Almost no stage in construction can be completed without polyurethane foam. It turns out that this material is in great demand. But for this there are different types of polyurethane foam and each of them has its own characteristics, is distinguished by individual characteristics, and sometimes by area of application. We propose to examine in more detail all the nuances of the sealant in this article.
Single-component polyurethane foam for use in construction Source onlinetrade.ru
Polyurethane foam: what it is and how it works
Foamed polymer is a universal material that hardens very quickly in the open air. We suggest studying the description of polyurethane foam, its composition and principle of action. The polymer is produced only in metal cylinders in which it is under high pressure. The foam inside the tank is in a liquid state.
What does polyurethane foam look like after being squeezed out of an aerosol can Source hlamer.ru
Types of polyurethane foam
For each manufacturer, the types of foam may differ not only in performance characteristics, but also in internal composition and even in area of application. We suggest exploring the possible options so that, in the future, when choosing them, you do not make mistakes:
- Household. One of the most common types. The bottle with this foam comes with a tube that allows you to fill any hard-to-reach places. This part helps eliminate the need to use a special mounting gun. The secondary expansion rate of this type of material is usually very large, but the output volume is maximum. A common practice is that the gas runs out much earlier than the polymer itself, so all that remains is to throw away the half-used cylinder. This is disadvantageous.
- Professional. A higher quality type of polyurethane foam, used for large-scale work. For example, if necessary, install metal-plastic windows, double-glazed balcony windows, and install window sills. The product cylinders are equipped with a special ring valve. It is necessary for screwing the mounting gun to the container. After installing the reservoir with the polymer in the nozzle, the foam passes into the latter until it stops at the cutter. The valve itself is subsequently controlled by a trigger when it is necessary to fill voids.
- One-component. This type of material consists only of polymer and extrusion binders. It is the simplest and is used for everyday needs and general use. Considered affordable.
- Two-component. Another variety with a small area of application. Also, this composition cannot be found on the open market, but is provided exclusively on order. To work with such a composition, you need to mix two components, and this requires special skills. After preparing the composition, it must be used quickly to avoid hardening.
- Summer. This type of polyurethane foam is used only at positive temperatures. That is, the material creates an effective seal when used in the temperature range from +5 and above.
- Winter. The composition of the polymer differs significantly from its predecessor. Therefore, it can be used in frosts down to -20 degrees. The same composition is effective for use in industrial refrigerators and freezers if necessary. But under such conditions, it must be taken into account that the temperature of the foam container must be positive.
Varieties of polyurethane foam with different volumes of composition output Source ferenc.ru
Consumption standards
Correct calculation of how much polyurethane foam will occupy seriously affects the final estimate for a large volume of work. Indicators may vary significantly for different types of compositions. You can make the necessary calculations if you know the following basic indicators:
- total output volume - indicated in liters;
- fillability in the seam - indicated in linear meters indicating the depth and width of the seam.
For example, Sika Boom®-580 Fix & Fill has an output of 42 liters and can fill 33 linear meters of a 20x50 mm joint. Based on these data, further calculations of the required amount of material can be made. There are foams with increased expansion rates. One of them is Sika Boom®-590 High Yield. With almost the same capacity of the tube, the output is 53 liters, which is equal to 36 linear meters of a seam measuring 20x50 mm. If you understand and have data on the exact value of the characteristics of the working composition, you can make calculations in accordance with specific indicators of the width and depth of the joint. Experts recommend purchasing with a small margin, which is due to various unevenness of the base, technological losses, changes in foam properties as a result of external influences, different shelf life and a number of other factors.
Flammability classes
The flammability class is one of the main technical parameters that is assigned to each building material. Therefore, polyurethane foam is no exception. Let's look at the notation and explanation:
- B1 - is fireproof;
- B2-considered flammable but self-extinguishing;
- B3—flammable.
The best option for all cases is a composition with a fire-resistant class. This can even be used when installing heating equipment, when contact with hot surfaces is inevitable.
Flammability class of one-component polyurethane foam Source onlinetrade.ru
Cylinder volumes
This section focuses on canister capacity and, in particular, how much work can be done with one unit of resin.
- 300 ml - this volume is characterized by a yield of approximately 20 liters. This amount will be enough to install the box when installing a standard double-glazed window with dimensions of 1.2x1.5 mm.
- 500 ml - yield can reach approximately 35 liters. Ideally, this volume is enough to fill a door frame in an opening measuring 0.8x2 meters. But this is only subject to rational use of the material.
- 750 ml - in this case, the output can fluctuate in the range of 40-70 liters. This amount of polyurethane foam should be enough to install three double-glazed windows with standard sizes.
Practice shows that the ideal solution when choosing a sealant is to choose a larger volume of material than initially needed, since it is always necessary to have some reserve.
Professional polyurethane foam for construction Source Yandex.Zen
Range of quality products
The Sika company offers its customers a range of polyurethane foam for winter, summer, universal professional or household use. We have been present on the market for more than 110 years, manufacturing products taking into account European quality standards. The foam is stable during expansion and has high performance properties. We invite you to familiarize yourself with the product catalog and consult with our specialists when choosing materials. We offer products to legal entities - construction companies and other organizations. We work with individuals through dealers on competitive terms.
