Method and apparatus for continuously attaching discrete, stretched elastic strands to predetermined isolated portions of disposable abosrbent products

• US 4,081,301 A
• Filed: 10/30/1975
• Issued: 03/28/1978
• Est. Priority Date: 10/30/1975
• Status: Expired due to Term

• Current Assignee: The Procter & Gamble Company
• Original Assignee: The Procter & Gamble Company
• Inventors: Buell, Kenneth B.
• Primary Examiner(s): Powell, William A.
• Assistant Examiner(s): Massie, Jerome W.
• Application Number:
  US05/627,405
• Time in Patent Office: 880 Days
• Field of Search: 156/160, 156/201, 156/202, 156/204, 156/213, 156/216, 156/222, 156/227, 156/229, 156/291, 156/295, 156/301, 156/464, 156/495, 156/522, 156/285, 128/284, 128/287, 2/400, 2/401, 156/269, 156/164, 156/523, 156/548, 156/549, 156/290, 156/582, 156/583
• US Class Current: 156/164
• CPC Class Codes: A61F 13/15593 having elastic ribbons fixed thereto; Devices for applying the ribbons
• CPC Class Codes: A61F 13/49017 the elastic means being located at the crotch region
• CPC Class Codes: Y10T 156/101 Prior to or during assembly with additional lamina
• CPC Class Codes: Y10T 156/1011 Overedge bending or overedge folding
• CPC Class Codes: Y10T 156/1034 Overedge bending of lamina about edges of sheetlike base
• CPC Class Codes: Y10T 156/1084 of continuous or running length bonded web
• CPC Class Codes: Y10T 156/1095 Opposed laminae are running length webs
• CPC Class Codes: Y10T 156/1343 Cutting indefinite length web after assembly with discrete article
• CPC Class Codes: Y10T 156/1348 Work traversing type
• CPC Class Codes: Y10T 156/1724 At spaced areas
• CPC Class Codes: Y10T 156/1727 Plural indefinite length or running length workpieces

Abstract

In a preferred embodiment, a continuous elastic ribbon is fed to a diaper web assembly station in a stretched condition. While traveling to the assembly station, an adhesive is applied to discrete lengths of the elastic ribbon at regularly spaced intervals. Simultaneously, discrete absorbent core segments as well as webs of moisture-impervious backsheet material and moisture-pervious topsheet material are fed to the diaper web assembly station. At the station, the stretched elastic ribbon is adhered to the moisture-impervious backsheet web in the discrete areas of the elastic which are covered by adhesive at predetermined points along the length of said web. After the adhesive has set up, the assembled web and the elastic contained therein is severed in its unadhered areas, whereupon the unadhered end portions become relaxed and inactive without affecting the functionality of the adhered portions in the ultimate assemblage. The inventive concept in its broadest sense relates to the continuous adherence of discrete lengths of stretched elastic to a continuously moving web at relativey high operating speeds and thereafter severing the elastic in the unadhered areas to produce elasticized structures having discrete strands of elastic adhered thereto at predetermined locations along their length. In a particularly preferred embodiment, the aforementioned process is utilized to apply discrete elastic leg bands to a disposable diaper structure to provide improved containment and fit therein.

Claims

1. A method for continuously attaching discrete lengths of elastic ribbon to isolated portions of a moving, substantially inelastic web of interconnected articles to impart an elasticized character to predetermined, isolated portions of said articles while preserving the substantially inelastic character of said articles in areas where said ribbon is unattached to said web, said method comprising the steps of:

(a) feeding an elastic ribbon to an assembly station in a stretched condition;

(b) applying adhesive intermittently to discrete lengths of said stretched elastic ribbon at predetermined intervals along the length of said ribbon while said stretched elastic ribbon is being fed to said assembly station;

(c) feeding a web of interconnected articles comprised of a substantially inelastic material to said assembly station;

(d) adhering the discrete lengths of stretched elastic ribbon to predetermined, isolated portions of the articles comprising said web at said assembly station in the discrete areas of said elastic ribbon having adhesive applied thereto;

(e) maintaining said elastic ribbon in a stretched condition at least until said adhesive sets up;

(f) cutting said elastic ribbon transversely in an area which is not adhered to said web, thereby forming severed, unadhered ends of elastic at both ends of each discrete length of stretched elastic ribbon adhered to said web; and

(g) allowing the severed, unadhered ends of said elastic ribbon to relax and contract to their unstretched state, whereby said unadhered ends do not impart an elasticized character to said web nor do they interfere with the functioning of the elasticized portions of the web to which said discrete lengths of elastic ribbon are adhered.

