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NEI Addresses Unmet Self-Healing Needs for Transparent Polymeric Films Market

June 18, 2019

Somerset, NJ (USA) – NEI Corporation announced today that it has successfully demonstrated application of its NANOMYTE® MEND 1000 self-healing coating technology on PET film. The coated film is able to recover from repeated scuffing and scratching after heating to 60°C, typically using hot water or a hair dryer. Self-healing is achieved by a thermally-induced, physical self-healing phenomenon which leads to gap closing and crack sealing. This allows the coating to heal repeatedly at the same defect location, which helps to reduce life cycle costs by increasing the service life of the coated material. NEI’s MEND coatings exploit a unique phase-separated morphology that facilitates delivery of the self-healing agent to the damage site (such as a scratch or crack), thereby restoring the coating appearance & function.

There are numerous applications for polymeric films produced in the roll-to-roll coating industry, including signage, vehicle wraps, interior and exterior wall wraps, and protective overlaminates such as those commonly found on touchscreens or installed over window glass. These films are typically relied upon to protect from physical damage or to reduce the transmission of light while providing heat rejection, features which are in high demand for automotive and architectural glass.

Roll-to-roll processes present unique challenges for coatings in terms of the speed and temperature necessary to achieve a sufficient cure. Line speed requirements will often dictate that curing occur within a period of 1-2 minutes at temperatures around 100°C. To increase the speed of cure to better suit continuous, roll-to-roll processing of coated film, NEI now supplies a catalyst additive which can reduce the dry-to-touch (DTT) time to as little as 1 minute at 100°C (exact time and temperature will depend on wet film thickness and other processing conditions), which has allowed its customers in the roll-to-roll coating industry to successfully process the coating.

NEI supplies three versions of its popular NANOMYTE® MEND self-healing coating products to meet different performance and processing requirements:

  • MEND 1000 – heat cure, 60°C healing temperature
  • MEND 2000 – heat cure, 25°C healing temperature
  • MEND 3000 – ambient cure, 60°C healing temperature

The coatings are supplied as 2 components, Parts A and B, which are mixed before application. Further customization can then be accomplished with the addition of a catalyst to speed up curing and/or a reducer to adjust viscosity. NEI can also supply coating formulations with increased viscosity to meet process requirements. Please refer to the product technical datasheets for further guidance. To enhance light-stability and weatherability, NEI also offers its MEND product line with UVP technology to protect sensitive surfaces by blocking UV light while preserving the coating performance. This feature can be critical for some applications, such as those which may cause yellowing of sensitive polymers. NANOMYTE® UVP coating products have demonstrated their ability to endure a minimum of 1000 hours of weatherability testing per ASTM D4587, “Accelerated Weathering under Fluorescent UV-Condensation Exposure”. The testing was performed in a QUV chamber under the conditions specified in ASTM G154, Cycle 1, the most commonly used exposure cycle designed to simulate severe outdoor service conditions.

NANOMYTE® MEND coating products can be applied by a variety of processes, including spraying, dipping and flowing. NEI also offers in-house coating services for customer’s parts as well as coating development services, wherein coating formulations are created to address specific customer requirements.

Links to Technical Data Sheets:

Additional Information: Safety Data Sheets ♦ MEND Product Page ♦ Demonstration Video

View / Download Press Release (pdf) ↓

About NEI Corporation: NEI Corporation is an application-driven company that utilizes nanotechnology to develop and produce advanced materials. The company’s core competencies are in synthesizing nanoscale materials and prototyping products that incorporate the advanced materials. NEI offers an array of Advanced Protective Coatings for metal and polymer surfaces. The coatings have tailored functionalities, such as anti-corrosion, self-healing, scratch resistance, ice-phobic, and self-cleaning.

For more information, give us a call or email us.

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The Development of NEI’s Anti-Ice Coating Technology for the Aerospace Industry

A Case Study of NANOMYTE® SuperAi from Concept to Implementation

The leading edge of the wing is where icing occurs

A manufacturer of de-icing systems brought up the idea of combining an active de-icing system with a coating that easily sheds ice. Ice formation on the leading edge of an aircraft is a common aviation danger, playing a key role in several catastrophic accidents over the years that have killed people and destroyed aircrafts. All commercial aircraft have a built-in ice protection system, which could be either a thermal, thermal-mechanical, electro-mechanical, or pneumatic system. A common issue with de-icing devices is that they consume substantial power.  Aircraft generally look to reduce power consumption, and with the advent of battery-powered aircraft, mechanisms or features that reduce power consumption are critically important. The aspect of reduced power is also relevant for battery powered drones. Applying a passive anti-ice coating that functions synergistically with the active de-icing device is an attractive approach. The advantages are reduced power consumption, improved service life of mechanical components, lighter electronics and extra protection in case of failure of active device.