Polyurethane foam - GOST
In addition to all other features and parameters, it is important to know the GOSTs that each type of polyurethane foam must comply with. We suggest studying everything in detail in the table.
| Property | Meaning |
| Density | 25-30 kg/m3 |
| Tensile resistance | 0.12 N/mm2 |
| Bending capabilities | 17 kg/cm2 |
| Tensile strength | 12 kg/cm2 |
| Drying the top layer | 20 minutes |
| Cutting time at 50% humidity | Not earlier than 4 hours later |
| Hardening period | 24 hours |
| Stability in volume | 7% |
| Compression/Adhesive Strength | 3 N/cm3 |
| Heat resistance | -40-+90 degrees |
| Ignition temperature | At least 400 degrees. |
The “spaghetti” effect - what is it and is it possible to cope with it?
Installers often use the term “spaghetti effect” when performing any work involving the use of foamed polymer. It implies incorrect release of polyurethane foam from the container, that is, when the material flows in in a thin stream and practically does not expand upon contact with air.
This happens when you buy a low-quality tank, especially with the tip, when it does not open completely, causing a defect.
Consequences of a faulty nozzle on a cylinder with polyurethane foam Source graficart.ru
Technical specifications
Polyurethane foam has the following characteristics:
- output volume;
- adhesion;
- primary and secondary expansion;
- viscosity.
When using mounting foam, the volume of the substance released is measured in liters. The indicated numerical value on the mounting foam 65 or 70 means the volume of propellant contained in the cylinder.
The strength of the connection with the working surfaces of different materials is an adhesion parameter. With concrete, brick, plastic, wood, this parameter is increased. With liquid substances, silicone, ice, adhesion almost does not occur.
When foaming occurs, the substance boils in the container. When it comes out of it, bubbles form. Silicone particles give the appearance of a foamy mass.
Expansion of polyurethane foam occurs after foaming. This is the reaction of the prepolymer to the external environment. When foam and moisture come into contact, carbon dioxide will be released and polyurethane substances will form. After the polymerization process, secondary expansion occurs. It can range from 15 to 100%. It is affected by high temperature and other environmental factors. If you buy high-quality polyurethane foam, it is not capable of spontaneous expansion and shrinkage does not occur.
The viscosity of a substance depends on its consistency, a sharp temperature change changes it, and the quality characteristics of the material decrease. The viscosity parameter of high-quality material is high.
Dried polyurethane foam has heat and sound insulation properties; the sealant has different densities and is light yellow in color. Insulation with polyurethane foam is used at joints and seams. Using such material for large spaces is an expensive pleasure. If repairs with polyurethane foam are not performed correctly, the color of the material changes to dark orange due to ultraviolet exposure.
Pros and cons of polyurethane foam
Any building material has certain pros and cons. Let's take a look at what concerns polyurethane foam.
Advantages:
- used not only as a sealant, but also as a heat and sound insulator;
- considered a binding material;
- does not conduct electric current;
- is not vulnerable to moisture;
- depending on the flammability class, it may be non-flammable;
- perfectly fills all voids due to good expansion
Minuses:
- under the influence of ultraviolet rays it tends to collapse;
- Full, unused cylinders should be stored at room temperature, away from heat emitters
- It can eat into the skin, and it is problematic to wipe it off, especially if it has already hardened.
In general, if you take precautions when using polyurethane foam, the material will be considered absolutely safe.
High-quality gun for spraying polyurethane foam Source onlinetrade.ru
How to properly use foamed polymer from a balloon
Before you start filling cracks with foam or making airtight connections, you need to thoroughly study the rules for using this material.
- Before installing the cylinder into the gun, put on gloves and a respirator (in particular, this applies to people who develop allergic reactions to spraying aerosol products).
- Before using the can directly, shake it for 30-60 seconds. The foam should mix well while still inside the container. If this procedure is omitted, then when you press the trigger of the gun, resin will come out of the nozzle.
- Wet the gap or any other area that will be filled with foam with water. Just do it lightly, not generously, for better fixation of the aerosol material.
- The next step is to turn the can over so that its bottom is facing up and slowly press the gun lever. Apply pressure evenly—the polymer should be well distributed over the desired area.
- If the gap is vertical, then fill it with material only from bottom to top and only to 1/3 of the depth. Since the material tends to expand, during the solidification process it will completely fill the entire gap.
Basically, the foam will be ready for cutting within thirty minutes after application, provided that the rules of use are followed. Also, immediately after removing the excess, the sealed areas can be plastered. Even if the composition is not completely dry inside, it will harden over time.
What to look for when purchasing
Of course, you won’t be able to evaluate the quality of the material right in the store, but there are several signs that will help you choose a truly high-quality product.
Such a quick visual inspection will tell you a lot about the product you are holding in your hands and will protect you from counterfeits.
