Stevens Polypropylene Geomembranes
Polypropylene was developed in 1954 by Nobel Prize winner Giulio Natta. Since then, various grades of Polypropylene have been used in automotive applications such as bumpers, as well as in house wares, recreational furniture, tubing, rope and geosynthetics. The reactor-processed Polypropylene resin Stevens uses to manufacture Stevens Polypropylene Geomembranes offers many benefits to engineers designing  geomembranes for applications including liners, caps and floating covers.

 

Polypropylene is a chemically inert polymer and does not contain any post reactor modifiers that can be extracted over time or have a negative impact on the surroundings. With Catalloy process technology, Polypropylene's molecular structure is modified to provide a product with specialized properties that meet the requirements of flexible geomembranes such as outstanding dimensional stability, low coefficient of expansion and contraction, wide temperature seaming range and good chemical resistance; all without stress cracking.

 

Stevens Polypropylene is manufactured by a proprietary process in which two layers of calendered Polypropylene compound fully encapsulate a polyester reinforcing scrim. Stevens Polypropylene is a thermoplastic material which permits seaming by thermal fusion methods including hot air, hot wedge and extrusion technologies.

ISO-9000

In addition, all Stevens PP Geomembranes are manufactured in an ISO-9001-2000 registered facility.

 

Features & Benefits

  • No plasticizers to leach out and cause embrittlement or cracking.

  • Low coefficient of thermal expansion and contraction provides excellent dimensional stability and lay-flat characteristics.

  • Does not environmental stress crack (ASTM D-1693).

  • Highly flexible for easy conformance to earth contours.

  • Scrim reinforcement provides enhanced tear and puncture resistance.

  • Excellent chemical resistance to most industrial effluents.

  • Available in both potable water and industrial grades in 36-, 45- and 60-mil (0.9 mm, 1.14 mm, and 1.52 mm) thickness.

  • Excellent UV resistance for outstanding weatherability in exposed applications. Stevens Geomembranes are backed by a long-term warranty.

  • Factory fabricated seams made in a controlled environment and require less in-field labor.

Product Specifications

 

Grades:

Polypropylene is available in Industrial or ANSI/NSF-61 certified potable water grades.

 

Color:

Standard color for Industrial Grade is Slate Brown/Black. Standard color for Potable Grade is Tan/White. Custom colors available on special order with 60 day lead time.

 

Dimensions:

  • 36 mil (0.9mm) is provided in rolls 75.75" wide x 900' long (1.92m x 275m).

  • 45 mil (1.14mm) is provided in rolls 75.75" wide x 900' long (1.92m x 275m).

  • 60 mil (1.50mm) is provided in rolls 75.75" wide x 600' long (1.92m x 183m).

Weight:

  • 36 mil weighs approx. 0.11 lbs./sf (0.54kg/m2) or 625 lbs (283 kg) per roll.

  • 45 mil weighs approximately .18 lbs./sf (0.88kg/m2) or 1,025 lbs (464 kg) per roll.

  • 60 mil weighs approximately .28 lbs./sf (1.34kg/m2) or 1,060 lbs (481 kg) per roll.

Drinking Water 

 

Stevens potable water Polypropylene Geomembranes meet the requirements for contact with drinking water, including ANSI/NSF-61, in addition to international standards such as WRC (British Water Regulation Commission) and DWI (British Drinking Water Inspectorate). Polypropylene has also been tested in accordance with all applicable ASTM, FTMS, NSF and GRI test methods.  Click HERE for NSF Standard 61 information.

 

Comparative Test Values* for R-PP and HDPE

Property Test Method R-PP 45  HDPE 40 HDPE 60 HDPE 80 HDPE 100
Thickness nominal, mil (mm) ASTM D 5199 41 (1.04) 36 (0.9) 54 (1.37) 72 (1.83) 90 (2.3)
Density, g/cm3 ASTM D 1505 91 94 94 94 94
Tensile, yield min,. lb/in. (kN/m) ASTM D 638, Type IV 200 (35) 86 (15) 130 (22.8) 170 (29.8) 210 (36.8)
Elongation at yield, % ASTM D 638, Type IV 21 13 13 13 13
Puncture Resistance, min., lbs. (kN) FTMS 101 C, Method 2031 210 (.93) - - - -
Method 2065 - 52 (0.23) 75 (0.33) 100 (0.45) 120 (0.53)
Tear Resistance, min., lbs. (kN) ASTM D 5884 55 (0.24) - - - -
ASTM D 1004 - 30 (0.13) 45 (0.20) 60 (0.27) 75 (0.33)
Dimension Stability, % ASTM D 1204 1 2 2 2 2
Envir. Stress Crack Resistance (min. hrs. no fail) ASTM D 1693 Not Affected Varies from 200 to 1500 hours, depending on compound
Coefficient of Thermal Expansion, cm/cm/C 10-5 ASTM D 696 40-80 C range 13 30 30 30 30
Crystallinity, %   < 15 50 to 60
Thermal Fusion Window for Seaming, F (C) n/a

550 - 1000 F

(288 - 538 C)

 750 F to 950 F (399 to 510 C) May vary with compound

* This chart is for comparison purposes only, not for specification, since the test methods cited are those used for unreinforced HDPE and not reinforced products such as Stevens Polypropylene or Hypalon Geomembranes.

 

 

Additional Information

 

Stevens PP Geomembrane End-Use Applications Chart

 

Stevens PP Geomembrane Physical Properties Chart

 

Stevens PP Geomembrane Chemical Resistance List

 

Stevens PP Geomembrane Brochure

 

If you have any questions about the line of Stevens Polypropylene Geomembranes, click HERE to send email.