Absorbent composites containing biodegradable reinforcing fibers

Abstract

An absorbent composite contains a superabsorbent material and thermoplastic biodegradable reinforcing fibers, and may also contain pulp fibers. The superabsorbent material may be biodegradable, providing a biodegradable absorbent composite. The superabsorbent material may have a gel strength from about 500 dynes / cm2 to about 80,000 dynes / cm2. The biodegradable reinforcing fibers may contain fibers of a polyester such as poly(lactic acid). The biodegradable reinforcing fibers may be wettable, reducing or eliminating the need for treating the surface of the fibers with a wetting agent such as a surfactant, and may provide desirable performance without being bonded to the other components.

Description

BACKGROUND [0001] Disposable absorbent products are used extensively for body waste management. These disposable absorbent products include one or more absorbent structures to manage body waste effectively. The absorbent structure within the disposable absorbent product takes up and retains the body waste within the absorbent product. A variety of other components may also be present in a typical absorbent product, including liquid impermeable backing sheets, liquid permeable liners, wicking layers, and components for securing the product to the user. The particular combination and configuration of components in an absorbent product will depend on the intended use of the product. [0002] Absorbent structures typically include a superabsorbent material, which can absorb large amounts of water or other aqueous liquids. One ongoing effort in the development of superabsorbent materials has been to increase the stiffness of the gel formed when the superabsorbent material has absorbed an a...

AI Technical Summary

Benefits of technology

[0011] These embodiments may further include absorbent composites wherein the thermoplastic biodegradable reinforcing fibers comprise poly(hydroxyalkanoate) fibers, wherein the thermoplastic biodegradable reinforcing fibers comprise poly(lactic acid) fibers, wherein the thermoplastic biodegradable reinforcing fibers are un-bonded, wherein the thermoplastic biodegradable reinforcing fibers are wettable, and wherein the composite is free of wetting agents.

[0012] These embodiments may further include absorbent composites wherein the biodegradable superabsorbent material comprises carboxymethyl cellulose, wherein the biodegradable superabsorbent is present in a loading from about 10 wt % to about 70 wt %, wherein the absorbent composite further comprises pulp fibers, wherein the pulp fibers are present in a loading from about 25 wt % to about 85 wt %, wherein the thermoplastic biodegradable reinforcing fibers are present in a loading from about 5 wt % to about 30 wt %, and wherein the gel strength of the superabsorbent is from about 500 dynes/cm2 to about 80,000 dynes/cm2.

[0013] In another embodiment of the invention, there is provided an absorbent composite, comprising from about 10 wt % to about 70 wt % of a biodegradable superabsorbent material, from about 25 wt % to about 85 wt % of pulp fibers, and from about 5 wt % to about 30 wt % of poly(lactic acid) reinforcing fibers.

[0014] These embodiments may further include absorbent composites wherein the poly(lactic acid) reinforcing fibers are un-bonded, wherein the poly(lactic acid) reinforcing fibers have a length from about 2 mm to about 60 mm, wherein the poly(lactic acid) reinforcing fibers have a diameter from about 1.5 denie...

Problems solved by technology

One potential drawback to stabilized absorbent composites is that conventional thermoplastic binder fibers tend to have low wettability due to their hydrophilic surfaces.

This low wettability can reduce the overall liquid intake and distribution of the absorbent structure, despite increasing the porosity.

However, these wetting agents can be dissolved in water, reducing the surface tension of the absorbed liquid and actually decreasing both the wicking of liquid into the composite and the subsequent distribution of the absorbed liquid.

Biodegradable superabsorbent materials typically have less desirable absorbent properties relative to conventional non-biodegradable superabsorbent materials such as polyacrylates.

Typically, absorbent composites made with biodegradable superabsorbents have tended to exhibit inferior intake, distribution and retention of liquids relative to absorbent composites based on polyacrylate superabsorbents.

However, reinforcing a biodegradable superabsorbent material with non-biodegradable fibers would undermine the goal of constructing a compeletely biodegradable absorbent product.

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