KR20080099236A - Method of reinforcing a bond between web materials and an absorbent article comprising bonded web materials - Google Patents

Abstract

A method of bonding a first and a second web material (2, 3) to each other, wherein the two web materials are brought together in the area to be bonded and thermal energy or ultrasonic energy is applied to at least one of the web materials in the area to be bonded. In order to improve the bonding strength an additional material (28) that is non-tacky at a temperature of 2O°C is applied to at least one of the web materials in at least a part of the area to be bonded prior to bringing the two web material (2, 3) together. In one aspect the web materials are components of a personal care absorbent article.

Description

METHOD OF REINFORCING A BOND BETWEEN WEB MATERIALS AND AN ABSORBENT ARTICLE COMPRISING BONDED WEB MATERIALS}

The present invention refers to a method of bonding a first web material to a second web material by applying thermal or ultrasonic energy to at least one of the web materials in the region to be bonded. The present invention specifically refers to web material forming portions of personal care absorbent articles. One important application is a panty absorbent article in which the web materials form part of the body panel and the area to be bonded forms a seam of the panty absorbent article.

Personal care absorbent articles include articles such as diapers, panty diapers, incontinence products, sanitary napkins, panty liners, and the like. These articles include thin web material layers bonded to each other in selected areas. Some of these bonded areas cause significant stress. This applies, for example, to the side seams of the panty-shaped absorbent article. Such articles can be pulled up and down on the wearer's buttock so that the wearer or caregiver can easily coat and remove the article when soiled. In conventional panty diapers the cover material is usually made of a double layer of nonwoven materials. In welded seams of this type of cover material, there are usually four layers of bonded nonwoven that provide sufficiently strong welded seams.

For example, it is also known to make panty absorbent articles having front and rear body panels of elastic web material in the form of elastic laminates comprising elastic yarns or elastic films sandwiched between layers of nonwoven material such as spunbond webs. have. Since the structure of the elastic laminate must be thin, it is suitable for providing optimum elasticity and at the same time a flexible fabric, which is bonded when bonding two elastic laminates together, such as at the side seams of a panty article by ultrasonic bonding or thermal bonding. It may also negatively affect strength. Thus, in particular, the bond strength at the side seam sometimes becomes insufficient for stress that occurs during use of the article.

Examples of elastic laminates are described in WO 03/047488. This publication describes an elastic laminate consisting of an elastic film applied between two thin nonwoven layers. During the manufacture of the elastic laminate, the nonwoven layers were connected to the film and then stretched until the bonds of the nonwoven layer were broken. The elasticity of the laminate is thus basically made equal to the elasticity of the elastic film. An important disadvantage of this solution is that the weld seam between two elastic laminates of this kind has significantly less strength than the weld seam in the conventional diaper panties.

Other examples of elastic laminates are described in PCT / SE2004 / 001004, PCT / SE2004 / 001005 and PCT / SE2004 / 001415. In contrast to the production process according to WO 03/047488, the joining portion of at least one of the nonwoven layers is not completely broken open and instead the layer has a constant residual strength. However, these types of elastic laminate furnace weld seams are also weaker than conventional diaper panties.

Further examples of absorbent articles made partially of elastic laminates can be found in US Pat. No. 6,476,289 and JP 10043235.

PCT / SE2005 / 000319 describes sanitary panties, such as diaper panties, wherein the weld seam comprises an elastic laminate reinforced by at least one nonwoven strip containing thermoplastic fibers. Elastic laminates were welded together by ultrasonic welding with nonwoven strips applied between them

US 6,837,961 discloses a panty diaper with a tear resistant side seam comprising a combination of an adhesive and an ultrasonic or thermal bond pattern. However, application of the adhesive may cause process problems and product quality problems.

There is still a need to improve the bond strength of the joints between certain web materials, for example elastic web materials such as elastic laminates, in an efficient and simple manner while maintaining high product quality.

Objects and most important features of the present invention

It is an object of the present invention to solve the above problem and to provide a cost-effective and simple method of improving the bond strength of the joint between the first and second web materials. The web materials are brought together in the area to be bonded and heat or ultrasonic energy is applied to at least one of the web materials in the area to be bonded. Prior to bringing the two web materials together an additional material which is non-tacky at a temperature of 20 ° C. is applied to at least one of the web materials in at least part of the area to be bonded. It is preferred that the further material is already non-tacky at a temperature of 30 ° C., preferably also at 40 ° C. and more preferably also at 60 ° C. The problem of handling adhesive materials that are also viscous below the application temperature is thereby avoided. The additional material is applied at a temperature that is at least partially melted or softened so that it adheres to the web material to be applied. The presence of additional material in the area to bond improves the bond strength of the bond between the two web materials.

