DE3740410C2 - - Google Patents

Description

The invention relates to a method for permanent Connecting thread-like or ribbon-shaped elements on a flat substrate using an adhesive, the thread-like or ribbon-like elements in the same sensible direction with the substrate below one Dispensing hot melt adhesive continuously or intermittently Spray heads are transported, as well as the application this process for the production of ruffled film web sections.

It is general and especially for the production of Diaper pants z. B. from DE-OS 34 47 442 and DE-PS 33 47 294 known when connecting thread or ribbon shaped elements with a flat substrate either the surfaces of the two parts to be connected to be provided with an adhesive and ver pressed surfaces together, or only the thread-like or ribbon-shaped elements or only that to provide a flat substrate with an adhesive, after which both parts are pressed together. Such procedure Ren are particularly in the manufacture of mass articles both time and equipment consuming. For example The adhesive must be applied with application rollers or nozzles least applied to the one element to be glued and this can then be pressed. The gluing of filiform elements on a flat substrate is particularly problematic when it comes to the thread-like elements around a tensioned one elastic thread acts, such as for Ruching of tightly closing flat structures made of plastic and / or random fiber fleece is used,  as it is in the hygiene area z. B. for diaper pants, but even with work clothing is required to a enable better conformability; similar problems occur in the manufacture of surgical caps and face masks ken used in the surgical field, and for numerous other articles in hygienic and medical scope.

It has also been proposed according to EP-A2 01 51 348 to stretch te elastomeric tapes with a non-elastic thermo to connect plastic film and the layered structure then shrink under the influence of heat and this Use disposable diapers. Apart from the disadvantages with the necessary reheating to shrink this way of working has not proven to be uneconomical enforced.

From US-PS 43 79 016 it is known, not tense stretchy ribbon-shaped elements on a ruffled Apply substrate by means of an adhesive, wherein the untensioned ribbon-like elements are practical on the protruding folds of the ruffled substrate be stuck on.

Ultimately, it is from DE-PS 37 07 349 and JP-OS 6 11 52 801 known, for the permanent connection of stretchable thread-like or ribbon-like elements in the same sensible direction with the substrate below spray heads to transport that is a hot melt adhesive deliver continuously or intermittently, where the thread or ribbon-shaped elements already in In contact with the substrate. This is true achieved good adhesion because of the hot melt adhesive on the stretched thread or ribbon-shaped element and places the adjacent areas of the substrate and  holds the thread-like or ribbon-like element on the substrate. However, it has been shown that the liability of the stretched Thread on the substrate or the unstretched thread on one ruffled substrate when pulling it apart is not sufficient.

The invention has for its object a new procedure for the permanent connection of thread or ribbon conveyors elements on a flat substrate an adhesive according to the preamble of claim 1 beat, which can be used without much effort and a permanent connection of in particular filiform elements on a flat substrate is suitable, preferably when under voltage standing elastic threads covered with a plastic location should be connected.

The invention is also based on the object of this new fastening methods for elastic threads in the Production of ruffled film web sections with in the respective edge area between a film and a stretchable thread or ribbon-shaped elements, one arranged between them absorbent insert and a covering To use fleece section in which the respective thread or ribbon-shaped elements held under expansion tension or guided and then sprayed with hot melt adhesive will.

To solve the problem of the invention once proposed a method according to the main claim, wherein particularly preferred embodiments in the Unteran say mentions, and on the other hand the application proposed this method according to claim 12 and 13.  

Surprisingly, it has been shown that thread or ribbon-shaped elements on a flat substrate can be easily glued in that one without previous Application of adhesive to the flat substrate or Coating the thread-like or ribbon-like element with adhesive now one or more thread or ribbon shaped elements spaced from the flat substrate arranges in the desired position and this with a Sprayed hot melt adhesive, the thread or thread or ribbon-shaped elements in the same direction transported with the substrate below the spray head and by reducing the distance to the substrate in Be brought in contact.

