BIODEGRADABLE LAMINATED FABRIC AND METHODS OF MAKING AND USING

THE SAME

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 62/567,780 filed October 4, 2017, the entire content of which is hereby incorporated by reference herein.

TECHNICAL FIELD

The presently disclosed subject matter relates to laminated fabrics having improved characteristics, such as biodegradability, absorbency, breathability, and fluid resistance. The presently disclosed subject matter further relates to methods of making and using the disclosed laminated fabrics.

BACKGROUND

Laminated fabrics are commonly used in a wide variety of applications, such as the manufacture of personal care articles, household items, bedding, packaging, and the like. However, current laminated fabrics are typically constructed with polymeric materials, such as polystyrene, polyethylene, thermoplastic polyurethane, and polypropylene. It is well known that environmental problems such as overflowing landfills are heightened by the stability and longevity of such polymeric materials. The cited polymers are generally very stable and can remain in the environment for up to 100 years. As a result, there has been substantial interest in developing laminated fabrics that are considered environmentally friendly and sustainable. It would therefore be beneficial to provide a laminated fabric with improved or enhanced biodegradability characteristics. SUMMARY

In some embodiments, the presently disclosed subject matter is directed to a laminated fabric comprising a breathable fabric layer. The breathable fabric layer comprises about 100 weight percent natural fibers. Alternatively, the breathable fabric layer can comprise a blend of about 50-80 weight percent natural fibers and about 20- 50 weight percent polylactic acid, polyhydroxyalkanoate, polyhydroxybutyrate, or combinations thereof, based on the total weight of the layer. The breathable fabric layer further comprises a waterproof substrate layer bonded to the fabric layer, wherein the substrate layer comprises about 100 weight percent polylactic acid, polyhydroxyalkanoate, polyhydroxybutyrate, or combinations thereof. The disclosed laminated fabric is biodegradable.

In some embodiments, the fabric layer comprises a knitted material, woven material, nonwoven material, or combinations thereof.

In some embodiments, the natural fibers are selected from cotton, linen, flax, rayon, cellulose acetate, cellulose triacetate, hemp, jute, ramie, nettle, Spanish broom, kenaf, wool, fur, suede, leather, silk, and combinations thereof.

In some embodiments, the fabric layer has a basis weight of about 15-200 grams per meter squared (gsm), about 50-200 grams per meters squared (gsm), or about 65- 400 grams per meter squared (gsm).

In some embodiments, the presently disclosed subject matter is directed to a product produced from the disclosed laminated fabric.

In some embodiments, the presently disclosed subject matter is directed to a method of producing a biodegradable laminated fabric, the method comprising selecting a fabric layer comprising a breathable fabric comprising about 100 weight percent natural fibers or a blend of natural fibers and polylactic acid, polyhydroxyalkanoate, polyhydroxybutyrate, or combinations thereof (e.g., about 50-80 weight percent natural fibers and about 20-50 weight percent polylactic acid, polyhydroxyalkanoate, polyhydroxybutyrate, or combinations thereof). The method further comprises selecting a waterproof substrate layer comprising about 100 weight percent polylactic acid, polyhydroxyalkanoate, polyhydroxybutyrate, or combinations thereof and bonding the fabric layer to the substrate layer to produce a laminated fabric.

In some embodiments, the bonding is achieved by heating the substrate layer to a temperature of about 10-20°C above or below its melting temperature, applying pressure of about 10-300 pounds per linear inch, or both.

BRIEF DESCRIPTION OF THE DRAWINGS

The previous summary and the following detailed descriptions are to be read in view of the drawings, which illustrate some (but not all) embodiments of the presently disclosed subject matter. It should be appreciated that the Figures herein are presented for reference only and are not necessarily drawn to scale.

FIG. 1 is a cross-sectional view of a fabric/substrate laminate according to some embodiments of the presently disclosed subject matter.

FIG. 2 is a schematic view of one process that can be used to join the layers of the disclosed laminated fabric together.

