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Bulletin #LG04 - 05/08

Laminated Glass Products With LoETM Coatings

LAMINATED GLASS HISTORY:

Laminated glass has been in the market place since the 1930's and is currently used in the following applications: · Automotive ­ windshields to provide non-lacerative effects to vehicle personnel in a crash · Safety Glazing ­ to provide break safe characteristics of glass laminates used in residential and commercial buildings and transportation vehicles · Acoustical Applications ­ to provide sound attenuation for homes, commercial buildings and transportation vehicles · Ultra-violet Radiation Reduction ­ to provide a lower UV transmission in glass products to reduce the opportunity of fading of furnishings · Hurricane Impact Codes ­ to provide impact resistance to flying debris during hurricanes

ATTRIBUTES OF SGP AND CONCERNS WITH THE USE OF SGP INTERLAYER LAMINATES:

· Is not hygroscopic therefore, will not have no cloudy appearance around the periphery of the laminate · Sputtered LoETM coatings can be used in the laminate because the interlayer does not absorb moisture · Has been used successfully in hurricane resistant laminated glass products · No benefit in sound attenuation because of the rigidity of the SGP

ENERGY CODES FOR HURRICANE ZONES:

To meet Solar Heat Gain Coefficient requirement of the energy codes in southern states, the use of sputtered LoETM laminated products may be required. With insulating glass units, the LoETM coatings can be applied to the non laminated glass lite. With monolithic laminated glass products, the coating would need to be on the #2 or #3 surface of the glass laminate and next to the interlayer.

CARDINAL EXPERIENCE: PRODUCTS:

· Polyvinyl Butyral (PVB) ­ dominant interlayer material in laminated glass products. US Manufacturers ­ DupontTM and Solutia · Sentry Glass® Plus Interlayer (SGP) ­ relatively new product that is used for hurricane impact codes. Manufactured by DupontTM Moisture is known to cause corrosion of sputtered LoE² ® coatings. PVB is a hygroscopic material, meaning that it attracts water molecules from the surrounding environment through absorption. The absorption of water molecules in PVB glass interlayers may result in milkiness or blush around the periphery of laminated glass products. This can be seen in Fig. LG04-1 which is a clear non LoETM coated PVB laminate exposed for 40 weeks in Cardinal's P-1 Chamber. The P-1 Chamber exposes the test samples to an environment of 140°F (60°C), constant water spray and constant UV radiation.

ATTRIBUTES AND CONCERNS WITH THE USE OF PVB INTERLAYER LAMINATES:

· Provides impact resistance to meet safety glazing codes · Provides sound attenuation · Reduces UV transmission · Is hygroscopic ­ absorbs moisture and in time can have a cloudy appearance around the periphery or cause delamination of the PVB · Has been used successfully in hurricane resistant laminated glass products · Should not be used with sputtered LoETM coatings because of the potential for coating corrosion to occur

Edge blush / milkiness caused by moisture absorption

Fig. LG04-1: Clear PVB Laminate exposed to P-1 Testing

Bulletin #LG04 05/08 Page 1 of 2

Bulletin #LG04 - 05/08

Cardinal has witnessed the corrosion of the sputtered LoE² ® coatings used with PVB laminates exposed to the P-1 test conditions and from product inspected in the field. Fig. LG04-2 shows the corrosion of Cardinal's LoE² ® coating after 40 weeks exposure in the P-1 test chamber.

Edge blush / milkiness LoE² ® corrosion

P-1 TESTING SUMMARY

Samples laminated with PVB interlayers exposed in the P-1 test developed LoE² ® corrosion starting at the edge of the glass with corrosion slowly migrating inward toward the center of the laminate. The first signs of corrosion were noted as early as 6 weeks after exposure to these conditions. After 40 weeks of exposure, corrosion had extended over 1" from the corners and over ½" inward along the edges of the samples. PVB interlayers from multiple manufactures were tested in the study and all showed the same tendency for corrosion. This is not surprising as it is well known that PVB interlayers are hygroscopic and that sputtered LoETM products will corrode when exposed to moisture. Testing of LoE² ® laminates made with the SGP interlayer did not show any corrosion through 40 weeks of P-1 testing. The P-1 test has not yet been directly correlated to outdoor exposure, though this testing experience indicates the potential for corrosion of the LoETM with PVB interlayers in the field. Installations with glazing systems that retain water are known to exasperate the problem of moisture absorption of PVB laminates, and are the most likely to show this phenomenon.

Fig. LG04-2: PVB laminate with LoE² ® coating exposed to P-1 testing.

Fig LG04-3 shows a PVB LoE² ® laminated glass product installed in a window in the field for approximately 5 years. The window was installed in Florida and it is not known when the first indication of corrosion occurred.

Edge blush / milkiness

CARDINAL RECOMMENDATIONS:

To meet energy and impact codes, Cardinal's LoE3-366 coating may be required in laminated glass products. From Cardinal's testing experience, Cardinal does not recommend the use of and will not supply the LoE3-366 coating in monolithic PVB laminated glass products. Cardinal does recommend for any monolithic applications of laminated glass where the LoE3-366 product is specified that the interlayer be SGP. For insulating glass products, it is recommended that the LoETM coatings be applied on the non-laminated lite of glass.

The information in this Technical Service Bulletin is subject to the disclaimers and other limitations appearing in the DISCLAIMER that accompanies this Bulletin and at www.cardinalcorp.com. ©Copyright 2008 Cardinal LG Company

LoE² ® corrosion

Fig. LG04-3: LoE² ® PVB laminated glass product after exposure to 5 years in the field.

Bulletin #LG04 05/08 Page 2 of 2

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