Method for manufacturing a non-reusable liquid absorbing article and the article.

The subject of the present invention is a process for the continuous manufacture of a single-use article intended to absorb liquids, using a machine comprising, a device for defibrating pulp, a forming section. of a continuous ribbon of defibrated dough, a device for cutting said ribbon into a succession of absorbent masses.

The present invention also relates to disposable articles intended to absorb liquids, in particular bodily fluids such as blood or urine.

These items can be dressings, period towels, diapers or complete diapers for incontinent babies or adults.

Generally such articles have a laminated structure formed by a. mattress. cellulosic fibers 15 for absorbing and · · retaining · liquid les, placed between a liquid-permeable sheet and a synthetic film playing the role of / barrier vis-à-vis liquids.

The permeable sheet is most often a nonwoven _r. composed of artificial and / or synthetic fibers. In the past 20 years, a great deal of research has been carried out on the structure of this nonwoven: depending on the method of manufacture and the nature of the fibers used, it is possible to obtain nonwovens which are quickly passed through by a liquid, ·, but retaining very little moisture after absorption of the liquid by a mattress 25 of cellulose fibers.

Thus, the surface of the absorbent articles, in contact with the skin of a user, remains little wet. Comfort is improved and the risks of irritation are significantly reduced.

The synthetic film, barrier to liquids, is. in general

30j an embossed polyethylene film glued to the nonwoven fabric along the longitudinal edges of the article: it protects clothing or underwear.

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In certain articles, such as complete diapers, the polyethylene film is folded over the periphery of the article so as to form a narrow hydrophobic and impermeable band, on the side of the non-woven side: thus, when the article is properly applied to the user, the liquids to be absorbed remain in the area delimited by the polyethylene strip. The risk of leaks is reduced, but the major drawback is that the user's skin is wet over the entire surface of the article.

Other articles, such as period towels, are completely wrapped in a nonwoven and are provided, between the absorbent mattress and the nonwoven, with a synthetic film in the form of a U-shape protecting not only the underside. of the article but also the sides. Recently appeared on. the towel market, periodicals comprising a synthetic film whose branches of the U are folded along the longitudinal edges, so as to form a kind of gutter: the risks of side leaks are thus practically eliminated but the ends of the article have no barrier, · to liquids.

To overcome the drawbacks of current articles, the present invention provides a new structure according to which is placed, between the nonwoven coming into contact with the skin of a user and the absorbent mass, an impermeable sheet provided with a zone permeable to liquids, said zone being arranged centrally with respect to the upper face of the absorbent mass.

According to the invention, the manufacturing process is characterized in that ':

a) an impermeable sheet is unrolled from a mother reel, then passed so as to form two continuous strips, in a device cutting it in its median zone according to a line formed by a succession of segments “straight, parallel to the longitudinal axis of the sheet, the said line segments being:

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- alternately staggered on either side of the said axis,

- offset relative to each other, the distance between two successive segments located on the same side of the leaf axis being greater than the length of the segments, and the ends of which are connected by segments cutting the leaf axis in the middle.

b) the first strip is offset laterally by a distance slightly less than the distance separating the segments situated on either side of the axis of the sheet,

c) the second strip follows a longer path than that of the first strip, of a length equal to the pitch of the cut-out,

d) les. two strips are then deposited on the absorbent masses so that the open areas delimited by said bands are located in the central region of the absorbent masses.

e) the scabbard obtained is sectioned into individual articles.

According to a variant of the invention, the two strips are thermally bonded or glued along the longitudinal edges of the article to a continuous impermeable film constituting the lower face.

According to a variant of the invention, the waterproof sheet is micro-perforated before cutting, for example by means of a spike roller and a foam counter-roller, the two rollers having a width identical to that of the sheet. . This embodiment makes it possible to obtain an article retaining liquids in a particularly satisfactory manner, while avoiding possible phenomena of maceration.

3O^! According to another variant of the invention, taken or not taken in combination with the previous ones, the cutting is ensured by a knife tracing a sinusoid, on the impermeable sheet in movement, the amplitude of the corresponding sinusoid

07331 at the half-width of the permeable zone and the half-wavelength being the length of the permeable zone.

