## Overview: Aromatic Isocyanate

Coating Applications Barbara Cummings Bayer MaterialScience February 15, 20122 

# Outline

• Coatings Terminology “101”



## • MDI/TDI
- based Polymer Coatings:



## • Market Segments



## • Crosslinking Technology, Application and Cure



## • Basic 1K and 2K Reactions



## • Application/End Uses



## • Summary3 

# Coatings Terminology 101

• Isocyanate Monomer = A “monomer” is the starting unit from which the polymer is formed. A diisocyanate monomer consists of two isocyanate groups.


### • Polyisocyanate = A short chain oligomer made from a single monomer by directly linking the monomeric units. Also known as a homopolymer

. 

### • Isocyanate - based Prepolymer = created by reacting monomeric isocyanates (diisocyanates) with diols or amines.



### • Blocked isocyanate = Formed by the reaction of an isocyanate with a blocking agent, which when heated releases the blocking group and crosslinks with the polyol

. 

### • Polyurethane Dispersion (PUD) = a fully reacted polyurethane dispersed in a medium, usually water.



### • Uralkyd = urethane modified alkyd (oil based); fully reacted NCO



### • Urethane Lacquer = solvent
- borne resin (high MW); fully reacted NCO4 

# Coatings Terminology 101 (cont.)

• 1K = one component (e.g., PUDs, moisture cure)



### • 2K = two component; common coreactants include: polyols (e.g., polyesters, polyethers ) and polyamines



### • Plural component spray = a spray coating system utilizing multiple components that are mixed upon application.



### • Solvent - borne = coating with a solvent carrier



### • Water - borne = coating with a water carrier



### • 100% solids = coating without solvent/water carrier



### • Moisture cure = coating cures using atmospheric moisture



### • E - coat = electrocoating (primers); electric current is used to deposit paint



### • OEM = original equipment manufacturer5 

# What do MDI/TDI - based Polymer Coatings 

# offer and where are they used?

• High durability

• Superior substrate adhesion

• Areas which “do not require” UV stability6 

# Market Segments

Wood Industrial Maintenance/ Infrastructure Military Agricultural/Construction/ Equipment (ACE) Transportation

ACE Transportation

Military Industrial

Wood7 

# Crosslinking Technology, 

# Application and Cure8 

# Basic 2K Isocyanate Reactions9 

# Basic 1K Moisture Cure Reaction10 

# MDI - based Polymer Coatings: Industrial (I), 

# Contractor - Applied (CA), and Consumer(C)

*(C) = predominantly marketed via specialty shops or internet sales; some potential for direct consumer access11 

# TDI - based Polymer Coatings: Industrial (I), 

# Contractor - Applied (CA), and Consumer(C)12 

# Uralkyd Chemistry13 

# Urethane Modified Alkyd ( Uralkyd )

• React glycerol, phthalic anhydride (PA) and fatty acid; hold out part of PA and substitute TDI



## • Cures via autoxidation to form cross
- linked coatings



## • Used in wood floor/furniture coatings and industrial (metal) primers (inexpensive)



## • Consumer use (i.e., wood “varnishes” and clear


### coats)



## • Fully reacted NCO ( isocyanate )14 

# Polyurethane Dispersion Chemistry

Diisocyanates

Hydrophilic group (ionic / non
- ionic) Diols: Monomeric (e.g., hexanediol) Polymeric (e.g., polyester)

Fatty Acid Based Polyols15 

# Polyurethane Dispersions (PUDs)

• Stable dispersion of high M.W. polyurethane
- urea particles in water



## • Film formed through coalescence of discrete particles



## • Low solvent content or solvent free



## • Ambient temperature or low bake drying



## • Fully reacted NCO ( isocyanate )16 

# Urethane Modified Lacquer Chemistry

Diisocyanates

Methyl Groups Diols: Monomeric (e.g., hexanediol) Polymeric (e.g., polyester)

High M.W. Polyol CH 317 

# Urethane Modified Lacquers

• High molecular weight polyurethane (i.e., polyol reacted with isocyanate ) polymer dissolved in solvent



## • High VOC content (~30% solids)



## • “Inexpensive”



## • Consumer market (e.g., clear, amber or colored varnish)



## • Fully reacted NCO ( isocyanate )18 

# Questions ?