Painting & Coating Industry (PCI) logo Powder coating summit logo
  • Sign In
  • Create Account
  • Sign Out
  • My Account
  • NEWS
  • PRODUCTS
  • MATERIALS
  • TECHNOLOGIES
  • FINISHING
  • RESOURCES
  • EVENTS
  • DIRECTORIES
  • EMAGAZINE
  • CONTACT
cart
facebook twitter linkedin youtube
  • NEWS
  • Latest News
  • Market Trends & Reports
  • Price Alerts
  • Subscribe to eNewsletters
  • Global Top 10/ PCI 25
  • Weekly Featured Article
  • COATLE Word Game
  • PRODUCTS
  • Product News
  • Must See Products and Services
  • MATERIALS
  • Additives
  • Resins/Polymers
  • Pigments
  • Equipment
  • Distributors
  • TECHNOLOGIES
  • Adhesives
  • Architectural Coatings
  • Industrial Coatings
  • Nanotechnology
  • Powder Coatings
  • Solventborne
  • Special Purpose Coatings
  • Sustainability
  • UV Coatings
  • Waterborne
  • Waterborne
  • FINISHING
  • Finishing News
  • Finishing Technologies
  • Finishing Equipment
  • RESOURCES
  • Columns
  • Blogs
  • Coatings Supplier Handbook
  • Podcasts and Videos
  • PCI Store
  • eBooks
  • Sponsor Insights
  • White Papers
  • COATLE Word Game
  • Columns
  • Ask Joe Powder
  • Did you know?
  • Distribution Dive
  • Focus on Canada
  • Formulating With Mike
  • Innovation Insights
  • Moody's Coatings Conundrums
  • Powder Coating Perspectives
  • Target the Market
  • TiO2 Insider
  • Blogs
  • Editor's Viewpoint
  • Industry Insights
  • Podcasts and Videos
  • COAT-IT! Podcast
  • Videos/PCI TV
  • EVENTS
  • Coatings Trends & Technologies Summit
  • Paint and Coatings Academy
  • Webinars
  • Calendar of Events
  • Lifetime Achievement Award
  • DIRECTORIES
  • Buyer's Guide
  • Equipment Directory
  • Materials Directory
  • EMAGAZINE
  • Current Issue
  • eMagazine Archive
  • China Issue Archive
  • Editorial Advisory Board
  • CONTACT
  • Contact Us
  • Advertise
  • Subscribe to eMagazine
  • Subscribe to eNewsletters
Painting & Coating Industry (PCI) logo Powder coating summit logo
search
cart
facebook twitter linkedin youtube
  • Sign In
  • Create Account
  • Sign Out
  • My Account
Painting & Coating Industry (PCI) logo Powder coating summit logo
  • NEWS
    • Latest News
    • Market Trends & Reports
    • Price Alerts
    • Subscribe to eNewsletters
    • Global Top 10/ PCI 25
    • Weekly Featured Article
    • COATLE Word Game
  • PRODUCTS
    • Product News
    • Must See Products and Services
  • MATERIALS
    • Additives
    • Resins/Polymers
    • Pigments
    • Equipment
    • Distributors
  • TECHNOLOGIES
    • Adhesives
    • Architectural Coatings
    • Industrial Coatings
    • Nanotechnology
    • Powder Coatings
    • Solventborne
    • Special Purpose Coatings
    • Sustainability
    • UV Coatings
    • Waterborne
    • FINISHING
      • Finishing News
      • Finishing Technologies
      • Finishing Equipment
    • RESOURCES
      • Columns
        • Ask Joe Powder
        • Did you know?
        • Distribution Dive
        • Focus on Canada
        • Formulating With Mike
        • Innovation Insights
        • Moody's Coatings Conundrums
        • Powder Coating Perspectives
        • Target the Market
        • TiO2 Insider
      • Blogs
        • Editor's Viewpoint
        • Industry Insights
      • Coatings Supplier Handbook
      • Podcasts and Videos
        • COAT-IT! Podcast
        • Videos/PCI TV
      • PCI Store
      • eBooks
      • Sponsor Insights
      • White Papers
      • COATLE Word Game
    • EVENTS
      • Coatings Trends & Technologies Summit
      • Paint and Coatings Academy
      • Webinars
      • Calendar of Events
      • Lifetime Achievement Award
    • DIRECTORIES
      • Buyer's Guide
      • Equipment Directory
      • Materials Directory
    • EMAGAZINE
      • Current Issue
      • eMagazine Archive
      • China Issue Archive
      • Editorial Advisory Board
    • CONTACT
      • Contact Us
      • Advertise
      • Subscribe to eMagazine
      • Subscribe to eNewsletters
    Paint and Coating PigmentsArchitectural CoatingsIndustrial Coatings

