Editing Paint (section)

==Components==

===Vehicle===
The vehicle is composed of binder; if it is necessary to thin it with a diluent like solvent or water, it is a combination of binder and diluent.<ref name="Wicks_5">{{cite book|last1=Wicks| first1=Zeno W. Jr. |last2=Jones|first2=Frank N.|last3=Pappas|first3=S. Peter|last4=Wicks|first4=Doublas A.|title=Organic Coatings: Science and Technology|date=2004|publisher=John Wiley & Sons, Inc.|location=Hoboken, New Jersey, USA|isbn=978-0-471-69806-7|page=5|edition=3rd}}</ref><ref>{{cite book|last1=Lambourne|first1=R|last2=Strivens|first2=T A|title=Paint and Surface Coatings: Theory and Practice|date=1999|publisher=Woodhead Publishing Limited|location=Abington, Cambridge, England|isbn=1-85573-348-X|page=6|edition=2nd}}</ref> In this case, once the paint has dried or cured very nearly all of the diluent has evaporated and only the binder is left on the coated surface. Thus, an important quantity in coatings formulation is the "vehicle solids", sometimes called the "resin solids" of the formula. This is the proportion of the wet coating weight that is binder, i.e., the polymer backbone of the film that will remain after drying or curing is complete. The volume of paint after it has dried, therefore only leaving the solids, is expressed as the [[volume solid]].

====Binder or film former====
The binder is the film-forming component of paint.<ref>{{Cite web|title = Vermeer's Palette: The Anatomy of Pigment and Binder|url = http://www.essentialvermeer.com/palette/palette_anatomy_of_paint.html#.VieiDCvQO6I|website = www.essentialvermeer.com|access-date = 2015-10-21}}</ref> It is the only component that is always present among all the various types of formulations. Many binders must be thick enough to be applied and thinned. The type of thinner, if present, varies with the binder.

The binder imparts properties such as gloss, durability, flexibility, and toughness.<ref>{{Cite book|url=https://books.google.com/books?id=McUi1PN4jgEC|title=CourseSmart International E-Book for Environmental Chemistry|last1=Baird|first1=Colin|last2=Cann|first2=Michael|date=2005 |publisher=W. H. Freeman|isbn=9780716748779|language=en}}</ref>

Binders include synthetic or natural resins such as [[alkyd]]s, [[acrylic resin|acrylic]]s, vinyl-acrylics, vinyl acetate/ethylene (VAE), [[polyurethane]]s, [[polyester]]s, [[melamine resin]]s, [[epoxy]], silanes or siloxanes or [[Drying oil|oil]]s.

Binders can be categorized according to the mechanisms for film formation. Thermoplastic mechanisms include drying and coalescence. Drying refers to simply evaporating the solvent or thinner to leave a coherent film behind. Coalescence refers to a mechanism that involves drying followed by actual interpenetration and fusion of formerly discrete particles. Thermoplastic film-forming mechanisms are sometimes described as "thermoplastic cure," but that is a misnomer because no chemical curing reactions are required to knit the film. On the other hand, thermosetting mechanisms are true curing mechanisms involving chemical reaction(s) among the polymers that make up the binder.<ref>{{cite web|last1=Baghdachi|first1=J.|title=Polymer Systems and Film Formation Mechanisms in High Solids, Powder and UV Cure Systems.|url=http://www.swst.org/meetings/AM04/Baghdachi.pdf|website=Society of Wood Science and Technology|access-date=2016-01-13}}</ref>

====Thermoplastic Mechanisms====
Some films are formed by simply cooling the binder. For example, [[Encaustic painting|encaustic]] or [[wax]] paints are liquid when warm, and harden upon cooling. In many cases, they re-soften or liquify if reheated.

Paints that dry by solvent evaporation and contain the solid binder dissolved in a solvent are known as [[lacquer]]s. A solid film forms when the solvent evaporates. Because no chemical crosslinking is involved, the film can re-dissolve in solvent; lacquers are unsuitable for applications where chemical resistance is important. Classic [[nitrocellulose]] lacquers fall into this category, as do non-grain raising stains composed of [[dyes]] dissolved in solvent. Performance varies by formulation, but lacquers generally tend to have better [[UV coating|UV resistance]] and lower corrosion resistance than comparable systems that cure by polymerization or coalescence.

The paint type known as [[Emulsion]] in the UK and [[Latex]] in the United States is a water-borne dispersion of sub-micrometer polymer particles. These terms in their respective countries cover all paints that use synthetic polymers such as acrylic, vinyl acrylic ([[Polyvinyl acetate|PVA]]), styrene acrylic, etc. as binders.<ref>{{cite web |url=http://dundean.com/tips_what_is_latex_paint.shtml |title=Water-based Alchemy |access-date=August 11, 2012 |archive-url=https://web.archive.org/web/20120829153753/http://dundean.com/tips_what_is_latex_paint.shtml |archive-date=August 29, 2012 |url-status=dead }}</ref> The term "latex" in the context of paint in the United States simply means an aqueous dispersion; [[latex]] rubber from the rubber tree is not an ingredient. These dispersions are prepared by [[emulsion polymerization]]. Such paints cure by a process called coalescence where first the water and then the trace, or coalescing, solvent, evaporate and draw together and soften the  binder particles and fuse them together into irreversibly bound networked structures, so that the paint cannot redissolve in the solvent/water that originally carried it. The residual [[surfactants in paint]], as well as [[Hydrolysis|hydrolytic]] effects with some polymers cause the paint to remain susceptible to softening and, over time, degradation by water. The general term of latex paint is usually used in the United States, while the term emulsion paint is used for the same products in the UK, and the term latex paint is not used at all.

