Extrusion coated textile laminate with improved peel strength

Abstract

The present invention relates to nonbreathable extrusion coated nonwoven structures. The structures comprise a nonwoven web comprised of monocomponent or bicomponent fibers having a coating comprising LDPE optionally blended with LLDPE and / or an elastomer. The monocomponent or bicomponent fibers comprise an ethylene based polymer, preferably at the surface of the fiber.

Description

FIELD OF INVENTION[0001]The present invention relates to non-breathable extrusion coated nonwoven structures comprising a nonwoven web of ethylene based fibers onto which has been extrusion coated a non-breathable ethylene-based film.BACKGROUND AND BRIEF SUMMARY OF THE INVENTION[0002]Nonwoven webs or fabrics are desirable for use in a variety of products such as bandaging materials, garments, disposable diapers, and other personal hygiene products, including pre-moistened wipes. Nonwoven webs having high levels of strength, softness, and abrasion resistance are desirable for disposable absorbent garments, such as diapers, incontinence briefs, training pants, feminine hygiene garments, and the like. For example, in a disposable diaper, it is highly desirable to have soft, strong, nonwoven components, such as top sheets or backsheets (also known as outer covers). For use in applications such as diapers it is desired that the fabric be non-breathable. Typically, this is achieved by lam...

AI Technical Summary

Benefits of technology

[0006]Tensile strength of nonwovens and tenacity of fibers is important because the manufacture of multicomponent articles typically involves multiple steps (e.g., rolling / unrolling, cutting, adhesion, etc.), and webs lacking tensile strength may not survive one or more of these steps. Fibers with a high tensile strength (also known as tenacity) are also advantaged over fibers with a low tensile strength because the former will experience fewer line breaks, and thus greater productivity will be obtained from the manufacturing line. Moreover, the end-use of many products also typically requires a level of tensile strength specific to the function of the component. Tensile strength must be balanced against the cost of the process used to achieve the higher tensile strength or to achieve higher tenacity. Optimized fabrics will have the minimum material consumption (basis weight) to achieve the minimum required tensile strength for the manufacture and end-use of the fiber, component (e.g., nonwoven fabric) and article.

[0008]Fiber extensibility / elasticity is another important criterion for nonwoven structures, particularly those used in hygiene and medical applications, because the characteristic translates to a better comfort and fit as the article made from the fiber will be able to be more body conforming in all situations. Diapers with elastic components will have less sagging in general as body size and shape and movement vary. With improved fit, the general well being of the user is improved through improved comfort, reduced leakage, and a closer resemblance of the article to cotton underwear.

[0011]To further downgauge a textile backsheet, the extrusion coating process can be used. Via extrusion coating, the film layer is deposited in melt form directly on top of a nonwoven layer. In this way, the basis weight of the film layer can be less than 10 GSM. Moreover, the typical production speeds of extrusion coating are above 300 m / min, further increasing the economical advantages of this process. However, when the standard polypropylene nonwovens are used in this process, the extrusion coated textile backsheet is perceived as significantly less soft than the hot-melt-adhesive-laminated textile backsheet. The elongation at break of such extrusion coated backsheets was also observed to be lower than what can be achieved via HMA lamination.

[0012]Accordingly, structures having extrusion coated films onto nonwovens are desired, where the structure is perceived as soft with relatively higher elongation to break.

[0013]Some of these advantages are obtained when using the present invention which, in a first aspect, is a coating of a LDPE optionally blended with LLDPE or an elastomer onto non-wovens made from bico or mono fibers having polyethylene on the surface. It has been discovered that when such nonwovens are used, the textile backsheet obtained via extrusion coating offers significantly better softness and higher elongation at break than if a polypropylene nonwoven is used. It also offers improved abrasion resistance than if polypropylene NW is used. Moreover, the extrusion coated textile backsheets with bico or mono PE nonwovens have similar softness and elongation at break than HMA laminated textile backsheet nonwoven structures.BRIEF DESCRIPTION OF THE DRAWINGS

Problems solved by technology

Fabrics made from hPP, particularly nonwoven fabrics, exhibit high modulus but poor elasticity and softness.

In comparison, polyethylene-based elastomers, and the fibers and fabrics made from these polymers, tend to exhibit low modulus and good elasticity, but they also tend to have low tenacity, stickiness and exhibit a hand feel which is generally considered as unacceptable for many applications.

In contrast, a fabric made from a higher modulus fiber, e.g., hPP, will feel harsher (stiffer) and will drape less well resulting in a poorer fit.

Fabrics made from polyethylene-based elastomers also tend to lack adequate hand feel as they tend to have an undesirable feel to the skin commonly characterized by descriptors such as tacky, sticky, clammy, rubbery, or wet.

This obviously limits further downgauging of the film.

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