    IR-Reflecting Pigments

    By Thomas Sowade
    Industrial Coatings
    October 1, 2011

    It is well known that modern IR-reflecting inorganic complex pigments not only impart super-durable colour shades to a surface, but enable coatings formulators to create products showing less interaction with solar radiation compared to using normal pigments, and therefore showing lower heat build-up.

    Figure 1 Click to enlarge

    The most well-known application is found in the area of coil coatings for facades and roofs (key word: cool roofs). The aim is to lower heat transfer into buildings, and as a result reduce energy consumption of air conditioners to cool down the interiors. A positive side effect – an enhanced lifetime of the coating due to reduced thermomechanical impact – has been observed. There are several programs available that define criteria and approve products for cool roof applications. Of these, the Energy Star and Cool Roof Rating Council of the United States are the best-known programs. Further programs are Green Globes (Canada and United States), LEED (United States) and one from the Singapore Environment Council. In Europe a similar program called Cool Roofs Europe has been started, and first products have been approved.
     

    Figure 2 Click to enlarge

    While the application of IR-reflecting pigments in coil coatings is accepted and subject to constant improvement, further applications are under development. This article will describe recent findings in car refinish paints and plasters for architectural thermal insulation systems, and present a new dark IR-reflecting pigment combining jetness with high solar reflection.

    Influence of Solar Radiation on Pigments

    Pigments interact with solar terrestrial radiation as described in Figure 1. Possible interactions are absorption (transmission), reflection and scattering. The interaction of colour pigments with the visible part of the electromag-netic spectrum (380 – 780 nm) is obvious in the form of our colour impression. Pigments can additionally interact with UV radiation (250 – 380 nm) and/or near-infrared (NIR 780 – 2500 nm) radiation. While the (detrimental) influence of UV radiation is well known (i.e., pigment fading), the interaction with the NIR radiation is its poor invisible cousin, although the integral energy of the NIR radiation accounts for approximately 50% of the total integral energy of solar radiation.

    Figure 3 Click to enlarge

    Heat Build-Up Effect of Different Pigments

    The amount of total energy absorbed and emitted by a topcoat determines the heat build-up of a coated surface and results in a final surface temperature after reaching an equilibrium state. Coating pigmentation has the main influence on heat build-up performance. To achieve cool surfaces, the pigments need to reflect as much energy as possible. This reflection ability can be expressed as the Total Solar Reflectance value (100% = total reflection; 0 % = total absorption). Therefore, pigments with high TSR values show a high reflection combined with low heat build-up, and vice versa.

    Pigments with the highest reflection ability are based on TiO2, while pigments with the lowest reflection are based on carbon black. If, from an aesthetic point of view, one prefers a dark colour instead of white, there is a choice of using dark inorganic complex pigments like P.Br. 29 (Chromium Iron Oxide) or P.Bk. 30 (Chrome Iron Nickel Black Spinel) as an IR-reflecting option. These pigments show higher TSR values compared to carbon black and are an excellent choice for grey colour shades; in mono-pigmented systems the TSR value is higher but the jetness is lower compared to carbon black.

    Figure 4 Click to enlarge

    Figures 2 and 3 illustrate TSR values of different pigmented topcoats with the corresponding heat build-up measurements.

    Heat Build-Up Effect in a Multi-Layer-System

    Although the use of black inorganic complex pigments with higher TSR values compared to carbon black is unlikely in full-shade car refinishes or OEM topcoats due to missing jetness, there is still some room for it in the total multi-layer set-up.
    Conventionally, pigmented topcoats (high-performance organic pigments) are transparent or at least partially transparent to NIR radiation. As a consequence, the NIR radiation passes through the topcoat, and the IR reflectance ability of this multi-layer system is then determined by the behaviour of the next layer, in this case the primer. Primers are available in different colours, including light grey and dark grey, to support the colour of the topcoat (in case of scratches).  