DETAILED DESCRIPTION

The presently disclosed subject matter is introduced with sufficient details to provide an understanding of one or more particular embodiments of broader inventive subject matters. The descriptions expound upon and exemplify features of those embodiments without limiting the inventive subject matters to the explicitly described embodiments and features. Considerations in view of these descriptions will likely give rise to additional and similar embodiments and features without departing from the scope of the presently disclosed subject matter.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the presently disclosed subject matter pertains. Although any methods, devices, and materials similar or equivalent to those described herein can be used in the practice or testing of the presently disclosed subject matter, representative methods, devices, and materials are now described. Following long-standing patent law convention, the terms "a", "an", and "the" refer to "one or more" when used in the subject specification, including the claims. Thus, for example, reference to "a laminate" can include a plurality of such laminates, and so forth.

Unless otherwise indicated, all numbers expressing quantities of components, conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the instant specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the presently disclosed subject matter.

As used herein, the term "about", when referring to a value or to an amount of mass, weight, time, volume, concentration, and/or percentage can encompass variations of, in some embodiments +/-20%, in some embodiments +/-10%, in some embodiments +/-5%, in some embodiments +/-1 %, in some embodiments +/-0.5%, and in some embodiments +/-0.1 %, from the specified amount, as such variations are appropriate in the disclosed packages and methods.

The presently disclosed subject matter is directed to a biodegradable laminate material comprising a biodegradable fabric laminated to a compostable or biodegradable substrate. As used herein, the term "biodegradable" refers to materials that can be readily decomposed by biological agents, such as environmental heat, moisture, and/or microbial action (e.g., bacteria, fungi, and/or algae), as set forth in ASTM D6340-98, the entire content of which is incorporated by reference herein. It should be understood that in some embodiments, the term "biodegradable" can refer to "100% biodegradable." The term "compostable" as used herein refers to a product that satisfies the requirements set by ASTM D6400 (incorporated by referenced herein) for aerobic composting in municipal and/or industrial facilities.

As shown in the cross-sectional view of FIG. 1 , laminated fabric 25 can be formed by laminating substrate film 10 to surface fibers 15 of fabric 20. As used herein, the terms "lamination" and "laminate" refer to the process and resulting product made by bonding together two or more layers together (e.g., a fabric and a film). Lamination can be accomplished by joining layers together with adhesives, the application of heat and pressure, with spread coating, and/or with extrusion coating.

Fabric 20 can include any biodegradable knitted, woven, or nonwoven material known or used in the art. For example, suitable knitted fabrics can include flat knits, circular knits, warp knits, narrow elastics, laces, and the like. The term "woven material" as used herein refers to a material (e.g., fabric) characterized by intersecting warp and fill yarns interlaced so that they cross each other at an angle (e.g., a right angle). Suitable woven fabrics can be of any construction, such as sateen, twill, plain weave, oxford weave, basket wave, narrow elastic, and the like. The term "nonwoven" refers to a fibrous web or sheet that has a structure of individual fibers and/or threads that are interlaid but not in any regular, repeating manner. Suitable nonwoven fabrics can be of any construction, such as meltblown, spun bonded, wet-laid, carded fiber-based staple webs, and the like.

Fabric 20 can be constructed from any biodegradable, natural fiber known or used in the art. The term "natural fiber" as used herein refers to fibers that are obtained from natural sources, such as cellulosic fibers and protein fibers, or those that are formed by the regeneration and/or processing of naturally-occurring fibers and/or products. For example, in some embodiments, suitable natural fibers can include cellulosic fibers from cotton, linen, flax, rayon, cellulose acetate, cellulose triacetate, hemp, jute, ramie, nettle, Spanish broom, kenaf, or combinations thereof. Alternatively or in addition, in some embodiments, suitable natural fibers can include protein fibers, such as wools (sheep, alpaca, vicuna, mohair, cashmere, guanaco, camel, llama, and the like), furs, suedes, leathers, silks, and combinations thereof.

In some embodiments, fabric 20 can comprise about 100% natural fibers. Alternatively, in some embodiments, fabric 20 can comprise a blend of natural fibers and polylactic acid (PLA), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), or combinations thereof. PLA is a biodegradable and bioactive thermoplastic polyester derived from renewable resources, such as corn starch, cassava roots, or sugarcane. PHA is a linear, biodegradable polyester produced in nature by bacterial fermentation of sugar or lipids. PHB is a polyhydroxyalkanoate. In some embodiments, the disclosed blends can comprise about 50-80 weight percent natural fibers, such as at least about (or no more than about) 50, 55, 60, 65, 70, 75, or 80 weight percent fibers, based on the total weight of the fabric blend. Thus, the disclosed blend can also comprise about 20- 50 weight percent PLA, PHA, and/or PHB, such as at least about (or no more than about) 20, 25, 30, 35, 40, 45, or 50 weight percent, based on the total weight of the blend. For example, in some embodiments the disclosed blend can comprise about 50/50, 60/40, or 80/20 weight percent fibers/PLA, PHB, and/or PHA. However, it should be understood that the disclosed blends are not limited and can include greater or lesser amounts of natural fibers and/or PLA, PHA, or PHB.

