The present invention relates to a method for making a body waste disposable article adapted to be utilized in combination with the other article such as a disposable diaper, disposable incontinent pants and the like.
Japanese Patent Application Disclosure Gazette No. 1993-293138 describes a method for forming a body-facing topsheet of a disposable diaper with an elastic opening. This topsheet is provided along a periphery of the opening with an elastic member secured thereto in an extended state so as to describe a circular arc. According to this disclosure, a sheet for forming the topsheet is continuously fed and the elastic member in an extended state is fed while the elastic member is swung transversely of the sheet using traverse means so that the elastic member may describe the circular arcs on the continuous topsheet.
The known method for forming the topsheet of the diaper with the elastic opening is disadvantageous in that, while the sheet can be fed at a relatively high speed, the speed at which the traverse means can be operated is limited and, in consequence, an output per unit time is also restricted. In addition, introduction of the traverse means into the production line for the diaper inevitably leads to an increase of the equipment investment and therefore to a corresponding increase in the manufacturing cost of the diaper.
In view of the problems as have been described above, it is an object of the present invention to provide a simplified method for making a body waste disposable article such as a disposable diaper having an elastic opening and thereby to solve the problems mentioned above.
According to the present invention, there is provided a body waste disposable article according to a first aspect of the present invention (referred to hereinafter as a,first invention), a first method for making this article according to a second aspect of the present invention (referred to hereinafter as the second invention) and a second method for making this article according to a third aspect of the present invention (referred to hereinafter as the third invention.
The first invention relates to a body waste disposable article having a body fluids absorbent means comprising a liquid-pervious topsheet, a liquid-impervious backsheet and a liquid-absorbent core disposed therebetween, a surrounding wall being defined by a portion of at least one of the topsheet and the backsheet extending outward beyond a peripheral edge of a absorbent means and folded back to partially cover a top surface of said absorbent means in proximity of the peripheral edge and thereby to leave an opening surrounded by the surrounding wall above a central zone of the absorbent means, and the surrounding wall being elastically stretchable and contractable along an edge of the opening.
In the article as has been described above, the first present invention is characterized in that the absorbent means has a longitudinal direction and a transverse direction being orthogonal to the longitudinal direction in which the absorbent means is composed of a front end, a rear end and an intermediate region extending between these front and rear ends so that the absorbent means is configured to have the largest width in the intermediate region.
The first invention includes various embodiments as follow:
(1) The absorbent means has its width progressively enlarged from the front and rear ends to the intermediate region.
(2) The intermediate region has the largest width at its position a little to the rear end.
(3) The front and rear ends are covered with the surrounding wall.
(4) The opening is provided along its edge with a belt-like elastic member having a width of 5-50 mm and, in the intermediate region, the surrounding wall is bonded to the lower surface of the elastic member along its transversely middle zone so that the elastic member and the surrounding wall present together a substantially T-shaped cross-section when the article is worn by a wearer.
The second invention relates to a method for making a body waste disposable article having a body fluids absorbent means comprising a liquid-pervious topsheet, a liquid-impervious backsheet and a liquid-absorbent core disposed therebetween, a surrounding wall being defined by a portion of at least one of the topsheet and the backsheet extending outward beyond a peripheral edge of the absorbent means and folded back to partially cover a top surface of the absorbent means in proximity of the peripheral edge and thereby to leave an opening surrounded by the surrounding wall above a central zone of the absorbent means, and the surrounding wall being elastically stretchable and contractable along an edge of the opening.
In the method as has been described above, the second invention is characterized by that the method comprises the steps of:
a. covering the core with the topsheet and the backsheet which are, in turn, bonded to each other along portions of the topsheet and the backsheet extending outward beyond a peripheral edge of the core to obtain a laminate;
b. bonding elastic members to any one of the topsheet and the backsheet with a rectilinear tension along transversely opposite edges of the topsheet or the backsheet extending in parallel to each other with the core lying therebetween;
c. folding the laminate back onto itself with the topsheet lying inside so that the elastic members on the side edges may be placed upon each other;
d. bonding respective halves of the laminate, which has been folded back onto itself, to each other along a pair of imaginary lines intersecting the side edges and extending in parallel to each other with the core lying therebetween; and
e. releasing the elastic members to contract after the step d.
According to an embodiment of the second invention, the elastic members are belt-like elastic members each being 5-50 mm wide and secured to the side edges along a transversely middle line of this belt-like elastic member. The method according to the second invention may further comprise a step of forming the backsheet with means used to fasten the article to a wearer""s garment.
The third invention also relates to a method for making a body waste disposable article having a body fluids absorbent means comprising a liquid-pervious topsheet, a liquid-impervious backsheet and a liquid-absorbent core disposed therebetween, a surrounding wall being defined by a portion of at least one of the topsheet and the backsheet extending outward beyond a peripheral edge of the absorbent means and folded back to partially cover a top surface of the absorbent means in proximity of the peripheral edge and thereby to leave an opening surrounded by the surrounding wall above a central zone of the absorbent means, and the surrounding wall being elastically stretchable and contractable along an edge of the opening.
In the method as has been described above, the third invention is characterized by that the method comprises the steps of:
a. continuously feeding a first web for forming the topsheet and a second web for forming the backsheet in one direction, respectively;
b. continuously feeding the elastic members in the one direction and securing them with a rectilinear tension to any one of the first and second webs along transversely opposite side edges of the web;
c. intermittently feeding the cores in the one direction onto any one of the first and second webs in transversely middle regions of the web;
d. placing the first and second webs upon each other to sandwich the cores therebetween, after the elastic members and the cores have been fed, and thereby to form a third web comprising these first and second webs, elastic members and cores;
e. folding the third web back onto itself with the first web lying inside so that the elastic members on the side edges may be placed upon each other;
f. bonding mutually facing halves of the first web making the part of the third web, which has been folded back onto itself, to each other in a region of the third web extending between each pair of the adjacent cores;
g. cutting the third web which has been folded onto and bonded to itself on the step f in the region extending between each pair of the adjacent cores along an imaginary line extending transversely of the third web so that the region may partially remain on both sides of the imaginary line; and
h. releasing the elastic members to contract after the step g.
According to an embodiment of the third invention, the elastic members are belt-like elastic members each being 5-50 mm wide and bonded to the side edges along a transversely middle line of the belt-like elastic member. The method according to the third invention may further comprise a step of forming the second web with means used to fasten the article to a wearer""s garment.