Hydrocarbon resins are petroleum-based low-molecular-weight thermoplastic resins used as tackifiers that provide tack and adhesion in adhesives, as film-forming resins that add hardness and gloss in coatings, and as additives that improve processability and reinforcement in rubber.

What is a hydrocarbon resin?

Hydrocarbon resins are low-molecular-weight thermoplastic resins produced by polymerising petrochemical streams (the C5 and C9 fractions formed during cracking). They are not used as a structural polymer on their own but are added to another polymer matrix to tune properties such as tack, hardness, compatibility and flow. They are selected by softening point, colour and compatibility profile.

C5 vs C9 vs hydrogenated resins

Resin typeCharacterTypical use
C5 (aliphatic)Soft, light colour, good tackHot-melt adhesives (HMA), pressure-sensitive adhesives
C9 (aromatic)Hard, darker, high softening pointCoatings, inks, rubber reinforcement
C5/C9 (copolymer)Balanced tack and compatibilityGeneral-purpose adhesives
HydrogenatedLight colour, odourless, light/heat stableLight-coloured adhesives, food-contact packaging
C5 resins generally offer better tack and lighter colour; C9 resins give a higher softening point and hardness. Many formulations use C5/C9 blends to reach the desired tack-softening balance.

Use in adhesives

Hydrocarbon resins play a critical role as tackifiers in hot-melt adhesives (HMA) and pressure-sensitive adhesives (PSA). By tuning the glass-transition temperature and viscosity of the base polymer (e.g. SIS, SBS, EVA or acrylic) they provide wet-out and fast adhesion to the substrate. The resin's softening point and compatibility with the base polymer directly determine final tack and shear strength.

  • Labels and tapes: tack and peel resistance in PSA formulations.
  • Packaging: fast set in case-and-carton hot-melt adhesives.
  • Hygiene products: elastic attachment and construction adhesives.

Use in coatings and inks

In coatings and printing inks, hydrocarbon resins (especially C9 aromatic grades) provide film hardness, gloss, water resistance and pigment wetting. They are used as a binder resin or binder modifier, preferred where low-cost hardness and fast drying are required.

Use in rubber

In rubber compounds, hydrocarbon resins act as a processing aid and reinforcing/tackifying resin. They improve processability, increase building tack and contribute to hardness/modulus adjustment. They are widely used in tyre and technical rubber production.

For the right resin choice, evaluate softening point, colour (Gardner/Hazen), compatibility and light/heat stability together against the formulation. For light colour and low odour, hydrogenated grades are recommended.
Resins are often processed molten at high temperature; use suitable protective equipment against burns and limit dust/vapour exposure. Refer to the safety data sheet (SDS).
What are hydrocarbon resins used for?

As tackifiers in adhesives, film-formers/hardness providers in coatings and inks, and processing aids/reinforcing resins in rubber. They are added to a polymer matrix to tune its properties rather than used alone.

What is the difference between C5 and C9 resins?

C5 aliphatic resins are soft, light-coloured and give good tack; common in hot-melt and pressure-sensitive adhesives. C9 aromatic resins are harder, darker and higher softening point; preferred in coatings, inks and rubber.

Which resin should I choose for an adhesive?

Compatibility with the base polymer (SIS, SBS, EVA, acrylic) and the desired tack-softening balance are decisive. For light colour and low odour choose hydrogenated grades; for high tack, C5-rich blends.

Why choose hydrogenated hydrocarbon resins?

Because they are light-coloured, odourless and have high light/heat stability, they are preferred in water-clear adhesives and food-contact packaging applications.