Volume 7, Issue 8 - September 2006

The Cutting Edge

Vinyl Extrusion Supply–Think Globally
by Jim Plavecsky

Have you noticed that the list of vinyl extrusion fabricators serving North America is rapidly growing? Yes, window manufacturers are interested in off-shore suppliers that can help them lower their material costs. But they also do not want to give up the comfort factor that domestic suppliers give when it comes to doing business with a supplier that fully understands the North American window market. So, window fabricators these days are looking for GLOCAL solutions to the problem of rising vinyl extrusion prices. They want to benefit from the increased competition for their business among GLOBAL vinyl suppliers but they still want the benefits that a LOCAL supplier traditionally has offered such as superior quality, adherence to local industry test standards, speed of delivery, technical service, local warehousing and marketing support based on a true understanding of the local market dynamics. 

Understanding the Extrusion Process
With this in mind, and tempted by the prospect of lower material costs, many manufacturers are seeking to understand more about vinyl itself so they can make informed decisions about their choice of vinyl supplier. Many are reluctant to let go of a system that, other than the issue of rapidly rising material prices, has served them well. They hear horror stories about vinyl compounds with lead stabilizers that can eventually leach out of the vinyl and cause potential health problems for consumers. This is largely based upon circumstances arising from the vinyl mini-blinds industry. 

Actually, all vinyl products are made from combinations of the base vinyl resin and various additives which provide particular properties depending upon the desired end use. Vinyl window extrusions typically are formulated with approximately 80 percent vinyl resin with a variety of compound additives. These include stabilizers, pigments, modifiers and process enhancers.

The stabilizers are used to help minimize the degradation of the vinyl during exposures to high temperatures in the extrusion process. Stabilizers are also used to prevent changes to the vinyl compound after it is produced during a lifetime of exposure to harsh outdoor weather conditions. Heat, humidity and UV-radiation can alter the properties of vinyl compounds significantly. This is actually the result of chemical reactions that take place with oxygen that are catalyzed by heat and UV. If the vinyl compound changes chemically over time, so will its properties. It may become brittle and lose its elasticity causing it to crack upon expansion and contraction. Vinyl stabilizers serve to inhibit these unwanted chemical reactions thereby preserving the original product properties. Without these very important additives, the vinyl window would not enjoy the reputation that it owns as a long-lasting and maintenance-free product. 

Modifiers can provide impact resistance or resistance to cracking or breaking during the fabrication process. Vinyl extrusions are exposed to a variety of operations such as sawing, routing and punching during the window fabrication process, and this must be done with speed and without damaging the extrusion in the process. So these additives help to make the end product more affordable by speeding up the fabrication process while reducing scrap. The same additives also improve resistance to “knock-around” abuse which takes place during transportation, storage and installation.

Once the additives have been combined with the resin, the resulting material is what we call a vinyl compound. The vinyl additives are mixed evenly throughout, which ensures the consistency of color, strength and UV resistance. This leads me to another important ingredient, the process additive. Process additives can also be used to increase dispersion characteristics of the compound. This helps to ensure uniformity of blending as various ingredients are mixed into a homogenous compound. This means that each foot of extrusion will have the same properties as the foot before it as well as the foot that is manufactured after it. After all, if the UV stabilizer is not mixed evenly, one might have one window lasting very long and the next window failing way before its time. 

Once compounded, these additives are chemically combined or locked into the structure of the profile material, minimizing any loss of properties or discoloration. The compound is then melted, dispersed evenly and then forced through the die in the process called extrusion. 

Look for AAMA Certification
High quality extrusions will be capable of withstanding abuse during shipping, fabrication and long term usage in the field. AAMA maintains a PVC Extrusion Certification Program which requires certified vinyl extrusion manufacturers to pass a series of ongoing laboratory and weathering tests of their extrusions which are selected randomly by the program’s administrator. These are tested for compliance to AAMA standards (AAMA 303 Specification). This is one of the first things to look for when selecting a GLOCAL supplier. 

In addition to this, the smart window fabricator will look for suppliers that have technical expertise based not only abroad (where it is important in maintaining production standards) but in North America as well (where it is important to meet not only local industry specifications). These include standards outlined in the AAMA program as well as internal standards that may be unique to the window manufacturer itself. The GLOCAL supplier will be able to do both!

Jim Plavecsky is the owner of Windowtech Sales Inc., a sales and consulting firm specializing in the door and window industry based in Columbus, Ohio. He may be reached at JimPlav@insight.rr.com.

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