In one aspect of the invention said additional material is applied by spraying.

In further aspects, the additional material is applied in the form of fibers or filaments.

In one embodiment the area to be bonded corresponds to less than 10% of the total surface area of each of the first and second web materials. In further embodiments, the area to be bonded has a defined length and width, said width being 30 mm or less, preferably 25 mm or less, and more preferably 20 mm or less.

According to one embodiment, the web material comprises a polymer material selected from polyolefins, polyesters, polyamides, including polyethylene and polypropylene, copolymers and mixtures of such polymer materials.

In further embodiments further materials include polymeric materials selected from polyolefins, polyesters, polyamides, including polyethylene and polypropylene, copolymers and mixtures of such polymeric materials.

In one aspect of the invention, the first and second web materials are components in a personal care absorbent article. In still further views they intended to form part of the first and second body panels of the panty absorbent article and the region to be bonded of the web materials to form a side seam of the panty absorbent article.

In one embodiment at least one of the first and second web materials comprises an elastic web material. In further embodiments both the first and second web materials comprise an elastic web material.

In still further embodiments the first and / or second web material is an elastic laminate. The elastic web material may be in a stretched state during bonding. For example, the untensioned length may be stretched to at least 20% greater length during bonding.

In further embodiments, additional material is applied to selected areas of the side seams.

In still further embodiments the elastic web material has a basis weight of 100 g / m 2 or less, preferably 90 g / m 2 or less.

The elastic web material may be an elastic laminate comprising an elastic film applied between the layers of fibrous material.

In one aspect of the invention, the elastic web material constitutes at least the bottom component of the first and second body panels in selected portions of the areas bonded together to form the side seams.

In further aspects the tensile strength of the side seams 9, 10 is at least 5N / 25.4 mm, preferably at least in the direction x transverse to the side seams in the portions reinforced by the additional material 28. 7N / 25.4mm, and more preferably at least 9N / 25.4mm.

In one embodiment the additional material is applied in an amount corresponding to a basis weight of at least 10 gsm, preferably at least 20 gsm and more preferably at least 30 gsm.

According to a further embodiment the elastic web material has at least 30%, preferably at least 50%, more preferably at least 70% elasticity in the transverse direction of the article as measured by the elasticity test specified in the detailed description. Have

The invention will be described in more detail below by way of examples with reference to the accompanying drawings.

1 shows a perspective view of a panty diaper.

Figure 2 shows a plan view of a panty diaper in a flat, unshrunk state before being formed, as seen from the side facing the body.

3 is a cross-sectional view taken along the line III-III of FIG. 2.

4 is a cross-sectional view of an enlarged scale of elastic laminate web material.

5 and 6 schematically illustrate a method of measuring tensile strength of side seams of panties.

Description of Preferred Embodiments

The present invention will be described in more detail below with reference to some embodiments shown in the accompanying drawings.

The figure shows one embodiment of the panty absorbent article 1. Examples of such panty absorbent articles are panty diapers, sanitary panties, and incontinence panties worn by incontinence adults. The panty absorbent article will now be referred to as panty diaper. The term "absorbent article" refers to a product placed on the skin of a wearer to absorb and contain body exudates such as urine, feces and menstrual blood. The present invention mainly refers to disposable absorbent articles, which refers to articles which are not intended to be washed after use or otherwise stored or reused as absorbent articles.

The panty diaper typically comprises a front panel 2, a rear panel 3 and a crotch portion 4. The article has a longitudinal direction y and a transverse direction x. The outer longitudinal edges 5 and 6 of the front panel 2 are connected to the respective longitudinal outer edges 7 and 8 of the rear panel 3 by thermal bonding or ultrasonic bonding, so that the side seams 9 and 10) form. The waist opening 11 and the pair of leg openings 12 and 13 are thereby formed.

The panty diaper comprises an outer cover sheet covering the front panel 2 and the rear panel 3, which is in the form of an elastic web material 14 that is at least elastic in the transverse x-direction of the article. The elasticity in the x-direction may be at least 30%, preferably at least 50%, more preferably at least 70% as measured by the elasticity test specified below.

Preferably, the elastic web material is also elastic in the y-direction of the article. However, the elasticity in the y-direction may preferably be lower than in the x-direction. In one embodiment the elasticity in the y-direction is at least 20%.

