DPR® 40

• The DPR products are low molecular weight, liquid polymers of natural rubber. The chemical backbone is cis-1,4 polyisoprene from natural rubber.
• DPR liquid rubber offers processing flexibility and performance options for a wide range of applications. The DPR products vulcanize at either ambient or elevated temperature with standard curatives for natural rubber. The cure cycles can be as short as a few minutes to as long as several days. The DPR products contain no solvents or additives; and they are compatible with a broad range of solvents, plasticizers, resins and polymers.
• Liquid natural rubber improves rubber and polymer compounding and final processing. It acts as a plasticizer to reduce cycle time and energy consumption. Since it cures by the same mechanism as natural rubber, it becomes part of the polymer matrix and remains non-fugitive. This extends the life of the finished products.
• DPR liquid natural rubber is available in several grades that vary by average molecular weight. The lower molecular weight grades have lower viscosity.
• DPR liquid rubber has excellent wetting characteristics. It is a superior dispersion aid for many synthetic fibers and other rubber reinforcements. DPR can bind more than ten times its weight in abrasives for grinding wheels and for other abrasive or friction products.
• DPR reduces the viscosity of uncured rubber when added at levels of 5-to-20 parts of rubber. This reduces power requirements, improves blend consistency, and reduces the risk of scorching. It can be used with natural rubber and such polymers as polychloroprene, EPDM, polybutadiene, SBR and acrylonitrile-isoprene.
• Liquid rubber supports high carbon black loading without the problems associated with fugitive plasticizers. Typical process oils allow high loadings of carbon black, but they reduce the final hardness and they can migrate from the finished product. Liquid rubber allows similarly high carbon black loading and reacts into the final rubber matrix. The cured rubber has superior properties, and it maintains the properties because the DPR does not become fugitive.
• DPR liquid rubber improves the stability of heavy-duty lubricants by increasing the resistance to flow on vertical surfaces and by holding dry additives in a more stable suspension.
• A minor addition of DPR liquid rubber to asphalt formulations reduces flow at high temperatures and maintains flexibility at cold temperatures. This combination of benefits is unique in asphalt compounds.
• DPR Industries offers a Compounding Guide with starting point formulations for these and other applications.
• DPR liquid rubber provides many performance properties into the finished polymer system. The attributes result from the inherent properties of natural rubber.

DPR liquid rubber provides all the performance properties of natural rubber in a convenient liquid. Liquid rubber performs many functions in a wide range of applications:

• Polymeric binder for grinding wheels and friction products.
• Reactive rubber processing aid
• Reactive vehicle for rubber additives
• Rheology modifier for lubricants
• Polymer base for molding and tooling systems
• Polymer base for electrical encapsulants
• Polymer base for automotive sealants
• Asphalt modifier

DPR liquid rubber is a low molecular weight natural rubber. It’s a viscous liquid at typical processing temperatures. The following table indicates the viscosity (cps.) at typicalconditions:

DPR products normally are packaged in 350 lb. 55-gallon steel open-head drums. They also are available in 5- gal pails and 4.4 lb (2 kg) or other low melt poly-bags. The poly-bags can be placed directly into a Banbury mixer when used for tire or other application. Alternatively, a pre-weighed amount can be poured into the mixer.Custom packaging is available.