Coreless roll of absorbent sheet and method for manufacturing the same

Abstract

A coreless roll of an absorbent sheet product, such as napkins, toilet paper, towels etc., is provided made of a spirally wound continuous web of absorbent material having a first end and a second end, wherein a coating composition comprising a specific polymer and a binding agent in a weight ratio polymer to binding agent of at least 92:8 is coated onto the second end. The coreless roll has excellent resistance to collapsing, as well as excellent flexibility and elasticity. Moreover, the coreless roll has excellent disintegrability in water and can be used up over its whole length. A process for the manufacture of the coreless roll is also provided.

What is claimed is: 
     
         1 . A coreless roll of an absorbent sheet product made of a spirally wound continuous web of absorbent material having a first end and a second end, the web of absorbent material being wound such as to define an axial hollow passageway centrally positioned relative to the coreless roll and extending from one edge to another edge of the coreless roll and such that the first end is located on the outer side of the roll and the second end is located at the axial hollow passageway;
 wherein the continuous web of absorbent material comprises a coating composition comprising:   (a) a polymer having:
 (i) a glass transition temperature lower than 20° C., preferably lower than 15° C., more preferably lower than 10° C., more preferably lower than 5° C., more preferably lower than 0° C., more preferably lower than −5° C., and more preferably lower than −10° C.; 
 (ii) a melting point greater than 20° C., more preferably greater than 25° C., more preferably greater than 30° C., more preferably greater than 35° C., more preferably greater than 40° C., and more preferably greater than 45° C.; 
 (iii) optionally a solubility in water at 25° C. of at least 40 g/l; and 
   (b) a binding agent selected from polyvinyl pyrrolidone (PVP), polyvinyl acetate (PVAc), poly(vinyl pyrrolidone-co-vinyl acetate) (PVP-PVAc) and combinations thereof;   wherein the weight ratio of polymer to binding agent is at least 92:8, preferably at least 96:4.   
     
     
         2 . The coreless roll of  claim 1 , wherein the second end of the continuous web of absorbent material comprises the coating composition. 
     
     
         3 . The coreless roll of  claim 2 , wherein the coreless roll is obtained by applying the coating composition to the second end of the continuous web of absorbent material. 
     
     
         4 . The coreless roll of  claim 1 , wherein the coating composition comprises:
 (α) at least 50 wt.-%, preferably at least 65 wt.-%, more preferably at least 80 wt.-% of the polymer and the binding agent;   (β) not more than 50 wt.-%, preferably not more than 35 wt.-%, more preferably not more than 20 wt.-% of further additives such as reinforcing agents, fragrance, and dyes;   (γ) optionally water in an amount of not more than 10 wt.-%, preferably in an amount of not more than 5 wt.-%;   each based on the total weight of the coating composition.   
     
     
         5 . The coreless roll of  claim 1 , wherein the coating composition is applied in molten form or, after the addition of water, as an aqueous solution. 
     
     
         6 . The coreless roll of  claim 1 , wherein the polymer is a polyether polyol, preferably a polyether polyol selected from polyethylene glycol, polypropylene glycol, and mixtures thereof, more preferably polyethylene glycol. 
     
     
         7 . The coreless roll of  claim 1 , wherein the polymer has a number-average molecular weight of 800 to 250000, preferably of 1000 to 50000, more preferably of 1500 to 15000, more preferably of 1500 to 10000, more preferably of 2000 to 7500, e.g. 2500 to 4000. 
     
     
         8 . The coreless roll of  claim 6 , wherein the polymer is polyethylene glycol having a number-average molecular weight of 800 to 250000, preferably of 1000 to 20000, more preferably of 1500 to 10000, more preferably of 2000 to 7500, more preferably of 2500 to 6500, even more preferably of 2500 to 4000. 
     
     
         9 . The coreless roll of  claim 1 , wherein the binding agent is polyvinyl pyrrolidone having a K-value of 10 to 100, preferably of 10 to 60, more preferably of 12 to 30, poly(vinyl pyrrolidone-co-vinyl acetate) having a K-value of 15 to 50, preferably of 20 to 40, more preferably of 20 to 35, or a combination thereof. 
     
     
         10 . The coreless roll of  claim 1 , wherein the coating composition is free of saccharide. 
     
     
         11 . The coreless roll of  claim 1 , wherein the axial hollow passageway has a circumference and the coating composition is circumferentially applied and is preferably applied such that the resulting coating covers at least 10% of the second end, preferably at least 20%, more preferably at least 50%, and even more preferably at least 75%, e.g. at least 95%, of the second end. 
     
     
         12 . The coreless roll of  claim 1 , wherein the coating composition is applied continuously in the machine and axial direction or intermittently in the machine and/or axial direction. 
     
     
         13 . The coreless roll of  claim 1 , wherein the second end consists of at least one turn, preferably of at least two turns, preferably at least three turns, for instance 3 to 50 turns, for instance 3 to 30 turns or 4 to 40 turns, preferably 3 to 30 turns, a turn being one circumvolution of the spirally wound continuous web about the axial hollow passageway. 
     
     
         14 . The coreless roll of  claim 1 , wherein the total amount of polymer and binding agent is from 0.1 to 20 g/roll, preferably 0.2 to 10 g/roll, more preferably 0.3 to 5 g/roll, in particular 0.4 to 2 g/roll. 
     
     
         15 . The coreless roll of  claim 1 , wherein the web of absorbent material is composed of 1 tissue paper ply or 2 to 6, in particular 2 to 5 superposed tissue paper plies. 
     
     
         16 . The coreless roll of  claim 1  being in a compressed form. 
     
     
         17 . The coreless roll of  claim 1 , which is an absorbent product chosen among the group comprising napkins, towels such as household towels, kitchen towels or hand towels, toilet papers, wipes, handkerchiefs, and facial tissues, wherein this absorbent product is preferably a toilet paper. 
     
     
         18 . A manufacturing method for manufacturing a coreless roll of an absorbent sheet product comprising the steps of:
 conveying a continuous web of absorbent material having a first end and a second end, which is preferably composed of 1 tissue paper ply or 2 to 6, in particular 2 to 5 superposed tissue paper plies;   optionally severing the continuous web of absorbent material substantially transversally to the machine direction to produce single but coherent sheets;   applying a coating composition as defined in  claim 1  to the second end;   spirally winding the continuous web of absorbent material so as to produce a log of web of absorbent material, the web of absorbent material being wound such as to define an axial hollow passageway centrally positioned relative to the log and extending from one edge to another edge of the log and such that the first end is located on the outer side of the log and the second end is located at the axial hollow passageway; and   cutting the log into multiple coreless rolls.   
     
     
         19 . The manufacturing method of  claim 18 , comprising the further step of
 subjecting the coreless roll to compression in a direction perpendicular to the axial hollow passageway to produce a coreless roll in a compressed form.   
     
     
         20 . (canceled)