High cellulose content, laminiferous nonwoven fabric
The present invention provides a laminiferous nonwoven fabric with a high woodpulp content suitable for use in wipes, absorbent articles and other applications, and a method of making the same. The laminiferous nonwoven comprises 3 layers bonded together, where the outer layers are lightweight meltspun webs and the middle layer comprises mainly woodpulp fibers. Each of the first ( 3 ), second ( 2 ) and third ( 4 ) nonwoven layer are preferably first formed separately and individually to be self-supported webs, whereafter the three self-supported webs are brought together essentially immediately before bonding them together. When used as a substrate for wet wipes, the inventive fabric exhibits a combination of several useful properties; good wet and dry softness and bulk, good wet abrasion resistance and low wet linting propensity, and where the majority raw material is woodpulp.
1. A laminiferous nonwoven fabric, comprising:
at least a first nonwoven layer, consisting essentially of natural cellulose fibres and thermoplastic fibres,
on both sides of said first layer, a second and a third nonwoven layer, which second and third nonwoven layers consist essentially of melt-spinnable fibres and each second and third nonwoven layer having a basis weight of 12 gsm or less, wherein
the first layer is formed by air forming process,
at least one of the second or third nonwoven layers is formed separately and individually to be a self-supporting web with a geometric mean wet tensile strength/basis weight ratio of at least 7 N/m per gsm,
the nonwoven fabric comprises at least 50% by weight cellulose, and
the three webs are bonded together using ultrasonic, thermal or adhesive bonding.
2. The fabric of claim 1 , wherein the fabric has a wet bulk of 7.5 cc/gram or higher.
3. The fabric of claim 1 , wherein the fibres of the first nonwoven layer are shortcut fibres.
4. The fabric of claim 1 , wherein the Wet Martindale abrasion resistance of the high cellulose content composite nonwoven fabric is better than 10 rubs.
5. The fabric of claim 1 , wherein both the second and the third nonwoven layers have a basis weight of 12 gsm or less.
6. The fabric of claim 1 , wherein both the second and the third nonwoven layers are manufactured with a high strength meltblown process.
7. The fabric of claim 1 , wherein the first, second and third nonwoven layer are thermally, ultrasonically or by glueing bonded together to form a laminiferous nonwoven fabric and that the boundary between any two adjacent nonwoven layers is distinct.
8. The fabric of claim 1 , wherein the basis weight of the laminiferous nonwoven fabric is less than 200 gsm.
9. The fabric of claim 1 , wherein the first nonwoven layer comprise more than 75% w/w of cellulose fibres and less than 25% w/w of thermoplastic material.
10. The fabric of claim 1 , wherein first, second and third layer comprise the same melt-spinnable material.
11. The fabric of claim 1 , wherein the laminiferous nonwoven fabric has the absorption capacity of more than 900% by wt.
12. The fabric of claim 1 , wherein the nonwoven fabric comprises at least 65% w/w cellulose fibres.
13. The fabric of claim 1 , wherein the wet lint value of the fabric as measured by the gravimetric method is 35 ppm or less.
14. The fabric of claim 1 , wherein the dry basis weight of the composite nonwoven fabric is between 40 gsm and 65 gsm and the outer nonwoven layers, each being a high strength meltblown polypropylene nonwoven web of about 6 gsm or less, the first nonwoven layer, being an airformed nonwoven web comprising a blend of debonded fluff pulp, and
shortcut polypropylene fibres or a mixture of shortcut polypropylene fibres and shortcut polyethylene sheath/polypropylene core bicomponent fibres,
the amount of debonded fluff pulp comprising between 70 to 90% w/w in the first nonwoven layer and wherein the three layers are bonded together by thermal or ultrasonic point-bonding and wherein the boundary between any two adjacent nonwoven layers is distinct in that fibres at or near the surfaces of such adjacent layers are not significantly intermingled.
15. The fabric of claim 1 , wherein the first nonwoven layer is patterned before the three webs are brought together.
16. The fabric of claim 1 , wherein the first layer is an essentially homogenous monolayer.
17. The fabric of claim 1 , wherein the first layer is a stratified or layered structure, wherein thermoplastic materials are concentrated near top and bottom surfaces of the first nonwoven layer.