=====Thermosetting Mechanisms=====
Paints that cure by polymerization are generally one- or two-package coatings that polymerize by way of a chemical reaction and cure into a cross-linked film. Depending on composition, they may need to dry first by evaporation of solvent. Classic two-package [[epoxy|epoxies]] or [[polyurethane]]s <ref>Gite, V. V., et al. "Polyurethane coatings using trimer of isophorone diisocyanate." (2004).</ref> would fall into this category.<ref name="Ber114">Berendsen, A. M., & Berendsen, A. M. (1989). ''Marine painting manual''. London: Graham & Trotman. {{ISBN|1-85333-286-0}} p. 114.</ref>

The "drying oils", counter-intuitively, cure by a crosslinking reaction even if they are not put through an oven cycle and seem to dry in air. The film formation mechanism of the simplest examples involves the first evaporation of solvents followed by a reaction with oxygen from the environment over a period of days, weeks, and even months to create a crosslinked network.<ref name="Wicks_5"/> Classic [[alkyd]] enamels would fall into this category. Oxidative cure coatings are catalyzed by metal complex driers such as [[cobalt naphthenate]] though cobalt octoate is more common.

Recent environmental requirements restrict the use of [[volatile organic compound]]s (VOCs), and alternative means of curing have been developed, generally for industrial purposes. [[UV curing]] paints, for example, enable formulation with very low amounts of solvent, or even none at all. This can be achieved because of the monomers and oligomers used in the coating have relatively very low molecular weight, and are therefore low enough in viscosity to enable good fluid flow without the need for additional thinner. If solvent is present in significant amounts, generally it is mostly evaporated first and then crosslinking is initiated by ultraviolet light. Similarly, [[powder coating]]s contain no solvent. Flow and cure are produced by the heating of the substrate after electrostatic application of the dry powder.<ref>{{cite web |url=https://coatings.specialchem.com/selection-guide/powder-coatings-formulation-tips |title=Powder Coating 101 |access-date=April 26, 2024 }}</ref>

=====Combination mechanisms=====
So-called "catalyzed" lacquers" or "crosslinking latex" coatings are designed to form films by a combination of methods: classic drying plus a curing reaction that benefits from the catalyst. There are paints called plastisols/organosols, which are made by blending PVC granules with a plasticiser. These are stoved and the mix coalesces.

====[[Paint thinner|Diluent or solvent or thinner]]====
The main purposes of the diluent are to dissolve the polymer and adjust the [[viscosity]] of the paint. It is volatile and does not become part of the paint film. It also controls flow and application properties, and in some cases can affect the stability of the paint while in liquid state. Its main function is as the carrier for the non-volatile components. To spread heavier oils (for example, linseed) as in oil-based interior house paint, a thinner oil is required. These volatile substances impart their properties temporarily—once the solvent has evaporated, the remaining paint is fixed to the surface.

This component is optional: some paints have no [[diluent]].

Water is the main diluent for water-borne paints, even the co-solvent types.

Solvent-borne, also called oil-based, paints can have various combinations of organic solvents as the diluent — often referred to as [[paint thinner]] — including [[Aliphatic compound|aliphatics]], [[Aromaticity|aromatics]], [[Alcohol (chemistry)|alcohol]]s, [[ketone]]s and [[white spirit]]. Specific examples are organic solvents such as [[turpentine substitute|petroleum distillate]], [[ester]]s, [[glycol]] ethers, and the like. Sometimes volatile low-molecular weight [[synthetic resin]]s also serve as diluents.

===Pigment, dye and filler===
{{main|Pigment}}
Pigments are solid particles or flakes incorporated in the paint, usually to contribute color to the paint film. Pigments impart color by selective absorption of certain wavelengths of light and/or by scattering or reflecting light. The particle size of the pigment is critical to the light-scattering mechanism. The size of such particles can be measured with a [[Hegman gauge]]. Dyes, on the other hand, are dissolve in the paint and impart color only by the selective absorption mechanism.<ref>{{Cite web|url=https://colour-index.com/definitions-of-a-dye-and-a-pigment|title=Definitions of a Dye and a Pigment |date=April 26, 2024 }}</ref> Paints can be formulated with only pigments, only dyes, both, or neither.

