Polyurethane foam is also called polyurethane foam sealant. This is one of the types of foamed polymer that is of industrial importance.
Why is polyurethane foam preferred in construction? What does polyurethane foam consist of?
Types of foamed polymers
Polystyrene foam can be obtained from almost any known plastic mass. But only certain types of foamed polymers are valuable for industry.
1. Polyvinyl chloride foams.
Available in the form of elastic strips or rolls. Widely used for insulation window frames for the winter.
2. Expanded polystyrene.
Available in slab form. It is used mainly in construction for thermal insulation of building walls, to form the inner layer in wall and roofing structures sandwich type.
3. Carbamide resins.
They are widely used on construction sites as cast foams and in the creation of thermal insulation layers.
4. Polyurethane foam (hard and elastic).
The scope of application of this material is quite wide:
- creation of seamless insulation (sealing and sealing of joints);
- insulation of floors, walls and roof structures;
- continuous insulation by spraying roofing and interfloor surfaces;
- insulation of windows and doorways, underground and above-ground pipelines;
- equipment for ventilation, heating, air conditioning systems; insulation of bridges and road surfaces, etc.
The prevalence of polyurethane foams is explained by their following qualities and characteristics:
- optimal physical and mechanical properties for construction work;
- high thermal, sealing and waterproofing performance;
- variety of technological process when creating an insulating layer.
The most interesting from the point of view of economics and practice are those materials that do not require complex and expensive devices and equipment; long time to get results. Polyurethane foam became such a material.
Introduction to polyurethane foam
1. When frozen, it is a gas-filled plastic mass based on polyurethane.
2. Solid polyurethane foam – rigid foam plastic with a closed-cell structure.
3. The polymer matrix of the sealant contains dispersed gas-air inclusions.
4. Polyurethane foam is available in small and convenient containers.
5. The initial composition is applied in the form of a jet, which the installer directs into the cavity using a nozzle.
The composition of polyurethane foam is complex. Let's name the main components:
- diisocyanate (polymerizes under the influence of ambient humidity);
- carbon dioxide (foaming agent);
- polyisocyanates.
The composition easily comes out of the container, rapidly foams and increases in volume, forming a mass that is homogeneous in structure with a yellow tint.
At this moment, complex chemical, physical and mechanical processes simultaneously occur inside the substance:
- increasing the viscosity of materials;
- increase in volume, structuring and loss of mobility;
- formation of a closed-cellular structure;
- hardening of the substance, formation of solid foam;
- gluing the polyurethane foam composition to the material of the surface being treated.
The stages of polymerization can be conventionally designated as follows:
- strong rise;
- moderate rise;
- slow rise.
The duration of these periods depends on the brand of polyurethane foam. If we compare the structure of the resulting foam and its physical and mechanical properties, significant differences will be noticed. For example, one foam produces a high-strength material, but with an uneven structure. Accordingly, the compositions of different brands of polyurethane foams are different.
The manufacturer can change the recipe for polyurethane foam sealant. Thanks to this, polyurethane foams are available on the market for domestic and professional needs, for residential buildings and industrial buildings With high level fire hazard, for summer and winter work.
Polyurethane foam is a very practical and convenient material, the advantages of which are appreciated not only by professionals, but also by home craftsmen. However, there are small tricks that will help you expand the scope of its use or use foam more competently.
Remember that polyurethane foam, like any other product, has a limited shelf life. When purchasing, be sure to check it on the bottom of the can.
Before starting work, shake the can thoroughly, and while working with it, hold it upside down. This is necessary so that the gas squeezing the contents out is above the foam.
How to apply polyurethane foam correctly
Since the polyurethane foam coming out of the can needs moisture for its effective expansion, which it mainly receives from the air, first slightly moisten the area being treated with it. However, remember that over-wetting may prevent it from sticking.
When the polyurethane foam has hardened, its excess is removed with a knife.
How to foam hard-to-reach places
If you need to foam some hard-to-reach place, the tube that usually comes with the can can be very difficult to work with. To perform this operation, you can put a thin flexible hose on the standard canister tube.
When the area being treated with foam is too high, the end of the flexible hose can be secured to some kind of holder or a regular stick. And don’t forget, you should always keep the can upside down!
When foaming a very narrow gap, you can heat the extension hose with a match, pull and break it.
At the point of rupture, the diameter of the hose will be very small, which will guarantee high quality sealing of a small space.
What to do if you lose the tube included with the can
If this much-needed tube is lost, then you can attach a heat-shrinkable tube to the spray can dispenser, and use a fairly wide washer as a dispensing stop.