Suitable fibers can have a diameter range of about 10-50 microns, such as at least about (or no more than about) 10, 15, 20, 25, 30, 35, 40, 45, or 50 microns. However, the presently disclosed fabric is not limited and can include fibers with greater or lesser diameters than the range set forth above.

The fabric can be blended using any method known or used in the art, such as (but not limited to) mechanical methods during staple fiber preparation and opening before web production. Such methods are well known to those of ordinary skill in the art.

In some embodiments, fabric 20 can be bleached to remove some or all of the natural coloring of the fibers and/or PLA, PHA, or PHB. Alternatively or in addition, in some embodiments, the fabric or fabric blend can be dyed to any desired color or colors. Such bleaching and coloring methods are well known in the art.

The basis weight of fabric 20 can range from about 15-200 grams per square meter (gsm). Thus, the weight of the fabric can be about 15-200 gsm, 25-175 gsm, 35- 150 gsm, 45-125 gsm, 55-100 gsm, or 65-75 gsm. However, it should be appreciated that fabric 20 is not limited and can have a greater or lesser basis weight than the ranges set forth herein. The term "basis weight" refers to the total weight of the material per unit area, as set forth in ASTM D3776-96, incorporated herein by reference.

In some embodiments, fabric 20 can be pre-bonded to improve its durability, strength, hand, aesthetics and/or other properties. For instance, in some embodiments the fiber can be thermally, ultrasonically, adhesively, and/or mechanically pre-bonded, as would be known to those of ordinary skill in the art. It should be appreciated that in some embodiments, the pre-bonding on the fabric layer is minimal to achieve optimal bonding between the fabric layer and the substrate layer. In some embodiments, the fibers in an unbonded or loosely bonded fiber layer can more easily intermesh with the substrate layer, so that the fibers are less likely to lint or abrade away in the laminated fabric. However, it may be found that the fabric layer cannot be easily or effectively rolled up and unwound without some pre-bonding. Thus, in some embodiments, fabric layer 20 is pre-bonded at the minimum contact area and temperature setting that will allow winding and unrolling.

Substrate 10 can comprise any biodegradable and/or compostable material known or used in the art, such as (but not limited to) PLA, PHA, and/or PHB. In some embodiments, the substrate can comprise about 100% PLA, PHA, or PHB. In some embodiments, the substrate can comprise about 20-50 weight percent PLA, PHA, and/or PHB blended with about 50-80 weight percent of one or more natural fibers. Thus, the substrate can comprise at least about (or no more than about) 20, 25, 30, 35, 40, 45, or 50 weight percent PLA, PHA, and/or PHB, based on the total weight of the substrate. The substrate can further comprise at least about (or no more than about) 50, 55, 60, 65, 70, 75, or 80 weight percent natural fiber(s), based on the total weight of the layer.

Substrate 10 can be waterproof. The term "waterproof" refers to the characteristic of being completely impermeable to liquids and/or oils in accordance with ASTM D1079, incorporated by reference herein. Accordingly, liquids and/or oils are unable to penetrate substrate 10. The waterproof characteristic of the substrate is achieved through selection of the materials used to construct the substrate, such as (but not limited to) PLA, PHA, PHB and blends thereof. Alternatively or in addition, the waterproof characteristic of the substrate can be achieved or enhanced by applying a waterproof coating to one or both sides. In some embodiments, the waterproof coating can be biodegradable.

The total basis weight of the substrate can be about 50-200 gsm. Thus, the substrate weight can range from about 50-200, 60-175, 70-150, 80-125, or 90-100 gsm. However, it should be appreciated that the basis weight of substrate 20 can be greater or lesser than the ranges set forth herein.

