Types of glues
The type and quality of the glue is an important factor in deciding the durability of standard mattresses.
The glues used in the mattress industry are of mainly seven following types:
- Methylene chloride-based adhesives
- n-Propyl bromide-based adhesives
- Acetone-based adhesives
- Adhesives based on acetone blends with other chemicals
- Water-based latex adhesives
- Water-based latex/synthetic adhesives
- Hot melt adhesives
Ingredients in adhesives
In any kind of adhesive, the main ingredients are:
- Solvent/water carrier
- Solid component
Solvent or water carrier
It is the main ingredient in solvent and water-based adhesive formulations. The function of these formulations is to dissolve the solids ingredients that are deposited while bonding two surfaces. All types of adhesives have solvent content except for hot melt adhesives which are 100-percent solid content and rely on heat to cure.
The solid component is responsible for the bonding of two surfaces. It is usually dissolved in the solvent and is deposited on the surface when the solvent evaporates. Most of the adhesives use a polymer called as styrene-butadiene-styrene block copolymer, as the solid component; except for the water-based adhesives that use latex.
Tackifying agents gives a sticky nature to the adhesives. The agent makes both surfaces in contact to “tack up”. Most of the adhesives use a rosin-based material as tackifying agent.
Antioxidants are an important ingredient in mattresses adhesives because they protect the glue for getting oxidized in their containers. Antioxidants account for 0.1 to 1% of the total volume.
Surfactant is an important component of water-based adhesives constituting 0.5 percent of the glue. Surface-active agents are chemicals that increase the emulsifying, foaming, dispersing, spreading and wetting properties of a product.
Some adhesives are unstable chemically or thermally, and need addition of stabilizers to function well. Some stabilizers neutralize acids and bases formed in the glue due to interaction between the ingredients.
Some adhesives used in mattresses use fillers. Filers are high-molecular-weight substances like wax used for strength.