RU2404895C2 - Elastic laminate and method of its production - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to the method of producing elastically elongating laminate 19 and to laminate produced by proposed method to be used in articles, say, disposable pants. Proposed laminate comprises at least three layers (1, 6, 18). Proposed method comprises the following jobs: a) fabrication of first laminate (8) including first linen (1) of inelastic fibrous nonwoven material and elastic film (6); b) activation of the first laminate (8) by stepwise stretching in at least one direction to impart said first laminate (8) ability of elastic elongation; c) stretching activated first laminate (8) for 10-200% in at least one direction; and d) jointing elongated first laminate (8) by lamination to second linen (18) of inelastic nonwoven materials.

EFFECT: elastic elongation, properties of textile, features high extension strength and high puncture resistance.

20 cl, 4 dwg, 1 tbl

Description

Description

FIELD OF TECHNOLOGY

The invention relates to a method for the production of an elastic laminate comprising at least three layers. The invention also relates to a stretchable laminate comprising a first canvas of inelastic non-woven fabric, a second canvas of inelastic non-woven fabric and an elastic perforated film between the first and second canvas of the non-woven fabric. The elastic laminates according to the invention are particularly suitable for use in disposable underwear such as underpants, panty diapers, hygiene underpants, incontinence underpants and the like. Such articles contain an absorbent element located in a cowl-shaped base part, and these articles are worn like a pair of underpants.

BACKGROUND OF THE INVENTION

Panty-type absorbent articles include a cowl-shaped base structure and an absorbent core component combined with it. When creating products such as underpants, the goal is to make them look like ordinary underwear as much as possible. Therefore, absorbent articles, such as diaper pants, hygiene pants and panties used for incontinence, are made with the possibility of their convenient and tight fit to the carrier. It is desirable that the products were made with the possibility of pulling them up and pulling them down the hips of the wearer in order to enable the wearer or someone who is caring for a child, patient, person with a disability, etc., to easily remove the stained product and replace it with a new one clean product. For these reasons, the base part of the product is usually made of a material that lends itself to elastic stretching, at least in areas intended for “overlay” over the hips of the wearer. In addition, it is desirable that the base portion surrounding the absorbent parts of a coward-type product be permeable to air and steam, that is, to be breathable. A breathable product prevents a situation in which moisture remains on the skin of the wearer and is more comfortable and less warm to wear than an airtight product. It is also preferable if the product is soft, smooth and similar to textiles so that it does not rub the skin of the wearer and looks like ordinary underwear as much as possible.

In addition, it is important that it is possible to stretch an absorbent article such as underpants over the thighs of the wearer without tearing. A common problem is that the wearer or caregiver spoils the underpants by inadvertently poking material with the fingers while trying to provide a good grip for pulling or pulling off the underpants.

The previously used elastic material for pant-type articles is a laminate comprising an elastic film located between two layers of inelastic non-woven material. To give the laminate the ability to stretch elastically, it is subjected to an activating treatment. A three-layer activated laminate is disclosed in international patent application No. WO 03/047488. An activated laminate is obtained by stretching a layer of elastic film with a defined pitch between two inelastic fabric-like layers. Step-by-step stretching is performed by passing a laminate between two engaged gear rollers. The activation of elastic laminates through stepwise stretching is also disclosed in US Pat. Nos. 5,143,679, 5,157,793, 5,167,897, 5,421,272, 5,592,690, 5,634,216 and 5,861,074. Inelastic tissue-like layers are completely or partially broken or torn during the activation process, so that the laminate elasticity after activation is mainly determined by the elasticity of the layer of elastic film. In the three-layer laminate in WO 03/047488, the inelastic layers are completely torn, so that the elasticity of the activated laminate is essentially the same as the elasticity of the elastic film layer.

Open laminates have excellent comfort properties and are soft, breathable and flexible. However, the main disadvantage associated with the known laminates is that the activation process leads to at least partial rupture and destruction of the tissue-like layers, as a result of which the activated laminate has a reduced tensile strength and reduced puncturing resistance. When used as a component of the base part in a disposable product such as underpants, the material is easily torn when exposed to the forces arising from putting on or removing a product such as underpants. This tearing problem is especially evident for those female carriers or women who care for a child, a sick person, a disabled person, etc., who often have long nails that can pierce and tear panties.

Therefore, there is a need for an improved, elastic stretchable, textile-like laminate for use in disposable underpants such as underpants. In addition, there is a need for a method of manufacturing such a laminate.

Accordingly, the object of the invention is to provide an elastic stretchable textile-like laminate having an increased tensile strength and an increased puncturing resistance. An additional object of the invention is to develop a method for producing a stretchable elastic like textile laminate having increased tensile strength and increased puncturing resistance.

SUMMARY OF THE INVENTION

In accordance with the invention, a method has been developed for producing a stretchable laminate comprising at least three layers. The method in accordance with the invention includes the following operations:

a) the production of the first laminate containing the first canvas of inelastic fibrous nonwoven material and an elastic film;

b) activating the first laminate by stepwise stretching to give the first laminate elastic resilience;

c) stretching the activated first laminate by 10-200% in at least one direction;

d) attaching the stretched first laminate by lamination to a second canvas of inelastic non-woven material.