In contrast to conventional adhesive processes there is no application of an adhesive layer between the two objects to be glued, namely thread-like according to element and substrate. Rather, training is enough a spray of the hot melt adhesive, which turns out to be a fine web of extremely thin threads of enamel adhesive around the thread or threads, from this down hangs or partly through a neighboring thread sets and by the airflow under the one or with Ab got to the substrate web led threads and thus spin into contact between the thread and the substrate thread-like "spun" on the substrate or thread structures leads. Depending on pressure and temperature and depending on the type of hot melt adhesive, cobweb-like Spray thread up to pattern-like overlapping spray thread in, for example, ring-like, oval or other far more or less evenly intertwined type order generated and applied.  

Any and all can be used for the process according to the invention known sprayable hot melt adhesives are used, which have a melting range of 80 to 200 ° C and their Viscosity allows it at these temperatures, below to be sprayed at a pressure of 1 to 50 bar. The Hot melt adhesives generally have a softening point from 70 to 140 ° C and a viscosity at 150 ° C in one Range from about 500 to 40,000 pPa · s. The processing the range of these hot melt adhesives is generally in one Temperature range from 105 to 180 ° C.

Plastic films are essentially used as substrates any type, for example those based on polyethylene or polypropylene but also impregnated paper webs or tangled nonwoven webs, while used as threads, which are to be attached to the substrate, usual ela elastic rubber threads or plastic threads, but also ela tische ribbon-shaped elements are used.

In, for example, the manufacture of diaper pants that should be ruffled in the crotch area is used as a substrate a plastic film and a nonwoven web as the top layer used between which the stretchable or stretched filament or ribbon-shaped element fixed or glued is. In general, the stretchable thread with the film by spraying on the cobweb-like hot melt adhesive threads and merging the film web glued and immediately then the fleece layer is pressed on, which coincides with adheres to the still adhesive hot melt adhesive. Analogue the stretchable thread can also first be connected to the nonwoven web the, which is then pressed with the film.

Although the production of the cobweb-like hot melt adhesive by spraying onto the substrate at a distance  guided stretchable thread, it is also possible to Spray hot melt adhesive onto the thread structure and then to bring the substrate web to contact.

In general, the thread or ribbon-shaped element in the stretched state at a distance from the substrate and constantly during the spraying and the following Contact with the substrate kept under tensile stress. After gluing, this area contracts and gives the desired frill. Not ruffling in that the area is not glued and the loose on the thread is still under tension cut when cutting the film sections.

In another embodiment of the invention The process can be done in little or no thread stretched condition at a distance from the already folded Arrange and glue the substrate. This procedure has the advantage that the not for the ruffled area imaginary stretchable threads immediately behind the pleating or frills can be cut off. This too The process can be carried out continuously, for example the manufacture of diaper pants using a the roller to be ruffled areas correspond with Carry out corresponding recesses according to EP-A1- 01 54 068.

According to another aspect of the present invention the inventive method also for the production of ruffled foil web sections with in the respective edge rich between a film web and a top layer stretchy thread or ribbon-shaped elements ten and an absorbent arranged between them Insert and a cover layer can be applied.  

When making panties diapers, it's not just that ruffled or ruffled section in the later step rich the diaper and cover with a fleece layer required; there must also be one in the middle of the Foil absorbent insert are provided. In the Manufacture of such diapers, it is appropriate that absorbent insert in the crotch area with the film or with an intermediate layer lying on the film ben. Therefore, to simplify the manufacturing process applied the method according to the invention, as in the Subclaims 12 and 13 are listed.

Here, the application of the cobweb-like melt threads on the stretchable thread still on the intermediate area between the respective stretchable arranged at the edge of the web Threads stretched. So one leaves with the concerned Areas of the spray of hot melt adhesive do not just spread out on the stretchable thread and its neighboring area deposit, but also sprayed the between the stretchy Threaded area, so that the later introduced Web made of absorbent material with the polyethylene film arrested.

