ANDISCO High Performance Hard Coating

Enhance Hardness & Scratch Resistance | Reduce Friction | Provide Corrosion/Oxidation Resistance | Improve Aesthetic Durability

A hard coating is a thin layer of a exceptionally hard and wear-resistant material applied to the surface of a softer, bulk material (called the substrate). Its primary purpose is to drastically improve the surface properties of the object—like its resistance to scratching, abrasion, and wear—without changing the desirable bulk properties of the underlying material, such as its toughness, weight, or cost.
Think of it as a protective, ultra-durable "armor" for an object.

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What is Hard Coating?

Hard coatings for plastic sheets, more commonly known in the industry as wear-resistant or scratch-resistant coatings, are a specially formulated surface treatment technology whose core purpose is to significantly enhance the surface mechanical properties and functionality of plastic substrates. These coatings are typically applied to the plastic surface in liquid form and then cured through a thermal or ultraviolet (UV) curing process to form a hard, dense, and optically transparent film protective barrier. The essence lies in altering the tribological properties and mechanical performance of the substrate's surface, enabling it to effectively resist surface damage caused by mechanical actions (such as friction, scratching, wear, and erosion) as well as chemical substances.

Core Value of Hard Coating

The core value of hard coating technology lies in the performance synergy it offers. High-performance plastics such as polycarbonate (PC) and polymethyl methacrylate (PMMA) have been widely used in various fields due to their unique physical advantages: PC is renowned for its exceptional impact resistance (virtually unbreakable), making it an ideal substitute for safety glass and bulletproof materials; PMMA, on the other hand, is favored for its excellent light transmittance and optical clarity, often regarded as a perfect alternative to glass. However, a significant weakness common to these materials is their relatively low surface hardness, which makes them prone to scratches from daily contact, friction, or cleaning, thereby compromising their visual appeal and functional integrity. The advent of hard coatings precisely addresses this inherent flaw by imparting the "hardness" attribute that the plastic substrates lack, creating a complementary composite material. This synergy ensures that coated PC retains its high impact resistance, while PMMA maintains its high light transmittance and lightweight characteristics. In this way, hard coating technology maximizes the advantages of plastic materials while effectively mitigating their drawbacks, enabling them to successfully replace traditional materials such as glass and metal without sacrificing performance, thereby meeting the contemporary industrial demands for lightweight and high durability.

Why Are Hard Coatings Used?

Within the contemporary global industrial landscape, particularly in the transportation and consumer electronics sectors, the demand for lightweight materials is increasingly pronounced, driven by more stringent environmental regulations and higher energy efficiency targets. Hard coating technology offers manufacturers a viable pathway to replace conventional glass and metal components with lighter and more durable plastic parts, thereby reducing overall weight and energy consumption.
Furthermore, the application of hard coating technology has significantly expanded the utilization scope of plastic materials. Prior to coating, many plastic components were unsuitable for harsh or high-contact environments due to inadequate surface durability. The advent of hard coating technology enables plastics to be deployed in more demanding and rigorous applications—such as automotive exterior parts, public touchscreens, architectural facades, industrial machinery protective covers, and security installations—without compromising performance. This technology not only extends product lifespan and reduces maintenance and replacement costs but also facilitates the broader integration of new materials into traditional domains, constituting an indispensable element of modern materials engineering.