In the embodiment shown in FIG. 4 described below, the elastic web material 14 is composed of first and second outer layers 15 and 16 of fibrous material and an intermediate elastic film layer located between the fibrous layers. It is an elastic laminate composed of (17). However, it is understood that other forms of elastic web material may be used, such as elastic nonwoven materials, non-elastic, but non-woven materials elasticized by elastic yarns and the like. The elastic web material may comprise one layer or two or more layers laminated.

In the elastic laminate shown and described below, the outer fibrous layers 15 and 16 are selected so that they provide a high puncture resistance to the material in combination with the inner elastic film layer 17. They also give the laminate a soft, cloth-like feel. Examples of suitable materials are carded web and spunbond materials. The basis weight of the fibrous material layers in the laminate should be 10 to 35 g / m 2, preferably 12 to 30 g / m 2, more preferably 15 to 25 g / m 2. Examples of suitable polymers for use in fibrous materials are polyethylene, polyester, polypropylene and other polyolefin homopolymers and copolymers. Natural fibers such as cotton may also be used as long as they provide the required properties. The mixture of polymers can contribute to the higher flexibility of the nonwoven layer, thereby providing the nonwoven material with higher elongation at maximum load. Mixtures of polyethylene and polypropylene polymers have been proven to provide good results in this regard. Mixtures of fibers of other polymers are also possible.

The intermediate layer 17 is an elastic film with holes having a basis weight of 20 to 80 g / m 2, preferably 20 to 60 g / m 2, according to one embodiment of the invention. The film can be any suitable elastomer, natural or synthetic. Some examples of materials suitable for elastic films include low crystallinity polyethylene, metallocene catalyzed low crystalline polyethylene, ethylene vinyl acetate copolymers (EVA), polyurethanes, polyisoprene, butadiene-styrene copolymers, styrene / isoprene / styrene (SIS), styrene / butadiene / styrene (SBS), or styrene block copolymers such as styrene / ethylene-butadiene / styrene block copolymers. Blends of these polymers may also be used and other modified elastomeric or nonelastic polymer materials may be used. One example of a suitable film is a three-layer elastomeric film with pores of PE-SEBS-PE.

   The total basis weight of the laminate is preferably 100 g / m 2 or less, more preferably 90 g / m 2 or less.

The elastic laminate 14 can be made according to the method disclosed in WO 03/047488, in which one spunbond layer 15 is applied to the film 17 in a tacky state and thus bonded to the film layer while the other The spunbond layer 16 is adhesively laminated to the film layer 17 using, for example, a pressure sensitive hot melt adhesive. Alternatively, the laminate is made according to a variant of this known method, in which the laminate is stretched and stretched to a point below the elongation at at least one peak load of the inelastic nonwoven layer (engaging gears, To retain some strength for at least one of the nonwoven layers) (through IMG). The other layer may also be stretched to a point below the elongation at peak load or to a point that is torn during stretching.

The method disclosed in WO 03/047488 involves the stretching of the laminate over the breaking point of the fibrous material so that the inelastic layer is completely destroyed. Therefore, as described in WO 03/047488, the elongation of the laminate is not limited by the stretch modulus of the inelastic material.

In a preferred embodiment, at least one, preferably both fibrous layers bonded to the elastic film are not completely torn in the manufacture of the laminate according to the invention as opposed to the method disclosed in WO 03/047488. The selection of the fibrous material with elongation at maximum load, which is greater than the elasticity of the elastic laminate, allows the elastic film to stretch without being disturbed by the fibrous layers. This choice also ensures that the fibrous layers do not tear or break completely during manufacture, contributing to the puncture resistance of the laminate. Preferably both fibrous layers, or at least one of the fibrous layers, have an elongation at maximum load, at least 10% higher than the elasticity of the laminate. This is described in more detail in PCT / SE2004 / 001005, which is incorporated herein by reference.

The opacity of the material layer is the characteristic ability of the material layer to visually hide what the underlying object or pattern looks like. Opacity is measured in%, 100% opacity means nothing is seen through the material layer and 0% means that the material layer is completely transparent. Opacity is measured by the Opacity Test disclosed in PCT / SE2004 / 001415.

The opacity of the laminate can be obtained by including the opaque filler in the laminate, specifically in the elastic film. Such pigments may be organic or inorganic dyes, colorants, or bleaches. Inorganic materials such as titanium dioxide, inorganic carbonates, synthetic carbonates, talc, stone, selenite, magnesium hydroxide, aluminum trihydrate, diatomaceous earth, mica, natural or synthetic silica, calcined clay and mixtures thereof are examples of preferred opaque fillers.

The filler is preferably added as a master batch at the time of extrusion of the film. One example of a suitable concentration is about 5% filler by weight of the film.

