Effective Rigid PVC Modification with DuPont™ Elvaloy®

DuPont™ Elvaloy® resin modifiers improve the performance and lower the cost of rigid PVC compounds

For makers of rigid PVC products, DuPont™ Elvaloy® resin modifiers widen the melt temperature processing window and lower PVC compound viscosity without increasing fusion time.

Benefits of Using Elvaloy®

  • Increased production rates due to ductile dart-drop impact performance at lower extrusion temperatures. Parts will cool faster, extrudate should be stiffer and easier to handle, size etc.
  • Reduced ingredient costs by increasing the low-cost filler level, reducing thermal stabilizers and/or reducing process aids
  • Better ductile impact performance at higher filler loadings that competitive products
  • Smoother extrudate surfaces, as evidence by higher gloss, will maintain impact performance longer and resists cracking better

The following table shows Gardner dart drop test* results comparing PVC impact brittleness for three different modification resins at three different processing temperatures:

PROCESS TEMPERATURE 

 ACRYLIC  ELVALOY® 4924   ELVALOY® HP661 
 180°C   Ductile  Ductile  Ductile
 170°C  Brittle  Ductile  Ductile
 160°C  Brittle  Brittle  Ductile
 

*Gardner Drop Dart: ASTM D4226 "Impact Resistance of Rigid PVC Building Products" - Procedure B. All samples are tested until either brittle failure or the capacity of the test was exceeded at 264 in.-lb.

A Range of Choices for PVC Impact Modification

The following table lists DuPont™ Elvaloy® terpolymers (arranged by chemical type) used for rigid PVC toughening:

ELVALOY® GRADE USED IN RIGID PVC

POLYMER TYPE   MELT INDEX (G/10 MIN.)   DENSITY (G/CM3)
 Elvaloy® 741   E/VA/CO  35   1
 Elvaloy® 742  E/VA/CO  35  1.02
 Elvaloy® 4924  E/VA/CO  15   1.03
 Elvaloy® HP441  E/nBA/CO  8  0.98
 Elvaloy® HP661  E/nBA/CO  12   0.96
 Elvaloy® HP662  E/nBA/CO  25   0.96
 

Although effective when used as the primary PVC impact modifier, Elvaloy® also can be used in combination with other impact modifiers to balance viscosity, die swell and cost.