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Polymer Modifiers

Using a solids phase (polymeric) additive to make flexible PVC

For flexible PVC, DuPont™ Elvaloy® solid-phase (polymeric) plasticizer adds permanent flexibility, enabling the development of higher-value products such as single-ply roofing, environmental liners, "no-dig" water and sewer pipe repair liners, coated fabrics, footwear, and wire and cable jacketing.


Many flexible PVC products such as these are built for long service life, requiring decades of flexibility and retained thermoplastic properties. There are polymeric plasticizers on the market which have low migration characteristics. However, Elvaloy® goes far beyond these in molecular weight (see table).

Type of Plasticizer Range of Molecular Weight
Monomeric Up to 500
Polymeric 1000 - 5000
DuPont™ Elvaloy® 250,000 - 400,000

The high molecular weight Elvaloy® (or permanent flexibilizer) won’t migrate to the surface of the flexible PVC and be lost to the environment. By “locking in” flexibility, it helps prevent brittle failure of the flexible PVC sheet or component. As shown in Graph 1, using Elvaloy® HP661 PVC modifier instead of another common plasticizer results in flexibility at much lower temperatures, with properties retained after extraction testing.

Low-temp blend test - Elvaloy® HP661 vs. DIDP

Graph 1:  Low-temperature blend test - Elvaloy® HP661 vs. DIDP

Increasing Flexible PVC Service Life
DuPont™ Elvaloy® is a pliable polymer that’s highly miscible with PVC. This makes it possible to incorporate into a  superior compound for flexible PVC. It can be especially useful in applications calling for long service life in climate or environmental exposures that might extract liquid plasticizers. Elvaloy® can’t migrate out of the system; its unique chemistry forms an alloy with PVC, locking in flexibility at the molecular level, rather than just mixing in like other plasticizers.

Product Selection for Flexible PVC
Popular DuPont resins used to flexibilize (plasticize) polyvinyl chloride (PVC) compounds include the following, arranged by melt index:

Plasticizer (Flexibilizer) Melt Index (g/10 min)
Elvaloy® HP 441


Elvaloy® HP 661


Elvaloy® HP 662


Elvaloy® 741


Elvaloy® 742


Elvaloy® HP 771


Technical Processing Information
More detailed information about flexible PVC formulating and compounding with DuPont™ Elvaloy® can be found here:

For additional product data or material safety data for any of these flexible PVC polymer additives, see the DuPont™ Elvaloy® Web site.

Application Examples
One of the leading applications for flexible PVC made with Elvaloy® is single-ply roofing, where membranes modified with Elvaloy® KEE face sun, hail, dropped tools, spilled or airborne oils and chemicals, and increasing foot traffic lately from “green roof” gardeners and white “cool roof” cleaners.

In flexible PVC fold-and-form pipe liners, durable wire and cable jacketing, pond liners, geomembranes and inflatable boats, building flexibility that lasts begins by choosing Elvaloy® plasticizer.