It is also preferred that the elastic laminate 10 has a breathability (water vapor transmission rate) according to ASTM E96-00 Procedure D of at least 1500 g / m 2 24h, preferably at least 3000 g / m 2 24h.

The panty diaper according to the figure has a core region 18 located in the crotch portion 4 of the article and extends a certain distance to the front panel 2 and the rear panel 3. The crotch portion 4 is thus defined as a narrow portion of the article intended to be worn in the crotch between the wearer's legs.

The panty diaper includes a liquid permeable top sheet 19 and a liquid impermeable back sheet 20 covering the core region 18. The absorbent core 21 is enclosed between the sheet 19 and the back sheet 20.

The liquid permeable topsheet 19 may be comprised of a nonwoven material such as spunbond, meltblown, carded, hydroentangled, wetlaid, and the like. Suitable nonwoven materials may consist of natural fibers such as woodpulp or cotton fibers, artificial fibers such as polyester, polyethylene, polypropylene, viscose, or the like, or mixtures of natural and artificial fibers. The topsheet material may also be composed of tow fibers, which may be bonded to each other in a bonding pattern, for example as disclosed in EP-A-1 035 818. Further examples of topsheet materials are porous foams, plastic films with holes, and the like. Suitable materials as the topsheet material should be flexible and nonirritating to the skin and intended for easy penetration of body fluids such as urine or menstrual blood. The topsheet may be different in other portions of the absorbent article.

The liquid impermeable backsheet 20 covering the core region 18 on the garment facing side of the absorbent core 21 is a liquid impermeable material such as a thin plastic film, for example polyethylene or polypropylene film, a liquid impermeable material. And a laminate comprising a nonwoven material, a hydrophobic nonwoven material resistant to liquid penetration, or a plastic film and a nonwoven material. The core region backsheet material 20 has the ability to breathe to allow vapor to escape from the absorbent core while still not allowing liquid to pass through. Examples of backsheet materials with a breathing function are porous polymer films, nonwoven laminates from spunbond and meltblown layers, porous polymer films and laminates from nonwovens. The backsheet 20 is preferably inelastic.

The absorbent core 21 can be any conventional one. Examples of commonly occurring absorbent materials are cellulose fluff pulp, tissue layers, high absorbent polymers (so-called superabsorbents), absorbent foam materials, absorbent nonwoven materials, and the like. It is common to combine cellulose fluff pulp with superabsorbent polymer in the absorbent core. Superabsorbent polymers are water swellable, water insoluble organic or inorganic materials capable of absorbing at least about 20 times their own weight in aqueous solutions containing 0.9 weight percent sodium chloride. Organic materials suitable for use as superabsorbents may include natural materials such as polysaccharides, polypeptides, and the like, as well as synthetic materials such as synthetic hydrogel polymers. Such hydrogel polymers include, for example, alkali metal salts such as polyacrylic acid, polyacrylamide, polyvinyl alcohol, polyacrylate, polyacrylamide, polyvinyl pyridine, and the like. Other suitable polymers include hydrolyzed acrylonitrile graft starch, acrylic acid graft starch, and isobutylene maleic anhydride copolymers and mixtures thereof. The hydrogel polymer is preferably lightly crosslinked to render the material substantially water insoluble. Preferred superabsorbent materials are further surface crosslinked such that outer surfaces or shells of superabsorbent particles, fibers, flakes, spheres and the like have a higher crosslink density than the interior of the superabsorbent. The superabsorbent material can be in any form suitable for use with an absorbent composite including particles, fibers, flakes, spheres, and the like.

High absorption capacity is provided by the use of high amounts of superabsorbent material. For absorbent cores comprising a matrix of hydrophilic fibers such as cellulose fibers and superabsorbent material, the ratio of superabsorbent material is preferably 10 to 90% by weight, more preferably 30 to 70% by weight.

With regard to liquid storage capacity, liquid distribution capacity and storage capacity, it is common in absorbent articles to have an absorbent core comprising layers of different properties. For example, thin absorbent bodies conventional in infant diapers and incontinence guards often include a structure consisting of a compressed blend or layer of cellulose fluff pulp and superabsorbent polymer. The size and absorbent dose of the absorbent core may vary to suit other uses, such as for infant or adult incontinence patients.

The absorbent core may also further comprise a capture distribution layer on top of the primary absorbent body, which is adapted to quickly receive and temporarily store the released liquid prior to being absorbed by the primary absorbent core. Such trap distribution layers are well known in the art and may be composed of porous fibrous waddings or foam materials.

