Heat-resistant sealant: features and scope

Under the word "sealant" is usually meant a polymer composition having a viscous consistency, which is applied to various seams and joints in order to seal the structure. When carrying out construction or repair work, there is often a need for tight connections that must withstand the load when working in a high-temperature environment. One of the ways to cope with the solution of this problem is the use of heat-resistant sealants.

The main active component in the composition of the sealant is a polymeric material. Depending on the purpose of the application, it may be silicone, silicate, rubber, bitumen. The sealant is produced in tubes designed for manual use or with the use of a special feeding device - a mounting gun.

Depending on its composition, heat-resistant sealant is produced in three types - one-, two- or three-component.

• One component sealant - This is a product that can be used in finished form, and the process of polymerization of the composition occurs at room temperature for several hours. In this case, a thick layer of sealant is not required - a layer of thickness from 2 to 10 millimeters will cope with the task entrusted to it. More specific parameters each manufacturer indicates on the packaging of its products and they may differ from different brands.

• Two component sealant consists of base and catalyst. The polymerization process occurs during the interaction of these two components. The resulting mixture should be used immediately, as it is not subject to storage.
• Three component sealant consists of a main component, a curing composition and a catalyst that accelerates the curing process.

Sealants used in high temperature conditions are divided into two categories.

• Heat resistant sealants withstand temperature load in the range of 1300 degrees.Components of such a sealant are able to contact with an open flame. In its composition, the product contains sodium silicate. In turn, heat-resistant sealants are fire-resistant or fire-resistant. The difference between them lies in the temperature regimes and a number of characteristics.
• Heat resistant sealants can be used on those parts of the structure that do not exceed a temperature of more than 350 degrees by heating. As a rule, these are elements of joints, joints and cracks on the external surfaces of the structure.

According to the composition of the polymeric substance, sealing products are of several kinds.

• Acidic - Sealants, which in the process of polymerization form acetaldehyde. This substance can destroy or deform the surface that will react with it. Therefore, acid sealants can be used only to a limited extent. For example, metal surfaces will quickly corrode, and concrete or cement will give powdered oxidation.
• Neutral - a type of sealants, which consist of heat-resistant silicone and in the polymerization process emit water and ethanol.Their use is safe for all types of surfaces, and therefore these sealants have a fairly wide range of uses. Silicone seam is perfectly restored after any deforming effects, and its service life is at least 15 years.

In addition to the distinctive features, all types of heat-resistant sealants combine common properties.

• Adhesiveness - polymer components that are part of all heat-resistant sealing products have good adhesion to working surfaces. They can be used on brick, concrete, metal, glass, ceramic, wood or plastic construction.
• Plasticity - sealing seams after a polymerization time has a certain plasticity. They do not crack, are resistant to vibration effects and temperature extremes.
• Water resistance - polymeric materials have a high resistance when interacting with water and steam.
• Resistance to UV radiation - polymer sealants are not subject to the damaging properties of ultraviolet rays.

According to the field of application, heat-resistant sealants can be divided into three types.

• for use in construction and installation works;
• used for the repair of road transport;
• seals specialty.

The most common area of ​​application for heat-resistant sealants are high-temperature connections for stoves, fireplaces, boilers, chimneys, and they are also used to repair various systems inside automobile and other equipment.

Like any product, heat-resistant sealing materials have their advantages and disadvantages.

Positive properties.

• The operating mode of using heat-resistant sealant ranges from 1,200 to 1,300 degrees, but its composition can withstand an increase in the working environment up to 1,500 degrees for a short period of time.
• The use of heat-resistant sealing compounds is universal - they are suitable for almost any surface, you just need to choose the right type of sealant.

• Manufacturers of silicone sealants currently produce products with a diverse color spectrum, which greatly simplifies the purchaser's task when choosing.
• Heat-resistant sealants, having sodium silicate in their composition, are now successfully squeezing asbestos products from the market, which are recognized as carcinogens worldwide.
• The use of sealant makes it possible to increase the degree of protection against the ignition of structures and structures. Often, sealants are used in the installation of ventilation ducts, the arrangement of a heated floor, and the installation of door panels.

