# Polyurethane Foam

Sealants
Tom Fishback Fomo Products February 15, 20122 

# Topics

• Foam sealants 101

• Types of products



# • Applications & End Users

• PPE and labeling considerations

• MDI exposure monitoring3 

# Basic PU Chemistry

• Polyurethane is formed by the mixing and reaction of two components:

• “A Side”

– diisocyanates

• “B Side

– polyol blend



## • With foam sealants, a third ingredient, the blowing agent, is added

• Low molecular weight hydrocarbon blowing agent used in consumer products4 

# Manufacturing

•

• Flammable or non - flammable

•

• Blend of up to 10 ingredients

•

•

• MDI (reacts with water ) PROPELLANT

POLYOL

ISOCYANATE5 

# Prepolymer Formation

• Solvent for the prepolymer

• Propellant for expelling prepolymer from the can

• ‘Blowing agent’ to build the cell structure

PRE - POLYMER After mixing both components together, polymerization begins with a conversion to a polyurethane prepolymer6 

# PU One - Component Foam Terminology

• OCF – One - component foam

• Most common term globally



## • Also known as IFS (insulating foam sealants)

• Tack - Free Time
– skin formed on foam surface

• Typically 3

– 20 min.



## • Cure Time
– maximum foam physical properties achieved

• Typically 12

- 24 hours

– Determined through testing of ultimate physical properties, i.e. compression strength7 

# OCF Sealants

• OCF sealants

• Isocyanate and Polyol combined in one container at time of manufacture



### • Mixed at slightly greater than 1:1 into container

• Forms NCO
- terminated PU in container

• 3
- 15% PMDI in container as marketed

• 3

– 10% DIY, 3

– 15% professional



### • Reacts with ambient moisture

• R
- NHCOOH + R
- NCO
--- > (R
- NHCO) 2 

### 0
--- > 

### R
- NHCONH
- R+ CO 28 

# Types of Products

• OCF dispensed with plastic straw



## – Professional & DIY



## • OCF dispensed with professional gun

– Professional9 

# Types of Products

• Cylinder OCF



# • 10

– 20 lbs of chemical

• Dispensed with brass wand

• Professional 

# product10 

# Energy Efficiency

• Main usage for OCF in US: air sealing for energy efficiency.



# • DOE states that up to 40% of heating and cooling energy is lost through air leakage in the building envelope12 

# Global Market Size and Manufacturers

• > 250M cans annually

• Manufacturers



# • N. America (3)

• Europe (>10)



# • China (>10)13



# PPE Information15 

# Typical Label Warnings18 

# Worker Exposure Monitoring Case Study

• Species monitored:

• MDI

• MDI & main oligomer (“3

- ring”, n=1)

• Occupational Exposure Guidelines



## • OSHA: 200 m g/m 3 

## MDI (20 ppb; ceiling)

• ACGIH TLV ® 

## : 51 m g/m 3 

## MDI (5 ppb; 8

- h TWA)19 

# MDI Monitoring Case Study

• In this study a cylinder foam product was used

– OCF cylinder foam contains 10

– 15% concentration of free MDI as opposed to 3

– 10% for OCF cans sold in DIY retail

– Foam bead dispensing times are typically longer for OCF cylinder products than for OCF cans purchased by consumers20 

# Results From MDI Workplace Exposure 

# Study: OCF Cylinder Foam Study 3,4,5: Lab Application

• Adhesive, single use container; 11

- 24 min application

• Area samples at 1

- 20’, source (  18”)

• Methods: Filter sampler (Study 3: IsoCheck ; Studies 4,5: 13mm) Sample Type MDI m g/m 3 ; Mean

[range] n* #ND
Personal

- Applicator ND(6) [ND(1)

–

ND(8)] 11 11 Area: Near (1
- 3’) Far (10
- 20’) ND(1)

[ olig =ND(6)] ND(0.9) [ olig =ND(5)] 1

1 1 1

Area: Source 9.2 [ND(6)

– 51] 15 13 *n= # of samples; #ND = # of samples that were below limit of detection21 

# Conclusion From Case Study

• Respirator use not necessary for typical OCF DIY application.22



# Questions?

# APPENDIX24 

# Sampler Types

– Coated Filter

– Impinger

– Impinger + filter Exposure Monitoring25 

# Iso Check Sampler Exposure Monitoring