2. The method of claim 1, wherein said articles and said elastic ribbon are simultaneously cut from said web at a predetermined point along the length of said web in an area in which said elastic ribbon is not adhered to said web while said web and said elastic ribbon are maintained in a stretched condition, thereby forming discrete elasticized articles having discrete elastic ribbons adhered thereto along a portion of their length.

3. The method of claim 1, wherein said adhesive is intermittently applied to said elastic ribbon in continuous beads.

4. The method of claim 3, wherein said adhesive is intermittently applied to said elastic ribbon in continuous beads having greater mass at their end points.

5. The method of claim 1, wherein said adhesive is intermittently applied to said elastic ribbon in the shape of discrete dots in the desired areas of adhesion between said ribbon and said web.

6. The method of claim 1, wherein said adhesive becomes elastomeric after set up to permit expansion and contraction of said web and the secured portions of said elastic ribbon without any substantial separation therebetween.

7. The method of claim 6, wherein said stretched elastic ribbon is adhered to said web by means of a hot melt adhesive.

8. The method of claim 1, wherein said discrete lengths of elastic ribbon are adhered to said web in the discrete areas having adhesive applied thereto by passing said web and said ribbon into the nip formed between a pair of combining rolls which exert pressure thereon, said pressure acting to extrude said adhesive and thereby minimize its thickness and maximize the area of contact between said adhesive, said elastic ribbon and said web.

9. A method for continuously attaching discrete lengths of elastic ribbon to isolated portions of a moving, substantially inelastic web of interconnected articles, to impart an elasticized character to predetermined, isolated portions of said articles while preserving the substantially inelastic character of said articles in areas where said ribbon is unattached to said web, said method comprising the steps of:

(a) feeding an elastic ribbon having a heatactivated adhesive coating on at least one surface thereof to an assembly station in a stretched condition;

(b) feeding a web of interconnected articles comprised of a substantially inelastic material to said assembly station;

(c) adhering discrete lengths of said stretched elastic ribbon to predetermined isolated portions of the articles comprising said web at said assembly station by activating said adhesive only in predetermined areas along the length of said elastic ribbon;

(d) maintaining said elastic ribbon in a stretched condition at least until said adhesive sets up;

(e) cutting said elastic ribbon transversely in an area which is not adhered to said web, thereby forming severed, unadhered ends of elastic at both ends of each discrete length of stretched elastic ribbon adhered to said web; and

(f) allowing the severed, unadhered ends of said elastic ribbon to relax and contract to their unstretched state, whereby said unadhered ends do not impart an elasticized character to said web nor do they interfere with the functioning of the elasticized portions of the web to which said discrete lengths of elastic ribbon are adhered.

10. A method of intermittently attaching an elastic ribbon to predetermined, isolated portions of at least one of a pair of continuously moving, substantially inelastic, superposed webs to impart an elasticized character thereto while preserving the substantially inelastic character thereof in areas where said ribbon is unattached to said web, said method comprising the steps of:

(a) feeding an elastic ribbon to an assembly station in a stretched condition;

(b) applying adhesive intermittently on said stretched elastic ribbon at predetermined intervals along the length of said ribbon while said stretched elastic ribbon is being fed to said assembly station;

(c) feeding first and second webs of substantially inelastic material to said assembly station;

(d) adhering the stretched elastic ribbon to predetermined, isolated portions of at least one of said webs at said assembly station in those discrete areas of the ribbon that have adhesive applied thereto;

(e) applying bands of adhesive to at least one of said webs while said webs are being fed to said assembly station, said bands being registered such that they will ultimately lie outside the area occupied by said stretched elastic ribbon;

(f) adhering said second web to said first web at said assembly station in the areas of said bands of adhesive;

(g) maintaining said elastic ribbon in a stretched condition at least until said adhesive on said ribbon sets up;

(h) cutting said webs into discrete articles transversely along a line severing said elastic ribbon in a portion of its length which is not adhered to either of said webs; and

(i) allowing the severed, unadhered ends of said elastic ribbon to relax and contract to their unstretched length, whereby said unadhered ends do not impart an elasticized character to the articles cut from said webs nor do they interfere with the functioning of the elasticized portions of said articles to which said elastic ribbon is adhered.