Negative properties.

• The overwhelming majority of high-temperature sealants have iron oxide in their composition, therefore, when they come into contact with working surfaces during the polymerization process, they are able to paint in a rust-brown color, which is undesirable in certain conditions and does not look quite aesthetically pleasing.
• Silicone, which is part of the sealant, does not allow paint to be applied to the sealing layer - it does not adhere to it. This is not always convenient, for example, when repairing a car.

• The sealant, which contains silicone, dries at a speed of approximately 2-3 millimeters per day.Thick seams may not solidify inside at all, since air is important for the polymerization process.
• It is possible to work with heat-resistant sealants only at temperatures above zero, low temperatures during installation work will lead to disastrous consequences due to the violation of the polymer process technology.

In order to understand the world of heat-resistant sealants, the easiest way is to start from their main constituent component.

Silicone Sealants - temperature resistant product, which is based on silicone rubber, which has the ability to cure in conditions from 2 to 40 degrees Celsius. Silicone sealants can be one- or two-component, and the chemical method of polymerization they are acidic and neutral. Used for construction, installation and highly specialized work. The working temperature averages 230-250 degrees, but the sealant can withstand for a short time and a maximum load of 350 degrees.

Used for:

• filling gaps in the chimney from the street;
• close fit of the roof to the chimney;
• installation work chimney;
• filling gaps in the brickwork from the outside of the furnace.

Pros:

• long service life of up to 15-20 years;
• the average operating temperature range is from minus 50 to plus 350 degrees;
• good adhesive properties, subject to compliance with the installation technology;
• it is easy to apply on any bends of the working surface without loss of elasticity.

Minuses:

• poor adhesiveness to wet surfaces;
• does not hold paint coatings;
• when laying on the old layer of silicone sealant - poor adhesiveness of the new layer;
• corrosive to metal and concrete.

Before applying the sealant, the surface requires some preparation. - cleansing from oils, fats, dust, dirt, moisture.

In the thiokol-based sealant, the main component is the chemical thiokol or, as it is also called, polysulfide rubber. Available in two- or three-component formulations. Polymerization time can take up to several days. The composition prepared after mixing of components is suitable for work within 2 hours. The operating temperature range is from minus 60 to plus 130 degrees.

Are used:

• for sealing metal structures in the repair of automotive systems, units;
• for sealing fuel systems, taking into account oil-resistant and petrol-resistant qualities;
• due to the low gas permeability, the product is suitable for sealing gas boilers;
• for sealing structures operating under the influence of acids and alkalis;
• for sealing steam and water boilers.

Pros:

• elasticity, strength of sealing seams;
• service life is up to 20 years;
• It has excellent adhesiveness with metals, including suitable for stainless steel products.

Minuses:

• after preparation, the composition must be quickly used, as it begins to polymerize in two hours;
• when exposed to the skin, the product has an irritating property, therefore it is prohibited to work with it without the use of protective equipment.

Before using the surface must be cleaned and degreased.

Bitumen based sealants The main component is bitumen, which, in combination with certain additives, forms a plastic polymerized mass. The material has a vapor and moisture insulating qualities, is able to work at a temperature mode from minus 50 to plus 150 degrees.

Are used:

• for fixing insulation materials to various types of surfaces;
• for sealing heating boilers and threaded connections in a humid environment;
• for sealing hot and cold water supplies.

Pros:

• possesses good adhesive ability;
• plastic and durable, service life is up to 20 years;
• resistant to vibrations, but only in an environment with positive temperatures.

Minuses:

• does not adhere well to surfaces contaminated with oil;
• loses vibration resistance at low temperatures;
• can not be used at the junction of the junction of the roof and the chimney, as the bitumen begins to melt;
• when it comes to hands it is very difficult to remove, therefore it requires the use of individual protective equipment;
• when applying a thick layer, the polymerization process is very bad.

