A pressure sensitive adhesive is a completely ugly compound that complies with a provided surface area when light stress is used. A pressure delicate sticky maintains a great equilibrium in between adhesion (holding power of the sticky on external substratums) and communication (holding power of the mixed inner elements of the adhesive). PSAs do not necessary a chain reaction to create adhesion forces.
Pressure Sensitive Tape Components and Key Terms
Adhesive: Regular adhesives are acrylic, natural rubber, or synthetic rubber. Unique adhesives with a smaller sized application base are silicone, butyl, or EVA (ethylene – plastic – acetate).
Backings: A backing (or carrier) is a relatively thin, flexible, webbased material. It can be made from various kinds of materials, such as paper, film, foil, foam, fabrics, non-wovens, and laminates. Backings are often chosen due to the function they fulfill, such as cushioning, dampening, maintaining a barrier, etc.
Primer: A primer is used to increase the holding power of the glue to the support. The primer could be a fluid compound layered into the support material, or a physical therapy, such as corona or fire treatment. This is specifically important if the tape has to remove easily, or if the tape is stressed permanently with a tons.
Release Liner: A launch lining is mostly utilized with doublesided tapes. Siliconized papers or films are the major kinds of release linings. The optimal liner selection relies on the application. If die-cut capacity is needed, polyester linings are preferable. If the tape is exposed to moisture, poly-coated papers are mostly made use of as a result of their dimensional security. For a lot of applications, paper liners are the linings of option.
Release Coating: The support of a single-sided tape, and the release liner for a double-sided tape, are alleviated with a release finish. The release finish ensures secure loosening up of the tape during the application. This is crucial for automatic applications in which the tape could be unwound at broadband. A launch layer could have various launch pressures for either simple taking a break or more challenging unwinding, depending on the customer’s requirements.
Adhesion: Attachment is the attraction pressure between adhesive and also substrate, which depends upon the glue, the substrate, and the application conditions such as: application stress, time period of stress, and also temperature level during application.
Cohesion: Communication explains the inner strength of a sticky. It matters for applications where the pressure, in effect, is alongside the bonding area. High cohesion goes hand-inhand with heat resistance, low-edge picking, as well as high holding power or shear resistance.
Tack: Tack is the moistening ability of a sticky to the substrate in the beginning get in touch with. Tack is effective under minimum pressure as well as for a brief period of call time. For the majority of applications, tack is not relevant due to the fact that time is necessaried to press the tape to the substrate. For applications such as flying splices in the paper as well as print market, tack is a vital criterion. Tack also supports attachment on harsh surfaces. The thumb examination is usually made use of to define a sticky, even though it provides no indicator of the bond or the total tape efficiency.
Shear: Shear is the ability of an adhesive to resist creep or slippage.
Tensile Strength: Tensile stamina is mainly essential for single-sidedtapes where the support for the application has to hold up against tensile anxiety. Container sealing tapes or strapping/bundling applications are most important. The tensile strength of tape is generally not important for double-sided tapes, as long as the bonding materials are not stretchable.
Predominate Types of Adhesive Tapes
For single-sided tapes, the backing can be comprised of a variety of flat web-based materials, such as film, paper, foil, fabrics, or foam. In many instances, the backing is treated with a release coating to enable stable unwinding forces, or with a primer to ensure that the adhesive sticks to the correct side of the backing.
For double-sided tapes, the backing is coated with a pressure sensitive adhesive on both sides. The backing materials can be the same as any of those mentioned for single-sided tapes. A release liner is utilized to prevent the adhesives from sticking to themselves. The release liner is normally a siliconecoated paper or filmic material
A transfer tape is considered a specialty product, as it does not harbor a backing material. The pressure sensitive adhesive is coated onto the release liner and wound onto a roll. A release liner is always part of the transfer tape structure.
Pressure sensitive tapes need to be stored under defined conditions.
Extreme high temperatures can lead to degradation of the adhesive or backing materials. Extreme low temperatures might influence the bonding characteristics.
The recommended storage conditions are:
• 68 – 72° F / 20 – 22° C
• 50% relative humidity
• Rolls store flat in their original packaging, away from direct sources of UV (i.e., lights, sun).
How Pressure Sensitive Tape is Manufactured
Traditional Production Process
The ingredients – adhesive, resin, filler, and other additives are mixed with organic solvents or water.
The solved adhesive is transported to the coating device, after which the adhesive is coated in an even layer onto the backing and dried in the drying channel until all the solvents have evaporated. The result is a long roll of tape. After the coating process, the long rolls are converted into the desired roll sizes.
In the hot-melt process, the adhesive and other ingredients are processed without solvents. Due to heat in the process, the adhesive remains in a liquid state to be coated.