Plastic colorants are chemical compounds used to color

plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...

. Those compounds come in a form of

dye A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution an ...

s and

pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...

s. The type of a colorant is chosen based on the type of a polymeric resin, that needs to be colored. Dyes are usually used with

polycarbonates Polycarbonates (PC) are a group of thermoplastic polymers containing carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, tough materials, and some grades are optically transparent. They are easily work ...

polystyrene Polystyrene (PS) is a synthetic polymer made from monomers of the aromatic hydrocarbon styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin per unit weight. It is a ...

and acrylic polymers. Pigments are better suited for use with

polyolefin A polyolefin is a type of polymer with the general formula (CH2CHR)n where R is an alkyl group. They are usually derived from a small set of simple olefins (alkenes). Dominant in a commercial sense are polyethylene and polypropylene. More speciali ...

s. The colorant must satisfy various constraints, for example, the compound must be chemically compatible with the base resin, be a suitable match with a color standard (see e.g.

International Color Consortium The International Color Consortium (ICC) was formed in 1993 by eight vendors in order to create an open, vendor-neutral color management system which would function transparently across all operating systems and software packages. Overview The ...

), be chemically stable, which in this case means being able to survive the stresses and processing temperature (

heat stability In materials science and molecular biology, thermostability is the ability of a substance to resist irreversible change in its chemical or physical structure, often by resisting decomposition or polymerization, at a high relative temperature. ...

) in the fabrication process and be durable enough to match the life duration of the product. The parameters of the compound vary with a desired effect, which may include the final product being

pearlescent Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear to gradually change color as the angle of view or the angle of illumination changes. Examples of iridescence include soap bubbles, feathers, butterf ...

, metallic,

fluorescent Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, tha ...

phosphorescent Phosphorescence is a type of photoluminescence related to fluorescence. When exposed to light (radiation) of a shorter wavelength, a phosphorescent substance will glow, absorbing the light and reemitting it at a longer wavelength. Unlike fluor ...

thermochromic Thermochromism is the property of substances to change color due to a change in temperature. A mood ring is an excellent example of this phenomenon, but thermochromism also has more practical uses, such as baby bottles which change to a differen ...

photochromic Photochromism is the reversible transformation of a chemical species (photoswitch) between two forms by the absorption of electromagnetic radiation (photoisomerization), where the two forms have different absorption spectra. In plain language, th ...

. The exact chemical formula will furthermore depend on the type of application: general purpose, food contact item,

toy A toy or plaything is an object that is used primarily to provide entertainment. Simple examples include toy blocks, board games, and dolls. Toys are often designed for use by children, although many are designed specifically for adults and pet ...

, package subject to

CONEG The Coalition of Northeastern Governors (CONEG) is a non-partisan organization of seven governors of the Northeastern United States. The organization was founded in 1976 and is headquartered in Washington, D.C. The organization deals with regional ...

, etc. Different methods for delivering colorants in molding plastics include

masterbatch Masterbatch (MB) is a solid additive used for coloring (color masterbatch) or imparting other properties (additive masterbatch) to plastics. Masterbatch is a concentrated mixture of pigments and/or additives which is manufactured by encapsulation du ...

es (concentrates), a method which involves a concentrate being separated into resin, cube blends ("salt & pepper mixes" - dry blending) which are natural polymers, already sprayed into natural polymers, surface

coating A coating is a covering that is applied to the surface of an object, usually referred to as the Substrate (materials science), substrate. The purpose of applying the coating may be decorative, functional, or both. Coatings may be applied as liquid ...

, and precolored resins, which involve using precolored materials to make manufacturing cheaper.

Examples

References

{{Chem-stub Plastics additives Dyes Pigments

Examples

See also

References