The elastic web material 14 may cover the entire article, including the core region 18 and the entire front and back panels 2 and 3. According to a preferred embodiment, however, a substantial part of the crotch portion 4 of the article is free from the elastic web material 14. As used herein, "substantial portion" refers to at least 50%, preferably at least 75%.

The crotch subweb material 22, which is preferably an inelastic nonwoven material, is disposed in the crotch portion 4 of the article and overlaps the elastic front and rear panels 2 and 3. The crotch web material 22 is joined in an overlapping manner with the front and rear panels 2 and 3 by means of ultrasonic welding 23, glue strings and the like.

There is also provided an elastic waist band 24 comprising a substantially inelastic nonwoven material that is elastically elastic by an elongate elastic member 25 such as an elastic yarn shrinkably fixed between layers of material, such as a nonwoven material. Elastic yarn 26 may also be disposed around the leg openings 5 and 6 of the article. The nonwoven material strip 29 is applied along the rear portion of the leg opening area.

The liquid impermeable back sheet material 20 lies underneath the absorbent core 21 and the adjacent regions lie just outside of the core region 21. The area covered by the liquid impermeable back sheet 20 is defined as the core area 18. The crotch nonwoven material 22 is disposed on the side facing the garment of the liquid impermeable back sheet 20 in the crotch portion 4 of the article. The core region 18 extends to the front and rear panels 2 and 3 such that the elastic web material 14 and the liquid impermeable back sheet 20 overlap outside the core region 18 and the elastic web material 14 ) Is disposed on the side facing the garment of the liquid impermeable back sheet 20.

The resilient web material constitutes the bottom component of at least a portion of the front and rear panels 2 and 3. As shown flat according to FIG. 2, at least 20%, preferably at least 25%, more preferably at least 30% and most preferably at least 40% of the total surface area of the article is the bottom configuration of the front and rear panels. Construct an element.

No additional elasticity side panels connected to the front and rear panels 2 and 3 are needed when using the elastic web material 14.

It is also preferred that the elastic web material has a puncture resistance of at least 15 N, measured according to ASTM Designation D3763-02. Preferably, the elastic web material of the present invention has a puncture resistance of at least 2ON, and more preferably 3ON.

The elastic web material may preferably have a softness according to Kawabata of at least 20, preferably at least 30 and most preferably at least 40. It is also preferred to have moldability according to Kawabata of at least 50, preferably at least 30, more preferably at least 20 and most preferably at least 10. In addition, the elastic web material preferably has a drape property according to Kawabata of 40 or more. Flexibility, formability and drape according to Kawabata are measured according to the test method provided in PCT / SE2004 / 001004.

Couplings between the aforementioned forms of elastic and inelastic thin web materials and other forms of elastic web material 14 are insufficient. An example of such an engagement is in the side seams 9 and 10, which are subject to significant stress when pulled over the hips of the wearer. These side seams 9 and 10 are usually achieved by ultrasonic welding or thermal bonding, and a bonding pattern is formed.

According to the invention, as in the side seams 9 and 10, the joint is reinforced by applying an additional material prior to bonding to at least one of the elastic web material 14, which further material is not sticky at a temperature of 20 ° C. Do not. The further material is not already sticky at a temperature of 30 ° C., preferably also at 40 ° C. and more preferably also at 60 ° C.

Additional material is applied in at least a portion of the area to be bonded. The problem of handling sticky adhesive material also below the application temperature is thereby avoided. The presence of additional material in the area to be bonded improves the bond strength of the bond between the two elastic web materials 14.

The additional material is applied at a temperature that at least partially melts or softens to adhere to the web material to be applied. One preferred method of applying additional material is by spraying. The spray device is schematically shown in FIG. 2 and referred to by numeral 27. The additional material is preferably applied in the form of discontinuous fibers 28 or continuous filaments of limited length by known spray application techniques.

Further materials, such as fibers 28, preferably comprise polymeric materials selected from polyolefins, polyesters, polyamides, including polyethylene and polypropylene, copolymers and mixtures of such polymeric materials.

Alternative methods of applying additional materials are coating, slot coating, printing, embossing and similar known application techniques.

The elastic web material 14 preferably also contains a polymer material selected from polyolefins, polyesters, polyamides, including polyethylene and polypropylene, copolymers and mixtures of such polymer materials.

