Lacquers are actually compounds formed by a combination of nitrocellulose, resin, plasticizer, solvent and solvent. Nitrocellulose are the main ingredient in lacquers. They are used for industrial and domestic purposes.
It is a type of varnish. The only difference is that varnish is used for wood products while lacquer is used for metal products. Resins and rosins are predominant in varnishes while nitrocellulose is predominant in lacquers.
Nitrogen solvents make lacquers hard and strong. Resin produce stickiness and plasticizer bring softness and elongation properties. Solvent helps to dry the lacquers.
As mentioned earlier, nitrocellulose is considered as the main ingredient of liqueurs.
. Esters should also be standard for high class lacquers. Nitrocellulose is obtained from waste films used in filmmaking.
Types of nitrocellulose
In the Lacquer industry various types of grades used like R-S Grade S-S Grade,
A-S grade of nitrocellulose are used.
Most of the lacquers used for general purposes are of the same grade, Nitrocellulose .It has a nitrogen weight ratio of 11.9 to 12.3%. It is usually supplied in 5 second and 40 second standards in viscosities of ½, 1/4, 1/10 inch.
For coating the outer parts of metals, Nitrocellulose with a viscosity of ½inch is used. 40 seconds high-viscosity nitrocellulose are added to lacquers used for coating fabrics in the aircraft and textile industries.
Spirit soluble nitrocelluloses are SS grade.
Lacquers made from it are used for coating cellophane paper and other high quality products.
This grade contains 10.9 to 11.1 percent nitrogen by weight. Its viscosity is 1/4 inch and 5 seconds.
These also dissolve in alcohol solutions. They have a nitrogen weight ratio of at least 11.3
And the maximum is 11.6 percent. The same resins are used in this which are easily dissolved in alcohol solution.
Solvents that dissolve nitrocellulose include ketones, acetone, glycols
And besides ethers, spirits and alcohols are included. Spirits and Alcohol A-S and S-S Graded nitrates are used for nitrocellulose
These include xylol, toluene.
Solvent and diluents
Lacquers made from nitrocellulose contain 30 to 40 percent of high-impact solvents and low-impact solvents include alcohol and spirits. Similarly, the ratio of diluents is kept at 45 to 55 percent.
Nitrocellulose Lacquer Manufacturing
Transparent types of lacquers are prepared in the same way as varnishes, but with less need
As compared to varnish, the consistency of lacquers is more thick and swollen. This hybrid form
The easiest way to control is to start with a small amount of nitrocellulose.
A small amount of solvent should be mixed well. Then the rest of the nitrocellulose and the solvent should not be mixed. In this way, the synthesis of liqueurs becomes easier.
The resin and diluent are mixed together and the nitrocelloluse dissolves
The solvent should also be blown and the two compounds should be combined
The remaining part is grinded along. In this way, resin solution, nitrocellulose solution and pigments paste are prepared separately and then they are mixed together in the mixer.
(1) First the resin is thoroughly mixed with solvent and when these two become one, they are kept separate.
(2) In the second step, the solvent is added to the nitrocellulose solution and mixed well. After becoming one soul, it is also kept separately.
(3) Pigments are made into a paste with thinner and it is also kept separately.
(4) In the fourth step, these three solutions are put into the mixer and mixed together.
This process should not be done too quickly.
Use of Lacquers
Lacquers are mostly used for interior decoration. This type of decoration also includes wooden furniture and other household items.
Lacquers are also widely used for automobiles coating .
Lacquers are also use for coating leather, paper, cotton fabrics and coils of transformers.
Lacquers are used as coatings for aluminum, copper and bronze products.
Apart from that lacquers are use in the coating on concrete ,blocks, ceramic tiles and bricks for decoration and protection.
Apart from this, cellophane is also used as a coating on the body of airplanes.