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Rubberised Coir
The following are the requirements prescribed for rubberised coir sheets for cushioning. It does not cover articles made from shredded rubberised coir or fabricated articles consisting of a cover of rubberised coir sheets enclosing springs or other cushioning material or industrial or packaging material.
Rubberised Coir
A Resilien product of porous structure containing curled coir fibre suitably coated and bonded with natural rubber, synthetic rubber or combination of both containing suitable ingredients, and vulcanised for the final set to the desired size and shade.
Indentation hardness Index
The indentation hardness index is the load in kgms.required to produce an identation in the sample equivalent in depth to 40% of the original thickness of the sample.
Original Thickness
The thickness determined by the needle gauge method for the whole sample will be termed as original thickness.
Note:-For samples having thickness less than 38mm, the original thickness shall be determined by superimposing minimum number of pieces to give a total thickness of about 38mm and the average taken as the original thickness of the sample.
The rubberised coir sheets for cushioning shall be graded on the basis of the identation hardness index and density as given below:-
Grade Identation hardness Index Density g/dm3
Soft 3.0 - 5.9 40 – 59
Medium  6.0 – 8.9 60 – 61
Firm    9.0 – 11.9 70 – 79
Extra Firm     12.0 – 14.9 9

80 - 99
However, density requirement is optional and has been given for guidance only. The identation hardness index of the central portion (One-Third, length wise) of rubberised coir sheets for cushioning may exceed up to +15% from the maximum value specified for any grade due to an additional re-inforcement piece at the centre. However the indentation hardness index of the remaining portion shall be within the range for the particular grade
Rubberised coir sheets shall be manufactured using unretted coir fibre mechanically extracted and curled to effectively utilise the resiliency of the fibre material, the fibres being bonded to each other by vulcanised rubber to keep them in position, utilizing rubber latex containing compounding ingredients of such nature and quality that the finished products with the requirements of this specification.

Rubberised coir sheets shall be of a resilient nature and porous structure in the form of sheetings or in fabricated sheets. Any special characteristics other than those prescribed in this specification which may be desired for specific application shall be as agreed to between the purchaser and the supplier.

The rubberised coir sheets shall present a uniform appearance through out the structure and shall not contain loose fibres or voids.

Due to manufacturing conditions, the material may have to be altered or repaired. The repaired or altered material shall be acceptable provided the material used in such repaires or alterations is of the same composition and quality as the original products and provided such alterations do not affect the requirements given in this specification. The odour of rubberised coir shall be as mild as possible and shall not be objectionable.
Rubberised coir sheets may be supplied in fabricated shapes or in sheets as specified by the purchaser. The dimension of rubberised coir sheets shall be as specified by the purchaser subject to the tolerance given below:
Length or Width Permissible Tolerance (mm)
Up to 1mm 6
1mm to 1.5mm 9
Over 1.5mm 12
Thickness Permissible Tolerance (mm)
Up to 12mm +3 -0
Over 12mm upto 38mm +6 -3
Over 38mm upto 100mm +12 -6
Over 100mm +15 -6
Indentation Hardness:-When tested different grades of rubberised coir products shall have the indentation hardness as prescribed

Resistance to Ageing- When tested the indentation hardness of the sample after ageing shall not vary by more than + 20% of the value obtained within aged sample.

Resistance to Flexing:- When tested the indentation hardness of the test specimen shall not vary by more than + 20%. This shall be calculated on the resultant thickness.

Compression set:- The Compression set of the sample shall not exceed 20%. When tested under atmospheric conditions, the compression set shall not exceed 15% after 3 hrs.recovery.

pH value:- The pH value of the aqueous extract of the material shall be within 5 to 8.5.

Chloride Content:- The Chloride Content of the material shall not exceed 0.3% by weight.

Sulphate Content:-Sulphate content of the aqueous extract of the material prepared ioshall not exceed 0.2% by wight.