The elastic web material 14 may be in a stretched state during bonding. For example, the untensioned length may be stretched in the longitudinal and / or transverse direction to a length that is at least 20% greater during bonding. In such cases where the need to reinforce the joint is emphasized, the elastic web material is thinner in the stretched state, which provides a weaker joint, such as when in an unstretched state. The additional material 28 may be applied to only one or both of the web materials to bond. Additional material 28 may be applied over the entire area of the web material to be bonded or only to selected areas thereof. Additional materials may be applied to areas that are larger than to bond to ensure that they are applied to areas large enough to provide the desired bond strength. Since the additional material solidifies to a non-tacky state after application, its presence outside the bonded area is more, for example, the side seams 9 and 10, for example, as the application of the adhesive outside the bonded area. It does not interfere with the above manufacturing process nor impair product quality. Additional materials may be applied between the web materials to be bonded together, ie inside the seams between the web materials, or may be applied to the outside thereof.

In the case of the embodiment shown in the figures, additional material 28 may be applied along the entire side seams 9 and 10 or more material layers that may provide only selected areas thereof, for example sufficient bond strength. It may also be applied to the outer portion of the waist band 24 including them. The additional nonwoven strip 29 present in the leg opening area may also provide a reinforcing effect on the bond strength, so in further embodiments the additional material 28 is only in the center region of the side seams 9 and 10. Is applied.

In other embodiments of panty diapers, the additional material 28 is applied only in areas adjacent to the waist and leg openings where stress on the side seams is most important.

The tensile strength of the side seams 9, 10 is at least 5 N / 25.4 mm, preferably at least 7 N / 25.4 in the direction x across the side seams at least in the portions reinforced by the additional material 28. mm, and more preferably at least 9N / 25.4mm.

Additional material 28 as well as in areas where elastic waistband 24 is coupled to body panels 9 and 10 and / or in areas where elastic web material 14 is coupled to crotch web material 22. It can be applied to other areas to be bonded, such as books.

The additional material 28 is applied at a basis weight of at least 10 gsm, preferably at least 20 gsm and more preferably at least 30 gsm.

It is understood that the present invention encompasses all embodiments in which two elastic or inelastic web materials are bonded to each other by applying thermal or ultrasonic energy thereto. In particular, bonding together web materials that are components of a personal care absorbent article. According to one aspect of the invention the web material has a basis weight of at least 100 gsm, preferably at least 90 gsm.

A three-layer elastic film with pores inside of PE-SEBS-PE having a basis weight of 36 g / m 2, and a spunbond material having a basis weight of 22 g / m 2, two outer layers of PP (polypropylene) Elastic laminate materials. The laminate applies one spunbond layer to the film in a viscous state and bonds to the film layer as such, while the other spunbond layer is applied to the film layer using, for example, a pressure sensitive hot melt adhesive (3 g / m2 glue). The adhesive lamination is made by a modified method of the method disclosed in WO 03/04788. The laminate increases and stretches, at which point the inelastic spunbond layers are stretched to a point below the elongation at maximum load to retain some strength in the spunbond layer. The elasticity of the laminate after stretching is close to that of the elastic film layer.

The base weight of the layers refers to the laminate finished after stretching. The base weight of the individual layers before stretching was 40 g / m 2 of the inner film layer, 25 g / m 2 of the outer spunbond layers, and 3 g / m 2 of the glue layer, respectively. Since the basis weights of the individual layers after lamination and stretching are difficult to measure, they are approximated from the basis weights of the layers before lamination and stretching. The laminate before stretching had a total basis weight before stretching of 93 g / m 2 and a basis weight of 85 g / m 2 after stretching, which meant about 10% strain. The deformation of the individual fiber layers and the film layer was then the same, ie about 10%.

Panty diapers as shown in FIGS. 1 to 3 and comprising elastic laminates as front and rear body panels as described above were prepared. Side seams between the front and rear body panels were reinforced by spray application of fibers of polypropylene, Borealis HL612FB, in some products. The application temperature for the polymer was 220-250 ° C. and the spray head was kept between 20-50 mm from the elastic laminate material to be coated. The fibers were sprayed between or on the outside of the material webs at the side seams. Tensile strength tests of the seam were performed and reported below.

Elasticity test

The method measures how the elastic material behaves in cycles with repeated and unloaded loads. The sample is stretched to a given elongation and periodic movements between zero and the given elongation are performed. Record the desired load and force at no load. The permanent, e.g., elongation, of the relaxed material is measured.

Use Lloyd LRX, a tension tester capable of performing periodic movements, equipped with a printer / plotter or software presentation. The sample is prepared by cutting it to a width of 25 mm and a length of preferably 20 mm longer than the distance between the clamps of the tension tester.

