The glue is cyanoacrylate. Description, composition, application

At the present time, no one is surprised with such a tool as cyanoacrylate second glue, better known for customers as superglue. These tools are used to easily and quickly connect different types of materials (metals, wood, glass, plastic, etc.).

A bit of history

The cyanoacrylate adhesive was created during the Second World War by the American scientist Harry Kuver. He worked at Eastman Kodak for the production of cameras. In wartime, the scientist was engaged in the development of transparent plastic, which could be used in optical sights. The resulting substance was unsuitable for the task. This was due to the change in properties when moisture hit: the substance became sticky.

And only after more than ten years, Kuver realized that the substance created by him could benefit people. At first, it was used to seal up wounds during the Vietnam War.

A year later cyanoacrylate adhesive was introduced to mankind. Since that time, it remains in demand among buyers.

The Chemical Side of the Process

The main component of the glue is cyanoacrylate, that is, cyanoacrylic acid ester. Its quantity can reach 90-99% of the total composition.

To the air plasticizers (up to 10%), thickeners, stabilizers, activators are added. An important feature is that the adhesive does not contain solvents.

The gluing process is based on the reaction of anionic polymerization of cyanoacrylate with a slightly alkaline agent (most often water). With a thin layer of glue (up to 1 mm), the humidity in the air and on the surfaces to be bonded is sufficient for the reaction to proceed. Under the influence of moisture, the stabilizer, which is in the glue, splits. This gives rise to a polymerization reaction between the surfaces.

The optimal conditions are room temperature and air humidity 40-60%. Under these conditions, the best results that cyanoacrylate adhesive can give are obtained. The application of the agent at a lower humidity will result in an increase in drying time. Higher humidity will reduce the quality of bonding, reduce strength.

Basic properties

Cyanoacrylate adhesive (price within 500 rubles for 50 grams) is a colorless substance with a weak odor that disappears after drying. It has the following technical data:

• Completely composed of dry substances.

• Without solvent.

• The viscosity is about 1.5 thousand cps.

The main properties of dried glue:

• Resistant to high temperatures (prolonged heating up to 80 degrees or short-term to 100 degrees).

• It withstands lower temperatures (up to minus 20 degrees). At lower temperatures, the tensile strength decreases.

• It remains immersed in water for several weeks.

• Resistant to the effects of solvents (acetone, alcohol, petroleum products, gasoline, motor oil) and chemicals. The strength of adhesion can be affected only by alkalines.

• Holds a load of 150-250 kg / cm ³ .

Application area

Cyanoacrylate adhesive is most often used for quick connection of non-porous materials: for mounting of radio equipment elements, rubber seals in a window (door) opening, fastening microcircuits, boards, bundles, separate parts of units in instrumentation.

One of the types of "super-glue", octyl-2-cyanoacrylate, due to the speed of setting and minimum toxicity is used in surgery to stop bleeding and gluing the wounds. Recently, it has become possible to use glue in fractures.

In household use superglue for filling of seams and cracks. To do this, it is combined with baking soda. The resulting mixture freezes very quickly and resembles plastic.

The cyanoacrylate adhesive can be considered a universal tool. It is used in all areas: medicine, toy production, aircraft construction, automobile manufacturing, the production of toys and jewelry, footwear, plumbing, advertising and many others.

Using

The surfaces to be bonded must be pre-cleaned from dust, rust and oil stains. The agent should be at room temperature for about 24 hours. After this, you can use cyanoacrylate adhesive. The activator may be needed in cases with unfavorable conditions, to cover large cracks. It can be used both before the moment of gluing (application to one surface) and after (spraying on the adhesive).

On one of the surfaces the adhesive is applied in minimum quantities. To make the layer smooth, you can use a plastic spatula. In large areas, the glue is applied with drops. Then the surfaces are joined and tightly compressed.

The glue stops at room temperature. At 20 degrees Celsius, this takes only a few minutes. This process can be accelerated if there is moisture on the surfaces to be bonded.

"Grabs" glue in just a couple of seconds. Completely freezes glue for a day at 20 degrees and humidity of air more than 55%.

Safety precautions

All work related to the use of cyanoacrylate adhesive, must be performed outdoors. Work in the room is allowed only if there is forced ventilation.

Avoid contact with skin, eyes, digestive system.

Dried in the tube glue can not be squeezed out by force, otherwise the uncontrolled stream of the product can get into the eyes. In this case, the spout is punctured with a pin (better - red-hot).

"Glued" fingers should not be torn with force or cut with a knife. This will only damage the skin. For such cases, use acetone (or similar), applied to a napkin. Acetone will soften the glue, but not instantly. This will take some time (in difficult situations up to an hour).

Strictly forbidden when working with glue, put on cotton clothes (in particular gloves). When the adhesive contacts the cellulose of the tissue, a reaction occurs with the release of a large amount of heat. This can lead to burns.