In modern life, pressure-sensitive labels are ubiquitous and face diverse application scenarios. Ensuring these labels adhere firmly to vastly different surfaces is a significant challenge. With ongoing technological advancements, such problems are gradually being solved.

Currently, the adhesives used for pressure-sensitive labels are categorized into three types: solvent-based, emulsion-based, and hot melt. Each is applied in different environments and scenarios.

Solvent-based adhesives, commonly known as "oil-based adhesives," use organic solvents as the dispersion medium. They feature strong adhesion, enabling them to bond securely to various surfaces with minimal risk of adhesive oozing, ensuring a neat appearance after application. They also offer good high-temperature resistance, making them suitable for labeling needs in high-heat environments. Their excellent bonding properties allow them to adhere to substrates of different materials. Furthermore, their rapid drying time allows labels to reach usable tack strength quickly after coating, enhancing application efficiency. They are typically used in fields requiring high-temperature labeling, such as identification labels for electronic devices and heat-resistant labels in automotive engine compartments.

Emulsion-based adhesives, also known as water-based adhesives, use water as the dispersion medium. They are highly environmentally friendly, containing no organic solvents, and are non-toxic and odorless. These adhesives provide good initial tack and strong final adhesion, maintaining a secure bond over time. Once dried, they exhibit high transparency, which does not affect the label's appearance or readability. Due to their excellent water resistance, they perform reliably in humid environments. Consequently, they are widely used for labels on food, pharmaceuticals, daily chemical products, and industrial goods with stringent environmental requirements. Examples include labels on food cans, adhesive for pharmaceutical leaflets, and labels on cosmetic bottles.

However, emulsion-based adhesives have slightly poorer heat resistance compared to solvent-based types. Their adhesion may decrease in high-temperature environments. Additionally, their drying speed is slower, particularly in high-humidity conditions, requiring more time to fully cure, which can impact production efficiency.

Hot Melt Adhesives are another common type used for pressure-sensitive labels. They are applied in a molten state when heated and achieve bonding upon cooling and solidifying. Hot melt adhesives have high fluidity and viscosity, making them particularly suitable for low-temperature labeling. They maintain good adhesion even in cold environments, ensuring label security. Being environmentally friendly, non-toxic, and free of harmful substances, they adhere well to surfaces with slight oil or moisture contamination. Complying with environmental and hygiene standards, they are frequently used for food, pharmaceuticals, and supermarket labels. Their rapid curing also enables high application efficiency.

However, hot melt adhesives perform poorly in high-temperature environments. They are generally used below 70°C (158°F), as their adhesion degrades significantly or is lost at higher temperatures. Also, their high initial and final tack result in poor repositionability. Crucially, they cannot adhere to PVC substrates due to plasticizer migration.

Different types of pressure-sensitive label adhesives leverage their unique properties to play crucial roles across various fields. Together, they drive the continuous advancement of the pressure-sensitive label industry, meeting increasingly diverse and specialized market demands.