The subject of the invention is also a single-use article intended to absorb liquids comprising an absorbent mass, at least the upper face of which consists of a liquid-permeable nonwoven, characterized in that between the absorbent mass and the a nonwoven sheet is placed which is impermeable to liquids, made up of at least two strips cut and assembled so as to form a permeable zone, of oblong shape, discovering at least 50% of the absorbent mass in its central region.

Another synthetic film forms the liquid barrier on the underside of the article. The ends of the article are thermally bonded or glued so as to avoid any passage of liquid from the absorbent mass to the upper and / or lower faces. The permeable zone is preferably less than 80% of the total surface of the absorbent mass.

Thanks to the present invention, there are now disposable articles intended for absorbing liquids, in which the absorbed liquid is enclosed in a waterproof pocket. Lifts of liquids on the sides or in the vicinity of the ends are impossible. .

These articles are generally manufactured using machines comprising a device for defibrating pulp, a section for forming a continuous ribbon of defibrated pulp, a device for cutting said ribbon into a succession of separate absorbent masses.

According to one form of the invention, the strips of impermeable sheets are combined by thermobonding or gluing with a nonwoven before being applied to the absorbent masses.

Other advantages and characteristics of the invention will appear in the description of several exemplary embodiments in which:

- Figure 1 shows a top view of an article according to a first formed of the invention.

07331 Figure -2 shows a top view of an article the central absorption area is delimited by cutouts, two waterproof strips in a sheet

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figure 10 figure 11 figure '12 figure 1 3 is is is is one of the of the

25View in section view in section end view of Figure 9 · figure figure according to AA.

according to BB.

a diagram of a principle of a machine for an article according to the invention.

according to the invention .. 'la la la before manufacturing 14 is a top view of a pre-cut film according to ψι ·. trace allowing the formation of absorption zones, FIG. 15. is a top view of two strips cut from a film according to FIG. 14 and associated so as to force open zones.

In the drawings of FIGS. 1 and 2 is shown an article according to the invention, comprising an absorbent mass having an upper face (2) and a lower face a

1, (3), made of a non-woven fabric (4) 'permeable to liquids. A liquid impermeable sheet (5) is placed between the absorbent mass (1) and the nonwoven (4) on the side of the upper face (2).

This sheet (5) is provided with a liquid-permeable zone (6) and can consist of two half-sheets (5a) and (5b). The article has ends (7) and (8).

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The drawing of Figure 3 shows a sectional view of Figure 1 along AA: the sheet (5) has an area (6) having a multiplicity of perforations (6a). The sheet (5) is coated with a nonwoven (4) and its longitudinal edges are glued or thermally bonded in (10).

The drawing of Figure 4 shows a sectional view of Figure 2 along AA: the waterproof sheet (5) consists of two half-sheets (5a) and (5b) cut and associated so as to form an oblong opening (6).

The half-sheets (5a) and 5b) coated with a nonwoven (4) completely surround the absorbent mass (t) and are glued or thermally bonded (at 10) on the side of the lower face (3) so that the absorbent mass (1) is completely wrapped except in the area (6).

Advantageously, the absorbent mass (1) is wrapped in a sheet of tissue (9) which ensures good diffusion of the liquid. The tissue sheet (9) is placed between the absorbent mass (1) and the waterproof sheet (5a, 5b).

The drawing of Figure 5 shows a sectional view of Figure 2 along BB: the two half-sheets (5a) and (5b) are, on the side of the upper face (2) as on the side of the 'lower face (3), ^ bonded or thermobonded so as to completely enclose the absorbent mass (1) in the vicinity of the ends (7) and (8), in 10a) and (10b).

Drawing of Figure 6 shows a sectional view of Figure 1h along BB: the sheet (5) completely surrounds the absorbent mass (1), and its longitudinal edges are glued under heat-sealed on the side of the underside (3) - of the article.

The drawings of Figures 7 and 8 are end views

30^: articles represented by FIGS. 1 and 2 j the sheet i (5) - or the two half-sheets (5a) and (5b) - are glued or thermally bonded transversely on themselves, so as to close the ends (7) and (8) of the article according to the invention.

