DE3740410A1 - Method of permanently joining stretchable elements in filament or ribbon form on a sheet-like substrate and use of the same for producing ruffled film web sections - Google Patents

Abstract

The invention relates to a method of permanently joining elements in filament or ribbon form on a sheet-like substrate by means of an adhesive, which method is characterised in that one or more elements in filament or ribbon form are guided in the desired position at a distance of about 1 to 3 cm from the sheet-like substrate and these elements in filament or ribbon form and the adjacent area of the substrate are sprayed with a hot-melt adhesive and, subsequently, the elements in filament or ribbon form are brought together with the film web; it relates furthermore to use of the method for producing ruffled film web sections having in their respective edge region stretchable elements in filament or ribbon form located between a film web and an outer layer, an absorbent inlay arranged between these elements and a nonwoven section covering this inlay.

Description

The invention relates to a method for permanent Ver tie thread or ribbon-shaped elements on one flat substrate by means of an adhesive as well as the Application of this method for the production of ruffled Foil sheet sections.

It is generally known when connecting thread or ribbon-shaped elements with a flat substrate either the surfaces of the two parts to be joined to be provided with an adhesive and this with adhesive provided surfaces to press 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 procedures are particularly useful in the manufacture of mass articles both time and equipment consuming. For example the adhesive with application rollers or nozzles at least applied to the one element to be glued and this are then pressed. The bonding of thread-like particular elements on a flat substrate then problems if the thread-like Elements around a tensioned elastic Thread acts as it does for example to close up  final flat structures made of plastic and / or Tangled fiber fleece is used, as is the case in the hygiene area e.g. required for diaper pants, but also for work clothing is to enable better conformability; Similar problems arise in the manufacture of surgical caps and face masks used in the surgical field and many other articles in the hygienic and medical scope.

The invention has set itself the task of creating a new one Process for the permanent connection of thread or ribbon shaped elements on a flat substrate to propose an adhesive that is easy to use can be used and for a permanent connection of especially filiform elements on a flat Substrate is suitable, and preferably at under Tension elastic threads with an art fabric underlay should be connected.

The invention has also set itself the task of this new fastening methods for elastic threads in the Production of desired film web sections with in respective edge area between a film web and a Stretchable thread or ribbon migen elements, an absorbent arranged between them gene insert and a fleece section covering this to apply.

To solve the problem of the invention, one time Proposed method according to the main claim, being particularly preferred embodiments mentioned in the subclaims are, and on the other hand the application of these methods according to Claims 14 and 15 proposed.  

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 thread and 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.

The spraying of hot melt adhesives through spray nozzles is known per se; So far, however, it has only been carried out on Purpose, the surfaces to be glued themselves with the enamel spraying glue, which were then pressed together.  

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 mPa · 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 appropriate deepening according to EU-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 14 and 15 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.

For optical and other reasons, it is advisable in many cases not to spray this intermediate area 27 directly on the polyethylene film, but rather to provide a thin layer of nonwoven-like material with adhesive in this central area. This has the advantage that any bonding points that would otherwise be on the polyethylene film inner surface and are recognizable from the outside do not appear. In this application of spider web-like hot melt adhesive thread in the intermediate area lying between the stretchable threads, the adhesive distribution can be carried out in such a way that the area sprayed in the intermediate 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; show it:  

Fig. 1 is a partially sectional view of a stretchable yarn, which is fixed on 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, two schematic illustrations of spinnwebarti gene or ornament-like Schmelzkleberfädchen,

Fig. 5 is a partially sectioned view of a supply to brin not or only slightly stretched thread-like element on a pre-folded web,

Fig. 6 is a schematic sectional view of a low supply Aufbrin stretched yarn with a continuous Fältelungsrad,

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 microns 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. A or according to FIG. 4B.

In the examples shown in Fig. 2 and Fig. 3 representations can be seen how the elastic strips 4 spaced from the substrate, which is a polypropylene film 2, hang down and when merged with the substrate of the distance of, for example ground in reducing initially about 1 Share up to 2 cm until contact with the film web and also get under the thread structure and finally Lich with the spider web-like hot melt adhesive thread k 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 an elastic thread 14 ' tangentially occupied by a roller 11 at the vertices and by means of nozzles with plastic cords 16 'glued like a cobweb and is pulled off for further processing in the direction of travel.

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 31 using a cutting tool.

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

example 1

In order to bring a substrate made of a polyethylene film with a film thickness of 20 to 25 µm into a ruched state in a hygienic article, a stretched elastic thread made of a polyether copolymer (e.g. Lycra XA) with a thread thickness of 940 was set at a distance of 10 mm from this film web dtex and with a hot melt adhesive consisting of
50% of a hydrocarbon resin with an R + K softening point of 115 ° C, 30% of a styrene-butadiene-styrene block copolymer 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 threads were guided under tensile stress analogously to Example 1 and sprayed with the hot melt adhesive according to Example 1. The spider web-like hot melt adhesive had a distance of 10 mm from each of the stretchable threads, but also extended into the central region 27 between the two threads, the hot melt adhesive application being carried out with 3 spray heads, of which the two outer ones for the Application on the stretchable threads correspondingly narrow and long, and which were wider and shorter for the middle area. Immediately afterwards, an absorbent fibrous web with a thickness of about 12 mm was introduced into the area between the threads 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 across the web direction using a cutting tool.