In many cases it is for optical and other reasons expedient, this intermediate area on the polyethylene foil not to spray directly, but one in this Mid-area guided thin layer of fleece-like mate rial with adhesive. This has the advantage that any gluing points that would otherwise be on the polyethylene would be the inner surface of the film and not recognizable from the outside appear. With this application of spinning web-like hot melt adhesive surfaces in the between the stretch bable threads lying in the intermediate area can the adhesive ver division be made so that in the intermediate area sprayed area is shorter than that in the edge areas.

In the following, the invention will be described in more detail with reference to drawings are explained; it shows  

Figure 1 is a partially sectioned representation of an extensible thread that is attached to a substrate according to the inventive method.

Figure 2 is a schematic representation of how sprayed with distance from a substrate, a stretched band structure and combined with the former, and is covered with a covering layer.

Fig. 3 is a view analogous to Fig. 2;

Fig. 4 shows two schematic representations of spinnwebarti gene or ornament-like hot melt adhesive thread;

Figure 5 is a partially sectioned representation of the introduction of an unstretched or only slightly stretched thread-like element on a pre-folded web.

Fig. 6 is a schematic sectional view of the Aufbrin supply of a slightly stretched thread with a continuous pleating wheel;

Fig. 7 is a schematic representation of the application of the inventive method in the continuous manufacture of diaper pants.

Fig. 1 shows a section of a substrate 2 which is microns in this case a polyethylene film having a wall thickness of 50. A thread 4 made of stretchable plastic is applied to this and held with a plurality of hot melt adhesive threads lying on one another in a spun weave.

These cobweb-like hot melt adhesive threads have been partly moved or pushed under the thread structure previously guided at a distance from the film; the rest cover the reachable surface of the thread 4 and are still on the adjacent area of the substrate 2 , with a distance d that is 1 to 15 mm wide from the outer edge of the elastic thread. The spider web-like hot melt adhesive applied by spraying consists of superimposed spray threads with a diameter of 20 to 400 μm or in an application density of 2 to 100 and preferably 5 to 40 g / m ² occupied area. Depending on the application conditions, the hot-melt adhesive can have, for example, a configuration according to FIG. 4a or according to FIG. 4b.

In the representations shown in Fig. 2 and Fig. 3 it can be seen how the elastic ribbons 4 hang at a distance from the substrate, which is a polypropylene film 2 , and web when merging with the substrate while reducing the distance of z. B. initially about 1 to 2 cm until contact with the film web ver and also get under the thread structure and finally Lich with the spider web-like hot melt adhesive thread 6 arrested on the substrate and covered with a cover layer, namely a polypropylene nonwoven 20 .

Fig. 5 shows how pre-folded substrate webs 12 has at its apex point 13 of an only slightly or not stretched in this case, the elastic belt 14 and are covered with the Schmelzkleberfädchen sixteenth

Analogously, in the schematic illustration shown in FIG. 6, the substrate 12 is brought into a folded configuration by means of a ruffled wheel or ruffled roller 30 with recesses arranged on the circumference, again with a stretchable thread 14 tangentially occupied by a roll 11 at the apexes and by means of nozzles glued with a plastic spider 16 like a spider web and pulled off for further processing in the running direction.

In the application of the method according to the invention shown schematically in FIG. 7 in the production of a film web suitable for pant diapers, the film web 22 was fed as a substrate in a first station in which two elastic or stretchable threads 24 and 24 ' in the edge region at a distance from Guided film web and have been sprayed with hot melt adhesive in the areas 26 and 26 ' . The adhesive extends from the side edge of the thread with a distance of 20 to 15 mm beyond the thread. However, in the present case the central region 27 of the substrate is also sprayed, the boundary lines of the sprayed region 27 lying transversely to the web direction being drawn in concavely toward the central axis, as is shown at 23 .

In a second station, an absorbent insert 28 is introduced as a web in the central region between the elastic threads 24, 24 ' ; this is covered in a third station with a nonwoven web 29 to over the area of the stretchable threads 24 and 24 ' covered with hot melt adhesive and then pressed. At the end of this station, the individual film sections are cut into sections with a cutting tool.