In this case, you can work with the foam just like with a regular original tube.
How can you clean drops of polyurethane foam?
If you accidentally drop foam somewhere, it is better not to smear it and wait until the foam mass dries. Then simply peel off the hardened material. If a drop of foam is still smeared, use regular acetone, which will easily dissolve the polyurethane composition.
And further. Don't forget that polyurethane foam is an excellent and reliable adhesive!
Modern construction sites cannot do without the use of polyurethane foam, specifications which played an important role in its mass use. Professional builders and amateur craftsmen who decided to cope with repair work on their own have recently not imagined installing doors, window sills and windows, as well as construction activities related to waterproofing pipelines and large containers, such as water heating tanks and bathtubs, without the use of polyurethane foam , the technique of using which will be discussed in the article.
Polyurethane foam: performance characteristics
The widespread use of polyurethane foam is, first of all, due to its performance characteristics, which make it possible to consider this material indispensable in almost all types of construction work. The main properties of polyurethane foam, at the same time recognized as its advantages, which every builder could appreciate, are as follows:
- Possibility of use as a sound and heat insulator;
- High resistance to moisture and low electrical conductivity;
- The operational features of some types of polyurethane foam indicate resistance to fire;
- The ability, after expansion, to fill voids and various cracks, ensuring high quality seams and joints;
- Possibility of gluing elements made of various materials using polyurethane foam.
Types of polyurethane foam
Today, manufacturers offer several varieties of polyurethane foam, among which the following varieties are of interest to builders:
- Professional polyurethane foam, for the use of which a specialized device is used - a gun, which allows you to increase the yield of polyurethane sealant and extend its service life;
- Household or semi-professional polyurethane foam, intended for one-time use. In addition, the main difference between household sealant is the significantly lower filling density of the cylinder.
By temperature conditions, in which it is permissible to apply polyurethane foam, a video of its use is presented in the article, the following varieties are distinguished:
- Summer polyurethane foam is used if the temperature of the treated surface varies from +5 to +35 degrees;
- Winter polyurethane foam can be used in winter, as it can withstand the temperature of the treated surface from -20 to +30 degrees;
- All-season polyurethane foam is characterized by a combination of properties of winter and summer modifications. The operating temperature of all-season foam is from -10 to +30 degrees.
Moreover, the manufacturer suggests that builders who prefer polyurethane foam should pay attention to a separate type of polyurethane sealant, which has special functional parameters - fire-resistant polyurethane foam. The use of non-flammable sealant that retains its performance characteristics when exposed to high temperatures and even open fire, is practiced in the construction of facilities for which the highest fire safety requirements are imposed.
How to choose the right polyurethane sealant?
When choosing polyurethane foam, the price of which directly depends on the quality, it is important to focus not only on the manufacturer, but also on the external characteristics of the cylinder in which the sealant is sold. A container with the best polyurethane foam is much heavier, and its contents, when shaken, roll from one end of the container to the other, and the price will speak for itself.
Factors affecting foam consumption
An important parameter that experts recommend taking into account when choosing a sealant is the consumption of polyurethane foam. It directly determines the amount of material that needs to be purchased to carry out certain work and is determined by a large number of external and internal factors.
Internal:
- Manufacturer of polyurethane foam, on which one of the important technical parameters material - primary expansion. In accordance with it, highly expanding modifications are distinguished, which include most household sealants, for example, Titanium foam. In addition, manufacturers offer mounting foams with medium and low expansion, suitable for more delicate work, among which we can note Macroflex mounting foam, which has all of the above properties, as well as Master mounting foam, characterized by minimal toxicity.
External:
- Ambient temperature;
- The material used to make the surface being treated is recognized as one of the fundamental parameters that must be taken into account when calculating sealant consumption.
Instructions for using polyurethane foam. Basic details of use
Regardless of which polyurethane foam you prefer, be it professional or household, before use, the foam container is preheated in hot water and shaken thoroughly. This is done in order to mix the components of the sealant, and thereby increase the yield of polyurethane foam, a photo of the use of which is presented in the article.
Further actions depend on the modification of the selected polyurethane sealant.
If it is semi-professional foam, then a tube that comes with it is put on the cylinder, while a cylinder with professional foam requires installing a gun on it after removing the cap from it.
It is important to remember that a properly functioning gun can ensure the safety of unused foam for 3 days.