    Figure 5 Click to enlarge

    We modified a conventional white primer to a light grey and a dark grey primer, one modification with carbon black, the other with inorganic IR-reflecting black. Both modifications were tinted to the same colouristic values. Due to the better tinting strength of carbon black, a higher amount of inorganic black was necessary to achieve the similar colouristic result (Figure 4).

    To check the influence of the primer pigmentation, we applied a blue and a red basecoat, including a clearcoat, onto the different primers to complete the full automotive refinish set-up (Figure 6).

    Figure 6 Click to enlarge

    In practice, a red basecoat is more likely to be combined with a white or light grey primer, while a blue basecoat is more likely to be combined with a light or dark grey primer, but not a white one.

    The TSR values including the maximum temperatures of the heat build-up measurements of different multilayer combinations are listed in Table 1.

    Table 1 Click to enlarge

    In both cases (red and blue basecoat), the modification of the standard grey primers (containing carbon black) with inorganic IR-reflecting black pigments showed a significant effect for the multi-layer set-up in total performance.

    Heat Build-Up Effect in a Composite Thermal Insulation System

    Modern composite thermal insulation systems are used to keep the interior of buildings warm in winter and cold in summer to reduce energy consumption for heating and cooling. The insulation layer (commonly expanded polystyrene, EPS) largely reduces heat transport in any direction.

    Figure 7 Click to enlarge

    The darkness of the applied plaster on the EPS is limited, as it may suffer from thermal/thermomechanical stress, especially at the interface between the plaster and EPS layer. Therefore, thermal insulation systems are only offered to a certain point of luminosity values, indicating the darkness of the plaster. Using IR-reflecting pigments, the heat build-up on the composite thermal insulation is reduced, with an expected positive impact on prevention of premature failure (Figure 7). As a consequence, using (dark) grey products with lower luminosity values is becoming a reality.

    In a lab experiment, grey plasters with a 1/3, 1/9 and 1/25 standard depth (STD) were formulated using  different pigment chemistry for each sample (P.Bk. 7, P.Bk. 11, P.Bk. 30 and P.Br. 29) and applied as a thermal insulation system.

    Figure 8 Click to enlarge

    In heat build-up tests for all standard depths, the systems with P.Bk.7 and P.Bk.11 showed a higher equilibrium temperature compared to the systems using P.Bk. 30 or P.Br. 29 (Figure 8).

    Following these lab findings, outdoor exposure tests were performed. During an extraordinarily warm summer day (38 °C maximum temperature), samples coloured with PBk30 and PBk7 at 1/3 STD and P.Br. 29 and PBk7 at 1/9 STD were placed in the sun in Langelsheim, Germany (51.9°N, 10.3°E) facing south.

    Figure 9 Click to enlarge

     

    While the non-NIR reflecting samples reached surface temperatures of around 100 °C, the NIR-reflecting modified samples stayed approximately 10 °C cooler (see set-up of experiment in Figure 9 and summary of results in Table 2).

    Table 2 Click to enlarge

    Optimized IR-Reflecting Inorganic Black Pigment

    While in full shade, the new pigment is more neutral compared to P.Br. 29 (Figure 12).

    This behaviour can also be found in the 1:1 reduction (Figure 13). To achieve this colour shift to the more neutral side while staying with the higher TSR value, a lower tinting strength needs to be accepted.

    Figure 10 Click to enlarge

    Conclusion

    Besides the well-known application of IR-reflecting pigments in coil coatings, possible benefits in two other areas have been found, and a new inorganic black pigment combining jetness and high TSR value was developed.

    In multilayer systems, it is possible to formulate brilliant surfaces combining the brilliance of an NIR transparent topcoat (organic pigments) with the NIR reflection ability of the below primer layer (NIR-reflecting pigments instead of carbon black) to reduce heat build-up of the whole system. Such multilayer systems can be found in automotive OEM or refinishes, as well as in other industrial coatings applications. Although in the automotive industry research is currently focused on optimizing the window glazing due to its higher influence on heat build-up in the car interior, it can be expected that attention will turn back to the coating once the research for glazing is finished and the contribution of the car body/reflective coating gets higher again in relation.
     

    Figure 11 Click to enlarge

    Positive findings for lower heat build-up of thermal insulation systems using IR-reflecting black pigments instead of carbon black or black iron oxide have been reported for lab and outdoor tests. Detrimental effects on the dimension-al integrity of the expanded polystyrene insulation layer can be seen under real outdoor conditions, which can be minimized using IR-reflecting pigments. All in all, one can expect lower energy consumption for cooling building interiors as well as an enhanced lifetime of the thermal insulation system, reducing thermomechanical stress at the EPS/plaster interface.

