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Rigid or Unplasticized PVC – Pipe & Fittings Using SMI Precipitated and Ground Calcium Carbonates

Polyvinyl Chloride (PVC) is a versatile polymer well suited for a variety of pipe applications ranging from large sewer piping to residential drain waste vent (DWV) piping, as well as smaller potable water piping and electrical conduit. Applications such as DWV are not pressure rated, which reduces the impact resistance required to function in the application. Others, such as residential potable water, carry ratings appropriate to their intended application. More recently, chlorinated PVC (CPVC) has been approved in some municipalities for use in hot water piping because of its superior high-temperature properties versus PVC.

Both Specialty Minerals Inc.’s (SMI’s) ground calcium carbonates (GCCs) and precipitated calcium carbonates (PCCs) contribute to the ultimate performance properties of this wide variety of piping applications. Product choice depends on the specific application and the property requirements of that application. For maximum property development and formulation flexibility, our surface-treated carbonates are designed to give good dispersion along with excellent incorporation in the polymer matrix.

Calcium carbonate improves the base properties of polyvinyl chloride by adding stiffness to the polymer matrix and improving impact resistance as particle sizes become smaller. Click here to read about the role of filler particle size on impact. Calcium carbonate also improves compounding performance by helping disperse various ingredients into the PVC powder blend and improves processing by making polymer flow more homogenous.

The relationship between a calcium carbonate’s particle size and the impact strength of the finished rigid PVC part also applies to extruded pipe and injection-molded fittings. The object is to produce an acceptable part at the lowest possible cost. This is achieved by minimizing the level of ingredients that add cost to the PVC formulation, such as impact modifier.

The ideal is to eliminate the use of impact modifier. This can be achieved in larger diameter pipes using a formulation containing a 2-3 micron calcium carbonate. The impact specification is usually more difficult to meet in a small diameter pipe, thus a finer calcium carbonate must be used—usually in the range of 1-2 microns. In applications that require an impact modifier, the amount of modifier can be minimized by using a very fine, submicron PCC such as Tuffgard®, Calofort® S, or Ultra-Pflex® PCCs. This approach is especially useful in demanding applications such as pipe fitting formulations and large diameter corrugated drainpipe.


Click on a product’s name on the chart to download the technical data sheet for that product.

PVC Pipe
 In modern life, we take the long-term performance benefits of PVC pipe for granted. PVC pipe functions without corrosion or leaking and repairs are simple to perform compared to cast iron or copper piping. To assure the purity of potable water supplies, ingredients for water-system piping used in the United States must be certified by the NSF (National Sanitation Foundation). SMI’s calcium carbonates are NSF-certified for plastics piping. These products include: Hi-Pflex® 100, Super-Fil®, Vicron® 15-15, Super-Pflex® 100, Super-Pflex® 200, Super-Pflex® MS, Tuffgard®, and Ultra-Pflex® calcium carbonates.

Choosing an SMI product generally depends on pipe diameter as well as the specific requirements of the application. The selector chart below gives some general guidelines.

Click on the name of a product of interest on the chart to download the technical data sheet for that product.


PVC Pipe Fittings
 Visit a home improvement store and look down the plumbing aisle for PVC fittings. You will see a myriad of fittings for pipe connection applications. To assure leak-proof, durable connections, fittings need to be molded to close tolerances with a predictable margin of shrinkage in the PVC compound.

SMI’s PCCs, including Ultra-Pflex®, Calofort® S, Tuffgard®, Super-Pflex® 200, and Super-Pflex® MS, possess the quality and performance needed for these demanding applications. All these products are certified by NSF for potable water applications.

 

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