Example 6

In a modification of the method according to Example 5, a thin polypropylene staple fiber nonwoven web was inserted with the supplied film web in the area between the tensioned threads, the subsequent application of the adhesive to the threads and to the central area of the hot melt adhesive in the central area 27 not in contact with the polypropylene film came and just 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 bonded to the plastic film in the edge areas.

In all cases an excellent durability of the bond is achieved, especially against so-called "creeping"; furthermore, with the method according to the invention, a thread structure can be obtained with a lower pretension of only 100% - compared to 300% in conventional methods - which leads to a much more supple concern, for example, of diapers.

Claims (15)

1. A process for the permanent connection of stretchable thread or ribbon-shaped elements on a flat substrate by means of an adhesive, characterized in that one or more thread or ribbon-shaped elements ( 4 ) at a distance from the flat substrate ( 2 ) in the desired Arranged position and sprayed with a hot melt adhesive ( 6 ), the thread or ribbon-shaped elements or elements ( 4 ) being transported in the same direction with the substrate below the spray head and brought into contact by reducing the distance to the substrate. 2. The method according to claim 1, characterized in that that one as thread-like or ribbon-shaped elements used from a stretchable material and these continuously during spraying and during Keeps contact with the substrate under tensile stress.   3. The method according to claim 1 and 2, characterized in that spraying the hot melt adhesive in the form of spider web-like to pattern-like overlapping spray thread with a diameter of 20 to 400 microns on the thread or ribbon-shaped elements ( 4 ). 4. The method according to claim 1 to 3, characterized in that one or more thread-like or ribbon-shaped elements ( 4 ) and the underlying Be areas of the substrate in a width ( d ) of 1 to 15 mm, measured from the longitudinal edge of the respective thread-like or tape-like element subsequently connected to the substrate or of the element or elements located on the edge with the sprayed adhesive. 5. The method according to claim 1 to 4, characterized in that applying the hot melt adhesive in an amount of 2 to 100 g / m ² and preferably from 5 to 40 g / m ² on the thread-like or ribbon-like elements ( 4 ) . 6. The method according to claim 1 to 5, characterized in that one or more thread-like or ribbon-shaped elements ( 4 ) sprayed continuously or intermittently with the hot melt adhesive. 7. The method according to claim 1 to 6, characterized in that one under tension the thread-like or ribbon-shaped elements ( 4 ), which have been sprayed at a distance of 0.5 to 3 cm from the substrate with the hot melt adhesive, under at an acute angle with the substrate. 8. The method according to claim 1 to 6, characterized in net that the tensioned thread- or ribbon-shaped elements outside the substrate sprayed with hot melt adhesive and then merges with the substrate web. 9. The method according to claim 1 and 3 to 6, characterized in that at least the protruding areas ( 13 ) of a ruffled or folded substrate ( 12 ) on which one or more thread-like or ribbon-shaped not or only slightly under tension Elements ( 14 ) are arranged or guided at a distance, are sprayed with the hot melt adhesive ( 16 ) before they are brought into contact with the substrate. 10. The method according to claim 1 to 9, characterized in that a plastic film or an impregnated paper or nonwoven web is used as the substrate ( 2 ). 11. The method according to claim 1 to 8, characterized net that one on the substrate and on the or thread-like or ribbon-like elements after opening spray the hot melt adhesive and immediately after merging them with the substrate Applies top layer and presses this if necessary. 12. The method according to claim 1 to 11, characterized in that a film ( 2 ) is used as the substrate and a fleece ( 8 ) is used as the cover layer. 13. The method according to claim 1 to 11, characterized in net, that as a substrate a fleece and as a top layer used a film. 14. Application of the method according to claim 1 to 13 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, characterized in that

• a) at a distance to the film serving as a substrate web or at least in the respective later ruched edge areas of this film holds or guides one or more thread-like or ribbon-shaped elements under tensile stress
• b) the respective thread-like or ribbon-shaped elements as well as their adjacent areas and at the same time the area lying between the thread-like or ribbon-like elements are intermittently sprayed with the hot-melt adhesive and then
• c) the thread-like or ribbon-shaped elements sprayed with hot melt adhesive is brought into contact with the substrate by bringing them together, and afterwards
• d) a web of absorbent padding material is applied to the area sprayed with hot-melt adhesive between the thread-like or ribbon-shaped element and
• e) a nonwoven web is applied to the film web and the web made of absorbent padding material in such a way 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,
• f) the nonwoven web is pressed with these at least in the area of the thread-like or ribbon-like elements and
• g) separating the composite material obtained in this way into sections transversely to the web direction.

15. The method according to claim 14, characterized in 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 merges at an acute angle with the film web and then the sheet of absorbent padding material and apply the nonwoven web.