Silicate Sodium Silicate Sealants - The main component of this flame retardant material is silicate sodium. The composition can be one- and two-component.Due to silicates, sealants are able to withstand an operating temperature of 1,200 to 1,500 degrees. Usually they are used in the furnace business, but these heat-resistant materials can be used wherever an increased flame retardant capacity is required. The process of deposition and polymerization should be carried out at positive temperatures of up to 40 degrees.

Are used:

• for sealing the connecting parts of chimneys;
• at the joints of the elements of the outer and inner contour of the furnace;
• for the repair of the exhaust unit of the car;
• for consolidation of a joint of cylinders of fuel feeding system of the engine;
• for sealing joints of powerful electric heating structures;
• to enhance the fire properties of various structures.

Pros:

• excellent refractory properties;
• the possibility of good adhesion with any building materials;
• well withstands exposure to open flame.

Minuses:

• sealing seam does not have elasticity;
• unable to withstand vibration and deformation of the sealing surface;
• a narrow range of optimal temperatures during application - the best conditions are an ambient temperature of 20 degrees.

Before applying the silicate sealing material, the surface to be treated must be clean and dry. After drying, some brands of such sealant require treating the seam with a gas torch.

The color of heat-resistant sealant may be important in the case when it performs its function when sealing the seams of structures that carry an aesthetic load - a stove, a fireplace, a chimney. In other cases, it is not so important. The bulk of sealants due to the content of iron oxides in them has a brown-red color. Sealing materials containing sodium silicate, as a rule, are gray or black. But they can be painted at their discretion after the polymerization process is completed. Silicone sealants allow a wider color gamut and can be transparent, white or colored.

The range of application of heat-resistant sealants is quite wide. They are used by specialists to perform narrow work and ordinary ordinary consumers for household needs. Often used sealants and in industrial fields.

Sealing materials are most in demand.having fire-resistant properties in the furnace sector. They are used to seal the various elements of furnaces, fireplaces, furnace chimney both indoors and on the roof, in places of joining with roofing materials. Often, sealants are treated with threaded and docking elements of heating boilers, installed in the steam room of a bath or sauna and made of metal or stainless steel.

Sealing in the industrial sector affects a wide range of applications, ranging from pipe connections of industrial equipment to high-power electrical installations. Often, sealants are needed when installing various fire-resistant panels, surface mount printed circuit boards, cooking panels, as well as they are used in sealing joints, assemblies and other important technological systems.

Motorists have found use for heat-resistant sealing materials for the repair of an internal combustion engine, exhaust manifold, radiator repair, automotive stove and other components that are heated during vehicle operation.

Before starting to work on the sealing of a surface, it is necessary to calculate how much sealant for this may be required. Experts believe that the minimum width of the seam should not be less than 3 millimeters, and in the ideal case, the sealing seam should be within 6 millimeters. The depth of the seam should always be half the width of the seam. Ideally, the depth of the seam should not reach 3 millimeters. In addition to these parameters, you need to determine the length of the seam. It will depend on the size of the particular object where the sealing material will be laid. Knowing these parameters, we will be able to determine the amount of consumable sealant in meters.

Manufacturers, in order to simplify this task for us, indicate on their products its volume and the number of running meters, which can be closed with this volume. Many manufacturers on online sites for consumers place special calculators with which you can determine the required number of units of their products according to the specified parameters of the coverage area. In addition, the manufacturers have a special table, where, depending on the width and depth of the seam, it is indicated which footage will be enough for one package of one or another sealant.For example, a cartridge, the volume of which is equal to 310 milliliters, can be processed 13 meters of the surface if the seam width is 6 millimeters and the depth is 4 millimeters. And if we take the width of the seam equal to 12 millimeters, then with the same depth of the seam equal to 4 millimeters, the cartridge is enough for us only for 6 meters.

