Pipeline Pigs Travel Further with DIPRANE™ 53 from Dow Hyperlast

Birch Vale, UK- September 1, 2009

Pipeline pigs manufactured from DIPRANE™ 53, a polyester quasi MDI prepolymer, experience less wear, allow for increased safety and energy savings, and have a longer working life than similar pigs manufactured from full TDI polyester prepolymers. DIPRANE 53 prepolymers are manufactured by Dow Hyperlast, part of Dow Polyurethane (PU) Systems, a business group of The Dow Chemical Company.

Dow Hyperlast collaborated with pig manufacturers to produce gauges made from three different compounds and then tested them in a transmission line of a major natural gas company. The pigs were run through an 80-mile pipeline at five miles per hour, and then examined for wear and tear, as well as cleaning effectiveness. The results were striking:

• The first type of pig, made with conventional toluene diisocyanate (TDI) polyester, showed significant wear after just one run (80 miles) and could not be used for a second run.
• The second type, manufactured from a low monomer TDI polyester prepolymer, showed better performance, but survived only two runs (160 miles) before wearing out.
• The third type, made from DIPRANE 53 quasi MDI prepolymer developed by Dow Hyperlast demonstrated the best cleaning capability, completed two runs (160 miles) successfully and was still ready for more, showing signs of only mild wear. According to the engineers who conducted the test, the quasi MDI pigs were able to “remove lots of material while showing excellent resistance to wear.”

The testing demonstrates that quasi MDI prepolymers offer considerable benefits in applications such as pipeline pigs, where they exhibit excellent performance in abrasion resistance. In hydrolytic tests they offered increased moisture resistance. The advantages of quasi MDI prepolymers, such as DIPRANE 53, include the flexibility to cover a wide range of hardnesses so machine down-time is reduced as fewer changes to production are required. This also increases efficiency in material planning, inventory management and warehousing of chemicals.

Due to their different properties, quasi MDI prepolymers may require different engineering controls than TDI prepolymers, which—in certain circumstances and conditions—can achieve greater efficiences in the manufacturing process. Quasi MDI prepolymers can also be processed at ambient temperatures, allowing for improved safety in the handling and manufacturing of the product, and up to 25% energy savings when compared with full TDI prepolymers.

Dow Hyperlast offers a comprehensive range of products for a variety of demanding applications across the oil and gas industry. Its DIPRANE™ polyurethane elastomer product range offers engineers and processors the opportunity to utilise the versatility of polyurethane chemistry to their full advantage.

DIPRANE polyurethane elastomers are available for cast or spray application and provide excellent tear and abrasion properties, improved solvent resistance over conventional ester urethanes, durability and toughness through a hardness range of 25 to 95 Shore A and antistatic properties to below 106 Ohms. DIPRANE polyurethane elastomers are available both as full prepolymers and as quasi MDI prepolymer for the manufacture of pipeline pigs providing excellent durability and longevity.

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For Editorial Information:
Elise Heffelfinger
The Dow Chemical Company
+41 44 728 3269

Tony Watson
Watsonlook
+44 (0) 1626 870289
tonywatson@watsonlook.co.uk