Often seemingly obvious things, when carefully familiarized with them, turn out to be not so commonplace. This also applies to the well-known, well-known polyurethane foam. Probably everyone knows what it is. And certainly everyone saw in the buildings being repaired a frozen bubble substance, with which large and small cracks and holes were generously sealed. [contents ]
One-component polyurethane foam sealant, in a special package with an aerosol nozzle - an incredibly popular building material, actively demanded in the market.
It is difficult to imagine how people used to do without this sealant when installing doors and windows, and when carrying out various repairs that require foam sealing.
It's easy, simple and incredibly convenient to use. No energy sources or additional devices are required, with the help of a special nozzle, the liquid mass penetrates into any hard-to-reach holes and recesses, solidifying after a while into a solid monolith.
Excess and irregularities are carefully cut from the dense porous mass, making the sealant almost invisible.
MP, or polyurethane foam, is purchased in cylinders, which are arranged in a special way.
In addition to the prepolymer in the liquid state, it also contains a propellant gas. When you press the "start", the contents of the cylinder are thrown out, and after a while freezes in air, that is, it polymerizes. It turns out a rather tough material - polyurethane foam .
This tool has the following qualities:
She also has other indisputable advantages.
During operation, the foam expands, completely filling all joints and hard-to-reach cavities. It is a versatile material that is widely used in a wide variety of industrial and construction work.
Few materials are an exception - silicone, polypropylene, teflon, polyethylene and others.
Polyurethane foam should be sufficiently elastic, not crumble and crumble after hardening (including at subzero temperatures). It is appreciated for its good adhesion to the processed surface, for its optimal consistency, which does not allow to drain from it.
The weight of a standard cylinder is usually 850-920 grams, the content of the working substance is about 750 mm.
MP: types and properties
Almost everyone has heard about the convenient and irreplaceable polyurethane foam, but how many are aware of its various types, and the differences between them? All manufactured polyurethane foam can be divided into four groups according to properties and purpose, which have cardinal differences:
Universal is sold in any hardware store. It is packaged both in professional packaging and in household packaging, intended for a wide range of works. With its help, all kinds of cracks, seams are sealed, gaps and voids are closed when installing doors, windows and other structures. She does not differ in any special individual qualities.
When buying, you should pay close attention to the filling of the cylinder and the density of its contents. These figures may differ from manufacturer to manufacturer. On average, the density of professional polyurethane foam is usually at least 1525 kg / m2, while for household foam it is higher, but not more than 2535 kg / m2. The difference in the value of this indicator can be clearly estimated when the material solidifies: the lower the density of the composition, the larger the bubbles will be. The data on the degree of filling of the cylinder must be presented on the packaging.
Thanks to the special properties of the foam, the box will stand rooted to the spot, without moving a single millimeter. All of the above properties of polyurethane sealants of this group are possessed, for example, by MP "Macroflex 65". This is a prominent representative of the group.
The hardened polymer becomes brittle and can crumble when pressed or even touched. In fact, it ceases to be a sealant, since it no longer fulfills its intended function. Therefore, for work in harsh weather conditions, a special frost-resistant MP was created. Usually its cold resistance is around -10 ° C. But there are representatives of the sealant that are designed to fully perform functions even at -25? cold.
There is a separate type of this material - it is foam glue. It no longer belongs to sealants, but this does not cease to be polyurethane foam.
It is actively used in the insulation of homes, fixing with its help heat-insulating foam plates. There are other varieties of such a composition, the purpose of which remains the same, but the direction of the action changes - they are designed to work with other materials. In general, this MP can be considered universal due to the highest level of its adhesion to almost any materials.
Before you start choosing the sealant that suits you best, you need to familiarize yourself with its main qualities. After all, it is on them that the final result of the work done and the convenience during it most often depends.
For the professional staff, these indicators are noticeably different, and amount to 180-300 percent. The indicator can vary from the influence of various external factors, which include the temperature of the polymer cylinder, the rate of its release, and even the skill of a particular user.
Indeed, for some purposes, one foam density is needed, and for some, a completely different one is required.
As a result, poor quality and unreliable sealing of a seam or joint. With a decrease in the shrinkage index, the quality of the MP increases.
48 MPa. To increase it, you can try to moisten the working surface of the material to be processed.
The best polyurethane foam, with excellent indicators of the noted qualities, should quickly and reliably adhere to the surface and be held there. If the foam does not have this property, then it will be extremely difficult to work with it.
It has already been noted above that the composition of different types of foam is quite similar.
But there is an essential design in the cylinders themselves. It is according to her that the product is divided into household and professional.
Household, or manual, or semi-professional MP foam does not imply the use of any additional devices, except for the cylinder itself. To get started, the supplied plastic tubing is attached to the valve. It is equipped with a special lever adapter.
This is the best option for small jobs. Such a sealant is used when an indicator such as expansion is not a determining factor in quality: when using foam for windows, in interpanel seams and ventilation wells.
Manufacturers themselves call professional MP a pistol. The cylinder is equipped with a special service valve. For its operation, a special dispensing device is required - an applicator gun for polyurethane foam.
It fits over the appropriate balloon valve, allowing the agent to be dispensed from the balloon.
This method provides significant savings in composition, in some cases up to 30 percent. It also allows the technician to operate with only one hand, which, together with the dispenser trigger and ergonomic handle, makes the process more convenient and productive. The thin and long metal barrel guarantees the supply of the mass even to the most inaccessible places.
The disadvantage of using a pistol is its rather substantial cost.
For this reason, choosing a pistol for occasional home events is not often preferred. It is more necessary for professional workers - repairmen and builders involved in various installation work.
In addition, such professional equipment needs special treatment after each, even one-time, use. The assembly gun is flushed with a solution that cleans all its internal cavities from the foam that has not yet thickened inside. The special cleaning agent is also in the bottle, equipped with special attachments that simplify the cleaning process under pressure.
Today, there are many companies on the construction market that produce polyurethane sealants. But a really high-quality product that meets all the necessary requirements is made by only a few of them.
Choosing the best of the best:
The choice is rich, there should be no difficulties with it. The main thing is that it should be made consciously, taking into account not only the manufacturer and working qualities, but also the nature of use and operating conditions. Now you know how different types of sealant differ, and you know how to choose a polyurethane foam.
A moment of humor:
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