Prepare the work surface before using the sealant. The adhesion of most sealants shows its properties well on surfaces that are dry and free from contamination, fats and oils. If the material is porous, it must either be cleaned or polished to a solid state, or it should be well primed. The surface of wood is recommended to first varnish or paint, and after they dry use a sealant. Metal, glass, ceramics, first degreased with alcohol-containing liquids or acetone. Polymers are best treated only with alcohol.

Sealing material is applied to the prepared surface. To do this, use a cartridge with a special nozzle or a special device in the form of a mounting gun. In place of the joint sealant is applied so that the joint was completely closed with a sealing compound.There are special devices that help align the seam, making it uniform and aesthetic. Sometimes the sealing compound is applied with a rubber spatula, the width of which is selected depending on the object being processed.

Heat-resistant sealants in Russia can be purchased both domestic and foreign production. According to analysts, Russian manufacturers in recent years tend to oust foreign suppliers.

The following companies are among the largest manufacturers of sealants in our country, producing products according to their own developments or foreign technologies:

• Lipetsk company Fenzi - The company produces sealants and glue according to Italian technology. As an example, one-component sealant "Butilver", which operates at temperatures from +120 to + 150 degrees.
• Bashkir company "Moment" produces sealants according to the technology of the German brand Henkel.The products are packaged convenient for professional and domestic use. The product called “Moment Germent” is produced on the basis of silicates, the working parameters for heating reach +315 degrees.

• Vladimir Scientific Production Company "Adhesive" develops and produces adhesives, sealants, elastomeric coatings. An example of this is the one-component sealant "Advaflex", which works in the temperature range up to + 90 degrees.
• Nizhny Novgorod company "Germast" - the manufacturer develops and produces sealants for various purposes. Sealant "Vikar" is designed for a wide range of applications, comes in the form of a cartridge with a volume of 310 ml and can withstand temperature loads up to +140 degrees.
• Moscow Company "Sazi" - the largest company that specializes in the production of sealing products. The range includes all types of sealants, ranging from household and ending with highly specialized.

• Trademark Hoby. The company Hermetic-Trade is its distributor in Russia and sells a line of sealants on the Russian market, among which we can highlight the heat-resistant silicate sealing product Hobby 1250s used for fireplaces, stoves and chimneys as an example.The composition of the sealant is able to work at temperatures up to +1250 degrees.
• Trademark Abro industrials - under this trademark, an American company began to produce high-quality temperature-resistant sealants of small packaging in the territory of Russia for use in the assembly and construction industry and automotive repair.

• Trademark Hilti produces sealants that are used for joints and seams of structures exposed to high temperatures. The most popular are the brand “P-301S, СР-606 - sealing seams of these products withstand deformation well and can be painted on them.
• Trademark Penosil owned by the Estonian company Krimelte. This brand specializes in the production of mounting foams, various types of adhesives, sealants and other polymer products. The company's products are quite popular in Russia and are used for professional and domestic needs. As an example of a flame retardant sealant, Penosil Premium Sealant + 1500c can be cited - the product is used to seal the seams of chimneys, chimneys, fireplaces, boilers, and stoves. It can withstand temperature loads up to +1500 degrees.

Experienced experts when using high-temperature sealant in the field of open flame are advised to pay attention when choosing a brand of product to a direct indication of the presence of refractory properties. After applying a sealing material, it needs some time for polymerization - each package has instructions with such data. The period of sealing should be strictly followed before proceeding to the next stages of work. In the case when the work must be carried out in conditions of negative temperatures, the sealant must be chosen with the properties of work in these temperature ranges and the possibility of adhesion to wet and frozen surfaces. If the joint to be sealed is located on a structure that has a certain degree of mobility, choose compounds that have high elasticity after polymerization.

Some household sealants can work in humid environments., but this does not mean that they will be resistant under water. Professionals recommend to use for such purposes highly specialized materials that are used in the field of shipbuilding. And the last - working with sealing compounds, take care of personal protective equipment for hands. If the sealant gets on the skin, it should be immediately washed off with water, because after a while this will be quite problematic.

On the features and scope of heat-resistant sealant, see the following video.