Advantages and Multiple Functions of Hard Coatings

Distinguished Wear Resistance and Abrasion Resistance

Abrasion and scratch resistance constitute the core value proposition of hard coatings. By forming a robust protective layer on plastic surfaces, these coatings effectively mitigate friction, abrasion, and scratching encountered during daily use, thereby preserving optical clarity and aesthetic integrity over extended service life. At the microscopic level, scratch formation primarily stems from three deformation mechanisms: plowing, micro-cracking, and ironing. Scratch-resistant materials within hard coatings (e.g., ceramic-based or polysiloxane-based formulations) counteract these mechanisms through tailored material properties—such as utilizing high-ductility materials to restrict plowing events or employing high-tensile-strength components to control micro-crack propagation—thereby significantly reducing scratch visibility.
Despite the nomenclature "hard coating," research across material systems reveals functionalities extending far beyond mere scratch resistance. Such coatings can be engineered as versatile surface enhancement platforms, offering a comprehensive portfolio of performance attributes. For instance, coatings may deliver low surface energy characteristics that effectively repel dirt, dust, and smudges, facilitating easier cleaning. Furthermore, by incorporating UV absorbers into the coating formulation, they provide critical protection against yellowing and degradation caused by prolonged outdoor exposure. Advanced techniques like plasma spraying can even confer specialized functionalities—including thermal resistance enhancement, electromagnetic interference (EMI) shielding, and friction reduction—onto plastic components. Consequently, engineers and designers can tailor coating solutions based on holistic application requirements rather than pursuing hardness alone, thereby optimizing product performance, longevity, and cost-effectiveness.

Enhanced Chemical Resistance

Hard coatings form a dense chemical barrier on plastic surfaces, effectively protecting the substrate from corrosion caused by cleaning agents, solvents, acids, alkalis, and other chemical substances. While many plastics inherently possess a degree of chemical resistance, certain solvents (such as acetone) or strong acids and alkalis can still cause permanent damage, leading to surface degradation or impaired optical performance. By encapsulating the substrate surface, hard coatings significantly enhance its chemical resistance. For instance, certain polysiloxane-based coatings have demonstrated no observable surface or performance degradation after exposure to acetone, 1% sodium hydroxide, 1% hydrochloric acid, and common cleaning agents like Windex.

Excellent Weather Resistance and UV Resistance

For plastic components that need to be used outdoors for a long time, ultraviolet (UV) radiation is the main cause of their degradation and performance decline. Hard coatings can effectively integrate ultraviolet (UV) absorbers, thereby preventing plastics from yellowing, embrittlement and decline in optical performance under long-term outdoor exposure. They are particularly suitable for applications such as car Windows, greenhouses, outdoor signs and public transportation bus shelters. For instance, a coating supplied by ANDISCO ,named OWP-100(Outdoor Weatherable Protection) can effectively block 90% of ultraviolet radiation with wavelengths less than 375 nm at a film thickness of approximately 6 microns. Moreover, it demonstrates high stability in accelerated aging tests, showing no cracking or delamination even after 250 hours of exposure to strong ultraviolet rays.
Based on our 8000-hour xenon ar c lamp exposure test data, in accordance with GB/T16422.2-2014 and HG/T3862-2006, this coating is resistant to aging and can help the board reduce micro-cracking, maintain a complete and beautiful appearance, and extend the service life of the board.

Xenon arc lamp irradiation yellowing test

Maintain optical clarity and light transmittance

Hardness maybe not the only indector among various applications ,while optical performance is defenitely important.Excellent hard coating would not only enhance surface hardness of the substrates,but also remain original high lighting transmission and low haze,it is No.1 quality principle for hard coated products.Scratches and wear can cause light to scatter on the surface, thereby increasing the haze of the material and affecting its optical clarity. Hard coatings, with their excellent wear resistance, effectively prevent scratches from occurring, thus maintaining a low haze level. For instance, a wear-resistant acrylic sheet named ACRYLITE® Optical Mar-Resistant, even after coating, still retains a light transmittance of 92%, making it an ideal choice for museum display cases and electronic displays.

Surprisingly, ANDISCO abrasion resistant coating has seen a more significant upgrade compared to ACRYLITE OPTICAL MAR RESISTANT COATING. It retains no less than 92% of the substrate's light transmittance and has excellent wear resistance. It also enhances the surface hydrophobic performance, which means that maintenance and cleaning will become easier and more feasible.

