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Lightweight nonwovens: H1 technology

F Senthil Chinnasami, Lohit Shastri, Mac McLean, S. S. Ramkumar

H1 needlepunching technology is one of the modern developments in dry laid nonwoven technologies. The needle zone in the H1 technology is not flat as in the case of conventional needleloom. The contoured zone needlepunching results in oblique angled needle penetration. H1 needlepunching technology has higher efficiency and high productivity. Texas Tech University is the first academic facility in the US to house the modern needleloom. This technology has been effectively used to develop cotton blended nonwoven webs. This paper elaborates the results from the cotton needlepunching study.

Materials used

Cotton fibre characteristics were measured using the HVI 900A. Cotton fibres are fed into the hopper feeder which will lead to the initial opening of fibre tufts. The fibres get individualised by double cylinder cards. There are ten carding zones between the worker and stripper rollers resulting in individualisation of fibre tufts. Carded webs are then layered into multilayer webs by the cross-lapper. The cross lapper then feeds the web to the H1 needlepunching machine. The H1 technology machine is capable of running at a maximum speed of 1300 strokes/min. In this study, the needleloom was operated at 750 strokes/min.

H1 needlepunched cotton and cotton blended webs

Cotton and cotton-polypropylene composites are developed at two different weights and all the samples are single punched by passing the carded web with only one pass in the needle zone.

Experimental results

Important physical and mechanical properties of the webs were evaluated based on ASTM D-5034. Instron constant rate of elongation tensile tester was used to evaluate the tensile properties of the nonwoven webs. Tensile characteristics were evaluated in both machine and cross directions. Tenacity values were higher in the cross direction than those in the machine direction. Similarly, extension at break values are higher in the cross direction than those in the machine direction. Furthermore, as the weight of nonwoven webs increases, breaking strength increases.

Structural arrangement

The structural arrangement of cotton fibres in the web was studied using scanning electron microscopy. The fibres are integrated in the web by interlocking. Also, the surface damage to the fibres is minimum since the interlocking is uniformly carried out by keeping the stitch density constant.

Conclusions

Results presented in the paper prove that 100 per cent cotton lightweight nonwoven can be successfully needlepunched on the H1 technology needlepunching machine. The nonwoven webs developed were found to have adequate strength and elongation.