Liquid foam: description, characteristics, methods of application

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The article will tell you about a new, easy-to-use material – liquid foam. You will learn how to make it yourself, as well as about the main operational properties. The article provides basic characteristics, analysis of the advantages and disadvantages of liquid foam.

Liquid foam. Description, characteristics, methods of application

Styrofoam is a material familiar to us since the early industrialization. It can be safely called irreplaceable, like all related foam materials – expanded polystyrene, polyurethane foam, penoizol and others. Today, the manufacturer has become so close to the consumer that a home craftsman can purchase or create with his own hands a plant for the production of almost any type of foam material..

What is Liquid Foam

It should be noted right away that the term or concept “foam” includes a large number of varieties of foam based on polymer resins. Their characteristics vary greatly and depend on factors:

  1. Appointment. Technical foam can significantly exceed the toxicity standards for residential premises (this is permissible). Therefore, they use cheap raw materials (polymer synthetic resins) of low purity.
  2. Production technology. Products made from solidified PP are considered to be conditionally safe – they may contain toxic fumes when heated (burned). Liquid PP, which is produced immediately before being applied to the structure, can emit harmful substances during operation.

Of all the possible options for raw materials, carbamide resin seems to be optimal. The full name of the product based on it is urea-formaldehyde foam.

Liquid PP production

Any of the types of slab insulation is obtained by hardening liquid foamed raw materials. If this foam is applied directly to the structure, the adhesion to it will be several times more effective than securing the formed plate. Therefore, in recent years, mobile stations for PCB production have become popular..

Liquid foam. Description, characteristics, methods of application

For the preparation of liquid PP, resin and hardener are used. The curing reaction is the same as with epoxy or polyurethane glue, the only difference is in the form of resin. The ingredients are mixed and whipped into foam with a special machine (station) – this foam can be called liquid foam. Then it is supplied by a pump under a pressure of 5 atm through a hose to the place of application.

A variety of foam generators are offered by factory manufacturers, but you can also assemble it yourself. The cost of a factory model can be quite high – up to 2500 USD. e. At the same time, you can create a foam station literally from the material at hand – a set of plumbing fittings, adapters, ball valves. The main “secret” of such a unit is a steel mesh for washing dishes..

Homemade foam generator on video

Such mini-stations, consisting of a compressor, receiver and hoses, are mobile and autonomous. They allow for on-site production and widespread use of liquid foam. It became a business idea, liquid foam is becoming more and more popular precisely because of the availability and prevalence..

Table. Properties of urea foam

Index Unit rev. Value A comment
Density kg / m2 12-30 Increases when pumped into confined spaces
Thermal conductivity W / m2·TO 0.012-0.047 Depends on the sparseness of the material
Compressive strength kg / cm 0.07-0.5 Depends on the upload method
Elasticity % 100-30 Depends on the balance of ingredients (resin and hardener)
Vapor permeability g / m h Pa 0.21-0.24 Average between mineral wool (0.5) and expanded polystyrene (0.05)
Water absorption % of volume in 24 hours 20 Also gives off moisture

Each material has strengths and weaknesses, and liquid PP is no exception..


  1. Excellent adhesion to any hard material.
  2. Fits on any surface without preparation – only minimal cleaning and drying is required.
  3. Forms a seamless homogeneous layer after application.
  4. Good vapor permeability – suitable for wood insulation.
  5. Fills the sinus completely without creating high overpressure.
  6. Leaks and excess can be easily removed – leaves no chemical residue.


  1. Formaldehyde emissions are too high for indoor use.
  2. Absorbs moisture (requires protection from the atmosphere).

The most common myth about liquid urea-formaldehyde foam is that it is deadly. Yes, the raw material contains formaldehyde and phenol-formaldehyde, which is also indispensable in chipboard, OSB, plywood, expanded polystyrene, plastic for windows and many other products. However, this does not mean that they are all dangerous – for this they are divided into classes of toxic safety.

It is in connection with the release (emission) of formaldehyde that liquid foam is recommended exclusively for outdoor use, or as an intermediate layer. The use of the material for other purposes (indoors) can result in complications (affect health), but if you use it correctly, it is absolutely harmless to people and animals.

The second most powerful myth is the flammability of this material. It is easy to verify the inability of the PP to self-combustion by conducting a flame test.

Application area

Horizontal planes. In the overwhelming majority of cases, these are attic floors of panel houses. However, liquid PP can be used to insulate the rafter space and inclined planes..

Filling the attic with foam on video

Cavities and sinuses. The consistency of dense foam is ideal for filling the space between two stable surfaces – the sides of stone formwork, false walls, or wooden floors. Moreover, the shape of the sinus can be absolutely any – even the slightest gap or hole will allow the sinuses to communicate, which will ensure high-quality uniform filling of hard-to-reach places.

Liquid foam. Description, characteristics, methods of application

Thermal insulation of containers. It is enough to install a conventional barrier around the tank at a distance from the wall and the resulting sinus can already be filled with foam.

Molded foam production. The foam generator unchanged can be used as stationary equipment for the production of PP boards and other products – plinth, stucco, baguette, relief, etc..

Handicraft “minifactories” are becoming more and more today – the technology is simplified and becomes available to everyone. This is often used by unscrupulous manufacturers, using cheap toxic materials. In order not to become a victim of dealers, the theoretical part of the work – the toxicological properties of resins and liquid foam – will need to be studied independently.

Using liquid foam as an adhesive

This material is produced packaged in cylinders under pressure. By the form of release and the principle of action, it is similar to polyurethane foam, or rather, it is its kind. Unlike polyurethane foam, liquid foam has better thermal conductivity and vapor permeability..

With its help, you can carry out internal insulation with any kind of plate insulation (except mineral wool) without anchoring.

Liquid foam. Description, characteristics, methods of application

Working process:

  1. Check the surface for defects – rust, looseness of the base, curvature.
  2. Clean and dust the insulated plane.
  3. Moisten the contact points of the adhesive with the stove with water. Ideally, liquid PP is applied to the entire plane of the slab, but an economical option is quite acceptable – along the perimeter and diagonals.
  4. After applying the composition, press the plate tightly at the place of insulation.
  5. Place subsequent slabs by applying PP from a balloon to the joints and the contact plane.

Keep in mind that thermal insulation with expanded polystyrene and polyurethane foam gives the effect of a “thermos” and without proper ventilation, condensation may form.

The cost of work on insulation with liquid foam depends on the volume and complexity. For the plane of the attic – 2-3 cu. eat2, sinuses, containers, walls – 3–8 cu. eat2. Using this material, you will receive high-quality insulated areas in the shortest possible time – in just a few hours. Creating your own foam generator will not only make it possible to produce high-quality PCBs, but also make it a profitable acquisition.

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