What is Spray Polyurethane Foam?
What is Spray Foam?
Spray foam is a complete insulation cellular thermoset plastic material and air barrier system that insulates and air seals walls, floors and ceiling cavities against air movement; including spaces around electrical outlets, baseboards, and where the walls meet windows and doors. Applied as a liquid, the foam instantly expands up to 120x its original size to fill in every nook and cranny. Spray foam is a polyurethane plastic predominately made from petroleum or recycled petroleum based products. Certain foams are partially made from soy and other agricultural contents.
Solstice Liquid Blowing Agent is the latest advance in foam blowing agent technology developed by Honeywell. Solstice based formulations have a slightly different reactivity profile which makes the optimization of pressure and temperature more important. Solstice products appear to require slightly higher temperatures for processing. A 3°F to 5°F increase in temperature using the same spray pressure of 1200 to 1400 psi appear to result in a 10 to 15 percent increase in yield as well as an improved R- Value.
What Is Polyurethane?
Polyurethane is a material that can be found in many of the products that we use in our daily lives. Incidental heating of polyurethanes or polyurethane containing articles may be necessary during some product applications or operations. When overheated, polyurethanes and other polymers may breakdown and produce smoke and/or vapors that contain various chemicals. This breakdown is often referred to as thermal degradation.
What is Thermal Degradation?
Thermal degradation can take place when the material is burning (i.e., flaming mode) or when it is exposed to elevated temperatures without burning (i.e., non-flaming mode). All combustible materials, whether synthetic or man-made, generally produce toxic products when burned. This document highlights toxic products that may be of concern when polyurethanes are thermally degraded, the risks of working in proximity to those toxic products and some worker safety and health precautions to consider.
Processing Spray Foam on the Jobsite
Spray Foam is created by mixing the a-side and B-side in the spray Gun.
- Mixing is by impingement- A & B streams collide at a high Velocity to mix properly.
- The spray gun creates a fine mist exiting the gun in a symmetrical pattern, most often is a round pattern, other types of mix chambers can be used to achieve patterns such as flat or spattered as needed.
- The most common spray gun used in the market today is the Graco AP Fusion with mix chamber sizes 1, 1 ½ , and 2 for most residential and commercial insulation jobs and a 3 for commercial roofing.
- Within seconds the mixture foams and reacts to form a tack-free urethane foam.
- Proper pressures and temperatures at the spray gun are important to insure a quality mix of both A&B. This is where the proper Spray Foam Reactor and supporting equipment comes into play.
- The desired temperatures and pressures will be located on the material Technical Data Sheets.
- Desired temperatures may need to be adjusted depending on the ambient air temperature, humidity and other uncontrollable conditions. Graco Reactor 2 can assist in storing these recipes to fine tune your spraying. Saving much wasted time tinkering with pressures and temperatures.
- It is also important that the Material in your drums are kept between 70 to 80 degrees.
- Pressures and temperatures will vary from one foam manufacture to another. So, if you are spraying XYZ company one week and ABC’s the next pay attention to the Data sheets provided by that material supplier.