11. The method of claim 10, wherein said substantially inelastic superposed webs and the stretched elastic ribbon secured thereto at spaced locations along its length are maintained in tension at least until said discrete elasticized articles are severed therefrom.

12. A method for continuously attaching discrete lengths of elastic ribbon to predetermined, isolated portions of a moving, substantially inelastic web to impart an elasticized character thereto while preserving the substantially inelastic character thereof in areas where said ribbon is unattached to said web, said method comprising the steps of:

(a) feeding a heat-sealable elastic ribbon to an assembly station in a stretched condition;

(b) feeding a web of substantially inelastic material to said assembly station;

(c) adhering discrete lengths of said heat-sealable elastic ribbon to predetermined, isolated portions of said web at said assembly station by elevating the surface temperature of said ribbon only in predetermined areas along the length of said elastic ribbon;

(d) maintaining said elastic ribbon in a stretched condition until the termperature of said ribbon has been lowered sufficiently to bond said ribbon to said web;

(e) cutting said elastic ribbon transversely in an area which is not adhered to said web, thereby forming severed, unadhered ends of elastic at both ends of each discrete length of stretched elastic ribbon adhered to said web; and

(f) allowing the severed, unadhered ends of said elastic ribbon to relax and contract to their unstretched state, whereby the unadhered ends do not impart an elasticized character to said web nor do they interfere with the functioning of the elasticized portions of said web to which said discrete lengths of elastic ribbon are adhered.

13. A method of intermittently attaching a pair of elastic ribbons intermediate the opposed waistband portions of the absorbent pad elements contained in a continuously moving, substantially inelastic web of interconnected disposable diapers to form a pair of discrete elasticized legbands in each of said diapers cut from said web, the waistband portions of said diapers being non-elasticized to provide improved wearer comfort and fit as well as to facilitate securement thereof about the wearer'"'"'s waist, said method comprising the steps of:

(a) feeding a pair of elastic ribbons to an assembly station in a stretched condition;

(b) applying adhesive intermittently on said stretched elastic ribbons at predetermined intervals along the length of said ribbons while said stretched elastic ribbons are being fed to said assembly station;

(c) feeding first and second webs of substantially inelastic material to said assembly station;

(d) feeding absorbent pad elements having opposed waistband portions intermediate said first and said second webs;

(e) adhering said stretched elastic ribbons to at least one of said webs at discrete locations intermediate the opposed waistband portions of said absorbent pad elements at said assembly station in those discrete areas of the ribbons that have adhesive applied thereto;

(f) applying bands to adhesive to at least one of said webs while said webs are being fed to said assembly station, said bands being registered such that they will ultimately lie outside the area occupied by said stretched elastic ribbons;

(g) adhering said second web, said absorbent pad elements and said first web in superposed relation at said assembly station in the areas of said bands of adhesive;

(h) maintaining said elastic ribbons in a stretched condition at least until said adhesive on said ribbons sets up;

(i) cutting said webs transversely into discrete disposable diapers along a line severing said elastic ribbons in a portion of their length which is not adhered to either of said webs; and

(j) allowing the severed, unadhered ends of said elastic ribbons to relax and contract to their unstretched length, whereby said unadhered ends do not impart an elasticized character to the waistband portions of said disposable diapers nor do they interfere with the functioning of the elasticized legband portions of said diapers to which said discrete lengths of elastic ribbon are adhered.

14. The method of claim 13, wherein said first web is comprised of moisture-impervious backsheet material and said second web is comprised of moisture-pervious topsheet material, said method including the step of continuously feeding discrete, hourglass-shaped absorbent pad elements intermediate said first and said second webs at predetermined points along the length of said webs, said elastic ribbons being adhered to said first web at points intermediate the opposed end portions of each of said hourglass-shaped absorbent pad elements to form a pair of discrete elasticized legbands in each of the discrete disposable diapers cut from said web.

15. The method of claim 14, wherein said stretched elastic ribbons are adhered to said web by means of a hotmelt adhesive which becomes elastomeric after set up, thereby permitting expansion and contraction of said web and the secured portions of said elastic ribbons without any substantial separation therebetween.

16. The method of claim 14, wherein said first and second webs, said absorbent elements, and said elastic ribbons are formed into a unitary elasticized assemblage by simultaneously passing them into a nip formed between a pair of combining rolls which exert pressure thereon to bring said elements into intimate contact with each other in the areas where adhesive is present, the moisture-pervious topsheet surface of said assemblage being thereafter subject to suction to secure the entire assemblage together until the adhesive employed to adhere said elastic ribbon has set up.