Selection of Substrates and Materials for Hard Coatings

Common Plastic Substrate

Polycarbonate (PC): PC is renowned for its unparalleled impact resistance and is almost indestructible. However, its surface is relatively soft and prone to scratches, which severely limits its application in scenarios requiring high optical clarity. Therefore, hard coatings are the ideal partners for PC and are commonly used in automotive windows, safety glass, bulletproof windows, and display covers, etc.
Acrylic (PMMA): PMMA boasts optical clarity comparable to that of glass (with a light transmittance of up to 92%), and is lightweight. However, its surface hardness is relatively low, making it prone to scratches. Through hard coating treatment, its scratch resistance and chemical resistance can be enhanced by up to 40 times, making it suitable for high-contact applications such as electronic displays, museum display cases, menu boards, and photo frames.
Other applicable substrates: The hard coating technology is also suitable for a variety of other plastic substrates, including polyethylene terephthalate (PET), polyvinyl chloride (PVC), polymethyl methacrylate copolymer (PMMA), and polyurethane (PU), etc. These substrates usually require surface pretreatment or the use of a primer before application to enhance the adhesion of the coating.

Chemical Composition of Coating Materials

Polysiloxane-based Coatings: This is the most common type of hard coating. It is an organic-inorganic hybrid material formulated from polyhedral oligomeric silsesquioxane sol-gel in alcohol or ethylene glycol ether solutions. After curing, these molecules crosslink to form a three-dimensional network, creating a glass-like, hard and rigid surface. Its advantages include excellent wear resistance, chemical resistance and optical clarity.
Nanocoatings: These coatings utilize nanoscale particles (such as titanium dioxide (TiO₂), zirconium dioxide (ZrO₂), aluminum oxide (AlOOH), etc.) as fillers or additives to enhance the hardness and wear resistance of the coating. Certain nanostructured composite coatings, such as NANOMYTE® SR-100RT, consist of an organic phase and an inorganic phase, and can provide excellent scratch and wear resistance.
Other technologies: In addition to the aforementioned materials, hard coatings can also be based on other chemical systems, such as polymer-based ones (for example, epoxy resins) and diamond-like carbon (DLC), etc. Each of these materials has its own unique properties and applicable scenarios.

Other technologies: In addition to the aforementioned materials, hard coatings can also be based on other chemical systems, such as polymer-based ones (for example, epoxy resins) and diamond-like carbon (DLC), etc. Each of these materials has its own unique properties and applicable scenarios.

Comparison of Properties between Common Plastic Substrates and Hard Coatings
Substrate	Advantage of Uncoated Substrates	Disadvantage of Uncoated Substrates	Enhanced Performance After Coating	Typical Application
Polycarbonate	Excellent Impact Resistance,not easy to be broken	Lower surface hardness ,easily scratched	Maintain high impact resistance and significantly enhance scratch resistance.	Automobile windows, safety glass, public display screens, security components
Acrylic (PMMA)	Outstanding optical clearity(lighting transmission≥92%),light weight	The surface is relatively soft and extremely prone to scratches.	Scratch resistance and chemical resistance can be enhanced by 40 times without affecting optical performance.	Electronic display screens, museum display cases, photo frames, furniture panels
Others (PET, PVC,PETG)	High flexibility, cost-effectiveness, etc.	Poor wear resistance and weather resistance.	Scratch resistance and chemical resistance can be enhanced by 40 times without affecting optical performance.	Industrial panels, outdoor signs, packaging materials

The Application Process and Procedures of Hard Coatings

Preprocessing Opearation

In coating applications, pretreatment is regarded as the crucial first step. As the saying goes, "The quality of any coating depends on its pretreatment." Pretreatment is a key step to ensure a strong adhesion between the coating and the substrate. If not handled properly, it will lead to delamination, peeling or cracking of the coating, which will seriously affect the performance and lifespan of the final product. Typical pretreatment steps include thorough cleaning, degreasing and drying of the substrate surface. For some materials, it may be necessary to use specific solvents (such as hexane and isopropyl alcohol) for thorough wiping, and then blow dry with ionized air or nitrogen to ensure that the surface is free of any residues, contaminants or dust.

