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Industry outlook for Pressure Sensitive Adhesives (PSAs) in Asia Pacific
PSAs form a major category of adhesive tapes, also known as self-adhesive or self-stick adhesive. Made of relatively thin and flexible material with single or double sided coating, PSAs adhere to a variety of substrates when applied with pressure to most clean and dry surfaces. PSAs are safer than glue sticks and more discrete than traditional tape. According to a research by Mordor Intelligence, Asia Pacific is the most promising market for PSAs, with over 40% of the global demand, and is likely to dominate the market in the near future. This can be attributed to the growing demand for tapes and labels in the region, especially in countries like China, India, Japan and South Korea. In the report, the PSAs market is also expected to register a CAGR of 6% during the period of 2020 to 2025, with Asia Pacific predicted to dominate globally due to the large market size.
The rise in popularity of PSAs can be attributed to advances in rubber, silicone and acyrlic technologies. These have allowed PSAs to come in a variety of forms and characteristics for many different surfaces, enabling them to fill out voids in the pressure-sensitive adhesive industry.
With the growing demand for PSAs, it is essential to better understand the different types of adhesives, technologies behind these adhesives, as well as considerations when choosing the right PSAs. It is also crucial to gain insights into the different forms and characteristics of these adhesives to decide which works best for your application.
PSAs improve processes and end-use products as they increase production efficiency by offering immediate adhesion and do not require curing time. This reduces assembly time and keeps production lines moving. In addition to efficient production, PSAs also heighten end-user safety as they can be formulated with flame retardancy. Additionally, PSAs can easily replace traditional mechanical fasteners, offering uniform adhesion and strength as well as increased durability. They also improve end-user comfort as they provide insulating seal and offer sound and vibration control in certain applications.
Types of pressure sensitive adhesives
Being heat, chemical and water resistant are some qualities of solvent-acrylic PSAs, thanks to the abundant variations of their molecular structures. Solvent-acrylic adhesives deliver the precise polymer performance to meet any adhesive needs, such as a selection of crosslinking mechanisms that enhance resistance to chemicals and other solvents.
Popular applications for solvent-based acrylics include safety labels on outdoor power equipment and automotive door seals, gaskets, baffles and filters.
Water-based acrylic PSAs
Water-based acrylics are typically made of adhesive polymers that have been synthesised from vinyl acrylic monomers. By using a variety of monomers, these PSAs are able to achieve performance properties such as tack, peel and shear.
Known for its environmentally-friendly properties and cost-effectiveness, water-based acrylic PSAs produce little emission when cured and are typically fast to run when coating.
Hot-melt pressure-sensitive adhesives (HMPSAs)
HMPSAs remain permanently sticky, offering excellent adhesion even after the glue is cooled. Known for its aggressive bond strength, low temperature flexibility and high heat resistance, the thermoplastic rubber-based adhesive can be formulated for both freezer grade and refrigeration applications, and are able to bond to both rough and smooth surfaces as a result.
General applications include packaging, product assembly, bottle labeling and clear labeling. For applications like labelling and general purpose, HMPSAs improve efficiency of application processes while delivering aesthetically appealing finishes. For example, label applications for health, beauty and care products.
UV-curable PSAs and moisture-cured PSAs
In today’s manufacturing landscape where environmental regulations are increasingly stringent, UV-curable PSAs serve as a good option for tapes and labels manufacturers, providing better high-temperature stability and solvent resistance. They have demonstrated improved performance on PVC, elastomers and polyethylene, and are applied in many industrial fields including packaging, transportation and electronics. The UV-curable hot melt adhesives are typically applied using standard roller- or slot-die coating machines, followed by in-line UV curing.
Separately, moisture cured technology gives PSAs good anti-ageing performance. The new technologies are able to replace the traditional high performance PSA – usually solvent based – for specialty applications with effective eco-friendliness.
Considerations when choosing pressure sensitive adhesives
As the foundation of PSAs has been laid out, it is now important to fully understand the performance properties to ensure the correct adhesives are chosen for your given labelling applications. These general key considerations are applicable to all types of PSAs available in the region. They are: level of bleed-through, degree of exposure, removability and repositionality as well as surface texture.
Level of bleed-through
PSAs have varying levels of bleed-through, which means that they may migrate into the face material, resulting in a product’s tainted appearance as well as performance issues. While customers have to ensure the chosen PSA is compatible with the face stock, primers can be added to improve the anchorage of the adhesive to the facestock.
Degree of exposure
While PSAs can withstand varying degrees of UV, solvents, weathering, moisture and temperature, it is important to understand the end-use application to help in choosing the adhesives that will not fail when exposed to certain conditions.
Sufficient testing and learning of their environmental performance levels enables better evaluation of which PSA is suitable for the specific application. For example, not all acrylic PSAs exhibit the same sensitivity to UV and aging; silicone PSAs are generally the best at handling exposure to solvents; and HMPSAs are 100% solids and can generally bond to another substrate under any time circumstances.
Level of removability and repositionality should also be considered, especially if the application requires removing shortly after assembly or at any time. Users have to bear in mind that some PSAs are permanent and cannot be removed. This also means that for each type of the PSAs mentioned above, there can be both permanent and removable applications hence understanding the end-user application is crucial.
Given today’s requirement for sustainability, companies should also consider recyclable adhesives in the process of decision-making.
The texture of the surface that the adhesives are applied on plays a large role in defining how well the adhesive will bond to it. With PSAs, the intimate contact of the adhesive molecules with the surface molecules can greatly impact performance.
For instance, the level of roughness on a surface impacts how well an adhesive can wet it out. It is important to ensure compatible adhesive properties and substrate properties are chosen.
Bostik acknowledges that extensive background research and careful considerations should be put in play when selecting the most appropriate adhesives for our customers. That is why we have innovated our PSAs to make them suitable for a wide range of applications.
With the growing demand for PSAs in the Asia Pacific region, we will continue to share our knowledge and capabilities with customers to ensure the right adhesive is chosen for even the most stringent tape and label needs.
This article was originally published in Chemical Today June 2020 issue