SELECTING EXTERIOR TOPCOATS BASED ON AESTHETIC PERFORMANCE

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Hilary Jackson
6 years ago
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1 SELECTING EXTERIOR TOPCOATS BASED ON AESTHETIC PERFORMANCE

2 COATINGS & ULTRAVIOLET LIGHT

3 What is a Coating Polymer? A carbon chain created primarily with by-products of the petroleum industry. These polymers, also known as resins, provide the framework for which the coating s performance is built upon Examples of a coating polymer include: Epoxy Urethane Acrylic Fluoropolymer

4 What Causes Coating Degradation? Light Exposure Primarily Ultraviolet (UV) light, along with oxygen and water, can induce slow degradation (aging) of many organic polymers found in coatings Elements Temperature fluctuations, pollution, chemical exposures, rain, etc. can also contribute to degradation, usually accelerating the process

5 Radiant Energy The Earth s atmosphere filters and absorbs most of the more powerful shorter wavelength radiation, including UV light.

6 Responses of Radiant Energy Transmission UV light harmlessly passes through film to the substrate Reflection UV light is reflected from coating surface Absorption Coatings absorb UV light but dissipate it as harmless heat

7 Mechanisms of Coating Degradation UV light absorbed by a coating excites the polymer, raising the energy level that must be eliminated This energy breaks the primary polymer bonds, creating free radicals and begins a chain reaction of degradation if UV exposure continues Depending on resin type, once degradation begins, a rapid breakdown will occur

8 Increasing UV Resistance UV Resistant Binders Reflective Pigments UV Absorbing Pigments UV Inhibitors

9 PIGMENT SELECTION

Bright organic colors are less expensive than bright inorganic

10 Organic vs. Inorganic Organic Pigments Synthetic Less color stable than inorganic Bright organic colors are less expensive than bright inorganic Inorganic Pigments Naturally occurring; metal based Color stable Less susceptible to free radicals Bright colors are more expensive to produce

11 Pigment Quality There are various grades of both inorganic and organic pigments Quality and performance can depend on: Material make-up Carbon content Pigment color Technology (organic vs. inorganic) Resistance to free radicals

12 EFFECTS OF ULTRAVIOLET LIGHT COLOR AND GLOSS

13 Ultraviolet Light (UV) on Color & Gloss Damage caused by UV light can discolor the binder, fade pigments and affect gloss Acrylic Polyurethane FEVE Fluoropolymer Panel demonstrates coating performance after 10,000 hrs. QUV-A Exposure

14 Viewing Gloss High gloss Low gloss High gloss Light is reflected causing coating to look brighter Low gloss Light is diffused causing coating to look duller

15 Viewing Color Color, or color perception, can be greatly affected by a light source or type Color indoors can be perceived much different than the same color outdoors Exact color and color differences can be determined using color equipment View color selection in same light source as exposure.

16 Comparing Color Color and color differences can be measured in Delta E (DE) in different ways: CIELAB2000 CMC FMC II Hunter Measurement scale should always be stated when comparing color

17 TOPCOAT SELECTION BASED ON GENERIC TYPE

18 Generic Coating Types Epoxies Alkyds Acrylics Polyurethanes Polysiloxanes FEVE Fluoropolymers Control 6 Months Exp. Waterbased Epoxy (black)

19 Epoxies UV Light Performance Poor UV stability Color Yellowing of binder Fading of pigment Chalking Gloss Extreme loss These chemical and abrasion resistant coatings generally degrade in UV light due to absorption by a polymer chain in the binder. Epoxies are not recommended as topcoats when aesthetics are required. Control 6 Months Exp.

20 Alkyds UV Light Performance Poor to moderate (depending on quality of oil) Color Some discoloration of binder Fading of pigments Chalking Gloss Will decrease at an accelerated rate Alkyds convenient application make them widely used and can provide basic UV performance if comprised of quality materials.

21 Acrylics UV Light Performance Good to very good Color Little change to binder Possible fading of pigments Gloss Moderate rate of loss While acrylic binder is not highly affected by UV, additives used to decrease cost and lower priced pigments can cause performance to decrease dramatically.

22 Aliphatic Polyurethanes UV Light Performance Very good Color Little change to binder Slow fading of pigments Gloss Slow rate of loss Binder is not highly affected by UV, but less costly additives and pigments can greatly affect performance. Generally provide good color and gloss retention.

23 Polysiloxanes UV Light Performance Color Gloss Very good Some yellowing of binder (epoxy) Less potential fading of pigments Slow rate of loss Polysiloxanes typically utilize epoxy, acrylic or urethane binders. Those with acrylics and urethanes will outperform epoxy versions in both color and gloss.

