Hot Melt Adhesives

Hot melt adhesives are widely used for flexible packaging lamination due to their fast bonding speeds and solvent-free nature. These adhesives are solid at room temperature but become liquid or fluid when heated above their melting points, enabling quick automated application and bonding. Some commonly used hot melt adhesives for flexible packaging include ethylene-vinyl acetate (EVA), polyolefin, polyamide, polyester, and polyurethane. EVA hot melts are popular for bonding polymers like polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), etc. and find usage in food packaging. Polyolefin hot melts offer excellent adhesion to PE and PP substrates and are suitable for dry and frozen food packaging.

Solvent-Based Adhesives

Solvent-based adhesives are also commonly utilized for flexible packaging lamination applications. These adhesives are dissolved or dispersed in organic solvents and offer great wettability and adhesion to various substrate materials. Commonly used solvent-based adhesives include polyurethane, polyamide, vinyl acetate, epoxy, and acrylic adhesives. Polyurethane adhesives exhibit outstanding adhesion, flexibility, water and chemical resistance. They are suitable for high-barrier packaging of edible oils, fruit juices etc. Polyamide adhesives demonstrate very good moisture barrier properties and are ideal for moist food packaging. Advantages of solvent-based adhesives include low curing temperature requirement and flexibility to control open assembly time. However, they have limitations like stringent volatile organic compound (VOC) regulations.

Water-Based Adhesives

With growing emphasis on environmental sustainability, water-based Lamination Adhesives For Flexible Packaging are gaining increased popularity for flexible packaging applications. Key advantages of these adhesives include low odor, non-flammability and compliance with strict health and safety standards. Common water-based adhesive chemistries used in flexible packaging include polyvinyl acetate (PVA), vinyl acetate ethylene (VAE), polyacrylate, and carboxylated styrene-butadiene latex. PVA adhesives offer good adhesion to Paper, PE, BOPP, and other substrates. VAE adhesives display high bond strength and heat resistance. Carboxylated styrene-butadiene latex adhesives exhibit excellent adhesion to diverse materials like paper, PE, PP, etc. Water-based adhesives require drying/curing at slightly higher temperatures but provide comparable functional performance to solvent systems.

Pressure Sensitive Adhesives

Pressure sensitive adhesives (PSAs) have become integral to flexible packaging lamination in the form of self-adhesive labels, graphic tapes, seals, and reclosable packaging. Major kinds of PSAs employed are rubber-based adhesives and acrylic adhesives. Rubber-based PSAs including natural rubber, styrene-butadiene rubber (SBR), and saturated polyisoprene provide strong and permanent bonds. Acrylic PSAs offer advantages like clarity, resistance to UV degradation and low temperature flexibility. They are suitable for removable and repositionable labels. Speciality PSAs like silicone and hybrid PSAs are also used for their heat and moisture resistance in barrier food packaging applications. PSAs enable hassle-free application of labels and packaging under light pressure without use of additional solvents or heat.

Functional Adhesives

Apart from basic adhesion characteristics, certain flexible packaging applications demand adhesives with specific functionalities. Some common functional adhesives used include hot melt sealant adhesives, high elongation adhesives, antifog adhesives, and high barrier adhesives. Hot melt sealant adhesives are capable of forming strong fusion seals for packaging formats like pouches, bags, wraps etc. High elongation adhesives accommodate stress caused by flexing, twisting or stretching of laminates. Antifog adhesives help maintain optical clarity of packaging films by preventing condensation of moisture. High oxygen and moisture barrier adhesives enable packaging of products with lengthy shelf life. There is also growing focus on developing environment-friendly bio-based and biodegradable adhesive solutions for flexible packaging.

Get more insights on Lamination Adhesives For Flexible Packaging