{"id":11548,"date":"2020-12-29T20:28:40","date_gmt":"2020-12-29T20:28:40","guid":{"rendered":"https:\/\/amb.se\/ytbehandlingsskolan-1\/"},"modified":"2022-12-16T19:28:39","modified_gmt":"2022-12-16T19:28:39","slug":"surface-treatment-of-plastics-1","status":"publish","type":"page","link":"https:\/\/amb.se\/en\/surface-treatment-of-plastics-1\/","title":{"rendered":"Surface treatment of plastics #1 \u2013 Why lacquering?"},"content":{"rendered":"
[vc_row full_width=”stretch_row” equal_height=”yes” content_placement=”middle” top_margin=”0″ bottom_margin=”0″ css=”.vc_custom_1509551730213{margin-bottom: -1px !important;padding-top: 30px !important;padding-bottom: 30px !important;background-color: #ffffff !important;}”][vc_column][vc_custom_heading text=”1. What is lacquer and why is it needed?” font_container=”tag:h1|font_size:36|text_align:left|color:%23990000|line_height:1″ use_theme_fonts=”yes” css_animation=”top-to-bottom” css=”.vc_custom_1609274705710{padding-top: 50px !important;padding-bottom: 20px !important;}”][vc_column_text 0=””]\n

Lacquered objects are everywhere around us and give products protection, beauty or other functions. With a well-thought-out strategy regarding function and market-specific parameters, the investment in lacquering can quickly pay off.<\/h3>\n[\/vc_column_text][vc_separator el_width=”80″][vc_column_text 0=””]We usually do not think about the colors of different surfaces \u2013 probably because they are so common and that we therefore take them for granted. Our cars are painted, walls are painted and also many everyday decorative or utility items. The lacquer that is perhaps most used everyday is probably nail polish.<\/p>\n

Lacquering as a technology is very old and was already used 7,500 years ago in China. The oldest preserved lacquer recipe dates from the 12th century and consisted of linseed oil as a binder and the red-orange mineral cinnabar as a pigment.<\/p>\n

The word lacquer<\/em> probably comes from Sanskrit l\u0101k\u1e63\u0101 which means “red lacquer”. Originally, the etymology of the word lacquer was related to various resinous breeding products formed by aphids that suck sap from milk-producing trees. Purified resin became shellac, which is still used as a surface treatment agent for certain foods and medicines and has historically been used in many different ways: from the main component in gramophone records to stiffeners for cylinder caps \u2013 which only further shows the varnishes’ incredibly extensive uses.<\/p>\n

Modern chemistry has created a huge range of paints for a wide variety of applications, such as fluorescent, electrically conductive, structure-giving or anti-corrosion paints. The wide use of paints is also reflected in their great economic importance. In 2007, their global value was estimated at over SEK 800 billion and the production volume at a staggering 28 billion liters, which corresponds to the volume of 6,8 Wembley Stadiums.[\/vc_column_text][vc_separator el_width=”80″][vc_column_text 0=””]\n

What exactly is a lacquer?<\/h3>\n

Lacquers are liquid surface treatment substances that are applied in thin layers to objects and which, through chemical or physical processes, form a fast film.<\/p>\n

A lacquer consists of volatile solvents and non-volatile components. The non-volatile components are binders, pigments, resins, fillers and various additives such as biocides.<\/p>\n

Solvent<\/h4>\n

The solvent (volatile component) evaporates during the drying process, while the non-volatile components adhere to the painted article as a smooth film. In the context of paints, a solvent is a substance that can be diluted without entering into chemical reactions with the solutes. The solvents are mainly used to adjust the properties of the paint during the painting process and during film formation.<\/p>\n

Some solvents can attack the plastic and that is one of the reasons why it is important to know which plastic is to be used for the product. Organic solvents or water are used as solvents, but water-based lacquers also often contain about 10% organic solvents.<\/p>\n

Binder<\/h4>\n

Binder ensures a good, uniform suspension with pigments and solvents in the lacquer. The binders are responsible for an optimal drying process (no blistering) and for the gloss after drying. A lacquer consists mainly of binders and solvents.<\/p>\n

Pigments and dyes<\/h4>\n

A pigment is a dye material that is completely or almost insoluble in water. Dyes, on the other hand, are soluble \u2013 at least at some stage of their use. In general, dyes are often organic compounds while pigments are often inorganic compounds. Pigments of historical value are, for example, ocher, charcoal and lapis lazuli. The word comes from the Latin pigmentum which means color.<\/p>\n

Both pigments and dyes can be more or less colorfast.<\/p>\n

Like all materials, a pigment color occurs because it only absorbs certain wavelengths of visible light. Light with other wavelengths is reflected or scattered. The reflected light spectrum defines the color.<\/p>\n

Color Index International<\/a> is a reference database containing over 34,500 dyes and pigments listed under 11,570 generic names.<\/p>\n

Fillers and additives<\/h4>\n

Various fillers reduce the cost when in some cases they can replace pigments. In addition, they help to regulate the degree of gloss, the surface structure and improve the mechanical properties.<\/p>\n

Additives are substances that improve the properties of the lacquer film. They can extend the durability through biocides, promote application and curing properties and make the lacquer film more elastic.[\/vc_column_text][vc_separator el_width=”80″][vc_column_text 0=””]\n

What does a lacquer add?<\/h3>\n

A lacquer should mainly:<\/p>\n