such as watch manufacturing, buzzer, assembly of mobile phone keypads, manufacture of electronic circuit boards, and manufacturing of polarizing components. In the field of daily necessities, such as the manufacture of glass furniture, the assembly of glass crafts, the assembly of decorations such as toys and jewelry, UV glue is also commonly used. Even traditional industries are using a large amount of UV glue for assembly, such as the assembly of magnetic motors. Get fast and efficient production efficiency.
As scientists and technicians continue to make progress, some of the shortcomings of UV adhesives have been overcome and the field of application has been expanded. For example, the application of a novel photoinitiator allows the curing wavelength to expand in the visible direction and can be cured with visible light; the application of a highly efficient photoinitiator can be used for bonding of colored or filler systems, and can be as low as 0.01 to 20% in light transmittance. The adhesion between the substrates. For another example, a UV curing technology, an anaerobic curing, and a thermal curing technology are combined to produce a dual-cured product, which not only can photocure light-transmitting portions, but also can perform anaerobic or thermal curing of non-transparent portions.
Tables 2 and 3 list the application of UV-curing adhesives in Europe, including medical, glass products, automotive, electrical, electronics, and optoelectronics.
Here are some of the main applications for UV glue:
1, in the application of medical supplies
Disposables have become one of the driving forces for the increase in the use of UV-curing adhesives. The technology has expanded to the use of a hypodermic needle attached to a syringe and an intravenous tube, as well as catheters and medical filters. The annual consumption of UV adhesives in this area in Europe is estimated at 20 tons with an annual growth rate of 5.4%.
2, in the glass and crafts, jewelry industry applications
The use of UV-curable adhesives has shown good momentum in other areas, including the use of kitchen windows and fittings in retail stores, building applications including stained glass, and, more importantly, the application of safety glass. The traditional process is to use polyvinyl butyral bonding, two layers of glass coated with this adhesive need to be rolled in a hot press, temperature 130 ° C, pressure 1.3MPa, and maintain a certain period of time. The total production time of this safety glass is about 20 hours. With UV-curing adhesives, the bonding process takes only seconds or minutes. This greatly shortens the production cycle, saves energy, and improves economic efficiency. In the jewellery and accessories industry, jewels, crystals and other mosaics and positioning can be quickly completed. Glass furniture is also an important application area, despite being influenced by fashion.
3, in the electrical and electronic industry applications
UV-curing adhesives are developing the fastest in electrical and electronic applications. The combined annual growth rate is an average of 9.2%. The estimated consumption has increased from 45 tons in 2000 to 70 tons in 2005. The main uses include:
1 Bonding and sealing of smart cards and conductive polymer displays;
2 Painting and sealing of terminals, relays, capacitors and micro-switches;
3 printed circuit board (PCB) paste surface elements;
4 printed circuit board integrated circuit block bonding;
5 coil wire terminal fixation and component bonding.
In the same way, automobile industry components are usually bonded in this area, and their applications cover the assembly of automotive lamps, reversing mirrors and airbag components, and fuel injection systems.
4, in the optoelectronics, information industry applications
Although the electrical, electronic, and automotive industries are the fastest growing segments, the largest consumer of optoelectronic information industry is the industry with huge potential, including three major consumer segments: digital disc manufacturing, optical fiber bonding, and liquid crystal and polymerization. Display.
Entering the information age, CD-ROM, as one of the most important information carriers, is in great demand and is expected to explode in the next five years. Whether it is now or in the future will be the largest application of UV-curing adhesives. CD, CD-R, and CD-RW are mainly used for the coating of a reflective film and a protective film. The larger amount is in the DVD manufacturing industry. There are two important points about DVD production: First, unlike its predecessor, the CD-ROM, its manufacture relies on the bonding of two layers of polycarbonate film to form a basic disk; secondly, Instead of sticking together at a point, the amount is increased. UV curing adhesives are also used for sealing covers for DVD packaging.
The demand trend of DVD shows that the DVD market has a very high growth rate, including home theater. Taking into account the development of potential technologies such as multi-layer DVDs, the market size for this area will grow tremendously, reaching 575 tons in 2005, and the corresponding annual growth rate of 45%.
Optical fiber and conductive pump display are also one of the application areas. The United States has used optical fiber instead of copper to transmit signals. China's development prospects are bright.
Liquid crystal and polymer displays are continuations of LCD technology. The most promising flat panel display technology, liquid crystal display (LCD), is experiencing rapid development and has become a hot spot in the market. Currently, LCDs are widely used in electronic devices. These devices include:
* Watch, calculator
*computer monitor
*TV screen
* Camera / Clock
* Tester reading plate
* Automotive Electronic Instrument Panel
* Personal Digital Assistant (PDA) display
The UV-curable adhesive is used in the manufacture of liquid crystal displays as follows:
1 Optoelectronic component alignment temporarily fixed;
2 motherboard seals;
3 port seals;
4 metal lead terminal bonding;
5 flexible closure;
6 bare chip placement;
7 Unidirectional and film bonding, and FCOG cap coating.
China is the main producer of liquid crystal displays in the world, and the materials used are still heavily imported. UV curing adhesives for LCD assembly use mainly products from Japan and other countries, represented by Three Bond.
In the manufacture of computer hard disks, the working procedure for the bonding of magnetic heads and flaps is to apply a small amount of glue to the tongues at the front end of the flaps, and then to insert the heads at the center to place the glue at the tongues. A certain amount of UV light is irradiated for a few seconds to cure the adhesive; it is then removed from the automatic bonder, placed in an oven after processing, and cured by heating at a set temperature. It is UV-thermal curing dual curing.
5, non-structural UV curing adhesive
The production of non-structural adhesives is relatively large. In 2000, it produced approximately 4,000 tons. The main types are pressure-sensitive adhesives and cardboard and packaging adhesives. Four good UV photosensitive tapes and labels for the market:
1 medical adhesive tape and repair medical pressure sensitive adhesive;
2 Dedicated engineering tapes, such as automotive and plumbing;
3 transparent film labels;
4 function tags.