In the following, the invention will be described in more detail by means of examples are explained.  

example 1

To make a substrate from a hygienic article Polyethylene film with a film thickness of 20 to 25 µm to get into a ruched state was with 10 mm distance to this film web a stretched elastic Thread made from a polyether copolymer (e.g. Lycra XA) with a thread size of 940 dtex and with a Hot melt adhesive consisting of

50% of a hydrocarbon resin with an R + K expansion point of 115 ° C, 30% of a styrene butadiene sty rol block copolymers and 20% mineral oil

at a temperature of 175 ° C at pressures of 2 to 8 bar in a width range of 15 mm intermittently sprayed in sections of 25 cm in length, the application thickness was 25 g / m ² . The film web was then brought into contact with the thread structure and cut transversely in the non-sprayed areas, the desired frilled web parts being obtained.

Example 2

In a further experiment, operation was carried out analogously to Example 1, a polypropylene spunbonded fabric having a thickness of approximately 0.22 mm and a weight per unit area of approximately 20 g / m ² then being pressed onto the previously fastened thread, so that the entire area the film web was covered with this spunbonded fabric at an appropriate distance from the edge of the film web, which adhered to the filament-like band coated with hot-melt adhesive.

Example 3

It was a stretchable tape made of polyether copolymers with a width of 3 mm and a thickness of 0.3 mm at a distance of 15 mm to a thermally bonded polypropylene staple fiber fleece and sprayed in a width range of 10 mm with the hot melt adhesive according to Example 1 , the application thickness being 42 g / m ² ; after reducing the distance, the adhesive was applied, after which a polypropylene film was pressed on and the web obtained was processed into sections.

Example 4

Analogously to FIG. 6, a polypropylene film with a width of 22 cm was fed in on a continuously operating plant for the production of diaper pants, which with the frill roller shown in FIG. 6 was vacuumed with sections with a depth of about 7 mm at a distance of 3 mm was provided. In the web direction, a stretchable tape made of polyurethane was carried along in the edge area of the film under low tension, which was sprayed intermittently with adhesive and then pulled off the frill roller and processed further.

Example 5

As shown in FIG. 7, a smooth sheet of polyethylene was processed on a diaper system; at a distance from the film web, two stretchable strips of polyurethane tape were guided at a distance from the film analogously to Example 1 under tension and sprayed with the hot melt adhesive according to Example 1. The hot melt adhesive depositing like a cobweb had a distance of 10 mm to the outside from the stretchable tapes, but also extends into the central region 27 between the two tapes, the hot melt adhesive application being carried out with 3 spray heads, the two outer ones for the application on the stretchable bands correspondingly narrow and long, and which were wider and shorter for the central area. After contact between the substrate and the stretchable polyurethane tapes, an absorbent fibrous web with a thickness of about 12 mm was introduced into the area between the tapes and then covered with the polypropylene spunbonded nonwoven web 29 used in Example 3. At the end of the station, the finished web was cut into individual sections transversely to the web direction by a cutting tool.

Example 6

In a modification of the method according to Example 5, a thin nonwoven web was inserted with the supplied film web in the area between the tensioned tapes, the subsequent application of the adhesive to the tapes and to the central area of the hot melt adhesive in the central area 27 not in contact with the polypropylene film came and only glued the absorbent insert in the crotch area. Since this interposed nonwoven layer was previously fixed on the polyethylene film, the absorbent insert cannot slip in the frill area, especially since it is subsequently covered by the cover layer, which is also glued to the plastic film in the edge areas.

In all cases, the durability is excellent Adhesion, in particular, good creep resistance reached; can also with the inventive method better frills can be achieved because the adhesive compared to an adhesive trace of contraction the elastic threads have less resistance put, which becomes a much more compliant concern of diapers, for example.

