Low odor, light color, disposable article construction adhesive

Abstract

We have found a novel spray-on adhesive composition made from components including a high melt index polymer and a high melt tackifier that interact to produce a composition that can form a low odor, light color, non-tacky, hot melt adhesive material that can be used in disposable article manufacture. The adhesive is thermally stable at hot melt application conditions, is low in cost, is easily applied and produces high quality disposable articles.

Description

FIELD OF THE INVENTION The invention relates to an adhesive and to a composite article made by joining components with the adhesive. In one embodiment, a disposable article can be made by adhesively bonding layers including a film, a woven or non-woven fabric, tissue or sheet to a sheet-like material using a novel hot melt adhesive that can be variously applied or can be sprayed. Still further, the invention relates to the manufacture of a disposable composite article having a cover and an absorbent layer, held within the cover. The cover can be formed from a porous sheet adhered to a fluid impervious backing layer and can have further fabrics, sheets or films added. The absorbent layer can be made of a tissue, an absorbent, or combinations of an absorbent and outer cover layers. The adhesive of the invention is used to bind the components in a mechanically stable article or to join the outer cover to the absorbent. The sprayable hot melt adhesive composition typically contains a n...

AI Technical Summary

Benefits of technology

The adhesive can comprise, in its entirety, one of a number of useful polymers, a blend of polymers, or alternatively the adhesive can comprise a hot melt adhesive comprising at least one polymer admixed with other thermoplastic diluents such as tackifying resins, etc. The polymer provides the properties such as cohesiveness and strength. The polymer is typically combined with a tackifier or other material to modify the adhesive properties for use in the intended application. The blend of materials is formulated to exhibit the same desired properties. In this material relatively high melt or high viscosity tackifier is combined with relatively low molecular weight (high MI) thermoplastic components to enhance the cohesive strength of the mixture while maintaining good processability.

In production of disposables, a hot melt adhesive (HMA) is typically extruded at elevated temperature onto the disposable. Layers of a fabric or film can be added and blended. Disposables with secure bonding that traps layers of fabric or tissue in the HMA can be made because the adhesive can be extruded directly on the work piece. In recent years, increasing attention has been directed to development of sprayable hot melt adhesives. The work piece or substrate-manufacturing regimen can use a spray-on adhesive to increase productivity. Such spray-on adhesives are delivered from a plurality of narrow orifices in the form of fibers, threads or filaments having a substantially circular cross-section with a diameter less than 0.05 inch, typically about 0.01 to 0.001 inch. Fine line or spiral spray patterns are used. The spray-on adhesive takes on the form of fibers that have substantial surface area in comparison to the mass of the fiber. Typically, after spraying, the adhesives reach ambient temperatures upon immediate contact with the work piece. Extruded hot melt adhesives retain a significant amount of heat after application. Ambient temperature is the temperature of the surrounding environment and temperature of the disposable. In these construction applications, the disposable and the temperature of the environment are typically not substantially different. Sprayed adhesives take the form of a solid matrix formed as a result of the combined application adhesive fibers creating an overlapping distribution of threads or fibers on the disposable. Spray adhesive technology is used to make disposable articles by combining, e.g. a film with a woven or non-woven fabric with the adhesive and forming a bond between the substrates or layers by pressure. Such conventional spray-on adhesives form typically a laminated adhesive bonding with the film sheet and the fabric layers.

Problems solved by technology

Extruded hot melt adhesives retain a significant amount of heat after application.