Testing and quality control of foam rubber

Foam rubber is a consumer product. Therefore various national standards organizations have taken steps to ensure the production and marketing of good quality foam rubber . Important properties tested for quality control and their specification limits are given in that follow.

• Indentation hardness index

• It is the load in kilograms required to give an indentation  in the sample equivalent to 40% of the original thickness of the sample under specified condition. It is a measure of the load bearing capacity of the foam rubber. Foam rubber product are graded by indentation hardness such as Code A has 7-14 indentation hardness.

• Compression set

• It is a measure of state of cure of the foam rubber . The test consists of compressong the test piece under specified condition of time, temperature and constant deflation and noting the effect on the height of the released test sample.The compression set of the sample when determined by the first method shall not exceed 15% and by the second method shall noe exceed 5%

• The color of latex foam rubber shall be as agreed between the purchaser and supplier.
• Flexing test that involves submitting the whole sample to a continuous flexing with an indenter for 2,500,000 cycles at 4 Hz and measuring the loss in hardness and thickness.
• Aging test 

• The test sample of aging test is kept in an oven at 70 +/- 1 *C for 168 hr. Upon removal from the oven after 10 hr, the hardness is measured. The hardness of the test sample after aging shall not vary by more than +/- 20% of the value obthained with the unaged test sample.

• Metallic Impurities

• The copper and manganese content in the test sample shall not be more than 0.001 and 0.005% respectively.