Urea formaldehyde resin: production, use and properties

Urea-Formaldehyde resins are widely used in construction, woodworking and some other industries. The industrial way to produce their first started in the USA in 1927. For water resistance and strength of polyester and epoxy resin materials are somewhat inferior. But making them is much cheaper.

Produce

Get KFS resin, as can be inferred by the name, by polycondensation of formaldehyde with urea. They represent is non-flammable aqueous suspension, the viscosity of which color may vary depending on the brand. Production of ureaformaldehyde resins typically involves the use of special, jacketed and a special stirrer apparatus. Just the process of making such products involves three basic steps:

• The polycondensation;

• Acidic condensation;

• Drying.

The Polycondensation resin is carried out in an alkaline medium when the pH of the reaction solution equal to 7.5-8. In the manufacturing process is monitored to ensure that the molar ratio of urea: formaldehyde was 1:1.6-1.9.

Acidic condensation is carried out in environment with pH=4.5-4.8. At this stage in connection with the increase in the molecular weight begins to increase sharply the viscosity of the fluid. At the end of the reaction the acidic condensation in the resin add Another batch of urea. Required quantity of this substance is calculated in such a way that the molar ratio of the components in the prepared solution was 1:1.3-1.4. At the stage of drying of the resin is adjusted to the required values of relative viscosity. The final stage Product cooled and is modified to reduce its toxicity.

Application Area

Used urea-formaldehyde resin (formula N=CH2 C=O and NH2 HOCH2NH C=O NH2) may, at the production:

• Fiberboard and particleboard;

• Plywood;

• Putties, varnishes and paints;

• Water-resistant paper and paperboard (impregnation);

• Foam.

Is Also often used resin Urea-formaldehyde (KF-MX2) in drilling. In this case it is used as the base cement slurries. The latter, in turn, represent the viscous mixture that can rapidly harden in the air. Cement slurries are used mainly for fixing the casing and to protect them from corrosion.

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Adhesive based on KFS

The wood-working industry pure CFS are rarely used. More often is the main element used in joinery urea-formaldehyde resin glue. The main varieties of such means, manufactured on the basis of CFS, there are five:

• The KF-B — fast-curing glue;

• The KF-On — General purpose (formaldehyde content not higher than 0.25 %);

• The KF-MT — have low toxicity, are used for the production of fiberboard and particleboard;

• The KF-Zh — with increased vitality;

• The KF-BJ — combines the advantages of the models of KF-B KF-Z.

Fast setting adhesives KF-B at the enterprises of woodworking industry are used mainly in the manufacture of plywood and veneer, furniture boards for single-span presses. Malotonazhnoy product KF-O is used at most only for gluing paper. Also, this adhesive can be used in the manufacture of plywood. Particleboard and fiberboard with its use do not make. For the production of boards based on the chips or fibers is applied product of the brand KF-MT.

Glue with high vitality is great for connecting all kinds of furniture pieces. In the construction in some cases it can be used to strengthen weak soil. Universal adhesives KF-BJ are often used in the manufacture of plywood and furniture. They can also be used in the manufacture of different kinds of joinery. Depending on the type of hardener, all adhesives based on KFS can be used for both hot and cold bonding.

Sometimes in construction, woodworking, etc. find application and special adhesives with various modifying additives.

Properties of the resin KF-MT

Technicalcharacteristics of urea-formaldehyde resin depending on the scope of application may be different. From the table given below you can obtain information about the properties of the most popular resin KF-MT, used in the production of fiberboard and particleboard.

From the other brands KF-resin KF-MT is distinguished primarily by a reduced viscosity at relatively high dry residue. These characteristics allow to enter it in mixers with airless spray. The use of such equipment, in turn, makes possible a significant reduction in the moisture content of the processed resin wood particles and, consequently, reducing the time of pressing plates.

Impregnating resin (SCFP)

This species of KFS used in the manufacture of moisture-proof cardboard and paper. Sometimes it is also used for impregnation of decorative roll, plywood, particleboard and fiberboard. The table below presents the characteristics of this product.

Characteristics of the resin used for coatings

For this purpose is usually applied product of the brand K-421-02 Is melamineformaldehyde resin transparent liquid and has the following properties:

Properties of KF-MX2

Urea Formaldehyde resin used to manufacture cement slurries must also fully comply with GOST.

