Additives


A standard waterborne adhesive consists of two components which do not like each other too much. One component (and this is no big surprise) is water and the other component is "the adhesive" a more or less hydrophobic polymer.


In a world without additives a mixture of these two components would separate immediately. Therefore, the polymer particles are stabilized by surfactants to form a dispersion. The beneficial water is as solvent e.g. from an environmental standpoint there also some major drawbacks which need to be compensated by additives. To make sure that the polymer particles do not settle down, the viscosity meets the requirements or the sprayability of the dispersion is guaranteed rheology modifiers are applied. Proper coating of an unpolar substrate can be achieved by using wetting agents and foam caused by the surfactants can be destroyed by a defoamer. For these and all other requirements on the adjustment of waterbased adhesives Evonik offers a complete range of additives

Adhesion promoters

A substance which is applied to a substrate to improve the adhesion of an adhesive or sealant to the substrate.

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Defoamer

Due to their chemical composition a number of aqueous adhesive dispersions tend to foam, i.e. either creation of macrofoam or microfoam.

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Mechanical properties

Reinforcing agents are for example active fillers like fumed silica and precipitated silica which improve the mechanical properties like tensile strength and tear resistance of adhesive & sealants.

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Silanes

Organo-functional silanes are molecules carrying two different reactive groups on their silicon atom so that they can react and couple with different materials (e.g. inorganic surfaces and organic resins via covalent bonds).

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Rheology modifiers

The science that studies the relation between flow of materials and applied forces is called rheology. As the example of dough shows, this relation is far from simple.

Wetting agents

Wetting agents are used to achieve very different effects, ranging from the wetting of critical substrates, e.g. label applications, to the wetting of fillers in construction adhesives or to enlarge open times of formulated adhesives.

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