The first laminate may be formed by any suitable method, including bonding, heat bonding and coating of an elastic film-forming polymer by extrusion onto a first canvas of a nonwoven material.

The degree of stretching of the first laminate is defined as a percentage of the initial length of the laminate in an unstretched state in the direction of stretching. As an example, a laminate having a first length in an unstretched state of 1 m and stretched by 50% has a second length in a stretched state of 1.5 m.

According to a preferred embodiment of the invention, the first laminate is formed by coating an elastic plastic film by extrusion onto a canvas of fibrous nonwoven material.

The elastic film is preferably perforated to ensure breathability of the formed laminate. When attaching the first canvas of the nonwoven material to the elastic film by extrusion coating, the perforating operation can be performed by passing the combined elastic layer and the canvas of the nonwoven material over the vacuum lamination drum while the elastic layer is in a molten or semi-molten state. A similar method is disclosed in US patent No. 5733628 and leads to the fact that the elastic film is converted into a three-dimensional layer of the laminate with holes.

The activation operation involves the stepwise stretching of the first laminate so that the inelastic material is torn, at least partially. Activation can be accomplished by means of heated or unheated gears engaged with gears having teeth located on the circumferential periphery that mesh and thereby allow the laminate to stretch. The activation operation provides the possibility of subsequent stretching of the laminate without noticeable limitation due to the canvas inelastic non-woven material. The degree of rupture of the inelastic nonwoven material determines the maximum possible elongation of the resulting laminate. If the nonwoven fabric is completely torn during activation, the laminate will have substantially the same maximum elongation as the elastic film layer.

Before performing the second lamination operation, the first laminate is stretched in at least one direction by 10-200% of its initial length in an unstretched state. By selecting and adjusting the degree of stretching, the desired elasticity of the final laminate can be obtained. The first laminate is preferably stretched to 35-180% of its length in the unstretched state, more preferably 50-150% of its length in the unstretched state, and most preferably 70-120% of its length in the unstretched state before joining the second canvas inelastic non-woven material by lamination.

The second canvas of the inelastic nonwoven fabric may be bonded to the activated first laminate.

Alternatively, the second canvas of the inelastic nonwoven fabric may be joined by heat welding or ultrasonic welding to the activated first laminate. The joint obtained by heat sealing or ultrasonic welding may take the form of invisible joints, such as spot welds or linear welds. By choosing a joint configuration in the form of sparse distributed spot welds, it is possible to provide higher flexibility of the resulting laminate than in the case of a joint configuration in which it occupies most of the contact surface between the joined layers.

The materials in the laminate preferably have the form of moving canvases. The canvases can have the same width to obtain a three-layer laminate, which can subsequently be continuously fed during the manufacturing process of a disposable product such as underpants and form elastic sections of the base part of the product. Alternatively, the laminate may be cut, and it may be shaped into individual elements that are used to make a disposable product such as underpants.

Alternatively, there is the possibility of producing a laminate in which the second canvas of the inelastic nonwoven fabric has a width exceeding the width of the first laminate. Such a three-layer laminate is respectively continuously fed in the process of manufacturing disposable products such as underpants, and such a three-layer laminate can form both elastic and inelastic portions of the base part of the product.

In addition, two or more moving canvases of the first laminate can be attached to the second canvas of the inelastic non-woven material. Different canvas with two laminates can be stretched to different degrees and / or can be made from different combinations of materials.

The first and second canvases of the inelastic fibrous nonwoven material may contain thermoplastic fibers. Examples of polymers suitable for use in fibrous nonwoven webs are polyethylene, polyesters, polypropylene and other polyolefin homopolymers and copolymers. It is especially good if a suitable nonwoven canvas contains thermoplastic fibers, which are a mixture of polypropylene and polyethylene fibers. Preferred canvases have a high content of thermoplastic fibers and contain at least 50% thermoplastic fibers and, preferably, at least 80% thermoplastic fibers. A second and / or non-elastic canvas of fibrous non-woven material will typically be used in joints (joints) and seams in a disposable item such as underpants. Therefore, it is highly desirable that nonwoven webs can be welded by heat sealing or ultrasonic welding processes.

Creped nonwoven fabric is a type of nonwoven fabric webs suitable for use in particular as a second canvas of non-elastic nonwoven fabric. Crepe non-woven materials generally have a higher degree of extensibility and flexibility than non-creped non-woven materials. By selecting a creped nonwoven material for a second canvas of inelastic nonwoven material, a final three-layer laminate having better properties in terms of softness and fit than using a non-creped nonwoven fabric can be obtained. The creped nonwoven fabric facilitates retraction of the three-layer laminate after elongation, resulting in increased elasticity compared to the corresponding laminate having a second layer of uncreated nonwoven fabric. If desired, the first canvas of the inelastic nonwoven fabric may also be a creped nonwoven fabric.

