COMPRESSIVE RESISTANCE OF PU FOAM REINFORCED NONWOVEN

Intelligent Textile Structures - Application, Production and Testing LIBEREC June 9 th 13 th Author: Hanuš Jaroslav Theme of lecture :

Corrugated nonwovens studies

part 4

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Problem: • Limited elasticity, rather high creep as well as rather high stress relaxation are counted among the textile structures’ negative properties often preventing mass application of textile products, not only in technical areas but also in health services; • The efforts to use textile pads as aids reducing the tissue pressure (replacements) were so far unsuccessful; the use of aids made of PU foam was more successful [2]. 2

The record of contact pressure values after 1 min.

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The record of contact pressure values after 60 min.

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Solution of the problem:

3D nonwoven – PU foam composite • 3D nonwoven will ensure the locally different compression resistance of the new composite; • PU foam will ensure above all its elasticity. 5

Research intention:

• Designe a proper composite (its components) for seats and antidecubite aids; • Manufacture a composite consisting of a 3D nonwoven as a fibre reinforcement and PU foam as a matrix; • Explain the synergism of properties of these componets in a composite by measurements. 6

What properties can be expected of 3D nonwoven – PU foam composite? • Lower permanent deformation of a composite than the permanent deformation of its textile components after long-lasting deformation; • The locally different compression resistance of the composite; • Elasticity similar to PU foam. 7

Experiment: Samples: • 3D nonwoven , consisting of 40% PP, 70dtex fibres, 40% PP, 30dtex fibres and 20% bonding fibres (PE), produced of web waves, square mass 400 g/m2, thickness 30 mm…X; • PU-foam, produced according to the system of “Huntsman polyuretanes”, Daflotex15240 (polyol), Suprasec 1065 (isocyanate). Chemicals were mixed 100pbw of Daflotex / 68pbw of Suprasec…Y; • Composite „3D nonwoven-PU foam“…Z. 8

Measurement: • All 3 samples (X,Y,Z) have been tested by identical method. Deformation has been done by a plane plate of diameter 52 mm; • The samples were compressed 6 times to 50% of their initial height. In the first and the fifth cycles, we recorded the deformation curves. In the sixth cycle we measured the compression resistance relaxation; • Permanent deformation after long-lasting deformation to 50% was measured. 9

Results:

Synergism - deformation curves

S yn e rg is m , 1. c yc le

S yn e rg is m , 5. c yc le

500

500 450

Composite

400 350 300 250 200

PU foam

150 100 50

3D nonwoven

0 0

5

10 15 20 25 30 35 De forma tion [mm]

Co mp re s s io n re s is ta n c e [N]

Co mp re s s io n re s is ta n c e [N]

450

Composite

400 350 300 250 200

PU foam

150 100 50

3D nonwoven

0 0

5

10 15 20 25 30 35 De forma tion [mm]

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Results:

Compressive resistance relaxation:

De c re as e o f c o m p re s s io n re s is tan c e

S a m p le s

Z

%

Y

N

X 0

50

100

150

De c re as e in [N] an d [%]

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Results:

Long-lasting deformation

Pe rma n e n t d e fo rma tio n [% ]

Lo n g -la s tin g d e fo rm a tio n 40 35 30 25

X

20 15

Y

Z

10 5 0 1

2

3

4

Lo g 1 0 T [min ]

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Conclusion: • The synergism of compression properties of composite components does exist; • The permanent deformation after longlasting deformation of a composite is lower than the permanent deformation of its textile component.

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References:

1. Hawkins, J.,E., CPT: The Effectiveness of Pressure-Reducing Table Pads as an Intervention to Reduce the Risk of Intraoperatively Acquired Pressure Sores. Military Medicine, Vol. 162. November 1997. 2. Bliss, M., R.: Preventing Pressure Sores in Elderly Patients: A Comparison of Seven Mattress Overlayes: Age and Ageing 1995. 3. Hanuš J., Novák O.: Rozložení kontaktního tlaku mezi pacientem a textilní podložkou: In: Strutex 2001. 4. Kosinová M.: Compression characteristic of the textile mattress. BC thesis, TU of Liberec 2002. 5. Neckář B.: Compression and Packing Density of Fibrous Assemblies. Textile Res.J. 67(2),123-130 (1997). 6. Hanuš J., Militký J., Arun Pal Aneja.: Local Compression of Corrugated Structures. In: Ninth International Conference on Composites Engineering, San Diego, July 1-6, 2002.

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