Tackifiers are chemical compounds used in formulating adhesives to increase the tack, the stickiness of the surface of the adhesive. They are usually low-

molecular weight A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioch ...

compounds with high

glass transition temperature The glass–liquid transition, or glass transition, is the gradual and reversible transition in amorphous materials (or in amorphous regions within semicrystalline materials) from a hard and relatively brittle "glassy" state into a viscous or rub ...

. At low strain rate, they provide higher stress compliance, and become stiffer at higher strain rates. Tackifiers tend to have low molecular weight, and glass transition and softening temperature above room temperature, providing them with suitable

viscoelastic In materials science and continuum mechanics, viscoelasticity is the property of materials that exhibit both viscous and elastic characteristics when undergoing deformation. Viscous materials, like water, resist shear flow and strain linear ...

properties. Tackifiers frequently represent most of both weight percentage and cost of

hot melt adhesive Hot-melt adhesive (HMA), also known as hot glue, is a form of thermoplastic adhesive that is commonly sold as solid cylindrical sticks of various diameters designed to be applied using a hot glue gun. The gun uses a continuous-duty heating elem ...

s and pressure-sensitive adhesives. In hot melt adhesives they can comprise up to about 40% of total mass. Tackifiers are usually

resin In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on n ...

s (e.g. rosins and their derivates,

terpene Terpenes () are a class of natural products consisting of compounds with the formula (C5H8)n for n > 1. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predominantly by plants, particularly conifers. Terpenes ar ...

s and modified terpenes,

aliphatic In organic chemistry, hydrocarbons ( compounds composed solely of carbon and hydrogen) are divided into two classes: aromatic compounds and aliphatic compounds (; G. ''aleiphar'', fat, oil). Aliphatic compounds can be saturated, like hexane, ...

, cycloaliphatic and aromatic resins (C5 aliphatic resins, C9 aromatic resins, and C5/C9 aliphatic/aromatic resins), hydrogenated hydrocarbon resins, and their mixtures, terpene-phenol resins (TPR, used often with ethylene-vinyl acetate adhesives)), novolacs. Many pressure-sensitive adhesives are a blend of rubbers (natural or synthetic) and a tackifying resin. Some acrylic adhesives also include an additional tackifier. Silicone rubber–based pressure-sensitive adhesives require special tackifiers based on "MQ" silicate resins, composed of a monofunctional trimethyl silane ("M") reacted with quadrafunctional

silicon tetrachloride Silicon tetrachloride or tetrachlorosilane is the inorganic compound with the formula SiCl4. It is a colourless volatile liquid that fumes in air. It is used to produce high purity silicon and silica for commercial applications. Preparation Sili ...

("Q"). Tackifiers are also used in tyres.

In popular culture

For ''Ghostbusters'' (2016 film), agricultural tackifier was a key ingredient in making the huge amounts of slime used during filming of the movie. ''Ghostbusters'' (2016 film) DVD, bonus feature ''Slime Time''

In popular culture

References

Further reading