The challenge presented to the engineers and scientists at NEI Corporation was to develop and demonstrate a coating that exhibits durable anti-ice performance and satisfactory wear and erosion resistance. More importantly, it needed to be practical for retrofitting in-service aircraft as well as be used by OEMs. In order to address the need, NEI developed its NANOMYTE® SuperAiTM coating technology to have the following features:

  • Extremely lubricating surface
  • Superior ice adhesion reduction factor
  • Thin coating (< 1 mil or 25 microns), providing a light weight solution
  • Durable anti-ice performance, suitable for permanent application
  • Room temperature cure
  • Easy application by spraying, dipping, or brushing

The development of the SuperAiTM coating started after numerous discussions with engineers at a major low-power ice protection system manufacturer. They brought to our attention the two basic technical requirements for an anti-ice coating to be applied on their de-icing systems, i.e., lower ice adhesion and durable anti-ice performance. We demonstrated both attributes after extensive experiments in NEI’s laboratory and iterative testing at an icing wind tunnel facility with prototype de-icing devices. The ice adhesion measurements taken at NEI were corroborated by work done at the Penn State Adverse Environment Rotor Test Stand (AERTS) facility, which repeatedly showed an ice adhesion strength as low as ~1.8 psi for the SuperAiTM coated aluminum substrate – this represents an 80% reduction compared to an uncoated polished aluminum substrate (Figure 1). Figure 1 shows a pure adhesive failure when an ice column was pulled off the SuperAiTM coated substrate. In contrast, a cohesive failure of ice is seen for the uncoated aluminum substrate.

Figure 1: Ice adhesion strength and locus of failure of SuperAiTM coated aluminum as compared to those of uncoated polished aluminum

To demonstrate the enhanced de-icing efficiency of a de-icing device with the use of SuperAiTM, coated prototypes of electro-mechanical and thermal-mechanical expulsion de-icing systems were tested in an icing tunnel under simulated in-flight icing conditions at our collaborator’s facility. Figure 2 shows the SuperAiTM coated leading edge being assembled with the thermal-mechanical expulsion de-icing system. We have repeatedly demonstrated that improved de-icing efficiency, along with a 45-70% reduction in power consumption of the active de-icing systems could be achieved with the use of the newly developed anti-ice coating (Figure 3).

Figure 2: Installation of leading edge and thermal-mechanical expulsion de-icing system assembly.

Figure 3: Snapshots taken from recording of icing tunnel test showing complete de-icing on coated leading edge (bottom) and no de-icing on uncoated leading edge (top), at power consumption level 70% lower than that of the nominal power needed for a regular functional uncoated de-icing system.

Abrasion resistance is of great importance for the targeted application. Figure 4 shows that the SuperAi coating was barely scratched at the wear track after 200 cycles of Taber abrasion. Note that the CS-10F Calibrase® wheel used in the test is composed of a binder and abrasive particles such as aluminum oxide and silicon carbide. The testing conditions simulate normal service abrasion and wear. Further, the contact angle at the wear track was measured to be 103° (vs. 105° of fresh unabraded surface), indicating that the hydrophobicity of the surface was minimally affected by the abrasion. The ice adhesion measurement at the wear track showed that the coating remained highly icephobic after 200 cycles of Taber abrasion (Figure 5).

Figure 4:  Optical micrograph taken at the wear track after Taber test showing excellent abrasion resistance of the SuperAiTM coating.

Other important aspects of an anti-ice coating for aircraft include its ability to resist rain erosion, chemical and solvent resistance, resistance to icing-deicing cycles and weatherability. These aspects were investigated with various durability tests. As can be seen in Figure 5, the SuperAiTM coating could survive repeated icing-deicing cycles. There was little change in ice adhesion after immersion in jet fuel, Skydrol® (an aviation hydraulic fluid), and water for an extended period of time. Further, the ice adhesion strength was minimally affected by abrasion, high-pressure power wash and UV-Con exposure.

Figure 5:  Ice adhesion results for SuperAiTM after various durability tests.

In summary, we were able to address an important need in the industry, using a disciplined and focused product development effort. The case study presented here is representative of the application-driven coatings development effort we undertake to address a problem or an opportunity. We work directly with customers and seek to develop, demonstrate, and implement a solution.

For more information, give us a call or email us.

NEI Corporation is extremely mindful of maintaining the confidentiality of its customer’s information, even without a non-disclosure agreement. Specific and sensitive information relating to customers have been withheld.

Download Case Study (pdf) ↓

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