Nitrocellulose varnishes (nitro-varnishes) - description, characteristics and properties

Furniture and other wooden products must be protected from aging and environmental factors. In this case, they will last an order of magnitude longer. For wood, a whole series of products is intended under the general name NTs varnish, or nitro-varnish.

Content:

• Material Features
• The composition of the varnish
• Material properties
• Varnish production
• Technical characteristics of varnishes
• NTs-62
• NTs-218
• NTs-243
• Other brands
• NTs-134
• NTs-223
• NTs-224
• NTs-225
• NTs-241
• NTs-551
• Nitro coat application

Material Features

Nitrocellulose lacquer (SC) is made on the basis of nitrocellulose, a chemical compound, cellulose nitrate ester. The resulting organic product has valuable properties - it helps protect wood from damage, creates a beautiful coating on it, which improves the aesthetic appearance of the products. The resulting lacquer film is transparent, without color, or color, quite durable.

An important feature of varnishes is the lack of special need for priming the surface, although sometimes the primer is still applied. You can use the product even in hot and cold conditions, but to obtain a high-quality coating, it is recommended to add a solvent - up to 5%. This will help to prevent the material from drying out.

The composition of the varnish

The basis, as already noted, is a polymer - high-quality wood or cotton cellulose. This substance is diluted with a special organic mixture to obtain varnish colloxylins. The composition also introduces additives:

• alkyd resins, shellac;
• amino formaldehyde resins;
• cyclohexanone formaldehyde resins;
• vinsol;
• rosin.

The amount of such additives can be in different proportions with colloxylin (up to 1: 1). To give the solution the desired consistency, the composition contains a mixture of solvents - propyl acetate, ethyl acetate, esters of acetic acid, xylene, toluene, various alcohols. Nitroparaffins may be present in the material; plasticizers (casterol, chloroparaffin, phosphates and others) must be present. As you can see, the composition of the varnish SC is very complex and multicomponent.

Material properties

Important advantages of the product are its ease of application, low cost and high quality. The created film, depending on the specific brand, can be:

• matte;
• glossy;
• semi-gloss, semi-gloss.

The coating will be homogeneous, even, hard, it has excellent adhesion to the base, it is well sanded. Operate products with such a coating should be at a temperature of + 12 ... + 60 degrees, at a higher temperature, the varnish will quickly collapse. The material is ideal for parquet and furniture (it is often called parquet or furniture varnish), wooden floors, doors, souvenirs and other wood products.

You can use these products indoors, most types of varnish are not intended for outdoor use. Also, the disadvantages of the tool include its small physico-chemical resistance, increased flammability, high sensitivity to the action of water and sunlight.

Varnish production

The manufacturing process of this paint material is quite complicated. It is based on the following steps:

• dissolution of resins and colloxylin in organic solvents;
• compound with plasticizers and other additives;
• measuring indicators of the material obtained;
• cleaning, filtering;
• spill in containers.

To get black varnish and its other shades, at a certain stage of production the necessary pigments are added. In their absence, colorless varnish is obtained. Each component is administered in a regulated amount, and the norm of the rest changes with a reference to the volume of colloxylin.

Attention! The preparation of colloxylin is carried out under special conditions because of its explosiveness and combustibility. This substance is stored only in sealed containers under special conditions.

In the production of the material, you can change its density - if it is too liquid, add colloxylin, thick - inject solvents. Uniformity is achieved by introducing high-quality and refined components, as well as subsequent cleaning in centrifuges.

Technical characteristics of varnishes

Depending on the particular brand, the technical characteristics of the products may vary. Varnishing is carried out after studying the recommendations and evaluating the parameters of a particular product.

Among the most widely used brands there are three main ones, we will consider them in more detail.

NTs-62

The material NTs-62 is used for decorative decoration of products, as the product gives them an attractive appearance. It can serve as a paint, as it is available in red, purple, green and other colors. In addition to wood, this product can be used to cover mosaic display cases, illumination lamps, glass, metal, and paper products.