Test the tension tester in accordance with the device instructions. The parameters required for the test (load and unload force) are adjusted as follows:

헤드 Crosshead speed: 500 mm / min

Clamp distance: 50 mm

Before load: 0.05 N

Place the sample along the mark in the clamp and ensure that the sample is centered and fixed vertically in the clamp. Start the tension tester and perform three cycles between zero and a given elongation, such as the highest prescribed first load. The sample is allowed to relax for one minute before the last cycle, then the permanent elongation is measured and elongation is read by stretching the sample until a force of 0.1 N is detected.

Permanent elongation after relaxation should be less than 10% and measured by the method described above. Thus, 30% elasticity is defined as the laminate must have permanent relaxation after less than 10% elongation after reaching 30% elongation in the tension tester. 30% elongation refers to the elongation to 30% longer than the initial length of the sample.

Tensile strength of side seam

Tensile strength of the side seam is measured according to the ASTM D 882 method described in patent application PCT / SE2004 / 001004. Test specimens are cut from the product as shown in FIG. 1 in areas reinforced with additional material. The test specimen is 25.4 mm wide and, if possible, 50 mm longer than the distance between the clamps in the tension test instrument Instron 4301. 5 and 6 illustrate how the test specimen is secured to the clamp.

To illustrate the effect of reinforcement of the side seams by the application of additional materials, Table 1 shows the side seams (ultrasound welded) of reinforced and non-reinforced additional materials in the form of sprayed fibers of polypropylene, Borealis HL612FB. The test result of the measurement of the tensile strength of ()) is shown. In Sample 1 additional material was sprayed on the outside of the side seams, while in Sample 2 it was sprayed on the inside of the side seams between the connected elastic laminate materials. In the reference material no additional material was applied to the side seams. The values shown in FIG. 1 are the average of 10 measurements.

Sample Force at 5% elongation (N) Force at 10% elongation (N) Force at 25% elongation (N) Force (N) Elongation at Full Load (%) Sample 1 0.27 0.58 1.32 16.2 117 Sample 2 0.29 0.57 1.35 17.5 115 standard 0.19 0.43 1.06 15.1 127

While the invention has been described with reference to preferred embodiments, various modifications are possible within the scope of the claims. Therefore, it is intended that the present invention cover any modification or equivalent within the art to which this invention pertains or which is well known in practice.

Claims (37)