Claims (13)

1. A method for the permanent connection of one or more stretchable thread-like or ribbon-shaped elements on a flat substrate by means of an adhesive, wherein the thread-like or ribbon-like elements are transported in the same direction with the substrate below by a hot melt adhesive or intermittent dispensing spray heads, characterized that the thread-like or ribbon-shaped elements (4) are arranged at a distance from the sheet-like substrate (2) in the desired position and after spraying with hot melt adhesive by reduced copy tion of the distance to the substrate is brought into contact are. 2. The method according to claim 1, characterized in that the thread-like or ribbon-shaped elements ( 4 ) during the spraying and upon contact with the sub strate are held under tensile stress. 3. The method according to claim 2, characterized in that the live filament or bändchenför shaped elements ( 4 ) after they have been sprayed with the melt adhesive at a distance of 0.5 to 3 cm from the substrate, under one acute angles are brought together with the substrate ( Fig. 2). 4. The method according to claim 1, characterized in that at least the protruding areas ( 13 ) of a ruffled or folded substrate ( 12 ) and the thread or ribbon-like elements ( 14 ) which are not or only slightly under tension, which are at a distance from the substrate ( 12 ) are arranged or guided, can be brought into contact with the substrate after spraying with the hot melt adhesive ( 16 ) ( FIG. 6). 5. The method according to any one of claims 1 to 4, characterized in that the hot melt adhesive in the form of spider-web to pattern-like overlapping spray thread with a diameter of 20 to 400 microns is sprayed onto the thread-like or ribbon-shaped elements ( 4, 14 ) . 6. The method according to any one of claims 1 to 5, characterized in that the thread-like or ribbon-shaped elements ( 4, 14 ) and the areas of the substrate lying below this in a width (d) of 1 to 15 mm, measured from the longitudinal edge of the respective filiform or ribbon-like element subsequently connected to the substrate, are covered with the sprayed adhesive. 7. The method according to any one of claims 1 to 6, characterized in that the hot melt adhesive in an amount of 2 to 100 g / m ^{2 is} applied to the thread-like or ribbon-shaped elements ( 4, 14 ). 8. The method according to any one of claims 1 to 7, characterized in that a plastic film or an impregnated paper or nonwoven web is used as the substrate ( 2 ). 9. The method according to any one of claims 1 to 8, characterized characterized in that on the substrate and on the  thread-like or ribbon-like elements after spraying of the hot melt adhesive and immediately after the assembly perform a top layer with the substrate brought and then pressed if necessary. 10. The method according to any one of claims 1 to 9, characterized in that a film ( 2 ) and a nonwoven ( 8 ) is used as the substrate. 11. The method according to any one of claims 1 to 9, characterized characterized in that as a substrate a fleece and as Top layer a film is used. 12. Application of the method according to claims 1 to 11 for the production of ruffled film web sections with stretchable thread-like or ribbon-shaped elements located in the respective edge region between a film web and a cover layer, an absorbent insert arranged between them and a non-woven section covering these, in which the respective filament-like or ribbon-shaped elements are held or guided under tension and then sprayed intermittently with the hot melt adhesive, characterized in that

• a) the thread-like or ribbon-like elements and their adjoining areas and at the same time the area lying between the thread-like or ribbon-like elements are sprayed with hot-melt adhesive and the ribbon-like elements are brought into contact with the substrate by bringing them together, and then
• b) a web of absorbent padding material is applied to the area sprayed with hot-melt adhesive between the thread-like or ribbon-shaped element,
• c) a nonwoven web is applied to the film web and the web made of absorbent padding material such that it both covers the absorbent padding material and rests in the area of the thread-like or ribbon-shaped elements sprayed with hot melt adhesive,
• d) the nonwoven web is pressed with these at least in the area of the thread-like or ribbon-like elements and
• e) the composite material thus obtained is separated into sections transversely to the web direction.

13. The method according to claim 12, characterized in that that the areas sprayed with hot melt adhesive the at a distance from the film web of 3 to 0.5 cm guided thread or ribbon-shaped elements under at an acute angle with the film guided and then the web of absorbent Upholstery material and the nonwoven web are applied.