Use and properties of electrical insulating varnishes KO-921, KO-916 and their varieties

Organosilicon varnishes have excellent electrical insulating properties. This type of paints and varnishes is often used in the creation of protective insulation of machinery, equipment. An example is the varnish KO-921 and a number of other brands.

Content:

• Description of organosilicon products for electrical insulation
• Popular brand brands
• KO-921
• KO-916
• KO-916A
• KO-916K
• Other brands
• KO-915
• KO-915A
• KO-915B
• KO-923
• KO-987
• KO-991-4

Description of organosilicon products for electrical insulation

Varnishes of the KO brand (organosilicon) are produced according to GOST 16508-70 and are solutions of film-forming substances (resins, cellulose ethers, industrial oils) on solvents. The composition necessarily introduces substances with dielectric properties - not able to conduct electric current, insulating it.

Varnishes can be of different types:

• impregnating - are needed to impregnate the windings of devices, to increase water resistance, increase thermal conductivity;
• integumentary - used to create a protective coating on the areas of insulating parts;
• gluing - are needed for gluing mica sheets with other materials to obtain a heat-resistant heat-insulating agent (for example, to create mikalenta).

Ways to dry varnishes vary. Some of them require hot drying - up to +200 degrees, others give a hard coating after drying at normal room temperature.

Popular brand brands

Among the most famous brands include KO-921, varnish KO-916 and its varieties. Below will be a detailed description of the materials.

KO-921

The tool is often used to impregnate the glass braid of cables, wires for the purpose of electrical insulation of machines, equipment. The material helps to create a heat-resistant coating (impregnation), which easily withstands high temperatures (up to +250 degrees). The tool protects the equipment from mold, liquids, fungus. KO-921 is a part of many heat-resistant enamels.

Specifications:

• coating - uniform, transparent, without impurities, colorless;
• the proportion of solids - 48 - 52%;
• viscosity according to the VZ-4 viscometer at +20 degrees - 17 - 27 s;
• film drying time to the degree of 3 - 15 minutes;
• thermoelasticity of the coating - 75 hours

Instructions for use indicate that before applying varnish, the surface must be cleaned, remove fats, dirt, thoroughly dry the base. Toluene can be used as a solvent; no more than 20% is added. Application methods - filling, dipping, temperature during work + 5 ... + 30 degrees, humidity - less than 80%.

KO-916

Material KO-916 is made for companies engaged in the repair of electrical equipment. Serves for electrical insulation and protection against moisture, corrosion. The tool is applied to the circuit board, cable, wire as an insulating impregnation. Methods of application - filling, dipping. Dry the product at + 190 ... + 210 degrees 15 minutes.

Specifications:

• film - colorless, uniform, transparent;
• fraction of solids - 65 - 69%;
• viscosity according to VZ-4 - 45 - 65 s;
• thermoelasticity at +200 degrees - 50 hours;
• coating strength according to ME-3 - 0.5 units at +20 degrees.

KO-916A

Varnish KO-916A is a variation of the previous product, but has its own characteristics. This material is used to create windings with fiberglass insulation, for applying to heat-resistant wires and cables. The resulting film has high water resistance, heat resistance, gas resistance, and weather resistance.

Unlike KO-916, this product has a more fluid texture (non-volatiles - 60%), lower viscosity (30 - 60 s). The remaining indicators are within the same range, the method of application is similar.

KO-916K

Varnish KO-916K is used to impregnate the electrical windings of machines, devices, equipment that operate for a long time at +180 degrees or less. The product is characterized by excellent impregnating ability, as it has a small viscosity. It adheres well to metal, dries quickly, cementes curls of wires and layers of winding. KO-916K gives the winding moisture resistance, is not harmful to copper.

Technical specifications:

• the proportion of solids - 64 - 68%;
• viscosity - 45 - 65 s;
• drying period - 15 minutes at +200 degrees;
• thermoelasticity - 50 hours at +200 degrees;
• hardness according to ME-3 - 0.5 units at 20 degrees, 0.2 units. at +180 degrees.

Other brands

On sale you can find other varnishes related to organosilicon, which have their own specifics and characteristics.

KO-915

Varnish KO-915 is an impregnating composition for the manufacture of glass lacquers, it is used to impregnate the insulation of equipment and devices. Technical specifications:

• viscosity according to the VZ-4 viscometer - 30 - 70 s;
• solids content - 65%;
• drying time at a temperature of +200 degrees - 35 minutes;
• thermoelasticity of the coating - 150 hours at +200 degrees.

KO-915A

The material KO-915A is used for the manufacture of fiberglass, glass-hollow, wires with fiberglass insulation. The substance is not dangerous, but threatens fire in contact with sparks. After application, the material gives a light yellow or brown film. The main indicators are similar to those for KO-915, the difference is only in the fraction of solids (67%), drying time (45 minutes).

KO-915B

Material KO-915B is used for the same purposes as the previous varnishes, and is additionally used to create electrical insulating paints. The tool gives high heat resistance, moisture resistance, has good adhesive and impregnating ability. Regarding the mass of solids, viscosity, thermoelasticity and drying time, the material does not differ from KO-915. There is a difference in viscosity - the indicator is 15 - 40 s.

KO-923

Varnish KO-923 allows you to create a durable film with resistance to high temperatures, excellent adhesive and impregnating ability. It is used to wet the windings of apparatuses and electric machines that are operated at temperatures up to +200 degrees and at high humidity. When applied to metal, it provides corrosion protection. The viscosity of the material is 17 - 27 s, the solids content is 52%, the drying time is 30 minutes at +200 degrees.

KO-987

Varnish KO-978 is an adhesive material that is applied when creating flexible composite materials based on mica sheets. It is widely used for applying to the winding apparatus and electrical machines. Specifications:

• solids content - 50%;
• conditional viscosity - 16 - 25 s;
• drying time - 30 minutes at +200 degrees.

Feature of the product in the presence of 0.07% aluminum in the composition. Cementing ability of at least 196 units.

KO-991-4

Insulating varnish KO-991-4 has high adhesive properties and is used for the manufacture of glass lacquers and for gluing mica-containing materials.The material gives a transparent film of yellow or brown. Its characteristics:

• the share of non-volatiles - 42 - 48%;
• viscosity - 15 - 40 s;
• drying time at +200 degrees - 120 minutes;
• thermoelasticity at +200 degrees - 30 hours

Varnishes are selected according to needs. Many of them can be used interchangeably, as they have similar properties. All materials are heat-resistant, after drying give a coating that is safe for humans, and when applied require strict observance of safety measures.