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Adhesives Ingredients
Polyurethane Resins (PU) for Adhesives & Sealants: A Comprehensive Guide

Use of PU Dispersions or TPU-based Adhesives

Polyurethanes are one of the versatile polymeric material that can be tailored to meet the demands of a number of adhesive and sealant systems. While TPU technology is ideal for numerous applications (e.g., transportation, furniture, footwear, textiles ) where it can demonstrate it excellent mechanical properties, on the other hand adhesives based on polyurethane dispersion are most exclusively used where strong adhesion to the substrate and great cohesion are a must in order to guarantee long lasting bond stability. Let's review some of the popular application segments for each of them.


Key Applications

Applications of Polyurethane Dispersions

Environmental advantages coupled with increasing solvent price and the excellent physical properties of these adhesives have steadily expanded their use in textile coatings, fiber sizing, and adhesives for a number of substrates. One of the most important applications of aqueous polyurethane adhesive is as a heat activated adhesive.

Important industrial applications for polyurethane dispersion based adhesives include the following:

  • Automotive (generally 2K) - Dashboards (foam to TPO/PVC, door panels (textile / wood / ABS) carpets, headliners). Requirements are good initial bond strength under low pressure and / or low activation temperature.

  • Furniture (generally 2K) - Kitchens (decorative PVC foil to wood or MDF-formed door panels). High tack and long life is necessary.

  • Footwear - Polyurethane dispersions are higher priced and less forgiving than solvent borne adhesive. Requirements are very high initial tack at low pressure and temperature, excellent water and plasticizer resistance and good adhesion to PVC / rubber /leather.

Polyurethane dispersion adhesives are also finding their way into food packaging applications. Table below shows a starting formulation for a waterborne polyurethane that is used as a heat sealing adhesive. It can be formulated as a thermoplastic or thermosetting system with the addition of isocyanate.

Parts by Weight
Sulfonated polyester polyol, 0.65 hydroxyl equivalents (Rucoflex XS-5570-55, Ruco Polymer Corp.)


Hexamethyl diisocyanate (0.8 isocyanate equivalents)

Isophorone diisocyanate (0.327 isocyanate equivalents)

Waterborne Polyurethane Heat Sealable Coating4

The polyol and isocyanate mixture was heated to 80°C for 2.5 hrs. When the isocyanate content reached approximately 2.6%, the NCO-terminated sulfonated polyurethane pre-polymers were dispersed in 1138gm of deionized water. The water temperature before dispersing was 40°C. The resulting dispersion had a pH of 6.5.

No VOCs, free of solvent, catalyst, and other additives

Peel strength

After aging
PET / Foil
24 hrs
192 hrs
Substrate failure
Peel strength
after addition of 2% crosslinker*
After aging
PET / Foil
24 hrs
Substrate failure
Substrate failure
192 hrs
Substrate failure
*WD-6314 from H.B. Fuller Co.

Table below shows polyurethane dispersion adhesive requirements for common substrates and applications. The application will decide the following characteristics of the adhesives film.

  • Hardness
  • Flexibility
  • Abrasion resistance
  • Chemical resistance and more

Substrate Application Area Product
  • Parquet flooring
  • Industrial wood finishes
  • Cork tiles
  • Hard
  • Flexible grades
  • High abrasion resistance
  • High chemical and solvent resistance
  • Good acrylic compatibility
  • uPVC and pPVC flooring
  • Laminates and films
  • ABS, PC, Nylon and PS automotive parts
  • TV/Hi-fi housings
  • Hard and soft types
  • Good adhesion to difficult substrates
  • Scratch resistance
  • Good acrylic compatibility

  • Weatherproof clothing
  • Synthetic leather
  • Glass fibre sizes
  • Hard and soft types
  • Good adhesion
  • High degree of flexibility / elasticity
  • Low cost
  • Architectural coatings
  • Interior concrete floors
  • Tiles and Walls
  • Mainly hard types to improve flexibility
  • Low temperature properties of acrylics
  • Good acrylic compatibility
Graphic arts
  • Overprint varnishes
  • Pigment binders
  • Laminating adhesives
  • Hard and soft types
  • Good adhesion and scuff resistance
  • Good chemical resistance
Polyurethane Dispersion Adhesive Applications5

Market Applications of Thermoplastic Polyurethanes

TPUs are the ideal adhesives in a wide range of markets, such as footwear, transportation, furniture or textile.


This market requires adhesives that have good hot green strength and an excellent final bond in order to meet the specific automotive specifications.

Thanks to the good performances obtained with the TPU-based adhesives, they are successfully used in this market, for a series of applications.

TPU adhesives are used in Transportation industry
Use of Thermoplastic Polyurethanes in Transportation

TPUs are raw materials offering an ever-increasing number of solutions to these requirements.

  • Automotive interior parts (door panel, instrument panel, attachment clip, bonding of components)
  • Heat sealable fabrics (soft trim, foam lamination)


In the furniture industry TPU-based adhesives are widely used in lamination of plastic films onto applications in kitchen or bathroom furniture:
TPU adhesives provide very good bonding to wood like MDF and to plastics such as PVC.

TPU adhesives are used in furniture industry
Use of Thermoplastic Polyurethanes in Furniture

There are applications (profile wrapping, edge banding, lamination), that need the use Reactive Hot Melt adhesives. The presence of TPUs in the formulations allows to improve the final performance of these adhesives.


TPU Hot Melt adhesives with different melt and viscosity characteristics are capable of providing solutions to most of the laminating combinations of textile substrates.

merquinsa adhesivethermoplastic polyurethane are used in textile industry
Use of Thermoplastic Polyurethanes in Textile Industry

TPU Hot Melts are mainly used for making heat sealable fabrics obtained by coating processes such as scattering or dot-coating (powder or paste). TPU Hot Melts are Oeko-Tex Class I compliant.


There is a wide variety of bondings in shoe production. Several factors are involved, such as: technological development, requested performances, shoe design and, most of all, an extraordinary variety of materials.

As a result, a very wide range of adhesives is needed for each specific part of the article.

TPU adhesives are used in footware industry
Use of Thermoplastic Polyurethanes in Footwear Industry

The main feature of footwear industrial production is its high productivity, which implies ever-shorter production cycles. TPUs are raw materials offering an ever-increasing number of solutions to these requirements.
In the furniture industry TPU-based adhesives are widely used in lamination of plastic films onto applications in kitchen or bathroom furniture
PU Adhesives are widely used for multi-material bonding in footwear industry
2K PU adhesives are used in automotive industry for dashboards, door panels, carpets, headliners, etc.



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