The ability of an elastic material to regain its shape after being deformed. It is expressed as a percent of the length regained after release from a given elongation. The term generally describing the flow behavior of liquid and semi-liquid materials when subjected to applied force. The reology of sealants is very important from an application standpoint since the ease of application of a sealant is often the determining factor in a product's acceptance in the market. In architectural applications, sealants and caulks use their ability to accommodate joint movement to seal out the intrusion of water, wind, pollutants, dust and insects.
Shore hardness is a strong indicator of modulus.
Low modulus sealants have shore hardnesses of 20 or less. A term used to describe a rheological property of a sealant. It indicates a low resistance to shearing action and yet the maintenance of good sag resistance. A good example would be the short peaks left in whipped cream when a finger is drawn through it. The ratio of the volatile ingredients in a sealant formula to the nonvolatile components, expressed as a percent.