Specifications:

• the viscosity of the device viscometer VZ-246 - 26-40 s;
• solids content - 7-12%;
• coating quality - colorless, color, transparent, glossy;
• consumption - 70–100 g / sq. m

Solvent No. 646 is used for dilution. Varnish is applied in 1–2 layers, moreover, it is necessary to achieve complete drying of each layer “on stick”.

NTs-218

This varnish is mainly used to cover furniture, wooden window sills. It dries very quickly - no more than an hour at room temperature. It is important that the surface is even and dry before application. Subject to all recommendations, the coating will last about 10 years.

A distinctive feature of the product is the special antiseptic components added to it, which will not allow rotting of wood and the appearance of insects in it. If you cover the inside of the cabinets with it, this will protect things from clues. Varnish allows you to mat the surface of the product, giving it a noble appearance.

Characteristics NTs-218:

• the viscosity on the instrument viscometer VZ-246 - 50–85 s;
• fraction of solids - 30–34%;
• bending film elasticity - 15 mm;
• TML - 0.2 at. e .;
• color is colorless.

NTs-243

Means NTs-243 can be used for processing any wooden items. It creates a film of a yellowish or pinkish tint, dries quickly, dulls, hides various defects. Coating drying time - hour.

Main parameters:

• light fastness - 1 hour;
• the coating strength of the M-3 device is 0.4 g. e .;
• fraction of solids - 26–32%;
• TML - 0.2 at. e .;
• the coating is even, without foreign matter, pockmarks, wrinkles, craters.

Other brands

In the series of nitrocellulose paints and varnishes, other brands are also used that are used in production and in everyday life.

NTs-134

Quick-drying varnish NTs-134 is used for painting wood and metal products, it can even be used for outdoor applications. To working viscosity it is diluted with solvents No. 645, 646.

Specifications:

• conditional viscosity for the device viscometer VZ-246 - 28-60 s;
• the appearance of the film is smooth, glossy;
• drying time - 30-60 minutes;
• the share of non-volatiles - 13-17%;
• acid number is 0.5 KOH / g.

NTs-223

Material NTs-223 is used only for internal work, it is used for coating wood and wood products.

Tool Options:

• coating - glossy, even;
• conditional viscosity on the device viscometer VZ-246 - up to 125 s;
• the share of non-volatiles - 33–36%;
• resistance to water - from 6 hours;
• the hardness of the film on the M-3 device is 0.55 g. e .;
• bending elasticity - 5 mm.

NTs-224

Varnish NTs-224 is distinguished by the presence of special esters and resins in its composition. This allows the film to crack less, it is better to sand. Dilution before application is not required. Application temperature + 18 ... + 20 degrees. The remaining indicators are similar to those of the previous funds.

NTs-225

Varnish NTs 225 is easy to polish, it is most often used to cover interior doors. The material perfectly tolerates hot drying at 70–75 degrees, due to this there are more film-forming substances in it, only 1-2 layers can be applied.

Technical specifications:

• fraction of solids - 35–40%;
• viscosity on the viscometer VZ-4 - 115 s;
• the thickness of one layer is 50 microns.

NTs-241

The NTs-241 tool includes special urea resins, which give it greater water resistance and frost resistance, which helps withstand temperature extremes. Two types of varnishes are available - transparent and matting. The difference from previous varnishes is in longer drying, the material dries for 1.5 hours.

NTs-551

Varnish NTs-551 is used for coating special-purpose fabrics in order to give them a number of properties. It looks like a liquid without impurities, foreign particles. The mass fraction of solids is 9%, the viscosity on the instrument viscometer VZ-1 - 130-160 s. After application to the fabric, its weight gain will be 75 g / sq. m. (4 layers of the product), shrinkage - 0.6%.

Nitro coat application

Before using materials, surface preparation is carried out - cleaning from dirt, dust, old coatings, and grinding it. Can be applied under varnish water-based stain. The first layer of nitrocellulose should be dried for 1-2 hours, use a construction hairdryer to speed it up.

To obtain a high-quality film, it is necessary to leave 6-8 hours for drying the second layer, after which grinding is carried out. Typically, NC varnishes are used on economy-class furniture, since more expensive materials last longer, but due to their economy they do not lose popularity.