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Thus, the liquids are absorbed in the absorbent mass (1) through the zone (6), diffuse throughout the absorbent mass (1), in particular in the parts contained in the impermeable sheet (5) î the ends (7) .and (8) being closed, the liquids cannot come to rewet the upper face (2) of the article and the nonwoven (4) possibly remains wet only in the zone (6).

The drawings of FIGS. 9 to 12 show the top view and sectional views of a complete diaper, the absorbent mass (11), surrounded by a sheet of tissue-wadding (19), being fixed on a film. , waterproof (22). Along the longitudinal edges of the absorbent mass (11), laminates are glued * s in the state, stretched on the film (22).

- ^ them strips (15a) and (15b) cut from an impermeable film 15 are arranged on the absorbent mass (11) and delimit a zone (16.) for the passage of liquids.

In the vicinity of the ends of the absorbent mass (11) the strips (15a), and 15b) overlap completely.

The ends (17) and (18) of the complete diaper are closed, the films (15a) (15b) and (22) being glued or thermally bonded transversely.

On the other hand, the longitudinal edges of the complete diaper are glued or thermally bonded.

The upper face (12) of the complete diaper consists of a liquid-permeable nonwoven (14), which is glued or thermally bonded over its entire surface to the two strips (15a) and _; (15b).

The drawing of Figure (13) is a block diagram of the method of manufacturing an article according to the invention.

A ribbon of defibrated dough (51) wrapped in a sheet of tissue-wadding passes between embossing rollers (32) then in a device for cutting the ribbon in a succession of | masses., separate absorbents (54).

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A waterproof sheet (35) is unrolled bôbine | .

beer (36), passes through a cutting device (370 î Qït ^ bti ^ t two half-bands (35a) and 35b).

The strip (35a) follows a longer path than the strip (35b) from>

so as to form the zones (6) (see figure 2).

Immediately before being applied to the Mbsorbent masses (34), the strips (35a) and (35b) are fixed using a gluing ramp (38) to the nonwoven fabric (39).

In a manner known per se, the separate absorbent masses (54) are conveyed on a synthetic film intended to constitute the rear face of the complete diaper.

A continuous sheath is thus obtained consisting of a succession of absorbent masses enclosed in an impermeable envelope, except in their upper central zone f a thermocoupe device, for example, separates the individual articles.

It is also possible to thermolier the articles transversely, pulsvde to separate them using a rotary knife.

The drawing of Figures 14 and 15 shows how, from a sheet (45), two half-strips ^ 45a) and (45b) are obtained.

your sheet. (45) is cut along a line (T) formed by a succession of straight line segments (Tp Tg, T ^ ...) of the same length I, parallel to the longitudinal axis-XX 'of there sheet (45), located staggered alternately on either side of XX ', 25 offset from one another, the distance between two. Segments (^) and (T ^) located on the same side of XX 'being greater than I.

The ends of two segments (Tp and (æ₂) located on either side of XX * are connected by a segment T '₁₂ of which the middle 30 of ïï₁₂ is on axis XX *.

The strip (45b) is offset laterally by a distance slightly greater than d ^ (distance between the Segments (Tj) _:(T₂) (T ^) and the axis XX *) then offset longitudinally by a length equal to the pitch of the cut (T) so that two segments such as (T ^) and (T₂) become symmetrical about the axis XX *.

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Thus, a succession of open areas (46) is formed, the bands (45a) and (45b.) Overlapping only between these areas (46).

By way of example to obtain a zone (46) the largest dimension of which is 315 mm and the width 110 mm, the dimensions of the article to be manufactured being 550 × 350 mm, we start with a polyethylene film 300 mm wide.

We cut segments (T-]), (T₂)> (T ^.) With a length of 205 mm, parallel to the axis XX 'and located at a distance of

30 mm from the latter.

The segments (), (æ₂), (^ 5) are arranged so that the distance M ^₂ 1 ^ 3 between two segments.

(T '₁₂), (T '₂j) ^{so-fc of 2}? 5 mm.

The pitch from there cut is 265 mm.

By laterally shifting the strip 45b by 50 mm and by longitudinally shifting it one step, that is 265.mm, we obtain a succession of open areas (46) of width 110 .. mm and maximum length 31^z5 mm.

The. two bands (45a) and (45b) t> e overlap longitiidi20 nally, · in the vicinity of. axis XX ', over 10 mm.