Solvent free adhesives and sealants for sustainable products
The growing interest and consciousness towards environmental responsibility is resulting in new technologies also in the adhesives and sealants industry. Solvent free adhesive and sealant systems are becoming more and more popular as they contribute to a greener future, user safety and reduced environmental impact.
For adhesives, sealants and hybrid adhesive sealants to be called solvent free, they must not contain more than 5% solvents. Therefore, several different technologies have been developed to reduce or eliminate the solvent content of the systems. The technologies include solvent free, hot melt and high solids as well as waterborne systems.
Ever increasing uses of solvent free solutions
First solvent free systems were a solution for low demand applications. However, as the technology is continuously improving, solvent free adhesives, sealants and hybrids are becoming a desired solution in many industries. The industries that already rely on solvent free solutions include:
- Automotive: interior fittings such as headlinings and dashboards
- Packaging: especially lamination systems for flexible packaging
- Furniture: bonding and sealing upholstery
- Mattress: bonding mattress layers together
- Paper: envelopes, bookbinding etc.
- Textile and shoes: apparel and footwear, bonding upper to the sole
- Hygiene: for example napkins, sanitary diapers
- Medical: pand-aids, surgical glues and cements for bones
solvent free adhesives and sealants beat solvent solutions
The main reason for choosing for solvent free adhesives and sealants is the reduced environmental impact they have. The nearly or completely solvent free systems are safer for the environment and for people due to the fact that they do not emit nor contain much VOC (volatile organic compound). Solvent free systems have, nevertheless, more advantages than just that.
- Lighter weight: products that do not contain solvents tend to be lighter in weight both during the production and in finished products.
- Fewer product requirements: many countries set high requirements for chemical products that are allowed to be imported, especially regarding VOC. As solvent free adhesives and sealants have close to zero VOC, export is also easier.
- Fewer occupational safety requirements: in regards of occupational safety, solvent free products have less requirements since processing them does not involve the possibility to inhale VOC emissions.
- Reduced health risk: The absence of VOC means safer end products since no hazardous chemicals have been used.
Solvent free adhesives and sealants by different technologies
As solvent free adhesives and sealants are increasing in demand, there are several ways to realize these systems. The technologies resulting in solvent free systems include hot melts, high solids, solventless and waterboren solutions which we will take a closer look at below.
Hot melt and high solid solutions
One of the newer solvent free technologies is hot melt glue and sealant. Generally, hot melts are 100% solids formulations leaving no space for solvents. They are thermoplastics which appear in a solid phase in room temperature. However, when the temperature is elevated, they become liquid with a good flow. After application, it only takes seconds before the solutions are back to solid phase forming strong bonds and seals – all without the use of solvents.
The hot melt adhesives and sealants are traditionally applied by spraying due to their reaction to temperature. However, they can be made rollable by reducing the solid share (usually to about 75%) making them liquid also in room temperature. This, however, means that some solvent will be involved but as long as it does not exceed 5%, they still can be classified as solvent free. Hot melts also exist as biodegradable systems currently used in the packaging industry.
Solventless adhesive and sealant systems
Solventless adhesives and sealants traditionally do not contain any solvent and were first developed for the packaging industry, more specifically as lamination for flexible packaging. Solventless adhesives and sealants were first used for low demand applications only. Due to continuous development, they are now good for any lamination application, even when high temperatures or chemicals are involved.
Solventless systems carry the benefit of lower machinery costs. Even though machinery made for solvent based products cannot be used for solventless, the initial investment of new machinery is remarkably lower.
Water based dispersion adhesives and sealants
The most traditional solvent free solution is water based. These adhesives and sealants use water instead of solvent as the carrier agent. They cure through water evaporation.
Please find more information on waterborne adhesive and sealant solutions in our article dedicated to the topic.
Take a step towards greener future with solvent free solutions
More and more organizations take their environmental responsibilities more seriously and aim at altering their production means to contribute to a greener future. If you are also looking for solvent free adhesives, sealants or hybrid adhesive sealants for your product, do not hesitate to contact us. Our specialists are happy to assist you in finding you the best possible solution.