Extensible laminar material, particularly for sanitary articles, and method of producing same
An extensible laminar material 100 includes an extensible layer 106 coupled to at least one laminar layer 102, 104 . The extension of the extensible layer 106 starting from a non-extended condition determines the extension of the laminar layer(s) 102, 104 while the return of the extensible layer 106 toward the non-extended condition determines the pulling of the laminar layer(s) 102, 104 into a wrinkled condition. The extensible layer 106 and at least one laminar layer 102, 104 are connected by welding to avoid their detachment. The extensible layer 106 is anchored to at least one laminar layer 102, 104 by lines of spread adhesive 108, 108 ′. The welded connection is absent in correspondence of the lines of spread adhesive 108, 108 ′. Preferably, the material is in the form of a web 100 extensible transversally to the longitudinal extension of the web with the lines of spread adhesive 108, 108 ′ extending along the sides of the web.
1. An extensible laminar material comprising:
an extensible layer configured to be extendable from a non-extended condition to an extended condition, and
at least one laminar layer, the extensible layer being coupled to the at least one laminar layer by welds arranged in a selected pattern and by lines of spread adhesive applied at selected locations such that the extension of said extensible layer from the non-extended condition to the extended condition causes the extension of said at least one laminar layer and the return of said extensible layer toward said non-extended condition causes the pulling of said at least one laminar layer into a wrinkled condition, wherein said welds are absent in all the selected locations where said extensible layer and said at least one laminar layer are coupled by said lines of spread adhesive.
2. The material according to claim 1 , further comprising an array of openings configured to confer aeriform-permeability characteristics to the material, wherein said openings are absent in locations where said extensible layer and said at least one laminar layer are coupled by said lines of spread adhesive.
3. The material according to claim 1 , having a sandwich structure with said extensible layer interposed between two of said laminar layers.
4. The material according to claim 3 , wherein said lines of spread adhesive are on both sides of said extensible layer causing it to be anchored with respect to both of said laminar layers.
5. The material according to claim 1 , wherein said lines of spread adhesive have a width between 2 and 10 mm.
6. The material according to claim 1 , wherein said at least one laminar layer is comprised of a material selected from the group consisting of a non-woven fabric and a film of plastic material.
7. The material according to claim 1 , wherein said welds comprise ultrasound welds.
8. The material according to claim 1 , wherein the material is arranged in the form of a web which is extensible transversally to a longitudinal extension of the web, and wherein said lines of spread adhesive extend along sides of the web.
9. The material according to claim 3 , wherein said sandwich structure comprises:
a base laminar layer with a plurality of pairs of said lines of spread adhesive applied thereto,
a plurality of said extensible layers anchored to said base laminar layer by means of corresponding pairs of said lines of spread adhesive, and
at least one additional laminar layer, wherein said extensible layers are interposed between said base laminar layer and said at least one additional laminar layer.
10. The material according to claim 1 , configured for the manufacture of sanitary articles.
11. The material according to claim 9 , further comprising an array of openings configured to confer aeriform-permeability characteristics to the material, wherein said openings are absent in locations where said extensible layer and said at least one laminar layer are coupled by said lines of spread adhesive.
12. The material according to claim 1 , wherein said lines of spread adhesive have a width between 4 and 6 mm.