17. A method of intermittently attaching an elastic ribbon to predetermined, isolated portions of at least one of a pair of continuously moving, substantially inelastic, superposed webs to impart an elasticized character thereto while preserving the substantially inelastic character thereof in areas where said ribbon is unattached to said web, said method comprising the steps of:

(a) feeding an elastic ribbon to an assembly station in a uniformly stretched condition by feeding said ribbon in an unstretched state into a first lowpressure nip formed between a first metering roll and a second metering roll, passing said ribbon partially about the periphery of said second metering roll directly to a third metering roll, passing said ribbon partially about the periphery of said third metering roll, and thereafter feeding said ribbon from said third metering roll to said assembly station by operating said metering rolls at a uniform peripheral velocity less than that of the incoming webs at said assembly station;

(b) applying adhesive intermittently on said stretched elastic ribbon at predetermined intervals along the length of said ribbon while said stretched elastic ribbon is being fed to said assembly station;

(c) feeding first and second webs of substantially inelastic material to said assembly station;

(d) adhering the stretched elastic ribbon to predetermined, isolated portions of at least one of said webs at said assembly station in those discrete areas of the ribbon that have adhesive applied thereto;

(e) applying bands of adhesive to at least one of said webs while said webs are being fed to said assembly station, said bands being registered such that they will ultimately lie outside the area occupied by said stretched elastic ribbon;

(f) adhering said second web to said first web at said assembly station in the areas of said bands of adhesive;

(g) maintaining said elastic ribbon in a stretched condition at least until said adhesive on said ribbon sets up;

(h) cutting said webs into discrete articles transversely along a line severing said elastic ribbon in a portion of its length which is not adhered to either of said webs; and

(i) allowing the severed, unadhered ends of said elastic ribbon to relax and contract to their unstretched length, whereby said unadhered ends do not impart an elasticized character to the articles cut from said webs nor do they interfere with the functioning of the elasticized portions of said articles to which said elastic ribbon is adhered.

18. A method of intermittently attaching an elastic ribbon to predetermined, isolated portions of at least one of a pair of continuously moving, substantially inelastic, superposed webs to impart an elasticized character thereto while preserving the substantially inelastic character thereof in areas where said ribbon is unattached to said web, said method comprising the steps of:

(a) feeding an elastic ribbon to an assembly station in a uniformly stretched condition by feeding said ribbon in an unstretched state into a first lowpressure nip formed between a first metering roll and a second metering roll, passing said ribbon partially about said second metering roll directly into a second low-pressure nip formed between said second metering roll and a third metering roll, and thereafter feeding said ribbon from said second nip to said assembly station by operating said metering rolls at a uniform peripheral velocity less than that of the incoming webs at said assembly station;

(b) applying adhesive intermittently on said stretched elastic ribbon at predetermined intervals along the length of said ribbon while said stretched elastic ribbon is being fed to said assembly station;

(c) feeding first and second webs of substantially inelastic material to said assembly station;

(d) adhering the stretched elastic ribbon to predetermined, isolated portions of at least one of said webs at said assembly station in those discrete areas of the ribbon that have adhesive applied thereto;

(e) applying bands of adhesive to at least one of said webs while said webs are being fed to said assembly station, said bands being registered such that they will ultimately lie outside the area occupied by said stretched elastic ribbon;

(f) adhering said second web to said first web at said assembly station in the areas of said bands of adhesive;

(g) maintaining said elastic ribbon in a stretched condition at least until said adhesive on said ribbon sets up;

(h) cutting said webs into discrete articles transversely along a line severing said elastic ribbon in a portion of its length which is not adhered to either of said webs; and

(i) allowing the severed, unadhered ends of said elastic ribbon to relax and contract to their unstretched length, whereby said unadhered ends do not impart an elasticized character to the articles cut from said webs nor do they interfere with the functioning of the elasticized portions of said articles to which said elastic ribbon is adhered.