The elastic film used to produce the three-layer laminate according to the invention can be made from any suitable elastic polymer, natural or synthetic. One example of an elastic film that has been proven to provide good elasticity and breathability is a three-layer elastomeric film with holes having a polyethylene-copolymer of styrene and ethylene / butadiene alternating between blocks of polyethylene (PE-SEBS-PE).

In this context, an elastic material is defined as a material having a residual elongation after relaxation of less than 10% after subjecting the material to an elongation of 30% in the elasticity test described in the description.

An inelastic material is a material that does not fall within the definition of an elastic material. Accordingly, the inelastic material in the sense used here is a material that may be extensible or inextensible. In the case of a stretchable material, the material has a residual elongation after stretching and relaxation of more than 10% after subjecting the material to an elongation of 30%, as determined in accordance with the elasticity test.

An elastic stretch laminate is also provided in accordance with the invention, comprising a first canvas of inelastic nonwoven fabric, a second canvas of inelastic nonwoven fabric, and an elastic perforated film between the first and second canvas of the nonwoven fabric. The first canvas of the non-elastic nonwoven fabric and the elastic perforated film form parts of the first elastic laminate, which has been elasticized by stepwise stretching and partial tearing of the canvas of the non-woven fabric. The first elastic laminate was then bonded to the second layer of nonwoven material when the first elastic laminate was stretched, whereby the laminate lends itself to elastic stretching.

Accordingly, a three-layer laminate according to the invention comprises a first elastic bi-laminate comprising a nonwoven fabric web and an elastic perforated film. An elastic two-layer laminate consists of a layer of fibrous material and an elastic layer. The fibrous layer is chosen so that it gives the laminate the ability to create a sensation of softness and appearance and a sensation of material like fabric. Examples of suitable materials are meltblown canvases and spunbond materials, and creped nonwoven materials, as described above. Similar materials are also suitable for a second canvas of non-woven material that is attached to a two-layer laminate. Nonetheless, any soft, flexible and preferably extensible nonwoven materials and non-woven materials laminates, such as laminates formed from spunbond material, meltblown material and spunbond material, can be used (SMS - Spunbond- Meltblown-Spunbond), non-woven materials obtained by carding and obtained by exposure to jets of liquid.

The density (weight 1 m ² ) of the first canvas of the nonwoven material is suitably from 10 to 80 g / m ² and preferably from 13 to 50 g / m ² . Examples of suitable polymers used in the fibrous material are polyethylene, polyesters, polypropylene and other polyolefin homopolymers and copolymers. Natural fibers, such as cotton, can also be used provided that they provide the desired properties. A mixture of polymers can contribute to a higher flexibility of the nonwoven layer and thereby give the nonwoven material a greater elongation at maximum load. It has been proven that a mixture of polyethylene and polypropylene polymers provides good results in this regard. A mixture of fibers from different polymers is also possible.

In accordance with one embodiment of the invention, the elastic layer is an elastic film with holes having a density of from 10 to 120 g / m ² , preferably from 15 to 60 g / m ² . The film may be made of any suitable flexible polymer, natural or synthetic. Some examples of suitable materials for elastic films are low crystallinity polyethylene catalyzed by metallocene, low crystallinity polyethylene, ethylene vinyl acetate (EVA) copolymers, polyurethane, polyisoprene, butadiene and styrene copolymers, styrene block copolymers such as styrene and block alternating isoprene (SIS), a strip alternating styrene-butadiene copolymer (SBS), or a strip alternating block copolymer of styrene and ethylene / butadiene. Mixtures of these polymers can also be used, as well as other modifying elastomeric or non-elastomeric materials. One example of a suitable film is a three-layer elastomeric film with holes made with a composition of polyethylene-copolymer of styrene and ethylene / butadiene with alternating blocks of polyethylene (PE-SEBS-PE).

An elastic two-layer laminate can, for example, be made and activated in accordance with any of the two methods disclosed in documents WO 03/047488 or EP 0715351, by applying a canvas of non-woven material on one side of the film. The nonwoven web and film may be bonded by extrusion or may be bonded by adhesive. The two-layer laminate is stretched stepwise to activate the elasticity of the film layer. Stepwise stretching can be performed to a level that is less than the relative elongation of the canvas of the inelastic nonwoven material at maximum load, to maintain some strength of the canvas of the nonwoven material. Alternatively, the stretching can be performed so that the nonwoven material is completely torn, as disclosed in document WO 03/047488.

The activated bilayer laminate according to the invention is additionally attached to the canvas of an inelastic nonwoven material by lamination. This second lamination process is carried out when a two-layer laminate is stretched in at least one direction by 10-200% of its initial length in an unstretched state, preferably 35-180% of its length in an unstretched state, more preferably 50- 150% of its length in an unstretched state, and most preferably 70-120% of its length in an unstretched state.

The second and / or first canvas of the inelastic non-woven material preferably has a high content of thermoplastic fibers, that is, contains at least 50% and, preferably, at least 80% of thermoplastic polymer fibers such as polyethylene, polypropylene and polyester. In a specific embodiment, the second and / or first canvas of the inelastic nonwoven fabric contains at least 80% polypropylene fibers.

