In premises with a high risk of fire, materials of special quality are used. One of them is heat-resistant polyurethane foam. Foamed polyurethane foam does not ignite if the temperature rises to critical values, it inhibits the spread of flame. Types are produced on a different basis, with additives that increase fire resistance.
Description of refractory polyurethane foam
The foamed mixture based on polyurethane foam is packed in aerosol cans. The result of resistance to high temperature depends on the viscosity, consistency. Quality material does not lose properties at temperatures up to + 1000 ° С... Entrances and exits from hazardous premises in terms of fire, hatches are also sealed with polyurethane foam for high temperatures.
Characteristics:
- resistance not only to flame, but also to water, so there will be no mold on the surface;
- foams of the cheap segment, when exposed to ultraviolet radiation, lose their elasticity, turn brown, expensive ones become light, but require external insulation;
- stabilizers, catalysts are added to the composition to resist critical temperatures.
The density of professional thermal foam is more than 35 kg / m³, while the final properties depend on the homogeneity of the structure of the material. The air cells must be the same size and the ratio of open and closed cavities must be balanced.
Composition and properties
During production in a cylinder, they are mixed flowable prepolymer and gaseous propellant... The second substance boils at high air pressure when exiting the cartridge, while the liquid produces many bubbles in the form of a foam.
Two main components:
- prepolymer - the composition formed by the reaction of polyalcohols and methylene diphenyldiisocyanates;
- propellant - a mixture of gases, half dissolved in the first substance, the second half is presented in the form of a gas.
Polymerization occurs from the beginning of the release of the composition and reaction with a wet plane and atmosphere. The foam absorbs water molecules, polyurethane bonds are formed, and gas is produced, which foams the mixture from the inside. The expansion process is bequeathed after the end of the polymerization.
The setting time is influenced by the ambient temperature. In rooms with heating, the hardening process is faster, as well as in humid places, for example, near water bodies, seas.
Scope of application
Common foam applications:
- the gaps between the door frame and the wall ends, the gaps between the window frame and the slopes;
- sealing and thermal insulation of gaps when installing board materials;
- filling intermediate joints between floor slabs;
- gluing foam elements on walls and ceilings in fire-hazardous rooms.
Thermal insulating foaming composition is used for sealing chimney ducts, fireplace pipes, stovesto reduce the risk of leakage.
Abrupt subcooling of refractory polyurethane foam leads to a decrease in protective characteristics. Storage of cylinders is allowed at temperature indicators not less than + 20 ° С.
Heat resistant polyurethane foam works well in high fire hazard environments electrical wires, highways, it is used for isolating switchboards in the entrances of houses and apartments.
Varieties of heat-resistant foam
Heat resistance degrees:
- IN 1 - foam with the highest degree of fire resistance. They are taken for buildings with a large crowd of people and an increased fire hazard. Does not support inflammation, retains insulating properties for a long time.
- AT 2 - is a representative of the middle class of fire resistance. It is used in buildings with a small degree of traffic. Resists fire for 30 - 40 minutes, then melts, but does not burn.
- IN 3 - combustible composition. May burn, but dies out if the flame source ceases to operate. Due to its low efficiency, it is not used as a polyurethane foam for high temperatures.
According to the number of its constituent elements, the foam is one-component and two-component.
One-component
The category includes foams more often household use... These materials are offered for sale in aerosol cans.
Act one-component formulations:
- a liquid prepolymer is present in the mixture before it is released from the balloon, which is mixed with the propellant in a gaseous state;
- the second substance can boil when the pressure rises, which it does when it leaves the container;
- liquid prepolymer forms a stable foam;
The first stage of polymerization occurs when the foam is ejected under pressure by reaction with a humid atmosphere or surface. The expansion of the mass stops at the end of the polymerization.
Two-component
The composition is mixed before use, usually the bulk must react with the hardener. The expansion coefficient matters. The indicator depends on temperature, humidity, exit rate. When laying the foam in the seam, take into account the free space for the expansion of the composition. Usually foams expand by 60 - 300%.
Extension details are on the packaging, but the information is valid for ideal conditions:
- ambient air humidity - 50%,
- temperature - 20 - 24 ° С.
Criterias of choice
The manufacturer, through the supplier network, must provide certificate of conformity for products... It confirms the quality of the goods, which complies with the requirements of GOST 30247.0-94 in terms of fire resistance.
Factors are taken into account:
- manufacturer, his fame and popularity;
- the weight of the container, which is determined in order to save;
- degree of fire resistance, composition, cost;
- the amount of space to be filled;
- shelf life;
- packaging option.
Domestic foam is sold with a removable tube.It is used for small volumes, for example, for foaming the outside of an entrance door. For large volumes, they take more professional packaging that is used with a special gun.
Recommendations for use
Flame retardant materials keep seam width up to 10 cm.
In order for the composition to work correctly, adhere to the rules:
- the plane during laying is heated up to + 35 ° С, and the balloon itself - up to +10 - + 30 ° С;
- the surface is moistened to increase adhesion and accelerate polymerization;
- when filling, they are laid on 1/3 of the seam, taking into account the expansion of the mass.
Any foam is protected from external factors. For this, plaster, moisture-resistant sealants, putty and paint are used.
Before using the balloon shake for 20 - 30 secondsso that the components connect and the pressure increases. During application, the can is held with the valve down. The curing time depends on the indoor climate and humidity.
Consumption
For calculation measure the width and depth of the gap... The values are multiplied to obtain the consumption of funds per 1 running meter. The weight of the foam on the label is indicated in liters, so the volume obtained is multiplied by the volumetric weight of the foam.
Popular manufacturers
- Henkel Finland, subsidiary brand Makrofleks;
- Den braven - German company;
- Soudal a division of the Tremko Illbruk subsidiary;
- Bison international - another company from the Netherlands;
- Bau master - Ireland;
- Penosil - manufacturer from Estonia;
- MasterNail, Putech, SHIP - Russian brands.
Manufacturers use innovative technologies in their production. At each stage of production, product quality control is carried out. Apply visual coordination, use electronic sensors to determine the accuracy of weighing ingredients, mixing, quality control.
The characteristics of the products determine the cost at the level of professional materials. Heat-resistant polyurethane foam for chimneys or fire-hazardous places in the house cannot be cheap.
