{{Short description|Chemical compounds used to color plastic}} '''Plastic colorants''' are chemical compounds used to color plastic. Those compounds come in a form of dyes and pigments. The type of a colorant is chosen based on the type of a polymeric resin, that needs to be colored. {{citation needed|date=September 2017}} Dyes are usually used with polycarbonates, polystyrene and acrylic polymers. Pigments are better suited for use with polyolefins.<ref>{{cite web | author=Nishikants | title=Plastic colorant and its role in plastic industry| website=Share and Discover Knowledge on LinkedIn SlideShare | date=2013-06-28 | url=https://www.slideshare.net/Royceintly/plastic-colorant-and-its-role-in-plastic-industry | access-date=2017-07-18}}</ref> <ref name="RevPart 2016">{{cite web | title=Plastic Colorants Guide for Injection Molded Parts | website=RevPart | date=2016-01-26 | url=https://revpart.com/using-plastic-colorants/ | access-date=2017-07-18}}</ref>
The colorant must satisfy various constraints, for example, the compound must be<ref name=" Sepe 2012">{{cite web | vauthors = Sepe M | title=Working with Color Concentrates | website=Plastics Technology | date=2012-01-28 | url=http://www.ptonline.com/columns/working-with-color-concentrates | access-date=2017-07-18}}</ref> chemically compatible with the base resin, be a suitable match with a color standard (see e.g. International Color Consortium), be chemically stable, which in this case means being able to survive the stresses and processing temperature (heat stability) 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, metallic, fluorescent, phosphorescent, thermochromic or photochromic.<ref name="dyespigm">{{cite web | title=Colorants for Plastic Industry, Dyes for Plastics Industry, Pigments for Plastics Industry | website=Dyes and Pigments, Dyes Manufacturers, Dyes Intermediates, Pigments Suppliers, Wholesale Dyes Intermediates | url=http://dyes-pigments.standardcon.com/colorants-plastic-industry.html | access-date=2017-07-18 | archive-url=https://web.archive.org/web/20190304084019/http://dyes-pigments.standardcon.com/colorants-plastic-industry.html | archive-date=2019-03-04 | url-status=dead }}</ref>
The exact chemical formula will furthermore depend on the type of application: general purpose, food contact item, toy, package subject to CONEG,<ref>{{cite web | title = Toxics in Packaging Clearinghouse | url = http://www.coneg.org/tpch | work = Collation of Northeastern Governors (CONEG) }}</ref> etc.<ref name="dyespigm"/>
Different methods for delivering colorants in molding plastics include masterbatches (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, and precolored resins, which involve using precolored materials to make manufacturing cheaper.<ref name="RTP Company">{{cite web | title=Methods of Coloring Plastics | website=RTP Company | date=October 2013 | url=https://www.rtpcompany.com/products/color/modes/ | access-date=2017-07-18}}</ref><ref name="Polyplastics.com">{{cite web | title=Effect of coloring methods on properties of plastics | website=Polyplastics.com | url=https://www.polyplastics.com/en/product/safety/coloring/ | access-date=2017-07-18}}</ref>
==Examples== {| class = "wikitable sortable" |- !Colorant!!Chemical class!!Type |- |Diarylide pigment|| azo dye || pigment |- |Sudan stain|| azo dye ||dye |- |Oil Blue A || anthraquinone||dye |- |Disperse Red 11||anthraquinone||dye |}
==See also== *Liquid color *Fuel dyes
==References== {{reflist}}
{{plastics}}
Category:Plastics additives Category:Dyes Category:Pigments
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