The two-stage laminating process results in the formation of a three-layer laminate having a smooth surface on the surface where the first nonwoven fabric is applied, and a somewhat “folded” wrinkled side on the opposite surface where the second non-woven fabric is applied. When using a three-layer laminate as a stretchable component in a pant-like product, the three-layer laminate can be oriented so that a smooth surface is on the inside of the product and the irregular surface is facing out. Thus, the parts of the laminate in contact with the skin will be particularly soft, smooth and non-irritating to the wearer's skin. However, in an alternative embodiment, it is possible to arrange the laminate so that a smooth surface will be on the outside of the absorbent article. In this way, an absorbent article having a smooth surface in contact with any garment worn over the absorbent article is obtained. A similar embodiment may be preferred when the product is a pair of hygiene pants or panties used for incontinence and intended for adults. The smooth surface of the laminate can prevent adhesion of the garment to the surface of the product due to frictional forces and reduces the risk of pulling out and wrinkling of pants and skirts in the area above the item in the form of pants. In addition, the smooth outer surface is aesthetically pleasing and will be less noticeable when the absorbent article is worn under thin or tight-fitting clothing.

The three-layer laminate according to the invention is soft, elastic and similar to textiles and has significantly greater tensile strength and greater puncture resistance than previously known laminates. Therefore, when using a three-layer laminate in a pant-like product, a three-layer laminate significantly reduces the risk of unintentional damage to the cowards when pulling them up or pulling them down on the thighs of the wearer.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described below in more detail with reference to the attached drawings, in which

figure 1 shows the lamination process in accordance with the invention,

figure 2 shows a three-layer laminate in accordance with the invention,

3 shows a plan view of a diaper-panties with open side connections, and

figure 4 shows the diaper of figure 3 with closed side connections.

MODES FOR CARRYING OUT THE INVENTION

Figure 1 schematically shows a method of manufacturing a stretchable three-layer laminate in accordance with the invention. The first canvas 1 of inelastic non-woven material is fed from the storage roll 2 into the first gap for connecting the rubber roller 3 and the metal roller 4. The molten polymer forming the elastic film 6 is extruded through the die 7 into this gap, and the first canvas 1 of the inelastic non-woven material, and the elastic film forms the first laminate 8, which is removed from the roller 9. The first laminate 8 is subsequently activated by passing the laminate between the gears engaged with each other thrust rollers 10, 11 so that the first laminate 8 is subjected to incremental stretching. There are a number of different stretching methods, as described in EP 0714351. Depending on the design of the gear rollers engaged with each other, stepwise stretching can be carried out to stretch the laminate diagonally, in the direction of movement of the material in the machine (MD) or in the transverse direction ( CD). The degree of tearing of the first canvas of the nonwoven material caused by stepwise stretching can be controlled by adjusting the "depth" of the engagement of the teeth of the engaged gear roller elements. Stepwise stretching leads to the "release" or activation of the elasticity of the elastic film and allows elastic elongation of the two-layer first laminate 8.

In the second lamination operation, the first laminate 8 is stretched by passing it between a pair of rollers 12, 13, driven at different speeds. The first laminate 8 is stretched in at least one direction by 10-200% of its initial extent in an unstretched state. By selecting and adjusting the degree of stretching, it is possible to obtain a predetermined (selected) elasticity in the final laminate. The first laminate 8 is preferably stretched to 35-180% of its length in an unstretched state, more preferably 50-150% of its length in an unstretched state, and most preferably 70-120% of its length in an unstressed state after activation and before by attaching it to the second canvas 18 of an inelastic nonwoven material by lamination. The degree of stretching of the first laminate 8 is the main factor in determining the elasticity of the final three-layer laminate 19. Other factors that affect the elasticity of the final three-layer laminate are the flexibility and extensibility of the second canvas 18 of the non-elastic non-woven material. The joint zone between the first laminate 8 and the second canvas of the non-elastic nonwoven fabric also affects the flexibility and elasticity of the three-layer laminate 19. Accordingly, a large joint zone will reduce the elasticity of the final laminate, while rarely distributed joints will have very little or little effect on the elasticity.

After stretching the activated first laminate 8, the film side 14 of the laminate 8 is coated with glue or glue is sprayed onto the film side 14 of the laminate 8, and subsequently the first laminate 8 is passed through the second joint between the two fastening rollers 16, 17 together with the second non-elastic non-woven canvas 18 material. Adhesive is preferably a thermoplastic adhesive, although other types of adhesives can be used if desired.

The resulting three-layer laminate 19 lends itself to elastic stretching and has a predetermined elasticity, depending mainly on the elasticity of the elastic film, the degree of tearing of the first canvas of the nonwoven material in the step-by-step stretching operation, and the degree of stretching of the first laminate 8 before joining the second canvas 18 of inelastic nonwoven material. However, as indicated above, the properties of the second canvas of the inelastic nonwoven material with respect to flexibility and extensibility and the degree of bonding achieved in the second lamination operation also affect the elasticity of the final laminate.