Pigments can also be used to give the paint special physical or optical properties, as opposed to imparting color, in which case they are called functional pigments.<ref>{{Cite web|url=https://www.ulprospector.com/knowledge/4751/pc-four-important-functional-pigments/#:~:text=Functional%20Pigments%20(FP)%20is%20a,types%2C%20but%20there%20are%20others.|title=Four Important Functional Pigments|date=April 26, 2024 }}</ref> Fillers or extenders are an important class of the functional pigments. These are typically used to build film thickness and/or reduce the cost of the paint, or they can impart toughness and texture to the film.<ref>{{Cite book|url=https://books.google.com/books?id=KfggDAAAQBAJ&q=Pigments+are+granular+solids+incorporated+in+the+paint+to+contribute+color&pg=PA59|title=Dyes and Pigments|last1=Gürses|first1=Ahmet|last2=Açıkyıldız|first2=Metin|last3=Güneş|first3=Kübra|last4=Gürses|first4=M. Sadi|date=2016-05-04|publisher=Springer|isbn=9783319338927|language=en}}</ref> Fillers are usually cheap and inert materials, such as [[diatomaceous earth]], [[talc]], [[lime (mineral)|lime]], [[barytes]], clay, etc. Floor paints that must resist abrasion may contain fine quartz sand as a filler. 

Sometimes, a single pigment can serve both decorative and functional purposes. For example some decorative pigments protect the substrate from the harmful effects of [[ultraviolet light]] by making the paint opaque to these wavelengths, i.e. by selectively absorbing them. These hiding pigments include [[titanium dioxide]], [[Phthalocyanine Blue BN|phthalo blue]], [[red iron oxide]], and many others.

Some pigments are toxic, such as the [[lead]] pigments that are used in [[lead paint]]. Paint manufacturers began replacing white lead pigments with  titanium white (titanium dioxide), before lead was banned in paint for residential use in 1978 by the US Consumer Product Safety Commission. The titanium dioxide used in most paints today is often coated with silica/alumina/zirconium for various reasons, such as better exterior durability, or better hiding performance (opacity) promoted by more optimal spacing within the paint film.<ref>{{Cite web|url=https://www.latimes.com/archives/la-xpm-2011-oct-14-la-sci-ancient-paint-20111014-story.html|title=Archives|website=[[Los Angeles Times]]|date=14 October 2011 }}</ref>

Micaceous [[Iron(III) oxide|iron oxide]] (MIO) is another alternative to lead for protection of steel, giving more protection against water and light damage than most paints. When MIO pigments are ground into fine particles, most cleave into shiny layers, which reflect light, thus minimising [[UV degradation]] and protecting the [[resin]] binder. Most pigments used in paint tend to be spherical, but lamellar pigments, such as glass flake and MIO have overlapping plates, which impede the path of water molecules.<ref>{{Cite web|url=http://www.duluxprotectivecoatings.com.au/technotespdf/5.2.1%20MIO%20Coatings%20-%20What%20Are%20They.pdf|title=MIO Coatings – What Are They?|date=2009|website=Dulux Protective Coatings}}</ref> For optimum performance MIO should have a high content of thin flake-like particles resembling [[mica]]. [[International Organization for Standardization|ISO]] 10601 sets two levels of MIO content.<ref>{{Cite web|url=https://www.iso.org/obp/ui/#iso:std:38753:en|title=ISO 10601:2007|website=Micaceous iron oxide pigments|publisher=International Organization for Standardization}}</ref> MIO is often derived from a form of [[hematite]].

Pigments can be classified as either natural or synthetic. Natural pigments are taken from the earth or plant sources and include colorants such as metal oxides or carbon black, or various [[clay]]s, [[calcium carbonate]], [[mica]], [[silica]]s, and [[talc]]s. Synthetics include a host of colorants created in the lab as well as engineered molecules, [[calcining|calcined]] clays, [[blanc fixe]], precipitated calcium carbonate, and synthetic pyrogenic silicas. The pigments and dyes that are used as colorants are classified by chemical type using the Color Index system, which is commercially significant.<ref>{{Cite web|url=https://colour-index.com/cicn-groups-sub-groups|title=CICN Groups and Sub-Groups|date=April 26, 2024 }}</ref>

===Additives===
Besides the three main categories of ingredients (binder, diluent, pigment), paint can have a wide variety of miscellaneous additives, which are usually added in small amounts, yet provide a significant effect on the product. Some examples include additives to modify texture, [[surface tension]], improve flow properties, improve the finished appearance, increase wet edge, improve pigment stability, impart [[antifreeze]] properties, control foaming, control skinning, create acrylic pouring cells, etc. Other types of additives include [[catalyst]]s, thickeners, stabilizers, [[emulsifier]]s, texturizers, adhesion promoters, UV stabilizers, flatteners (de-glossing agents), biocides to fight [[bacteria]]l growth and the like.

Additives normally do not significantly alter the percentages of individual components in a formulation.<ref>[http://www.frpdesigns.com/formulation%20calculations.htm frpdesigns.com] {{webarchive|url=https://web.archive.org/web/20100211213714/http://www.frpdesigns.com/formulation%20calculations.htm |date=2010-02-11 }}, "Formulations, Fundamentals, Manipulation, Calculation and Data Management" p. 61.</ref>