TOPSHEET OF BODY FLUID ABSORPTD7E tive articles comprising this liquid-permeable topsheet
ARTICLES AND METHOD FOR MAKING including a plurality of liquid passages each extending
SAME therethrough from an upper opening to a lower opening and
a skin-contacting area extending continuously around the This application is a division of application Ser. No. 5 upper openings of said liquid passages, a liquid08/230,517 filed Apr. 20, 1994, now abandoned. impermeable backsheet and a liquid-absorbent core sand
wiched between these sheets, said topsheet comprising: a BACKGROUND OF THE INVENTION first sheet made of thermoplasitc synthetic resin sheet and
_ . , , . , , provided with said liquid passages and said skin-contacting
The present invention relates to a topsheet used for body ^ and a second sheet underlying said ^ sheet
fluid absorptive articles such as sanitary napkins and dis- TM bonded thereto around the lower openings of the respective
posable diapers and also to a method for making the top- Uquid passages; wherein said second sheet is made of
sneet- mechanically intertwined fibres only and has a density
It is well known to form a topsheet used for body fluid higher than a density of fibres contained in said liquid
absoptive articles, to provide this sheet with a plurality of absorbent core.
liquid passages each extending through the sheet from an 15 preferably, the second sheet of said topsheet is fibreupper opening to a lower opening so that the upper surface oriented in the longitudinal direction of said topsheet and the comes in contact with a wearer's skin, and the lower second sheet is composed of a mixture of 70 to 100% by openings of the liquid passages are in contact with a liquid- weight of cellulose fibres and 30 to 0% by weight of absorbent core, and thus body fluids are introduced into the thermoplastic synthetic fibres
liquid-absorbent core under a capillary action occurring 20 The object set forfll aboye .g achieved> according t0 wrthin the respective liquid passages. another aspect of the invention( by a metnod for a For example, Japanese Patent Publication No. 1982- topsheet used in body fluid absorptive articles comprising 17081 discloses a technique such that a topsheet made of tnis liquid-permeable topsheet including a plurality of liquid polyethylene sheet is provided with liquid passages each in 2J passages each extending therethrough from an upper openthe form of truncated cone-shaped capillary tube and a lower mg t0 a lower opening and a skin-contacting area extending end of each liquid passage is arranged in close contact with continuously around the upper openings of said liquid a liquid-absorbent core. passages, a liquid-impermeable backsheet and a liquidJapanese patent application Disclosure No. 1995-58950 absorbent core sandwiched between these sheets, said discloses a technique Such that thermoplastic synthetic 30 method comprising steps of: blowing molten fibres from a fibres are melt-blown to form nonwoven fabric which is then melt-blow extruder against a forming die having a plurality formed with liquid passages and fibrous fluff is formed of protrusions dimensioned substantially in a uniform around lower openings of the liquid passages to obtain a height, said protrusions having flat tops, to form melt-blown topsheet. nonwoven fabric following the configuration of said forming In both of the above-mentioned prior techniques, the 35 die; bringing a heating element in contact with said meltlower end of each liquid passage should be always in close blown nonwoven fabric at said tops to form openings each contact with the liquid-absorbent core. However, the top- defined by an indented periphery; and feeding fibrous web sheet which is thin and less rigid is readily wrinkled during comprising mechanically intertwined fibres only and having the practical use of the body fluid absorptive articles and, in a density higher than a density of fibres contained in said consequence, the lower end of each liquid passage is sepa- 40 liquid-absorbent core onto said melt-blown nonwoven fabric rated from the liquid-absorbent core, preventing the body and thereby mechanically entwining said fibrous web around' fluids from being smoothly transferred into the liquid- said indented peripheries to obtain said topsheet absorbent core. Preferably, the fibrous web is fibre-oriented in the longiGenerally, the soft touch is indispensable to the body fluid tudinal direction of said topsheet. The fibrous web is prefabsorptive articles. For example, in the case of the liquid- 45 erably composed of a mixture of 70 to 100% by weight of absorbent core formed of fluff pulp, a density thereof is cellulose fibres and 30 to 0% by weight of thermoplastic limited, since an excessively high density of the fluff pulp synthetic fibres.
would give a wearer the unpleasant stiff touch. However, an In the topsheet constructed in the above-mentioned manexcessively low density of the fluff pulp would reduce the ner according to the invention, the second sheet is bonded to diffusibility of the body fluids. As a result, the body fluids 50 the first sheet around the lower openings of the respective transferring from the liquid passages to the liquid-absorbent liquid passages and thereby integrated with the first sheet core can not rapidly diffuse laterally from the lower open- Thus, the topsheet has its rigidity improved sufficiently to ings and the body fluids stay on the topsheet for a corre- prevent the topsheet from being wrinkled and to restrict the spondingly longer time, giving a wearer the discomfortable deformation of the lower openings. Consequently, the liquid feel of wetness. 55 passages are not readily clogged. The periphery of each Accordingly, it is a principal object of the invention to lower opening is bonded to the second sheet having a density solve the problem encountered by the previously mentioned higher than a density of the fibres contained by the liquidprior techniques by composing a topsheet from a first sheet absorbent core, on one hand, and the second sheet is in and a second sheet, bonding the second sheet to the first contact with the liquid-absorbent core, on the other hand, so sheet around lower openings of respective liquid passages 60 the body fluids having reached the lower openings of the formed through the first sheet and adjusting a density of the respective liquid passages not only can be smoothly transsecond sheet at a level of a density of a liquid-absorbent ferred immediately downward through the second sheet into core the liquid-absorbent core but also can be rapidly diffused
through the second sheet in the surface-direction and then
SUMMARY OF THE INVENTION 65 transferred into the liquid-absorbent core.
The object set forth above is achieved, according to an The second sheet is fibre-oriented in a desired direction aspect of the invention, by a topsheet for body fluid absorp- and the body fluids can be easily diffused particularly in the