Bonding the two web materials to each other by bringing the first web material 2 and the second web material 3 together in the area to be bonded and applying to the at least one of the web materials in the area to which thermal energy or ultrasonic energy is to be bonded. In the method, prior to bringing the two web materials together, an additional material 28 which is non-tacky at a temperature of 20 ° C. is applied to at least one of the web materials in at least a portion of the area to be bonded, wherein the additional material 28 ) Is applied at a temperature that is at least partially melted or softened so that it adheres to the web material (2, 3) to be applied. The method according to claim 1, wherein the additional material is applied by spraying. 3. Method according to claim 2, characterized in that the additional material (28) is applied in the form of fibers or continuous filaments. Method according to one of the preceding claims, characterized in that the area to be bonded corresponds to less than 10% of the total surface area of each of the first and second web materials (2, 3). 5. A method according to claim 4, wherein the area to be bonded has a defined length and width, said width being 30 mm or less, preferably 25 mm or less, and more preferably 20 mm or less. The method according to any one of the preceding claims, wherein the web materials (2, 3) comprise a polymer material selected from polyolefins, polyesters, polyamides, including polyethylene and polypropylene, copolymers and mixtures of such polymer materials. How to feature. The method of claim 1, wherein the additional material 28 comprises a polymer material selected from polyolefins, polyesters, polyamides, including polyethylene and polypropylene, copolymers and mixtures of such polymer materials. How to feature. The method according to any one of the preceding claims, characterized in that the further material (28) is non-tacky at a temperature of 30 ° C, preferably also at 40 ° C and more preferably at 60 ° C. Method according to any of the preceding claims, characterized in that the first and second web materials (2, 3) are components in a personal care absorbent article. 10. The absorbent article according to claim 9, wherein the first and second web materials form part of the first and second body panels (2, 3) of the panty-shaped absorbent article (1) and the area to be bonded of the web materials is panty-shaped absorbent. Characterized in that it is intended to form side seams (9, 10) of the article. Method according to one of the preceding claims, characterized in that at least one of the first and second web materials (2, 3) comprises an elastic web material. 12. The method according to claim 11, wherein the first and second web materials (2, 3) are both elastic web materials. The method according to claim 11 or 12, characterized in that the first and / or second web material (2, 3) is an elastic laminate. 14. A method according to any one of claims 11 to 13, wherein the elastic web material is in a stretched state during bonding. 15. The method of claim 14, wherein the elastic web material is stretched to a length of at least 20% greater than the untensioned length during bonding. Method according to one of the claims 10 to 15, characterized in that the additional material is applied to selected areas of the side seam (9, 10). 17. The method according to any one of claims 11 to 16, wherein the elastic web material has a basis weight of 100 g / m 2 or less, preferably 90 g / m 2 or less. 18. The method according to any one of claims 11 to 17, wherein the elastic web material is an elastic laminate (14) comprising an elastic film (17) applied between the layers (15, 17) of fibrous material. . 19. The method according to any of claims 11 to 18, wherein the elastic web material is bonded together to form at least the first and second body panels (2, 3) in selected portions of the areas forming the side seams (9, 10). Constructing the floor component. 20. The article of claim 11, wherein the elastic web material is at least 30%, preferably at least 50%, more preferably at least 70%, as measured according to the elasticity test specified in the detailed description. And having elasticity in the transverse direction of the. The method according to claim 1, wherein the additional material 28 is applied in an amount corresponding to a basis weight of at least 10 gsm, preferably at least 20 gsm and more preferably at least 30 gsm. . In a personal care absorbent article comprising an absorbent structure and first and second web materials joined together by thermal bonding or ultrasonic bonding to form a bonded area, further materials that are non-tacky at a temperature of 20 ° C. 28 ) Is present in at least a portion of the bonded area, and the additional material 28 is applied at a temperature that is at least partially melted or softened such that it adheres to at least one of the web materials. Absorbent articles. 23. The absorbent article as in claim 22, wherein said additional material (28) is in the form of fibers or filaments. The absorbent article according to claim 22 or 23, wherein the bonded area corresponds to less than 10% of the total surface area of each of the first and second web materials (2, 3). 25. The absorbent article as in claim 24, wherein the bonded area has a defined length and width, wherein the width is 30 mm or less, preferably 25 mm or less, and more preferably 20 mm or less. 26. A pair according to any one of claims 22 to 25, wherein the article is a pair of first and second body panels (2, 3) bonded together to form side seams (9, 10) of the panty-shaped absorbent article. A panty-shaped absorbent article comprising an intermediate crotch portion 4 having leg openings 12, 13, wherein the first and second web materials are at least a portion of the first and second body panels 2, 3. And the bonded area is the side seam (9,10) of the panty-shaped absorbent article. 27. An absorbent article according to any of claims 22 to 26, wherein at least one of the first and second web materials (2, 3) comprises an elastic web material. 28. The absorbent article as in claim 27, wherein said first and second web materials (2, 3) both comprise elastic web materials. 29. The absorbent article of claim 27 or 28, wherein the elastic web material has a basis weight of 100 g / m 2 or less, preferably 90 g / m 2 or less. 30. Absorbent according to any of claims 27 to 29, characterized in that the elastic web material is an elastic laminate 14 comprising an elastic film 17 applied between the layers 15, 17 of fibrous material. article. 31. An absorbent article as claimed in claim 26, wherein the additional material is applied in selected areas of the side seams. 32. At least one of the first and second body panels 2, 3 in the selected portion of the areas of the elastic web material bonded together to form the side seams 9, 10. An absorbent article, comprising a bottom component of the < RTI ID = 0.0 > 33. The article of any of claims 27-32, wherein the elastic web material is at least 30%, preferably at least 50%, more preferably at least 70%, as measured according to the elasticity test specified in the detailed description. The absorbent article, characterized in that it has elasticity in the transverse direction of the. 34. The method according to any of claims 22 to 33, wherein the additional material 28 is present in an amount corresponding to a basis weight of at least 10 gsm, preferably at least 20 gsm and more preferably at least 30 gsm. An absorbent article characterized by the above. 35. The polymeric material according to any one of claims 22 to 34, wherein the web materials (2, 3) are selected from polyolefins, polyesters, polyamides, including polyethylene and polypropylene, copolymers and mixtures of such polymeric materials. Absorbent article comprising a. 36. The method of any of claims 22 to 35, wherein the additional material 28 comprises a polymeric material selected from polyolefins, polyesters, polyamides, including polyethylene and polypropylene, copolymers and mixtures of such polymeric materials. An absorbent article comprising a. 37. The direction x according to any one of claims 26 to 36, wherein the tensile strength of the side seams 9, 10 is at least transverse to the side seam, in the portions reinforced by the additional material 28. At least 5N / 25.4mm, preferably at least 7N / 25.4mm, and more preferably at least 9N / 25.4mm.

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