The Basics of Adhesion: Learning from Adhesive Tape Technology

Screws being replaced by adhesive tape

Screws have long been used to attach and secure parts, but that is now changing in the production of IT devices such as smartphones, tablet PCs, and laptops. Adhesive tapes from Dexerials and other chemical companies are being used instead of screws with rapidly increasing frequency.

Let’s begin by considering why screws are used to secure parts—it’s because even after a screw is tightened to secure a part, the parts can be disassembled non-destructively and secured with the same screws afterward if necessary. This is called “reworkability” in production settings. Advances in adhesives and adhesive tapes mean that tape is now being used even in cases where reworkability is required.

For example, adhesive tape is used to secure many parts in the smartphones everyone uses. The adhesive tape used for displays and touch panels not only secures them to the housing but features functionality such as water resistance, impact resistance, conductivity, and light blocking.

While a screw secures parts at a single point, adhesive tape can be cut in contiguous shapes to securely affix parts across a wide surface. As a result, tape can be used to increase bond strength above what a screw can offer, and reduce the loosening and rattling that can occur as a device secured with screws is used over time. In addition, the use of screws requires steps to drill holes for the screws and a device housing thick enough to contain the entire length of the screw. Adhesive tape can conform to any shape and thickness can be adjusted in a wide range from less than 10 microns to several hundred microns. As digital devices grow ever thinner and smaller, the advantages of tape over screws become increasingly evident.

Dexerials has been developing adhesive tape since its inception.

Dexerials has a long history of developing and producing functional tapes. In 1962, our precursor, Sony Chemicals Corporation, was founded to manufacture and sell copper foil products for circuits used in transistor radios as well as industrial adhesives.

The next year in 1963, the company began the manufacture and sale of liquid adhesives for industrial and home use, become a core pillar of new business for the company. This marked the beginning of dedicated development in adhesives for securing electronic parts in electrical appliances.

In 1965, the company leveraged its adhesives technology to begin production of double coated tapes. Following the introduction of the Tuck Master series for home and industrial use, model #1477J launched in 1968 and earned a particularly strong reputation. It developed into the T4000 Series, which became the gold standard for high-performance double coated tape. Production of the Sony Flex flexible printed circuit boards (FPCs) began in 1973, contributing to reductions in the size and weight of electronic devices, and the T4100 Series of double coated tape for FPCs went to market two years later.

As more home audio equipment, TVs, and video equipment came into widespread use in the mid-70s, the company supplied electronic devices such as magnetic tape heads and ferrite cores for Sony products. The reliable, high-precision fabrication and assembly techniques as well as the thin-film technology that was developed during this time are the foundation for the submicron-scale precision needed for modern electronic products.

Then as LCD panels for digital cameras and mobile phones and LCD displays for TVs and monitors came into widespread use, in 1977 the company led the industry in commercializing Anisotropic Conductive Film (ACF) with electric connectivity, which is indispensable for the evolution of LCD devices.

The company again led the industry in 1998, this time in efforts to reduce environmental impact by developing products such as the halogen-free G9000 double coated tape produced through UV curing without organic solvents.

The technology to mix (materials), coat (appropriately), and cut (into required shapes) honed through the adhesive and tape business forms the foundation of Dexerials’ technology. The ability to secure parts with high precision at the micron level is indispensable for the stable, long-term functionality of electronic devices, and prevents degradation or malfunction.

At the same time, further improvement to the functionality of adhesive tapes is needed to enable greater reductions in device sizes and thicknesses. Dexerials will continue to refine its technologies to mix, coat, and cut to create products that meet market demand.