Urea-Formaldehyde foam: field of use

This product is mainly used in construction as insulation material. It can be used for insulation from the cold.

• Walls;

• Roof space

• The floors and ceilings.

In comparison with conventional expanded polystyrene, Styrofoam KFS has one important advantage. This material is absolutely non-combustible. Urea formaldehyde resin Belong to the group of thermosetting substances. That is, the reverse reaction to occur can not, by definition. Accordingly, the CFS-foam during a fire does not melt. The only — under the influence of high temperature it loses little mass, highlighting non-hazardous to human health the nitrogen and carbon dioxide. The life of the foam of this variety is about the same as extruded polystyrene — about 80 years. To use this material maybe in the form of plates and in liquid state. In the latter case the mass is simply poured into a cavity of different kinds of building structures.

How to make a foam KFS

For the First time this material has appeared in the late 30-ies in Germany. In Europe in the construction of buildings and structures it is used very widely. In 30% of cases with insulation of different kinds of walling used this material. In recent years more and more popular KFS-foam becomes and in Russia.

The Technology of manufacture of this heater is relatively simple. In the sale there is even a special, relativelycheap equipment, to acquire which, in principle, can be anyone. Work such installations are as follows:

• In one of the containers filled with a water solution of phosphoric acid and foaming agents;

• In another container is placed actually own a urea-formaldehyde resin;

• In the barrel open the taps.

For mixing material components is used powerful pump. Urea-formaldehyde resin and foam flow distilled them in a special mixer. Received in this capacity mass is poured into cavities of building structures through the hose nozzle.

Properties of the resin used for the production of foam

For this purpose, the construction is usually applied product of the brand CFI-PV. This liquid resin is white or light brown color, technical specifications which must exactly match the requirements of GOST.

Labeled As KF-resin

Thus, found very widespread in industry and construction urea-formaldehyde resin application. This product is marked according to the requirements of GOST 14192. Container labels with CFS or invoice must be present:

• The name of the manufacturer with his trademark;

• Net weight

• Grade resin;

• Date of manufacture;

• The batch number;

• The designation of the standard.

How should be Packed resin

Woodworking and Large construction companies purchase this product is usually in very large quantities. In this case, the urea-formaldehyde resin KF is delivered to your destination in rail tank cars. The party of smaller bottled product in steel drums. Latest before use, according to GOST 13950, should be thoroughly washed. The standards allow for the pouring of the resin including in the multi-barrels with a small exterior defects.

Test Methods

Take urea-formaldehyde resin at the enterprises of the parties (with the same characteristics and weight not more than 200 tons). To check the quality of the product being tested. The first stage produces:

• A fence point of the sample metal tube;

• Connection on all samples, with placement in a glass jar;

• Labeling with date and place of sampling.

The Actual testing may include visual inspection and determination in laboratory conditions:

• The mass of dry residue of each sample;

• Mass fraction of free formaldehyde;

• The concentration of hydrogen ions;

• Time of gelatinization;

• Of mixing with water;

• Strength.

How to transport and store

Be Transported resin, urea formaldehyde (hazard class of the substance — II) may on all modes of transport. When the air temperature is below 0 ^OWith use only tanks with heat exchangers or thermal insulation coatings. In the latter case, the heating is done by hot water in the jacket tank. The temperature of KFS after this procedure should not exceed the 25 ^OC. to Produce heating of the product vapor is prohibited.

In the Summer, t on air from the 25 ^OC, to transport the resin can no longer than within 10 days. Store the product at temperatures below 5 ^OC and 20 ^OC in a tightly closed container. Not allowed to keep the barrel or tank with the resin in direct sunlight. Also GOST instructs to store the container with the product under a canopy, avoiding exposure to the rain.

Urea Formaldehyde resin: manufacturers and brands

Today in Russia produced about 500 thousand tons of CFS per year. The largest domestic companies involved in the production of this product are:

• «Ugra lespromkholding”

• “Shatura”

• The Volga and the Cherepovets plywood and furniture factories;

Also do we have in the country the manufacture of products such as urea-formaldehyde resin, manufacturers of the Russian-Finnish. Specializiruetsya in the production of this material, for example, ZAO “Metadinea” and a member of the European company Swiss Krono Group company “Kronostar-East”. In addition, CFS is one of the varieties of products produced such giants of chemical industry as “Akron” and “Metafox”.