a water absorbing layer is shed after treatment with the resin for making stronger, more flexible and more dry surface

摘要

1494525 Folding edges; laminates PROCTER & GAMBLE CO 18 March 1975 [18 March 1974] 11246/76 Headings B5K and B5N [Also in Divisions D1-D2 and A3] A reinforced absorbent web 13 for a diaper is formed by treating at least one surface of an uncompacted absorbent web 1 of hydrophilic fibres having a basis weight of 80 to 500 g/mSP2/SP and a density of 0À03 to 0À05 g/cc. by applying a hydrophobia, film-forming material thereto to give a total treated depth not exceeding 50% of the total thickness of the uncompacted web, drying the film-forming material and compacting the web to an overall density of 0À07 to 0À15 gms/cc., the density of the treated surface(s) being lower than that of the untreated portions, thereby providing a graduation of capillary size favourable for the transmission of liquid from the treated to the untreated portions. Unspecified hydrophilic cellulosic fibres are air laid at 2 and the continuous web sprayed at 3 with a 10 to 55% aqueous dispersion of a styrene-butadiene or acrylic resin having a glass transition temperature of -15‹ C. to + 35‹ C. to give a 5 to 16 g/cmSP2/SP uptake of solids. Selected areas may have different or zero amounts of resin applied. The moisture content is reduced to less than 5% and the resin cured by air at at least 270‹ F. supplied by dryer 5. The web is then calendered by rolls 9, 10, the resin preventing inter-fibre hydrogen bonding in the treated portion 13b whilst the untreated portion 13a is densified. Diapers, laminating, seaming.-The endless web 1 is cut into pads 13 by knife 11 and the pads separated. An impervious matt finish polyethylene backing 15 is sprayed with a soft pressure-sensitive polyvinyl acetate copolymer adhesive 17 and laminated to the spaced assembly of pads 13. A low density hydrophobic top sheet 16 comprising a needle bunched polyester fabric or a viscose rayon fabric printed with discrete areas of hydrophobic binder is pressed against the resin treated portion 13b of each pad. Beads 19 of hot melt adhesive are applied to each edge of sheet 16. Ploughs 21 turn over each edge of sheets 15, 16. Hardsurfaced rolls 22, 24 press each turned over edge together and press the adhesive coated sheet 15 to the top sheet 16 in the areas between the pads 13, roll 22 having recessed areas 23 to accomodate pads 13. The turning over of the edges prevents rucking by top sheet 16. Alternatively this can be achieved without turning over by sizing the edges of sheet 16. Pressure sensitive tape for securing the diaper is applied to each pad, the pads folded to the configuration of Fig. 6 and the pads separated by cutting the sheets 15, 16.