新海绵术语大全帮助.doc

Density
Density is weight per unit volume, weight/volume, and is expressed as lbs/ft3 (pcf).
Density is usually measured in grams/cm3 and multiplied by to convert to lbs/ft3 (pcf).
Density can be obtained from any sample size. Density is not related to pore size, ., coarse pore and fine pore foams can have equal densities.
Density is not a measure of firmness, stiffness, or load bearing capacity. That is defined by Indentation Force Deflection (IFD) pression Force Deflection (CFD).
 
Indentation Force Deflection (IFD)
IFD (previously ILD) is one test method to determine load bearing capacity (firmness or stiffness), and is expressed in pounds force per 50 at a given percent deflection of the foam.
For example: P215-50, FHA grade carpet cushion foam has a target IFD of 50 lbs/50 in2 at a deflection depth of 25% of the original thickness of the sample after a rest period of one minute, 25%R.
To obtain the 25%R value, a 50 circular indenter platen is driven into a 15” x 15” x 4” foam sample, stopping when it reaches a deflection of 1”, 25% of the 4-inch thickness. The testing device records the force in pounds required to hold this foam indented after one minute. The higher the force reading, the higher the load bearing capacity of the foam. This result can be reported in metric and the sample size can be varied.
Sag Factor (Modulus) is the ratio of the