19. An apparatus for continuously attaching discrete lengths of elastic ribbon to predetermined, isolated portions of a moving, substantially inelastic web to impart an elasticized character thereto while preserving the substantially inelastic character of said web in areas where said ribbon is unattached to said web, said apparatus comprising:

(a) means for feeding an elastic ribbon to an assembly station in a stretched condition;

(b) means for applying adhesive intermittently to discrete lengths of said elastic ribbon at predetermined intervals along the length of said ribbon while said stretched elastic ribbon is being fed to said assembly station;

(c) means for feeding a web of substantially inelastic material to said assembly station;

(d) means for adhering said discrete lengths of stretched elastic ribbon to predetermined, isolated portions of said web at said assembly station in the discrete areas of said stretched elastic ribbon having adhesive applied thereto;

(e) means for maintaining said elastic ribbon in a stretched condition at least until said adhesive sets up;

(f) means for cutting said elastic ribbon transversely in an area which is not adhered to said web, thereby forming severed, unadhered ends of elastic at both ends of each discrete length of stretched elastic ribbon adhered to said web.

20. The apparatus of claim 19, wherein said means for feeding said elastic ribbon to said assembly station in a stretched condition is comprised of a low-pressure nip formed between first and second metering rolls and a third metering roll independent of said first and second metering rolls, said elastic ribbon being passed into said nip in an unstretched state, partially about the periphery of said second metering roll directly to said third metering roll, partially about said third metering roll, and from said third metering roll to said assembly station, said metering rolls being operated at a uniform peripheral velocity less than that of the incoming webs at said assembly station.

21. The apparatus of claim 19, wherein said means for feeding said elastic ribbon to said assembly station in a stretched condition is comprised of a first low-pressure nip formed between a first metering roll and a second metering roll and a second low-pressure nip formed between said second metering roll and a third metering roll, said elastic ribbon being passed into said first nip in an unstretched state, partially about the periphery of said second metering roll directly into said second low-pressure nip, and from said second nip to said assembly station, said metering rolls being operated at a uniform peripheral velocity less than that of the incoming webs at said assembly station.

22. The apparatus of claim 19, wherein said means for adhering said discrete lengths of stretched elastic to said web at said assembly station in the discrete areas having adhesive applied thereto is comprised of a nip formed between a pair of combining rolls.

23. The apparatus of claim 22, wherein said nip has a fixed gap clearance small enough to apply pressure to said web, said elastic ribbon, and the adhesive joining said ribbon to said web as they pass therethrough.

24. The apparatus of claim 22, wherein said nip has a variable-gap clearance, and a constant force is applied thereto as said web, said elastic ribbon, and the adhesive joining said ribboon to said web pass therethrough.

25. The apparatus of claim 19, wherein said means for cutting said elastic ribbon transversely in an area which is not adhered to said web functions to simultaneously cut discrete articles from said web at a predetermined point along the length of said web.

26. An apparatus for continuously attaching discrete lengths of elastic ribbon to predetermined, isolated portions of a moving, substantially inelastic web to impart an elasticized character thereto while preserving the substantially inelastic character of said web in areas where said ribbon is unattached to said web, said apparatus comprising:

(a) means for feeding an elastic ribbon having a heat-activated adhesive coating on at least one surface thereof to an assembly station in a stretched condition;

(b) means for feeding a web of substantially inelastic material to said assembly station;

(c) means for activating said adhesive coating only at predetermined areas along the length of said elastic ribbon to adhere discrete lengths of said stretched elastic ribbon to predetermined, isolated portions of said web at said assembly station;

(d) means for maintaining said elastic ribbon in a stretched condition at least until said heatactivated adhesive sets up; and

(e) means for cutting said elastic ribbon transversely in an area which is not adhered to said web, thereby forming severed, unadhered ends of elastic at both ends of each discrete length of stretched elastic ribbon adhered to said web.

27. An apparatus for continuously attaching discrete lengths of elastic ribbon to predetermined, isolated portions of a moving, substantially inelastic web to impart an elasticized character thereto while preserving the substantially inelastic character of said web in areas where said ribbon is unattached to said web, said apparatus comprising:

(a) means for feeding a heat-sealable elastic ribbon to an assembly station in a stretched condition;

(b) means for feeding a web of substantially inelastic material to said assembly station;

(c) means for adhering discrete lengths of said heat-sealable elastic ribbon to predetermined, isolated portions of said web at said assembly station by elevating the surface temperature of said ribbon only in predetermined areas along the length of said ribbon;

(d) means for maintaining said heat-sealable elastic ribbon in a stretched condition until the temperature of said ribbon has been lowered sufficiently to bond said ribbon to said web; and

(e) means for cutting said elastic ribbon transversely in an area which is not adhered to said web, thereby forming severed, unadhered ends of elastic at both ends of each discrete length of stretched elastic ribbon adhered to said web.