Soluble microfilament-generating multicomponent fibers

Abstract

Microfilament-generating multicomponent fibers are provided that include a first polymer component and a second polymer component extruded together in separate contiguous polymer segments extending along the length of the fiber. The first polymer component comprises a synthetic melt-processable polymer that is substantially soluble in a first relatively benign solvent selected from water, aqueous caustic solution, and non-halogenated organic solvents. The second polymer component is formed from a second synthetic melt-processable polymer dimensioned to produce one or more microfilaments upon dissolution of the first polymer, and that is substantially soluble in an aqueous solvent selected from water and aqueous caustic solution. The two polymer components are dissolvable in different solvents.

Description

FIELD OF THE INVENTION[0001] The invention is directed to microfilament-generating multicomponent fibers comprising two or more soluble polymer components and methods of making such fibers. BACKGROUND OF THE INVENTION [0002] The use of nonwoven fabrics has become increasingly prevalent in a number of industries, and in particular, has found increasing usefulness as a component of a variety of consumer products. Exemplary uses for nonwoven fabrics include, without limitation, absorbent personal care products such as diapers, incontinence pads, feminine hygiene products and the like; medical products such as surgical drapes and sterile wipes; filtration devices; interlinings; disposable wipes; furniture and bedding construction; insulating products; apparel and the like. A variety of thermoplastic and thermobondable synthetic fibers have been found to be particularly useful for nonwoven fabric manufacture due to their advantageous strength and weight characteristics, as well as their ...

AI Technical Summary

Benefits of technology

[0006] The present invention provides a microfilament-generating multicomponent fiber comprising at least two polymer components that are soluble in different, but relatively benign, solvents. That is to say, both the polymer component that is dissolved during fiber or fabric manufacture to form the microfilaments, and the resulting microfilaments themselves, are soluble in relatively benign solvents. In a preferred embodiment, the polymer component that is removed to form the microfilaments is a synthetic melt-processable polymer that is substantially soluble in water at a temperature of 70° C. or above, water at a temperature of less than 70° C., aqueous caustic solution, or a non-halogenated organic solvent. The microfilament-generating multicomponent fiber further comprises a second synthetic melt-processable polymer, at least a portion of which is dimensioned to produce one or more microfilaments upon dissolution of the first polymer. The second synthetic melt-processable polymer is substantially soluble in an aqueous solvent, such as water (e.g., water at a temperature of 70° C. or above or water at a temperature of less than 70° C.), or an aqueous caustic solution. The solvent for the first polymer component and the solvent for the second polymer component are different such that the first polymer component can be removed to form the microfilaments without substantially degrading the microfilament-forming second polymer component. In this manner, microfilaments can be generated that are soluble in a relatively benign aqueous solvent. The present invention provides an economical means for producing a fiber bundle of microfilaments or microfibers that can be easily dissolved in a relatively benign solvent at the end of its useful life, or the useful life of the article of manufacture incorporating the fiber bundle. In some cases, the dissolved solution of the microfilament-generating polymer can be recycled and reused in a fiber-forming process.

Problems solved by technology

Conventional thermoplastic synthetic fibers, however, do not naturally degrade, thus creating problems associated with the disposal of products containing such fibers.

The recycling of articles containing nonwoven fabrics is generally not cost-effective, leading to the creation of non-degradable waste material.

Millions of diapers are discarded every year, thereby contributing to landfill capacity problems.

However, the synthetic polymers conventionally used to form the microfilaments are neither biodegradable nor soluble in relatively benign solvents.

Thus, the use of such microfilaments contributes to the waste problems discussed above.

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