The metal roller 4 in the first gripping region is preferably a vacuum (suction) roller with holes, so that three-dimensional molding and hole formation on the extruded elastic film 6 are carried out simultaneously with the film 6 attached to the first canvas 1 of non-woven material.

The second lamination operation can alternatively be performed by heat welding or ultrasonic welding.

Figure 1 is a very schematic illustration of a method in accordance with the invention. However, all individual operations are well known and described in the art. In addition, figure 1 does not show the width of individual canvases. A multilayer material can be formed with all the canvases having the same width or length in the transverse direction. Alternatively, the second canvas of the nonwoven fabric may have a wider width than the elastic film 6 and the first canvas 1 of the nonwoven fabric, and may extend beyond the first laminate on one or both sides thereof.

The three-layer laminate 19, shown in figure 2, contains the first two-layer laminate 8, consisting of a layer 1 of inelastic fibrous non-woven material and an elastic film. Holes are formed in the elastic film, and it has a plurality of through holes. The holes may be holes formed with a three-dimensional shape, as disclosed in WO 03/047488, or may be simple two-dimensional holes passing through a film. Laminate 19 further includes a second layer 18 of inelastic non-woven material that is attached to the first laminate 8 by means of glue or by heat sealing, for example by applying heat or using ultrasound.

The three-layer laminate 19 has a smooth surface 21 from the side of the first nonwoven fabric layer 1 and an irregular wrinkled surface 22 from the side of the second nonwoven fabric layer 18. This is because the second layer 18 of nonwoven material was attached to the first two-layer laminate 8 when the two-layer laminate was in an elastically stretched state. The three-layer laminate 19 is soft, drapable, has a predetermined, selected elasticity and is extremely well suited for use in various types of disposable products such as underpants. The non-woven stretched second layer of non-woven material provides hardening of the laminate, provides higher tensile strength in the direction perpendicular to the direction of stretching, makes the laminate resistant to puncturing, and allows the laminate to be subjected to pulling forces and tensile forces arising from putting on and taking off the garment type without breaking or tearing.

In addition, by selecting non-woven materials having thermoplastic properties, it is possible to obtain a laminate that can easily be incorporated into a disposable product by heat sealing methods. For example, in an article in which the laminate is oriented so that the first nonwoven fabric layer 1 is located on the inside of the product, it may be preferable if the first nonwoven fabric layer is substantially or completely formed from thermoplastic fibers, preferably polypropylene fibers. In this case, the first layer of nonwoven material can be used to form side seams with good tensile strength. On the contrary, if the laminate is oriented so that the second layer of nonwoven material is located on the inside of the product, such as pants, respectively, it may be preferable to choose a thermoplastic material for the second layer of nonwoven material. Since bonds formed by heat sealing and used in side seams usually “penetrate” into the materials to be welded, the orientation of the laminate with respect to the first and second layers of nonwoven materials is usually not key to obtaining a welded joint, provided that, at least one of the layers is predominantly formed of thermoplastic fibers, or a combination of two layers contains a sufficient amount of thermoplastic material to provide sufficient bond strength.

The panty diaper 300 shown in FIGS. 3 and 4 is intended to encompass the lower part of the wearer's body like a normal undergarment. In Fig. 3, the diaper is shown from the inside, that is, from the side facing the wearer when the product is worn, and in Fig. 4, the diaper is shown from the outside, that is, from the side facing the garment, which is the side facing away from the wearer when wearing a diaper.

The diaper has a front panel 301, a rear panel 302 and a crotch panel 303 extending between the front and rear panels 301, 302 and having a relatively small width compared to the front and rear panels 301, 302. The front and rear panels 301, 302 are made so that they covered the wearer's thighs and extended over the abdomen and back of the wearer to cover the lower part of the wearer's body.

The diaper further comprises a central zone 304 extending from the crotch panel 303 to the front panel 301 and the rear panel 302. The front and rear panels 301, 302 form part of the base portion 307, which extends from the side of the diaper 300 facing the garment and closes and surrounds the central zone 304. The base portion 307 includes a front panel 301, a rear panel 302, a crotch panel 303, and an elastic waistband 309 attached to the front and rear panels. Each of the front and rear panels has a waist edge, a crotch edge and, accordingly, a pair of side edges.

Accordingly, the term “panel” is used here to indicate the functional part of the base part of the diaper, while the terms “zone” and “part (section)” are used to indicate the location of a particular element of the diaper in the base part or to describe the intended location of a certain part of the diaper relative to the body user. The panel may be a separate component or part integrally with the base part. The zone or section may have a length in which they fully or partially cover one or more panels.

The front and rear panels are connected to each other along their side edges by heat bonding, ultrasonic welding, adhesive cords (strips) or the like to form side seams 308, as best shown in FIG. 4. The elastic belt 309 consists of a front and a back that are attached to the front panel 301 and the rear panel 302, respectively. These parts of the belt 309 are also connected to each other along the side seams 308. By connecting the front and rear panels 301, 302 and the diaper belt 309 -pants 300 will be formed with a hole 310 for the waist and two holes 311 for the legs.

