Лако-красочные материалы — производство

The introduction of environmental legislation across Europe since the early 1980’s has resulted in increased research into VOC compliant coatings. This can be achieved through a combination of high solids acrylic polyols, low viscosity/100% solids isocyanate prepolymers and reactive diluents. Reactive diluents based on low molecular weight polyester or polyether polyols, castor oil derivatives, oxazolidines […]

UV absorbers are used in clear unpigmented top coats to enhance the durability of the coating and provide protection to the base coat in clear over base systems. The UV absorber system is made up of a UV absorber, normally of the benzotriazole or oxalanalide type and a hindered amine light stabiliser (HALS). The most […]

There are two main types of catalyst for the hydroxyl acrylic/isocyanate reaction, namely metallic salts and tertiary amines. Dibutyl tin dilaurate (DBTDL) is the most commonly used metallic salt, although salts of bismuth, cobalt, zinc, lead and manganese can also be used. The level of catalyst used can vary from 0.001% — 0.5% in the […]

The main rule to follow in 2 component isocyanate systems is to avoid solvents which contain active hydrogen. For instance, alcohols can react with the isocyanate reducing the crosslink density. In severe cases, this can lead to a decrease in resistance and adhesion characteristics resulting in unacceptable coatings. The water content of solvents has to […]

In general, polyurethane coatings offer few pigmentation problems. Care should be taken to control the residual moisture content of pigments since the reaction between water and the isocyanate can affect the pot life and lead to the formation of carbon dioxide resulting in film defects.

A large number of resins can be used to modify the properties of the two pack acrylic system. The most common are high viscosity hard resins with good colour and colour retention, which are added to achieve quicker initial drying and earlier handleability of the coated object. Those frequently used are: • cellulose acetate butyrate […]

1. Co-reactants A large number of multifunctional isocyanate curing agents are commercially available for crosslinking of the hydroxyl functional resin. These isocyanate adducts are mostly derived from a limited number of aliphatic and aromatic monomeric isocyanates, whose structures can be seen in Figure 5-2. TDI — toluene diisocyanate MDI — diphenyl methane diisocyanate HMDI — […]

I INTRODUCTION Polyurethanes can trace their commercial origin to the development work undertaken by Otto Bayer et al in the 1930’s(1). Since then, this family of products has adapted extremely well for use in a wide variety of applications, such as fibres, foams, plastics, adhesives, textiles and coatings to name but a few. In the […]

DWI can manufacture in Europe has been dominated by the use of white basecoat and non-varnish ink. The short cycle pin ovens often installed operate at air temperatures well in excess of 300°C, in order to achieve peak metal temperatures of 170-180°C in the 4-6 seconds total dwell time for the can in the oven. […]

Internal lacquers for deep drawn or draw and redrawn (DRD) food cans are not based on acrylics resins, although the external basecoat may be for shallow drawn cans. Inks are distortion printed. The drawing process places high demands on the coating system. From a flat sheet, a can of up to five cm. in height […]