Patents with Abstracts
1.“Asphalt i/ˈæsfɔːlt/ or /ˈæʃfɔːlt/ or /ˈæsʃfɛlt/, also known as bitumen, is the sticky, black and highly viscous liquid or semi-solid present in most crude petroleums and in some natural deposits; it is a substance classed as a pitch. Until the 20th century, the term asphaltum was also used.
The primary use of asphalt is in road construction, where it is used as the glue or binder mixed with aggregate particles to create asphalt concrete. Its other main uses are for bituminous waterproofing products, including production of roofing felt and for sealing flat roofs.
The terms asphalt and bitumen are often used interchangeably to mean both natural and manufactured forms of the substance. In American English, asphalt (or asphalt cement) is the carefully refined residue from the distillation process of selected crude oils. Outside the United States, the product is often called bitumen. Natural deposits terminology also sometimes uses the word bitumen, such as at the La Brea Tar Pits.
Naturally occurring asphalt is sometimes specified by the term "crude bitumen"; its viscosity is similar to that of cold molasses. whilst the material obtained from the fractional distillation of crude oil [boiling at 525 °C (977 °F)] is sometimes referred to as "refined bitumen.”
(Wikipedia, Asphalt – Bitumen, 9/20/2012)
2. Bitumen is a complex natural compound that is produced by the refining industry. Its composition is variable based on the origin of the supplies and certain bitumens are not satisfactory because of the increasingly intense stresses to which they are subjected.
One of the main improvements is introducing elastomers and thermoplastics into the bitumen to correct the defects. This actually makes it possible to improve significantly the mechanical properties and the durability by increasing the cohesion, the capacity for deformation and the elastic recovery over the largest range with the extreme temperatures of use. 3 to 7 % polymers are added to the bitumen. Liquid bitumen is heated to 140 and 180C and stirred with the polymer.
Ethylene vinyl acetate (EVA) copolymers, elastomer copolymers of stereoregulated type, di- or tri-blocks, styrene butadiene (SB) or styrene butadiene styrene (SBS) are effective. Useful bitumens include solid asphaltite of mining origin or bituminous coke.
[Lopez, US Patent 8,258,212 (9/4/2012)]
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Roger D. Corneliussen
Maro Polymer Links
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Copyright 2012 by Roger D. Corneliussen.
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* Date of latest addition; date of first entry is 9/4/2012.