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User:MatthewUCSB/sandbox/Anti-Scratch Coating(Draft)

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Anti-Scratch Coating is a type of protective coating that when applied to a substrate (surface) provides resistance against scratches. Scratches are the marks left in a object following scratching. Anti-Scratch Coatings share similar mechanical and chemical properties such as high elasticity, hardness, and low friction. However, in spite of shared properties, Anti-Scratch Coatings can differ greatly in material composition. Ranging from carbon base to metal based. Like coatings in general, Anti-scratch Coatings are made up of thin film ranging from nanometer to micrometer. Creating this thin film requires a solvent (dissolves substances), chemical additives/pigments and a resin polymer structure. Adhesion of Anti-Scratch Coating to a substrate is done through methods such as deposition, Spraying and roll to roll. Commercially, Anti-Scratch Coatings are most commonly used in the automotive, optical, plastics, and technology sectors.

Overview of Scratches

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Scratches are small permanent cuts to a surface of a object that occur as a result of scratching. Scratching occurs when a hard and more pointed object comes into contact with a softer object. Scratching is a form of Abrasion, which is the wear of a object due to stress from mechanical (physical) forces. The change in structure as a result of scratching and other forms of Abrasion is called Deformations.

On the atomic level, Scratching causes two atomic planes to slide pass each other resulting in dislocation, the movement of atoms planes into new weaker positions. In the case of Scratching, the weaken atomic planes causes the object to be more prone to wear and the potential that future cuts can reach the internal structure of an object, which will decrease the lifespan of a product[1].

An objects resistance to scratching can be shown using the strain rate equation (measures how much stress a object can tolerate before damage) and the Archard wear equations.(which shows that a rougher surface in more prone to scratches due to Friction)

Note that these equations can not be applied with particles at the nano-level, due to an very different physical environment at this level, which is a reason certain anti-scratch coats contain nano-sized particles.

Testing a object resistance to scratching is done with a scratch specific versions of the strain test.

Properties of Anti-Scratch Coating

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Anti-Scratch Coating must (1) contain properties known to provide Scratch resistance and (2) allows for the adhesion of a coating to a substrate, and meet necessary decorative requirements. [2]

Hardness

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A Hard object dose not break easily. Anti-Scratch coatings are hard.

Elasticity

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Elasticity is the ability of a object to return to its original form after being impacted by a object. Elasticity is similar to flexiblity. Anti-Scratch coatings contain high Elasticity.

Friction

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Friction is a type of force that slows an object down. Anti-Scratch coatings contain low Friction. Low Friction objects can be characterized as smooth

Adhesion

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Adhesion is the ability of a object to bond on something.

Brittleness

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Clear

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Pigment Concentration

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Thickness

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viscosity

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Common Components of Anti-Scratch coating

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(metals, Alloy,refractory components oxides, nitrides,carbides), intermetalic compounds, polymers[3]

surface coatings[4]

Blinders (resin)

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The name of a coating often refers to the special type of Blinder used. Blinders hold the material in a cohesive manner.

Blinders are largely organic polymers.

Common Blinders and (Resins) used in anti-starch film-based coatings
Key properties that gives the (Resin) that allows it it provide

starch resistance.

Drawbacks popularity
polyesters
acrylic-based
epoxies
alkyd
polyurethanes
silicone resin
polyurethanes
melamine
polyamides
phenolic

(https://pdhonline.com/courses/m223/EM%201110-2-3400_Chapter4.pdf)

mposite materials consisting of pigment particles and other additives dispersed in a continuous matrix of polymer

(Extender) pigments[5]

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Anti-starch coating contains functional pigments called Extenders pigments. Extender pigments when dispersed in the matrix (structure) of the resin enhances the functional properties of a resin. Anti-starch coating extender pigments specially contain anti-starch properties.

metals, Alloy,refractory components oxides, nitrides,carbides

Extender pigments
nitrides
carbides
carbon-based
oxides
borides

Additives (Defoamers)

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Additives are tiny particles that often make less than 1 percent of the coats volume, that are added in a solvent during the coat formation process for maximum coat performance.

Coating formation Process

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Coats can be applied with brushes, spraying, and by various industrial techniques. The type of process that can be used depends on substrate and the coating materials. Coats are formed when a liquid or gas is added to a solid substrate. Many processes use deposition, which turns gas particles into a solid coating.

Solvents are used during the coating formation to dissolve additives and blinders[6]. Solvents evaporate after curing.

  • Vapor deposition: A film coating of gas particles are added to a substrate
  • Plasma deposition
  • Chemical and electrochemical techniques
  • Spraying
  • Roll to roll coating processes
  • Physical coating processes.

Applications Uses

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Automotive

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Optical

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Plastics

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Technology

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See Also

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References

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  1. ^ A Critical Study On Scratch Resistance Test Methods (pcoatingsintl.com)
  2. ^ "Abrasion & Wear Resistance in Paint & Coatings: Basics & Test Methods". coatings.specialchem.com. Retrieved 2021-10-16.
  3. ^ Quintino, Luisa (2014-01-01), Miranda, Rosa (ed.), "1 - Overview of coating technologies", Surface Modification by Solid State Processing, Woodhead Publishing, pp. 1–24, ISBN 978-0-85709-468-1, retrieved 2021-10-16
  4. ^ "Surface coating - Solvents and carrier liquids". Encyclopedia Britannica. Retrieved 2021-10-16.
  5. ^ Hoornaert, T.; Hua, Z. K.; Zhang, J. H. (2010). Luo, Jianbin; Meng, Yonggang; Shao, Tianmin; Zhao, Qian (eds.). "Hard Wear-Resistant Coatings: A Review". Advanced Tribology. Berlin, Heidelberg: Springer: 774–779. doi:10.1007/978-3-642-03653-8_257. ISBN 978-3-642-03653-8.
  6. ^ "Solvent in Paints and Coatings: Types, Uses and Properties". coatings.specialchem.com. Retrieved 2021-10-16.
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