24 FEVE Fluoropolymers UV Light Performance Color Gloss Excellent Outstanding binder Very good pigment tolerance to UV exposure Extremely slow rate of loss Fluoropolymers utilize binders that have a tenacious chemical bond, which are not highly affected by UV and typically use additives and pigments of high quality that do not affect color and gloss performance.

25 Life-Cycle Cost of Topcoat Aesthetics Only 20 Year Life-Cycle of 30,000 FT 2 Polymer Type # of Applications Years Between Touch-Up/Recoat Service Life Final Cost Alkyd Years 20 Years $ 230, Acrylic Years 20 Years $ 140, Polyurethane Years 20 Years $ 96, Polysiloxane Years 20 Years $ 77, Fluoropolymer (FEVE) Years 20 Years $ 71, Note: Figures listed are for topcoats only; they do not include primer and intermediate coat application and material costs.

26 OTHER CONSIDERATIONS COATING PERFORMANCE AND TESTING

27 Other Factors, Which Can Affect Aesthetics Surface preparation Coating compatibility Complete coating system selection Performance for specific environments Application equipment & technique Specification requirements

28 Writing Specifications Write performance based specifications with standards and minimum result requirements Place coatings in Division 9: Section High- Performance Coatings Utilize Division 9 Sub-Sections to better define the scope of work & differentiate critical design elements Seek assistance for side-by-side comparison of products considered for substitution Request slight, but noticeable variation in color between intermediate coat and topcoat to ensure proper coverage.

29 Specifications By incorporating performance standards into a specification, the owner is assured suitable, high-quality products South Florida/Arizona exposures AAMA (weathering standards only) EMMAQUA: ASTM D 4141 QUV: ASTM G 53 or ASTM D 4587 Prohesion: ASTM G 85 Salt Fog: ASTM B 117

30 Exterior Testing Florida Exposure Various angles to the sun Extreme sun exposure Salt air and spray Arizona Exposure Intense Heat Various exposure angles Minimum cloud cover to maximize radiation exposure Dry harsh conditions

31 Real World Limitations High-performance coating systems could take 20 years before coating degradation Coating technology is dynamic and initial performance results are required quickly

32 Accelerated Testing Natural exposures can take years to obtain results Accelerated testing is utilized to emulate natural exposures with high concentrations of elements. UV Exposure Sunlight Concentrator EMMAQUA UV/Prohesion Humidity

hours condensation 8 hours UV/4 hours condensation

33 Accelerated Weathering UV Exposure (QUV-A) Closely simulates natural sun Cycles Include: EMMAQUA 4 hours UV/4 hours condensation 8 hours UV/4 hours condensation Equatorial mount with mirrors and water Intensity of 8 suns Tracks sun movement

34 Gloss Retention (White) QUV Exposure (ASTM D 4587)

35 Color Change (White) QUV Exposure (ASTM D 4587)

36 Importance of Systems Unprimed 32 hrs. Alkyd 500 hrs. Epoxy 4,000 hrs. Zinc-Rich Urethane 10,000 hrs.

Utilizing Results Performance specification and minimum results based on both laboratory and natural exposures Key Criteria Color retention - Delta E (color

37 Utilizing Results Performance specification and minimum results based on both laboratory and natural exposures Key Criteria Color retention - Delta E (color space) Gloss Retention (change from standard) Chalking Adhesion (system must remain in place) Retain sample panels Product warranty required (outline acceptable ranges)

38 CASE STUDIES EXTENDING PERFORMANCE WITH FEVE FLUOROPOLYMERS

39 Water Storage Tank Mt. Jackson, VA Finish Coat: FEVE Fluoropolymer

40 OBSERVATION DECK PORT CANVERAL, FL Finish Coat: FEVE Fluoropolymer

41 Finish Coat: FEVE Fluoropolymer (Metallic) CAST IRON FAÇADE SALT LAKE CITY, UT

42 High Rise New York, NY 12+ years of Performance (2002) Finish Coat: FEVE Fluoropolymer (Metallic)

43 Important Points UV light degrades coatings by activating free radicals in binder, pigments and additives. Various binders react differently to free radicals. Additives can also be used to limit their effect. Color and gloss retention depends on performance of binder, pigments and additives. High-performance coatings like FEVE Fluoropolymers, despite being more expensive, provide longer-term aesthetic performance and lower life-cycle cost.

44 Thank you for your participation in today s presentation. QUESTIONS?

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