Technical Guide for Hard Coatings on Plastic Sheets
Coating Method	Applicable Substrate&Shapes	Typical Advantages	Typical Disadvantages	Cost	Representative applications
Dip Coating	Simple shapes, large output	The coating is uniform and the production efficiency is high.	A large amount of paint is needed and it is not suitable for complex shapes.	High	Lenses, small displays, spectacle lenses
Flow Coating	Large flat surface, single-sided coating	Paint saving, one-time thick coating, suitable for large items.	It is prone to the "wedge effect", and the process control requirements are high.	Middle	Building panels, large display screens, public signs
Spay Coating	Complex shapes, local coating	High flexibility and can be endowed with special properties (such as EMI shielding)）	Uniformity may be limited and the cost is relatively high.	Low	Automobile interiors, instrument panels, sensor covers, aircraft cockpit canopies

Dip Coating

Dip coating is a widely used coating process. Its basic principle is to immerse the pre-treated substrate into liquid coating and then lift it up at a controlled rate. The advantages of this process lie in its ability to achieve extremely uniform coating thickness, high production efficiency and good cost-effectiveness. It is particularly suitable for simple-shaped parts with large production volumes. However, its limitations include the need to maintain a large amount of coating in the coating tank and its inapplicability to all complex-shaped parts.

Flow Coating

The flow coating method is an automated process. Its core principle is that the coating solution flows over the substrate surface in a controlled manner under the force of gravity, and the excess coating is collected below and recycled after filtration. The advantages of this process lie in its ability to effectively save coating materials, its applicability to large panels or components that require coating on one side, and the ability to obtain a thick and smooth coating in a single operation without the need for multiple applications. However, this process also has inherent challenges, such as the possible occurrence of the "wedge effect", where the coating thickness is thinner at the top and thicker at the bottom of the component, as well as the issue of solvent reflux. To ensure uniformity, it is necessary to strictly control the flow rate of the coating, the evaporation rate of the solvent, and the solid content of the coating.

Spay Coating

Spray coating is a process that applies coatings to the surface of substrates through a spray. Among them, plasma spray coating is an advanced spraying technology that deposits special materials such as metals, ceramics or polymers to endow plastic components with more advanced properties. This technology forms a protective barrier, enabling plastic parts to withstand extreme conditions, such as increasing thermal resistance, reducing friction, and even providing electromagnetic interference (EMI) shielding functions, making it suitable for high-demand industries such as aerospace and automotive. Spray coating technology is usually used for components with complex shapes or those requiring local coatings, and it is a performance-enhancing coating rather than a simple scratch-resistant treatment.

Dip coating, flow coating and spray coating are not merely simple alternatives but strategic choices based on different product requirements and production scales. Dip coating, due to its cost-effectiveness and uniform coating, is suitable for batch production of small and simply-shaped components; flow coating excels in handling large flat surfaces, ensuring coating quality through precise control of flow rate; while advanced spray coating techniques such as plasma spraying are specifically designed for complex-shaped components that require specific high-performance properties, such as EMI shielding or high-temperature resistance. This diverse range of process options reflects the maturity and flexibility of the hard coating industry in meeting the demands of various markets, ranging from mass consumer goods to high-tech precision components.

Quality Control and Performance Testing Standards

Evaluation indicators of coating performance

To ensure the quality and performance of hard coated plastic sheets,a series of standard testing are adopted in the industry to evaluate their key performance indicators.

Hardness: Hardness is the ability of a coating to resist plastic deformation. It can be evaluated by various methods, among which the pencil hardness test is the simplest and most commonly used method. It involves using pencils of different hardness grades to scratch the coating surface to determine its resistance to scratching. More precise methods include the ball indentation test and Rockwell hardness test, which determine the hardness value by measuring the indentation depth and follow standards such as ISO 2039-1/-2 and ASTM D785.

Abrasion Resistance: This is a core indicator for evaluating the durability of coatings. The Taber Abrasion Test is the industry gold standard. This test quantifies abrasion resistance by placing two abrasive wheels with a specific load (such as 500g) on a rotating sample and then measuring the change in haze (Δ % Haze) or weight loss after a specific number of rotations (such as 500 times). A smaller haze change value indicates better abrasion resistance of the coating. Other methods include the steel wool scratch test, which assesses the material's scratch resistance by simulating the friction in actual use.

Adhesion: Adhesion is a crucial indicator of the bonding strength between a coating and its substrate. Poor adhesion can lead to delamination, peeling, or cracking of the coating, resulting in a limited product lifespan. The critical load (Lc), which is the load at which the coating begins to peel from the substrate, can be measured using a scratch tester to quantify the adhesion performance.

