Survey of Chemical Substances in Consumer Products, No. 59 – Survey and assessmens of chemical substances in glass and porcelain colours

Survey and assessmens of chemical substances in glass and porcelain colours

2 Composition of and typical constituent substances in hobby colours

2.1 Pigments
2.2 Binders
2.3 Diluent
2.4 Additives

Colours and paint contain four basic components. There is a large difference between the selected basic components depending on the function of the colour and requirement to appearance and durability. The four basic components are:

Pigments
Binders
Diluent/vehicle
Additives

A short description is given in the following of the four types of content.

2.1 Pigments

Primary pigments add whiteness and colour to the product. TiO₂, titandioxid is typically used as white pigment. Colour pigments add colour by selective absorption of light. Organic colour pigments are used (bright/sparkling colours) and inorganic colour pigments (earth colours). Of organic pigments can be mentioned phthalo blue. Inorganic pigments could for example be metal oxides (iron oxide). The actual pigments are normally powder form and they are mixed with the binder and thinned with a dilutent in order to obtain the actual colour.

2.2 Binders

Binders are used to bind the pigment and act as glue. There are oil based and latex based binders. The oil based binder dries/oxidises when exposed to air. Oil based binders may consist of linseed oil or soya oil. Also alkyd can be used in oil based binders.

Latex based binders are used in water based paints. The binder is a solid, plastic like material. The particles are microscopic and contained in the paint. Latex based binders may consist of acrylic or vinyle acrylic (poly vinyl acetate, PVA) or styrene acrylic. Polyurethanpolymerer may also act as a binder.

2.3 Diluent

For oil based paint and alkyd paint a diluter is used. Typically an organic solvent and for latex based paint, water is used as vehicle.

2.4 Additives

Additives are for example:

Thickeners
Surface active substances
Biocides
Anti-foam material
Solvents (co-solvents)

Thickeners are used to give the paint the right consistency when used. Surface active substances stabilise the paint so it does not divide and give increased dispersion of pigments. Preservatives prevent undesired bacteria in the paint when stored or after being used. Anti-foam materials prevent foam at blending and applied. Co-solvents are used for non-water based paint and are typically an organic solvent that improves the dissolution of one or several of the components.