One component polyurethane foam (hereafter called “PU foam”) is an active chemical material, many problems may occur while application.
So how to use spray expanding foam in expert way? Here are brief introductions to pu foam spray application and cautions:
- Application of PU foam
- Temperature of foam tube should be 5℃~35℃, the best temperature is 20℃~30℃.
- Environment humidity should be above 45%RH, high humidity could promote curing speed of foam.
- Construction surface should be solid, clean, no oil and dust. Spray some water mist for wetting if possible, but no puddles.
- The bond interface should not be PTFE or silicone resin.
- Application procedure of PU foam
- Using special detergent for PU foam to clean the specific sealant gun, ensuring that it’s unblocked.
- Getting a bottle of polyurethane foam spray, handing the middle of tube tightly, then shaking it vigorously for at least 20 times, ensuring the prepolymer in the tube has been mixed fully.
- Removing the protective cover of the valve on PU foam thread ring and the detergent on foam gun, and putting the PU foam tube on the interface of foam gun as the thread.
- Making sure the tube is placed above and foam gun is paced below the tube, then opening the flow control valve behind foam gun, and applying a little foam until the extruded foam is in the ordinary shape.
- Pointing the gun head at the bottom or inside of the part to be filled, pulling the trigger slightly, then starting construction.
- After spraying a tube, if it still needs to be filled, removing the empty tube and reinstalling a tube of PU foam to continue construction.
- After finishing construction, removing tube in time and replacing special detergent to clean foam gun, in case of blocking foam gun because of the residual material.
- Cautious while the construction of PU foam
- If the temperature of material in the tube is relatively low (below 5℃), it is recommended to move PU foam spay to the storage condition with higher temperature several hours in advance. Preheating in hot water at 40℃～50℃ for 15 to 30 minutes is also recommended.
- Workers should wear work clothes and eye equipment. Worker is prohibited to smoke while construction. Product can’t be close to open flame. Empty tube is not allowed to burn or puncture, or even be given to children for play.
- Filling amount: PU foam has certain after-expansion effect to ensure gap to be filled fully. Therefore, it’s not necessary to fill the gap absolutely. Filling amount depends on different products, it should be about 90% for pre-expansion type and 50% for after-expansion type.
- Filling way: The gun head should be horizontal or slightly downward for vertical gap, and filling it from bottom to up to prevent foam from sagging downward. The gun head should be horizontal or slightly downward for horizontal gap, and filling it from left to right, of course, it could be different due to personal operation habit. When comes to very big gap, it should not be filled at one time, construction should be carried out by stages, and second construction should be done after the last foam is stable.
- Construction is not recommended when wind is strong. Otherwise, PU foam may be blown off or deformed by the wind.
- When filling for confined space, ensuring that there is enough moisture in the cavity, and applying in batches. It’s general to spray a layer of water mist and apply a layer of PU foam.
- If there is liquid spilled on clothes while construction, scraping most foam and cleaning it with detergent, or peeling the foam by hand after curing. If there is liquid spilled on skin, wiping it with clothe immediately, then cleaning it with soap or detergent.
- A tube of PU foam is recommended to use at one time. If there is still residual material after construction, leaving the foam tube on tube and close the flow control valve, letting it standing upright in the shade and using it in the next day. If long time storge is needed, removing the foam tube, turning the upside down and cleaning the tube valve continuously by detergent until melted foam is cleaned up. Putting foam tube vertically for storage after the detergent evaporating.
- Curing speed is slow when temperature and humidity are low. Spraying a little water on the bond interface before application and swinging the nozzle to fill so that foam could be fully exposed to air to reduce the curing time. If construction time is short, pre-expansion product could be selected, this kind of PU foam could reduce curing time. Generally, surface treatment could be done 40 minutes after application, the foam will be cured and shaped, and will not expand or shrink.
- The special detergent for PU foam is only effective before the foam is cured, it can melt the foam into liquid. So, clean should be done in time while construction.
Guangzhou Jointas Chemical Co., Ltd ,
pu foam manufacturer. Provide foam sealant, epoxy grout sealant,acrylic sealant,exterior sealant,joint sealant compound,potting silicone.You can browse related products and initiate consultations on our website.
