Hot-Melt Pressure-Sensitive Adhesives (HMPSA): Composition, Properties & Typical Formulations

What is Hot-Melt Pressure-Sensitive Adhesive (HMPSA)?

Hot-melt pressure-sensitive adhesives are prepared using thermoplastic elastomers as the base resin. They have the qualities of both hot-melt adhesives and pressure-sensitive adhesives: they are solid when it's cool, turn into a liquid when heated, and create a sticky film after being applied to a surface and then cooled down.

Key Properties & Advantages of HMPSA

• Like hot-melt adhesives, it has a solid content of 100% and is solvent-free, eliminating environmental hazards associated with organic solvents and promoting environmental protection and safe production.
• It allows for rapid application of thick adhesive layers, offers a high degree of automation, and results in low production costs. Its price is 50% to 70% that of solvent-based pressure-sensitive adhesives, and it does not leave behind residual solvents or water.
• It is suitable for the production of a wide variety of products in small batches.
• The pressure-sensitive adhesive offers excellent performance and can bond difficult-to-adhere materials such as polyethylene and polypropylene.
• It is extremely convenient for packaging, transportation, and use.

Many HMPSA products have been developed worldwide and are now widely used in double-sided tapes, medical and healthcare products, feminine hygiene products, labels, and footwear.

Core Components of Hot-Melt Pressure-Sensitive Adhesives

The main components of hot-melt pressure-sensitive adhesives include thermoplastic elastomers, tackifiers (natural and petroleum resins), plasticizers (various minerals, liquid polyisobutylene, etc.), fillers, and antioxidants.

C9 Cold Polymerized Petroleum Resin

C9 Thermally Polymerized Petroleum Resin

C5 Petroleum Resin

C5/C9 Copolymer Petroleum Resin CAS 68131-77-1

C5 Hydrogenated Petroleum Resin

C9 Hydrogenated Petroleum Resin

Thermoplastic Elastomers: The Base Polymer of HMPSA

Common thermoplastic elastomers used in hot-melt pressure-sensitive adhesives include SBS, SIS, SEBS, polyurethane, EVA, and acrylates. The most notable characteristic of thermoplastic elastomers is that they exhibit the mechanical properties of conventional vulcanized rubber at room temperature while retaining the processing characteristics of thermoplastics at high temperatures.

Tackifiers

The primary functions of tackifier resins are to improve wettability, cohesion, peel strength, and shear strength. Due to the unique two-phase structure of styrenic thermoplastic elastomers, compatibility with both phases must be considered when selecting resins.

Resins compatible only with the PS phase include aromatic petroleum resins, coumarone-indene resins, and high-softening-point terpene resins. These can increase the elastic modulus and cohesive strength of hot-melt pressure-sensitive adhesives but do not contribute to initial tack or peel strength.

Resins compatible only with the PB and PI phases include terpene resins, rosin, hydrogenated rosin, rosin esters, and C₅ petroleum resins. These tend to reduce the elastic modulus and cohesive strength of HMPSA but provide excellent initial tack and peel strength.

Aromatic petroleum resins with relatively low softening points are compatible with both phases. In practice, different types of resins are often blended to achieve balanced performance, as only resins compatible with both phases of styrenic thermoplastic elastomers deliver optimal overall properties.

Refined Light-colored Rosin

Special Grade Rosin

KT101 Rosin

Colorless Hydrogenated rosin resin

Plasticizers

Plasticizers or mineral oils can effectively and significantly reduce the hardness and melt viscosity of adhesives, improve the low-temperature performance of hot-melt pressure-sensitive adhesives, and simultaneously lower the formulation cost of the adhesive. There are two types of plasticizers commonly used in SBC-based hot-melt pressure-sensitive adhesive formulations: mineral oil and polybutene oil.

Antioxidants

The chemical market offers a wide variety of antioxidants, such as amines and phenols, as well as secondary antioxidants, such as thiols and phosphites. Generally speaking, an appropriate antioxidant should be able to effectively neutralize reactive free radicals generated by thermal aging, mechanical shearing, and environmental factors during long-term storage, thereby preventing or reducing the degradation of hot-melt pressure-sensitive adhesives.

Antioxidant 4500 CAS 13003-12-8

Antioxidant 1315 CAS 171090-93-0

Antioxidant 245 CAS 36443-68-2

Antioxidant 1135 CAS 125643-61-0

Antioxidant 1076 CAS 2082-79-3

Antioxidant 1520 CAS 110553-27-0

Antioxidant 1500 Phosphite

Antioxidant 1010 CAS 6683-19-8

Antioxidant 101 CAS 1261240-30-5

Antioxidant 445 CAS 10081-67-1

5 Proven HMPSA Formulations for Industrial Applications

HMPSA Formulation for Metal Pipe Protective Tapes

HMPSA Formulation for General-Purpose Pressure-Sensitive Tapes

HMPSA Formulation for Pressure-Sensitive Adhesive Labels

Crosslinkable HMPSA Formulation Formulation 4

2,2-Diethoxyacetophenone CAS 6175-45-7

2,2-Dimethoxy-2-phenylacetophenone CAS 24650-42-8

Trimethylolpropane triacrylate(TMPTA) CAS 15625-89-5

Propoxylated Trimethylolpropane Triacrylate CAS 53879-54-2

High-Heat Resistance Crosslinkable HMPSA Formulation

Formulations 4 and 5 are two types of adhesives that can be strengthened by using electron beam irradiation after they are applied to a surface in a nitrogen environment, which gives them excellent heat resistance.

Why Choose Kerton Chemicals as Your HMPSA Raw Material Supplier?

Kerton Chemicals is a trusted global supplier of high-quality raw materials for hot-melt pressure-sensitive adhesives (HMPSA).

To start cooperation, you can visit our official website: https://www.kerton-industry.com contact our team for product inquiries, samples, customized solutions, or bulk orders. We pledge to serve as your long-term partner, providing stable and high-performance HMPSA raw materials.