After preparing the material, it is necessary to take care of thoroughly preparing the working plane, which will later be used for applying the sealant. Experts advise cleaning it from dirt and dust particles, and also moistening it with water, which accelerates the polymerization of the polyurethane precursor included in the sealant. In addition, this contributes to the speedy adhesion of the polyurethane foam to the surface being treated.
The process of applying polyurethane sealant is not difficult; the only thing you need to pay close attention to is the correct dosage of foam output from the container.
In this regard, it is easier to work with professional foam, the container with which is equipped with a special gun that regulates the output of the sealant using a valve. In the case of using household cylinders, this process is regulated by pressing the pressure on the cylinder valve. It is important to consider that during the process of applying foam to the surface, the container must be held vertically with the valve down.
After applying the sealant, you must wait until it dries completely. According to the manufacturer, complete polymerization of the material occurs within 6-7 hours, but its final hardening often depends on the volume of foam used and can take up to 11-12 hours.
After the polyurethane foam has hardened, many people ask the question: “How to remove the polyurethane foam?” This event also does not require special skills. The excess foam remaining after it hardens is cut off with a metal file or a sharply sharpened knife.
If the polyurethane foam was used outdoors, after it has completely dried and subsequent removal of excess, it is covered with cement mortar or plaster. It is also not prohibited to paint it, which protects it from exposure to ultraviolet radiation. The need for this measure is due to the high sensitivity of even the best polyurethane foam to ultraviolet radiation, which contributes to color change and premature destruction of the material.
If, when applying polyurethane foam, it gets on your hands, do not panic. It can be removed using the solvent used to wash the gun.
IN modern world used in almost all types of repair and construction work. It is used during the installation of doors, windows and window sills, and plumbing fixtures. This building material has also found wide application as insulation - it is used to seal cracks and cracks, sandwich panels and various insulation materials are made from it.
The main advantage of polyurethane foam is its convenience and ease of use.
Types of polyurethane foam
In order to figure out how to use polyurethane foam correctly, let’s look at its varieties. Today, modern industry produces three types of this material: professional and household cylinders, as well as two-component polyurethane foam (we will not consider it in this article, since it is used only in production conditions). What is their difference? Which type should you prefer? How to use a balloon with polyurethane foam The main criterion for choosing this material is its purpose.
Foam for professional use (gun)
This material is sold in cylinders starting from 1.5 liters and is distinguished by the fact that it can only be used with the help. It is used, as a rule, by professional builders, since this design allows the work to be done easily and quickly.
Using a gun makes dosing the material much easier. For one-time work in domestic conditions, the material is not very convenient, because after use you need to wash the gun, and this is an additional financial cost. There are manufacturers that complete the cylinders with a spray tube. But applying professional foam from it is not economical, since strong pressure increases its consumption.
Foam for household use
Sold in tubes with a capacity of 0.6-0.8 liters and equipped with a straw. It is intended for one-time use. Convenient for filling small spaces and correcting various installation defects. Household polyurethane foam has the same properties as professional use. The kit must include a tube. If necessary, you can use both a cylinder and a gun.
The cost of professional foam is much higher than household foam, and this is mainly due to the difference in their volume.
Pistol design
Before we learn how to use a spray foam can, first let's look at the design of the gun. Regardless of manufacturer? its structure is the same and quite simple:
- If household foam is supplied through a PVC tube, then in a gun it is supplied through a metal tube with a special tip - a nozzle. The tip hole is 5 times smaller than the cross-section of the supply tube, thereby increasing the working pressure of the mixture.
- The cylinder is connected through an adapter, which is attached to the gun body.
- The purpose of the adjusting screw is to dose the mixture output.
- Pen of this instrument can be aluminum or plastic. It is attached to the barrel with a nut. Thanks to collapsible design The gun is easy to clean from frozen residues.
- The trigger is used to supply the mixture from the cylinder.
How to install a cylinder on a pistol
In order to learn how to properly use a foam gun, let’s first consider how to insert it:
- The first thing to do is to warm the foam canister in hot water to room temperature and shake thoroughly for 20-25 seconds to bring the polyurethane foam substance to a homogeneous state. The foam will come out with a uniform consistency and in full volume.
- The container is closed on top with a protective cap, which must be removed before installation. Then place the gun with the handle down. When connecting, hold the device firmly by the handle with one hand, and screw the cylinder onto the adapter with a rotational movement with the other. Evidence of connection will be hissing, which indicates the arrival of foam. If there is no sound, this indicates a malfunction of the inlet ball valve or the expiration date of the foam itself. To fix this problem, the gun will have to be disassembled and cleaned of dried old material.