Figure 3 shows the diaper in a flat state, with any elastic components that are attached to the base part 307 in the state when they were under tensile load, stretched to the full dimensions of the base part 307 in its unstretched state. Figure 4 shows the diaper-panties 300 in the form in which it looks when the side seams 308 are formed, the load from the stretched elastic elements is removed and it is possible to tighten and fold on the base material to form elasticized leg openings 311, 310 and waist.

The elastic laminate 320 in accordance with the invention can cover the entire diaper between the front and back of the belt 309, including the central zone 304. However, it is preferable that a substantial portion, that is, at least 50% and preferably at least 75%, the crotch panel 303 of the diaper-panty 300 was free of elastic laminate.

Therefore, crotch material 312, which is preferably an inelastic material, such as inelastic non-woven material, is located in the center region 304 of the article and overlaps the elastic front and back panels 301, 302. The crotch material 312 is connected along its transverse edges 313, 314 c the front and rear panels 301, 302. In the shown embodiment, the material of the crotch part 312 is attached via seams 315 of the crotch part to the front and rear panels 301, 302 with overlapping and forms a crotch panel 303. The connection can be made by any suitable method, for example by means of ultrasonic welding, by means of adhesive adhesion or the like. In alternative embodiments, the outer nonwoven fabric may extend continuously across the front and rear panels 301, 302 and the crotch panel 303, so that no seams between the panels 303, 301, 302 are required.

In the example shown, elastic waistband 309 comprises first and second layers of a substantially inelastic nonwoven material that is elasticized by one or more elongated elastic members 316, such as elastic threads or tapes. The first and second layers can be formed from one layer of material that has been bent onto it itself or can be two separate strips of material. Elastic elements 316 are placed in the belt 309 in a stretched state so that they are pulled together and provide for the collection of non-woven material in the folds in the belt when it is possible to weaken them, as shown in FIG. 4.

An elastic belt 309 is attached to the front and rear panels 301, 302 with elastic elements 316 in a stretched state and with front and rear panel material located between the nonwoven layers in the belt. Alternatively, the elastic waistband may be a component that is prefabricated and attached to the outer side or inner side of the front and rear panels 301, 302, respectively. The waist connection 317 between the waistband 309 and the front and rear panels 301, 302 can be made in any suitable manner, for example by means of ultrasonic welding, heat sealing or by means of adhesive adhesion. An additional option is to form a belt 309 from one or more layers of inelastic nonwoven materials, which also represent parts of the front and rear panels 301, 302 and form their continuous protruding parts.

Elastic elements 316 are also located at the edges of the leg openings 311 and serve to give elasticity to the leg openings. The elastic elements at the openings for the legs can be conventional elastic elements of any type, such as elastic threads, ribbons, strips of foam material or similar elements.

The extension of the central zone 304 in the plane is formed by a liquid impervious back sheet 318 located between the absorbent core 319 and the base portion 307. The liquid impermeable back sheet 318 has a rectangular shape, and the absorbent core has an hourglass shape. Therefore, the liquid-impervious back sheet 318 is located below the absorbent core 319 and adjacent areas located directly outside the absorbent core 319. The nonwoven fabric in the crotch panel 303 is located on the garment side of the liquid-impermeable back sheet 318. The central zone 304 extends into the front and rear panels 301, 302 so that the elastic laminate 320 in these panels overlaps the liquid impermeable back sheet 318 in the outer parts of the central zone 304, as seen and Figure 3. The elastic laminate 320 is placed on the side of the liquid impermeable back sheet 318 facing the garment.

As shown in the drawings, the elastic three-layer laminate 320 in accordance with the invention preferably forms the front and rear panels 301, 302 of the diaper-panties 300. Nevertheless, it is possible to make only portions of the corresponding front and rear panels 301, 302 of the elastic three-layer laminate 320. B such embodiments, 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 base portion Single visible in the flat state shown in Figure 3, is formed by an elastic three-layer laminate according to the invention. As an example, an elastic laminate can be used only in those parts of the front and rear panels 301, 302 that are designed to be placed over the thighs of the wearer and thus form elastic side panels. In addition, there is the possibility of creating a product such as pants without any overlap between the Central zone 304 and the elastic laminated material of the front and rear panels 301, 302.

No additional elasticized side panels are required when using the elastic laminate 320 in accordance with the invention. If desired, additional elasticized side panels can be provided, in particular, in cases where the elastic laminate 320 is located only in areas of the front and / or rear panels 301, 302.

DESCRIPTION OF TEST METHODS

Tensile Strength (Ref: ASTM D 882 (ASTM - American Society of Testing Materials))

The method allows to determine the tensile strength and elongation of various elastic materials. The tensile strength and elongation of a well-defined test piece are determined by testing with a tensile tester.

Device: Instron 4301

- A tensile tester connected to a computer;

- slide speed: 500 mm / min;

- distance between clamps: 50 mm.