    A new inorganic black pigment has been developed combining jetness and a neutral colour shade in reductions with an extraordinary IR-reflecting ability bridging the gap between existing products.

    Figure 12 Click to enlarge
    Figure 13 Click to enlarge

    Note: Cited TSR values have been determined in a 20% pigmentation in alkyd/melamine. The powder pigments themselves show even higher TSR values.

    This paper was presented at the 2011 European Coatings Congress, Nuremberg, Germany.

    KEYWORDS: Automotive Coatings Coil Coatings Inorganic Pigments IR-Reflecting Pigments Solar Coatings

    Share This Story

    Looking for a reprint of this article?
    From high-res PDFs to custom plaques, order your copy today!

    Marketing/Business Development Manager, Heubach GmbH, Germany

    Recommended Content

    JOIN TODAY
    to unlock your recommendations.

    Already have an account? Sign In

    • PCI-0724-Global10-Feature-1440.png

      2024 Global Top 10: Top Paint and Coatings Companies

      Who ranks on top? PCI’s annual ranking of the top 10...
      Global Top 10 and PCI 25
      By: Courtney Bassett
    • PCI-0724-PCI25-Feature-1440.png

      2024 PCI 25: Top Paint and Coatings Companies

      PCI's annual ranking of the top 25 North American paint...
      Global Top 10 and PCI 25
      By: Courtney Bassett
    • pci1022-Kinaltek-Lead-1170.jpg

      A Novel Pigment Production Technology

      Following an extensive R&D program that demonstrated...
      Paint and Coating Pigments
      By: Jawad Haidar and Nitin Soni
    You must login or register in order to post a comment.

    Peter Henshaw
    June 21, 2012
    I have seen a lot of different companies switch to the white roof because the black tar roofs absorb too much heat. Then they make the buildings too hot and drives up energy costs. Now with the white roofs, offered by Indianapolis Roofing Contractors for example, is starting to take over the roofing industry.

    Report Abusive Comment

    Subscribe For Free!
    • eMagazine
    • eNewsletter
    • Online Registration
    • Subscription Customer Service

    The Coatings Minute: Your Inside Look at PCInnovations

    The Coatings Minute: Your Inside Look at PCInnovations

    CTT Registration Now Open

    CTT Registration Now Open

    The Coatings Minute: Why Industry News Matters More Than Ever

    The Coatings Minute: Why Industry News Matters More Than Ever

    The Coatings Minute: Print Returns with PCI’s New Showcase Issue

    The Coatings Minute: Print Returns with PCI’s New Showcase Issue

    More Videos

    Sponsored Content

    Sponsored Content is a special paid section where industry companies provide high quality, objective, non-commercial content around topics of interest to the PCI audience. All Sponsored Content is supplied by the advertising company and any opinions expressed in this article are those of the author and not necessarily reflect the views of PCI or its parent company, BNP Media. Interested in participating in our Sponsored Content section? Contact your local rep!

    close
    • Modern arapartment complex painted in bright colors.
      Sponsored byEPS - Engineered Polymer Solutions

      Architectural Polymers Leading the Way in Coatings Innovation

    • paint sprayer in a workshop
      Sponsored byallnex

      Enabling Performance and Compliance: allnex Introduces a New Line of VOC Exempt Solvent-Borne Resins

    Popular Stories

    No. 3 AkzoNobel

    AkzoNobel to Close Two Manufacturing Sites

    A collage of products using non-PFAS

    A Surge in Non-PFAS Releases

    Default Aerospace Image

    PPG Plans Major Aerospace Facility



    PCI Buyers Guide

    Submit a Request for Proposal (RFP) to suppliers of your choice with details on what you need with a click of a button

    Start your RFP

    Browse our Buyers Guide for manufacturers and distributors of all types of coatings products and much more!

    Find Suppliers

    Events

    September 3, 2025

    Coatings Trends & Technologies Summit

    The Coatings Trends & Technologies (CTT) Summit is an annual conference for both liquid and powder coatings formulators and manufacturers to discuss innovations in coatings technology. This event combines high-quality technical presentations, a resource-rich exhibit hall, and dedicated networking opportunities to connect scientific minds, foster innovation, and cultivate game-changing new ideas!

