Polyurethane Foam Environmental Issues
Polyurethane Foam is used to make a variety of different materials the process and used materials used does obtain environmental and cultural issues.
Montreal Protocol
In USA 1978 the Montreal Protocol mandated was produce, stating industries to eliminate Chlorofluorocarbons (CFCs), based upon research that scientist made about the manufacturing process that effected the depletion of the earths ozone layer. The EPA's and OSHA are continually to develop better process that eliminate the emissions of chemicals. The Polyurethane Foam Association (PFA) began the role to find alternatives to CFCs immediately. (Polyurethane Foam and the Environment)
CFCs used as the auxiliary blowing agent (ABAs) and was the chemical that made it an option to produce soft or low density foams in the manufacturing of furniture. Once the Montreal Protocol was put in place is was set for all CFCs chemicals used by manufactories had to be eliminated by 2000, but ended up achieving that goal by 1992, by use of other alternative foam chemistries and mechanical equipment. (Polyurethane Foam and the Environment)
Chemical Solutions for Reducing ABAz
Methylene Chloride is now the main chosen alternative ABA's, that produces lower density, softer foams and is economical, but EPA and OSHA have established limitations to the about of emissions that the Methylene Chloride create for each manufacture. Other alternative production methods were created that didn't used ABA's and still achieving a quality standard. There are now five primary technology alternative, these are: (Polyurethane Foam and the Environment)
Alternative Blowing Agents
Controlled Pressure Foaming
Chemical Additives
Carbon Dioxide Systems
Forced Foam Coolings
Alternative Agents for Blowing (ABAs)
Acetone is another ABA alternative, it has advantages over Methylene Chloride, because the use of this chemical during the process has little impact on the environment and it only need a small number of formulation changes. But there are disadvantage compared to Methylene Chloride, Acetone is highly flammable so extra precautions are used to avoid fires like spark-proof and explosion-proof handing equipment. (Polyurethane Foam and the Environment)
Mechanical Methods
1. The Forced Cooling Process
Figure 1
Force cooling or other wise know as vacuum cooling. Air is the cooling medium, basically the air is flow through the FPF at a uniform rate. Timing of the cooling is critical if not done right autoignition will occur. The cooling process is a number of vacuum plates surrounding the FPF to pull the air through and cool the product. This process removes hot gases as the product reacts and volatile impurities and so the FPF os cooled to a safe temperature. Forced Cooling can be used with a range of other chemicals and mechanical methods. (Polyurethane Foam and the Environment)
2. Controlled Pressure Foaming
Figure 2
Controlled Pressure Foaming is created in a sealed enclosed chamber which prevents chemical and gas emission into the plant environment and the atmosphere emissions are controlled so they are easily absorbed into plants. Reducing the amount of pressure will effect the rise of the FPF chemicals that create the product. Inside the sir-tight chamber the controls are also used the change the heat and humidity which will affect the way the chemicals mix together. Controlled Pressure Foaming is one of the latest alternative. (Polyurethane Foam and the Environment)
3. CO2 Foaming
Figure 3
This is a chemical reaction process, including reactions between;
Polyol + TDI Polymer
Water + TDI CO2+ Polyutrea Polymer.
The chemical reaction created with different materials create the CO2 gas the makes the foaming process (FPF). This process is more safe the others because it is not toxic and not flammable, which is a plus for the environment, but creating the CO2 costly This is used a lot by the industry.(Polyurethane Foam and the Environment) Main process:
"Reactants are mixed under high pressure with liquid CO2
Mixed materials passes through a pressure drop zone/ lay-down device.
Specialized raw materials may be needed to achieve the results wanted.
The system froths components with CO2 prior to the reaction.
Material is released onto the conveyor as a froth. " (Polyurethane Foam and the Environment)
Polyurethane Insulation
"The U.S. Environmental Protection Agency (EPA) has released a new action plan for chemicals used in spray polyurethane foam (SPF) insulation. Isocyanates, such as MDI (methylene diphenyl diisocyanate), are highly reactive chemicals that can cause skin, eye, and lung irritation, asthma, and chemical sensitization when absorbed through the skin or inhaled.) EPA Take Action of Spray-Foam Health Risk)
Figure 4
Photos and diagrams are taken from Polyurethane Foam and the Environment print.
Figure 1: Forced Cooling Process
Figure Controlled Pressure Foaming
Figure 3: Co2 Foaming
Figure 4: Glossary
References:
Peter Yost, " EPA Take Action of Spray-Foam Health Risk" Building Green, May 3 2011, website > (http://www.buildinggreen.com/auth/article.cfm/2011/5/3/EPA-Takes-Action-on-Spray-Foam-Health-Risks/)<
Polyurethane Foam Association, "Polyurethane Foam and the Environment: A Progress Report". IN-TOUCH Information on Flexible Polyurethane Foam. 6(1997): 1-6. Scholarly Journal Article.
Hayley Bush 300250858