Sample preparation: Test specimens are cut from the entire width of the material. The width of the sample should be 25.4 mm and the length should be at least 50 mm greater than the distance between the clamps, if possible. It is important that the edges of the sample are flat and free from tears and incisions. Samples are incubated for at least 4 hours at a relative humidity of 50% ± 5% and a temperature of 23 ° C ± 2 ° C before testing.

Procedure: The tensile tester is calibrated in accordance with the instructions for the device and set to zero. The sample is fixed and ensured that it is not fixed obliquely or unevenly. Prevent slipping of material by using clamps coated with galun or similar material. The tensile tester is started and stopped after the material ruptures (in the absence of automatic control). Measurement data obtained as a result of premature rupture (i.e., the sample ruptures in the clamp or is damaged during preparation) are ignored, if possible.

The following results are displayed using a tensile tester / computer:

- maximum force, N / 25.4 mm;

- elongation at maximum effort,%;

- tearing force, N / 25.4 mm;

- elongation at breaking stress,%;

- bend point (characteristics) N /%.

Elasticity test

The method allows to determine how the elastic material behaves with repeated loading and unloading cycles. The sample is stretched to a predetermined elongation and a cyclic motion from 0 to the specified, predetermined elongation is performed. Target forces during loading and unloading are recorded. The residual, that is, remaining, elongation of the material from which the load is removed is measured.

An Lloyd LRX tensile tester is used, with the ability to perform cyclic movements and equipped with a printer / plotter or software for presenting data. A sample is prepared by cutting it with a width of 25 mm and a length that is preferably 20 mm greater than the distance between the clamps in the tensile testing apparatus.

The tensile tester is calibrated in accordance with the instructions for the device. The parameters required for the test (efforts under loading and unloading) are adjusted to the following values:

500 мм/мин;- slider speed:

500 mm / min;

50 мм;- distance between clamps:

50 mm;

0,05 Н.- preload:

0.05 N.

The sample is placed in the clamps in accordance with the marks and ensure that the sample is centered and fixed perpendicular to the clamps. The tensile tester is started and three cycles are performed from 0 to a predetermined elongation corresponding to the largest given first load. Before the last cycle, the sample is kept in an unstressed state for 1 minute, then the residual elongation is measured by stretching the sample until a force of 0.1 N is determined, and the elongation is recorded.

An elastic material is defined as a material having a residual elongation after relaxation of less than 10% after subjecting the material to an elongation of 30% in the above test. Elongation of 30% means elongation to a length that is 30% more than the original length of the sample.

An inelastic material, as used herein, is a material that has a residual elongation after stretching and relaxation of more than 10% after subjecting the material to elongation of 30%, as determined in accordance with the elasticity test.

Puncture strength

Puncture resistance is measured in accordance with ASTM Designation D3763-02. From the shock type penetration tests by this method, the data of the load versus displacement are obtained. The maximum load for each sample is calculated.

EXAMPLES

The tensile strength in the direction of movement of the material in the machine (MD) and in the transverse direction (CD) was measured for three samples.

Sample A is a conventional activated three-layer laminate containing an inner three-layer elastomeric film with holes made of styrene-ethylene / butadiene copolymer with alternating polyethylene blocks (PE-SEBS-PE) and having a density of 36 g / m ² and two the outer layer of the material of the spunbond production method, namely from PP (polypropylene), each of which has a density of 22 g / m ² . Laminate was obtained by applying one layer of nonwoven fabric of spunbond production method to the film when the film was in an sticky state, and another layer of nonwoven fabric of spunbond production method was attached to the film layer by adhesive lamination using, for example, hot-melt adhesive, pressure sensitive adhesive (c the amount of glue 3 g / m ² ). The laminate was subjected to step-by-step stretching, in which the layers of inelastic nonwoven fabric of the spunbond production method were stretched to a value less than the relative elongation at maximum load to maintain some strength of the layers of nonwoven fabric of the spunbond production method.

The density values of the layers in the laminate are the density values after activation. Before activation, the density of the individual layers was as follows: the inner layer of the film was 40 g / m ² , the outer layers of non-woven spunbond materials were 25 g / m ² in each layer, and the adhesive layer was 3 g / m ² .

Sample B is a three-layer laminate containing the first activated two-layer laminate, containing a layer of nonwoven polypropylene material of a spunbond production method having a density of 22 g / m ² , and a three-layer elastomeric film with holes made of styrene-ethylene / butadiene polyethylene copolymer with alternating blocks -polyethylene (PE-SEBS-PE) and having a density of 36 g / m ² , which was subjected to additional joining under tension by 70% by lamination to a layer of nonwoven spunbond material with production allowance having a density of 18 g / m ² (S1800PHW from Union Industries SpA).

Sample C is a three-layer laminate containing an activated two-layer laminate from sample B, which was additionally joined by stretching by 70% by laminating a spunbond production method having a density of 20 g / m ² to the layer (Lutrasil 9520XF from Freudenberg Fliesstoffe KG).