    January 1, 2030

    Webinar Sponsorship Information

    For webinar sponsorship information, visit www.bnpevents.com/webinars or email webinars@bnpmedia.com.

    View All Submit An Event

    Poll

    Longest-running laboratory experiment

    What is the longest-running laboratory experiment?
    View Results Poll Archive

    Products

    CTT Summit Short Courses (Live 9/3/25)

    Coatings Trends & Technologies Summit is expanding its offerings with four short courses. These short courses will offer an extensive day of interactive learning.

    See More Products
    pci  webinar april 2025

    PCI CASE EBOOK

    Related Articles

    • IR-Reflective Pigments: A Black Rainbow of Options

      IR-Reflective Pigments: A Black Rainbow of Options

      See More
    • pci0412-Eck-open-422.jpg

      IR-Reflective Pigment Helps Conserve Energy

      See More
    • New Products

      Huntsman Pigments Showcases Broader Pigments and Additives Range

      See More

    Related Products

    See More Products
    • auto-paints-and-coatings

      Automotive Paints and Coatings, 2nd Edition

    See More Products
    ×

    Keep the info flowing with our eNewsletters!

    Get the latest industry updates tailored your way.

    JOIN TODAY!
    • RESOURCES
      • Advertise
      • Contact Us
      • Directories
      • Store
      • Want More
    • SIGN UP TODAY
      • Create Account
      • eMagazine
      • eNewsletters
      • Customer Service
      • Manage Preferences
    • SERVICES
      • Marketing Services
      • Reprints
      • Market Research
      • List Rental
      • Survey & Sample
    • STAY CONNECTED
      • LinkedIn
      • Facebook
      • Youtube
      • X (Twitter)
    • PRIVACY
      • PRIVACY POLICY
      • TERMS & CONDITIONS
      • DO NOT SELL MY PERSONAL INFORMATION
      • PRIVACY REQUEST
      • ACCESSIBILITY

    Copyright ©2025. All Rights Reserved BNP Media.

    Design, CMS, Hosting & Web Development :: ePublishing

    Painting & Coating Industry (PCI) logo Powder coating summit logo
    search
    cart
    facebook twitter linkedin youtube
    • Sign In
    • Create Account
    • Sign Out
    • My Account
    Painting & Coating Industry (PCI) logo Powder coating summit logo
    • NEWS
      • Latest News
      • Market Trends & Reports
      • Price Alerts
      • Subscribe to eNewsletters
      • Global Top 10/ PCI 25
      • Weekly Featured Article
      • COATLE Word Game
    • PRODUCTS
      • Product News
      • Must See Products and Services
    • MATERIALS
      • Additives
      • Resins/Polymers
      • Pigments
      • Equipment
      • Distributors
    • TECHNOLOGIES
      • Adhesives
      • Architectural Coatings
      • Industrial Coatings
      • Nanotechnology
      • Powder Coatings
      • Solventborne
      • Special Purpose Coatings
      • Sustainability
      • UV Coatings
      • Waterborne
      • FINISHING
        • Finishing News
        • Finishing Technologies
        • Finishing Equipment
      • RESOURCES
        • Columns
          • Ask Joe Powder
          • Did you know?
          • Distribution Dive
          • Focus on Canada
          • Formulating With Mike
          • Innovation Insights
          • Moody's Coatings Conundrums
          • Powder Coating Perspectives
          • Target the Market
          • TiO2 Insider
        • Blogs
          • Editor's Viewpoint
          • Industry Insights
        • Coatings Supplier Handbook
        • Podcasts and Videos
          • COAT-IT! Podcast
          • Videos/PCI TV
        • PCI Store
        • eBooks
        • Sponsor Insights
        • White Papers
        • COATLE Word Game
      • EVENTS
        • Coatings Trends & Technologies Summit
        • Paint and Coatings Academy
        • Webinars
        • Calendar of Events
        • Lifetime Achievement Award
      • DIRECTORIES
        • Buyer's Guide
        • Equipment Directory
        • Materials Directory
      • EMAGAZINE
        • Current Issue
        • eMagazine Archive
        • China Issue Archive
        • Editorial Advisory Board
      • CONTACT
        • Contact Us
        • Advertise
        • Subscribe to eMagazine
        • Subscribe to eNewsletters