polyurethane-chemical-formula

green wheelUrethane versus polyurethane? These terms are heard most often when dealing with paint finishes. If that’s what you need, we’re not for you.

That might seem confusing so here’s a quick explanation.

Gallagher tends to use urethane and polyurethane interchangeably. It refers to various compounds used to cast or injection mold custom parts. That might seem confusing so here’s a quick explanation of why that is.

However, the question still remains: Urethane versus polyurethane? Why are the terms interchangeable?

Polyurethane is a polymer. A polymer is a chemical compound or a mixture of compounds. They are formed by polymerization and consist of repeating structural units. Some of the repeating units are urethane groups — chemical linkage of a specific assembly of atoms in a particular pattern.

This being the case, there is no difference between a urethane part and a polyurethane part — they are all made up of urethane groups. The term polyurethane means there are multiple urethanes used.

Polyurethane elastomers (urethane elastomers) are one type of a large family of elastic polymers called rubber.

There are 14 types of rubber in general use. They are all commercially successful, but they are all different in several ways.

Gallagher Corporation has the technical expertise and equipment to process any of these materials. The most typical combinations at

The urethane group is shown highlighted in yellow in the chemical structure shown above.

The most typical combination at Gallagher include:

  • Gallagher polyurethane partsTDI Polyester with hardness ranging from 70A to 70D
  • MDI Polyester with hardness ranging from 85A to 95A
  • TDI PTMEG Polyether with hardness ranging from 90A to 70D
  • MDI PTMEG Polyether with hardness ranging from 60A to 95A
  • TDI Polycaprolactone with hardness ranging from 60A to 55D
  • NDI Polyester (Vulkollan®) with hardness ranging from 65A to 60D

TDI Polyester materials cured with MOCA produce tough elastomers. They have outstanding abrasion resistance and excellent oil and aliphatic solvent resistance.

MDI Polyester materials cured with 1,4-Butanediol produce FDA wet and dry food grade urethanes. They are tough, abrasion and tear resistant.

TDI PTMEG Polyether materials cured with MOCA have excellent low-temperature flexibility. They have excellent dynamic properties and are resistant to microbial attack and hydrolysis.

MDI PTMEG Polyether materials cured with 1,4-Butanediol have high resilience — even at low temperatures. They have great dynamic properties, outstanding hydrolysis resistance, and improved resistance to impingement type abrasion. Some MDI Ethers can be formulated to be FDA wet and dry food approved.

TDI Polycaprolactone materials cured with MOCA have better hydrolysis resistance than other polyesters. Yet they maintain great resistance to abrasion. These materials also have great tear strength even at a low hardness.

NDI Polyester cured with 1,4-Butanediol is trademarked with the name Vulkollan®. Vulkollan® is an ultra-high performance material that has the highest mechanical load bearing ability. It is the best choice for dynamic applications.

Gallagher has been producing parts made from urethane and polyurethane for over 50 years. Contact us for more information on how we can help.