Sample D is a three-layer laminate containing an activated two-layer laminate from sample B, which was additionally joined by stretching by 25% by lamination to a creped non-woven spunbond material having a density of 20 g / m ² (From First Quality). Crepe nonwoven fabric was 50% sealed when creped.

Sample E is the same three-layer laminate as in sample D, but with a two-layer laminate stretched 40% during bonding with a creped nonwoven layer by lamination.

The test results are shown in the table below.

Table Sample Tensile strength in the direction of movement of the material in the machine, N / 25 mm Tensile strength in the transverse direction, N / 25 mm Piercing force, N BUT 34 9 40 AT 42 26 74 FROM 40 33 80 D 25 38 73 E 22 44 77

As can be seen in the table, the laminates B-E in accordance with the invention have a significantly higher tensile strength in the direction of movement of the material in the machine and in the transverse direction and greater puncture resistance than a three-layer laminate according to the prior art.

Claims (20)

1. A method of manufacturing a stretchable laminate (19) containing at least three layers (1, 6, 18),
characterized in that it includes the following operations:
a) the production of the first laminate (8) containing the first canvas (1) of inelastic fibrous nonwoven material and an elastic film (6);
b) activating the first laminate (8) by stepwise stretching in at least one direction to give the first laminate (8) elastic stretchability;
c) stretching the activated first laminate (8) by 10-200% in at least one direction; and
d) attaching the stretched first laminate (8) by lamination to a second canvas (18) of inelastic non-woven material. 2. The method according to claim 1, in which the first laminate (8) is obtained by coating from an elastic film (6) by extrusion onto the first canvas (1) of a fibrous non-woven material. 3. The method according to claim 1 or 2, in which the elastic film (6) is perforated. 4. The method according to claim 1 or 2, in which the second canvas of the inelastic nonwoven material is connected by bonding with the activated first laminate (8). 5. The method according to claim 1 or 2, in which the second canvas (18) of the inelastic nonwoven material is connected by heat welding or ultrasonic welding with the activated first laminate (8). 6. The method according to claim 1 or 2, in which the first laminate (8) is stretched by 35-180% of its length in an unstretched state, more preferably 50-150% of its length in an unstretched state, and most preferably 70-120 % before joining the second canvas (18) inelastic non-woven material by lamination. 7. The method according to claim 1 or 2, in which the second canvas (18) of the inelastic non-woven material has a width exceeding the width of the first laminate (8). 8. The method according to claim 1 or 2, in which the first and / or second canvas (1, 18) of the inelastic fibrous nonwoven material contains thermoplastic fibers. 9. The method of claim 8, in which the first and / or second canvas of the inelastic fibrous nonwoven material contains at least 50% thermoplastic fibers and, preferably, at least 80% thermoplastic fibers. 10. The method according to claim 1 or 2, in which the second canvas of the inelastic nonwoven material is tensile. 11. The method according to claim 10, in which the second canvas of the inelastic non-woven material is a creped non-woven material. 12. A stretchable three-layer laminate (19) comprising a first canvas (1) of inelastic non-woven material, a second canvas (18) of inelastic non-woven material and an elastic film (6) between the first and second canvases (1, 18) of non-woven material, characterized in that the first canvas (1) of the non-elastic non-woven material and the elastic film (6) form parts of the first elastic laminate (8), which was elasticized by stepwise stretching and partial tearing of the first canvas (1) of the non-woven material, wherein first elastic laminate (8) was attached to the second layer (18) non-elastic nonwoven material in a stretched condition, whereby the laminate is elastically stretchable. 13. A flexible stretch laminate according to claim 12, wherein the elastic film (6) is perforated. 14. A stretchable laminate according to claim 12 or 13, wherein the first canvas (1) of the nonwoven fabric is a canvas of the nonwoven fabric obtained from the melt aerodynamically, or the canvas of the nonwoven fabric of the spunbond production method, and the second canvas (18) of the nonwoven fabric represents a canvas of a nonwoven material obtained by the aerodynamic method from a melt, or a canvas of a nonwoven material of a spunbond production method. 15. A stretchable laminate according to claims 12 or 13, wherein the first nonwoven fabric web (1) has a density (weight of 1 m ² ) of 10 to 80 g / m ² and preferably has a density of 13 to 50 g / m ² . 16. The elastic stretch laminate according to claims 12 or 13, wherein the elastic film layer has a density (weight of 1 m ² ) from 10 to 120 g / m ² , preferably from 15 to 60 g / m ² . 17. A flexible stretch laminate according to claims 12 or 13, wherein the first and / or second canvas (1, 18) of the inelastic non-woven material contains thermoplastic fibers. 18. A stretchable laminate according to claim 17, wherein the first and / or second canvas of the inelastic fibrous nonwoven fabric contains at least 50% thermoplastic fibers, preferably at least 80% thermoplastic fibers. 19. A stretchable laminate according to claims 12 or 13, wherein the second canvas of the non-elastic nonwoven fabric is stretchable. 20. A stretchable laminate according to claim 19, wherein the second canvas of the inelastic nonwoven fabric is a creped nonwoven fabric.

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