Thickness: Coating thickness is an important control parameter to ensure consistent performance. Insufficient thickness may lead to poor wear resistance, while excessive thickness may cause coating cracking or delamination. Coating thickness can be quickly measured by methods such as the rotating ball method (Calotest).

Industry Standards and Specifications

Standardized testing serves as the cornerstone for ensuring product quality, achieving global recognition, and building industry trust. These standards transform the subjective experience of "scratch resistance" into quantifiable technical indicators such as "Δ Haze < 1%", providing manufacturers with objective performance evaluation methods and customers with reliable quality assurance.

This standardization process is a necessary condition for the maturation and expansion of the hard-coated plastic market. Firstly, it enables fair and objective comparisons of product performance among different suppliers, thereby promoting healthy competition. Secondly, it provides a basis for regulatory compliance in key industries such as automotive and aviation, ensuring the safety and reliability of products. Finally, for customers, product labels that comply with ASTM or ISO standards represent a reliable guarantee of quality and performance. By transforming subjective experiences into quantifiable technical indicators, the standardization process reduces market risks and accelerates the adoption of new materials and technologies, making it an indispensable part of the mainstream application of hard coating technology.

Main Performance Tests and Standards for Hard Coatings
Performance Evaluation	Typical Testing Method	Testing Standard	Assessment Purpose
Hardness	Rockwell Hardness Ball Indentation Test	ISO 2039-1/-2, ASTM D785, DIN EN 13523-4	Evaluate the coating's ability to resist plastic deformation and scratches.
Abrasion Resistance	Taber Abrasion Test Steel Wool Abrasion Test	ISO 9352, ASTM D1044, ASTM D4060, ISO 5470	Quantify the coating's resistance to friction, scratching and wear.
Adhension	Scratch Tester (Critical Load Lc)	ISO 20502, ASTM C1624	Evaluate the bonding strength between the coating and the substrate.
Thickness	Calotest	-	Ensure that the coating thickness is within the range of optimal performance.

Application Fields of Hard-coated Plastic Sheets

Transportation

Hard-coated plastics play a crucial role in the transportation sector. They are widely used in automotive components such as headlamps, windows, sunroofs, interior panels, displays, and instrument panels. These applications demand stringent requirements for lightweighting, high durability, and weather resistance, while maintaining optical clarity. Hard-coated plastics offer lighter and more design-flexible solutions compared to traditional glass, and they comply with the strict regulations and performance standards of the automotive industry. This is essential for developing more energy-efficient vehicles in the future.

Side Window and Door of High-speed Train

Electronic and Display Technology

In electronic devices such as touch screens, displays, sensor covers, and camera lenses, hard coatings are indispensable protective layers. These devices frequently come into contact with human hands and hard objects during daily use, making them highly susceptible to scratches. Hard coatings can effectively protect screens and lenses from daily scratches and wear, ensuring image clarity and distortion-free, thereby extending the overall lifespan of the devices.

Architecture and Security

Hard-coated plastics offer a safer and more durable alternative to glass in the fields of architecture and security. The combination of high-impact PC substrates with hard coatings makes them ideal for use in anti-burst windows, building skylights, greenhouses, sound barriers, and ice rink enclosures. This material not only provides high security but also maintains stable performance in outdoor applications due to its wear resistance and weather resistance, and is less likely to be damaged by wind and sand, cleaning, or daily contact.

Industrial and Consumer Products

Hard-coated plastics are also widely used in various industrial and consumer products, such as mechanical protective covers, industrial instrument panels, outdoor signs, furniture, and photo frames. In these applications, the products are often exposed to high-frequency contact or harsh environments. The hard coating can protect their surfaces, effectively reducing maintenance and replacement costs and extending the product lifespan.

Call to Action

ANDISCO Hard coating technology has become a crucial advancement in modern materials science. By offering multiple advantages, including superior wear and scratch resistance, enhanced chemical resistance, excellent weatherability, and the ability to maintain optical clarity, it has successfully transformed plastic materials such as polycarbonate and acrylic from single-purpose to high-performance, multi-functional engineering materials.
For more product information and technical support on hard coatings, please feel free to contact our technical support team at any time at info@polyteching.com.