Лако-красочные материалы — производство

These products are manufactured by copolymerising together in emulsion from two or more monomers, one of which is carboxyl containing. There are a number of options available both in terms of the carboxyl entity and in terms of the comonomers. Components are selected according to ease of copolymerisation and end performance as thickeners. TABLE 2-2: […]

The application and storage properties of water based coatings depends largely upon the selection of the thickener and rheology modifier package. To do this, a wide variety of thickening and rheology modifiers is used. It is generally interpreted that thickening agents are used to prevent pigment settling and provide ‘in can’ stability, and rheology modifiers […]

To maximise the electrostatic repulsion between pigment particles, it is necessary to incorporate a high concentration of ionic groupings. These are usually anionic in character which are introduced using either carboxylic or sulphonic acid groupings. Carboxylic acids such as: • maleic anhydride • itaconic acid • acrylic acid • methacrylic acid and sulphonic acids: • […]

An extensive range of speciality acrylic polymers is commercially available for very wide usage as important formulating additives which consist of pigment dispersing agents and viscosity/rheology modifiers.

Hybrid systems represent a group of resins which combine more than one generic class of polymer. The technique is akin to the surfactant free approach through which the phases are of different generic classes. The most widely used commercial techniques are the dispersed phase which is either acrylic or styrene acrylic and the continuous phase […]

Classically, emulsion polymers are prepared using surfactants of appropriate HLB values to achieve the emulsion state. As was stated earlier, a surfactant may be any molecule which contains a hydrophobic portion and a hydrophillic portion. A wide range of ‘microemulsions’ is commercially available. They are manufactured using, for example, a surface active alkali soluble acrylic, […]

(i) Core Shell This technique provides for the sequential addition of monomer so that particle morphology is manipulated, to meet optimum end-use requirements. In essence, the technique involves changing the composition of the monomer phase in a sequential manner as the polymerisation progresses. This leads to a variation in polymer composition from the particle core […]

In recent years the elimination of all volatile organic compounds (VOC) from coating formulations has been ideally sought but has proved extremely difficult in certain areas of high performance requirements. In that quest, several variations to the standard method of emulsion manufacture have been introduced, in order to improve aspects of film formation, e. g. […]

Buffers are often added to stabilise the pH of the reaction mass. The reasons for the need for buffers are as below: a) some surfactants are pH sensitive with regard to micelle formation and latex stability b) some initiators are pH sensitive c) copolymerisation may occur better at a specific pH, e. g. acrylic acid […]

Chain transfer agents and other polymerisation modifiers may be added to the monomer premix. The principles and chemical types are the same as for acrylic polymerisation in general. The main object of the chain transfer agent is to control the molecular weight by reducing the growing chain length. However, unlike the solution polymerised products the […]