- After shaking, the device is placed in the working position with the handle down. The adjusting screw is turned a quarter turn and the trigger is pulled, pointing the barrel into the bag. When the consistency of the foam is normal, start working.
Polyurethane foam: how to use a spray can with a gun?
Working with polyurethane foam does not require any special skills. It will be enough to try to foam something once or twice, and everything will work out. Let's consider the order of work and some nuances:
Polyurethane foam is a material sensitive to ultraviolet rays, which, under their influence, is destroyed, changes color and crumbles. If used outdoors, then after complete drying and removal of excess, you need to cover it with cement mortar.
How to use polyurethane foam with a tube?
If a gun is not provided for the cylinder (in household foam), then instead the kit includes a PVC tube that is screwed onto the adapter. The operating principle is identical to professional foaming. It is not always convenient to work with such a cylinder, but it is great for one-time use. This option will be ideal in a situation where you plan to seal small seams.
So, what are the disadvantages of polyurethane foam? We have already figured out how to use it. Now let's look at the disadvantages of this material:
- It is impossible to dose the contents of the container, which increases the consumption of polyurethane foam.
- Inconvenience of working with this tool. Holding the balloon upside down by hand is quite tiring and even uncomfortable. The hand often gets tired and constant breaks are needed.
Using polyurethane foam without a gun or tube
Sometimes professional polyurethane foam can be used without a gun. How to use the balloon? In this situation, you will have to choose a tube to release the foam yourself and figure out how to press the valve. This process can be represented figuratively as follows: you need to release the air so that all of it can get to the desired point without getting caught in your hands.
In this case, choose a tube of 3 parts: the first and third are flexible, and the second is hard. The middle part presses the valve, the first prevents the foam from spraying, and the third brings it to the treatment site.
Conclusion
So, we examined polyurethane foam. We also studied how to use such material. But do not forget about protecting your hands and face, since the foam is quite difficult to wash off. It is much cheaper to buy an extra pair of gloves than to buy solvent or walk around with dirty hands.
Polyurethane foam is an excellent sealant and insulation material. It is used both for the installation of such large-scale structures as doors and windows, and for repairing minor defects. This material is used to patch various cracks and crevices, restore tightness at joints, and even make other Construction Materials. Foamed polyurethane is quite easy to use, but you need to follow certain rules for working with it and be quite careful so that the seam is smooth and lasts a long time.
Peculiarities
Cured polyurethane foam is an elastic, solid material of a yellowish-white color. This is very light substance has excellent heat and sound insulation properties. It very quickly loses its properties under the influence of ultraviolet radiation, so it is used mainly indoors.
This type of foam has a number of advantages that make it stand out from other materials:
- increased moisture resistance, high levels of sound and heat insulation;
- low current conductivity, which allows it to be used when installing electrical networks;
- many types of foam are resistant to fire, which allows expanding the scope of its application;
- after leaving the cylinder, such foam expands in volume and fills even those microcracks into which it is impossible to insert the gun tube;
- polyurethane can be used to glue surfaces made of different materials, for example, wood or brick;
- The foam is absolutely non-toxic and resistant to chemical attack.
Almost all of the above properties must be indicated by the manufacturer in the appropriate certificates, which can be requested from the seller.
The following information must be printed on the packaging itself:
- foam expansion volume. It can range from 10 to 300%, but most often the actual foam is still slightly less, since this percentage is indicated for ideal conditions;
- its viscosity;
- the volume of the container itself.
Most often, all these characteristics depend on the type and purpose of the foam, so you need to know which polyurethane it is and what it should be used for.
Release form
All types of polyurethane insulation differ according to several criteria.
Depending on the method of application and form of release, they can be of two types.
- Professional foam is produced in special cylinders, which are inserted into a plastic gun with metal clamps. This gun allows you to use polyurethane economically and in equal portions. The main thing is to thoroughly rinse the device after use so that any remaining substances in it do not harden.
- Instead of a gun, household foam packages are equipped with a small tube that is placed on the lever. It is not suitable for large repairs, but it will cope well with minor defects.
Depending on what time of year and at what temperature the polyurethane will expand and harden, the following types of polyurethane foam are distinguished:
- summer – used at temperatures from +5 to +35 degrees;
- winter – used at temperatures from -18 to +35 degrees;
- universal - costs much more, but can be used all year round.
It is worth noting that the temperature ranges are indicated not for air, but for the surface on which the composition will be applied. The lower its temperature, the less expansion of the finished layer will be.
In addition, foam can vary in type depending on the flammability class:
- B3 – flammable substance;
- B2 – self-extinguishing substance;
- B1 – fire-resistant compounds.
Finally, polyurethane foams vary in composition. They can be one- or two-component. However, the latter type of foam is so difficult to handle that it is practically not used for private construction and when renovating premises with your own hands. Two-component foam hardens in a quarter of an hour and there is practically no time left to eliminate defects, so only experienced professional builders use it.
Scope of application
Most often, polyurethane foam is used in the process of installing windows and doors, laying electrical wiring and pipelines. Due to the high thermal insulation in this way, it is possible to foam seams and grooves in cooling and heating systems, cracks in the roof and when insulating the surface of walls, floors or ceilings. She attaches perfectly Wall panels and foam boards, providing excellent waterproofing. It is applied to the outside of steel or cast iron bathtubs to reduce heat transfer from the metal when the bathtub is filled with hot water. Using polyurethane, you can insulate the space behind the sheathing of PVC panels. In almost half of the repair processes it remains an indispensable material.
In order to avoid any problems with both small and major renovation own house or apartment, you need to be able to use both professional and household foam. To work correctly with the first one, you must correctly install and use a special construction gun.
Gun installation includes the following steps:
- to begin with, the foam balloon is heated in warm water before room temperatures, then shake it vigorously for 30 seconds. This will give the polyurethane a homogeneous state, which will allow it to come out of the cylinder smoothly and in full;
- The protective cap is removed from the upper tank of the gun, it is turned with the handle down and the cylinder is screwed into it. The container is screwed in with force until a hissing sound appears, which means that the mixture has begun to flow into the tool;
- if the gun has been previously used and has not been thoroughly washed, then the hissing will not be heard and you will have to purchase a new tool;
- The system of connected elements is shaken vigorously several more times, the adjustment screw is turned a quarter turn and, holding the trigger, they begin to apply.
Working with such equipment does not require specific skills, but it will require considerable dexterity if this is the first time.
Applying foam from a gun is performed as follows:
- first you need to clean the working surface from dust and dirt, then lightly wet it with a regular spray, since the foam interacts better with a wet surface;
- the tool nozzle is directed to the surface;
- foam is supplied in the right amount by smoothly pressing the trigger;
- to pour the composition into a vertical recess, it must be applied from bottom to top;
- wide spaces are filled with zigzag movements of no more than a third of the volume, since the foam expands greatly in air;
- It is better to replenish the area afterwards than to cut off excess hardened substance.
The gun barrel itself is quite long, but in order to glue materials into hard to reach places, for example, to fill the voids between a false wall, it is worth additionally purchasing an extension hose that fits over it.
Despite the fact that the packaging most often indicates a hardening time of up to 8 hours, in fact this process can take up to half a day. After complete hardening, the excess is cut off with a regular stationery knife or metal file.
Unlike a convenient construction gun, household polyurethane foam is equipped with only a small PVC tube, which is put on an adapter. In principle, the sequence of work itself is practically the same, however, more effort will have to be made to fill the gap of the same volume. Such a tube is convenient for small volumes of work, because with it it is impossible to release the solution in equal portions. In addition, you have to constantly hold the balloon upside down, which causes your hand to constantly go numb, making it difficult to maintain smooth movements. If such a tube and adapter were not sold complete with polyurethane insulation, you will have to purchase them separately.
You will learn more about how to use polyurethane foam in the video.
Most often, polyurethane foam is purchased in the required volume for one time and after use, even if it is unfinished, is thrown away. And also it is not bought in advance, as it has a limited shelf life. It is worth considering the nuances described below in more detail in order to be able to save money.
Can it be used multiple times?
There is a widespread belief among buyers that professional foam with a gun can be reused, but the household type with a flexible tube, alas, is disposable and cannot be reapplied to the surface. Indeed, most often, if you leave the cylinder on the gun and block the trigger with a dispenser, the gun will not allow air to enter the cylinder and the composition will not harden. The next time you use it, it will be enough to remove the remaining frozen foam from the nozzle and you can start working again. However, exactly the same can be achieved from a household product. To do this, you need to start releasing the foam from the balloon, but without letting it come out, bend and tie the soft tube with wire. The foam at its end will harden, but the bend will not allow air to penetrate further and spoil the entire volume of the substance. The next time you use it, the cured edge of the PVC tube is simply cut off and the foam is ready for use. The container can be stored in this form for no more than a few weeks.