In some embodiments, fabric 20 can be laminated to substrate 10 using a heated roll process. For example, as shown in FIG. 2, substrate 10 can be heated via a heated roll and then subjected to pressure to form the disclosed laminated fabric. Particularly, a layer of substrate 10 can be supplied from substrate supply roll 30 through one or more guide rolls 35, and a layer of fabric 20 can be supplied from fabric supply roll 45 through one or more guide rolls 35 to heated roll 40, as indicated by Arrows A. As shown in the Figure, the substrate and fabric materials are disposed in surface-to- surface contact with each other. Particularly, the fabric and substrate materials are superimposed such that their inner surfaces 50 face one another (i.e., they are in contact) once they reach the heated roll. Outer surface 55 of substrate 10 is configured to directly contact heated roll 40. The outer surface of the fabric material is positioned on the opposite side (exterior) of the substrate, and does not contact the heated roll. Heated roll 40 acts as a heat source for at least partially melting or softening substrate 10. Thus, in some embodiments, the heated roll can have a temperature of at least about the melting temperature of substrate 10. For example, in some embodiments, the heated roll can be heated to a temperature of about 5-10°C less than the melting temperature of PLA (e.g., 140-155°C). It should be appreciated that the temperature of the heated roll can vary greatly depending on the construction of fabric 20 (substrate 10 in particular). Thus, the heated roll can be heated to within about +/- 10-20% of the melting temperature of the substrate.

The substrate and fabric are pressed together at the heated roll by pressure nip roll 60, as shown by Arrows B. In some embodiments, pressures of about 10-300 PLI (pounds per linear inch) can be used to bond the substrate and the fabric. As a result, the melted or softened substrate is forced into the interstices of the fabric construction to bond the substrate and fabric together and form fabric laminate 25. Nip roll 60 can be heated if desired, but can also be cooled or non-heated. Process times can vary from about five minutes at higher temperatures to about two days at very low temperatures. As the heated roll temperature is increased, process time can be reduced. Conversely, at lower process temperatures, the time required to create a usable substrate-to-fabric bond can increase rapidly. For a given temperature, higher pressures at nip roll 60 decreases the time required for lamination.

Laminated fabric 25 is then wound onto laminate rewind roll 65 by one or more guide rolls 35, shown by Arrow C. The laminated fabric product can then be cut to a desired shape and size for an intended use. In some embodiments, process times can range from about less than 1 second to about 30 seconds.

It should be appreciated that the methods used to construct laminated fabric 25 are not limited and can include any lamination method known or used in the art. In some embodiments, the disclosed laminated fabric can be constructed without the use of adhesives.

The total basis weight of the laminated fabric can be about 65-400 gsm. Thus, the laminate weight can range from about 65-400, 75-375, 85-350, 95-325, 105-300, 1 15- 275, 125-250, 135-225, 145-200, or 155-175 gsm. However, it should be appreciated that the basis weight of the laminated fabric can be greater or lesser than the ranges set forth herein.

In some embodiments, laminated fabric 25 does not include additives to enable biodegradability. Rather, the materials used to construct substrate 10 and fabric 20 are biodegradable and thereby confer biodegradable characteristics to the laminate structure without the need for additives. For example, prior art polypropylene nonwovens require additives to induce degradation. Thus, manufacture of the disclosed laminated fabric is less costly and is more ecologically-friendly compared to prior art materials because no additives are required.

Further, the biodegradable characteristics render the disclosed laminated fabric environmentally friendly. Particularly, solid waste in landfills, garbage receptacles, and the like are reduced. In some embodiments, the disclosed laminated fabric reduces the degradable life cycle of products made therefrom. For example, the degradable life cycle can be reduced from 15 years to about 5 years in some embodiments. Because laminated fabric 25 is constructed from 100% or about 100% biodegradable materials, the production of greenhouse gases is thereby reduced. Laminated fabric 25 is also waterproof. Particularly, the materials used to construct substrate 10 confer waterproofing characteristics such that the laminate has a high resistance to liquid and/or oil transmission.

Advantageously, the disclosed laminated fabric is breathable. The term "breathable" as used herein refers a material that is permeable to vapor and/or gas but forms a barrier against the passage of liquid. In some embodiments, the laminated fabric has a moisture vapor transmission rate (MVTR) of at least about 100 g/m ² /day.

Laminated fabric 25 can be used in any desired application where waterproofing, biodegradability, and/or breathability are desired. For example, the disclosed laminated fabric can be used to construct products in the personal care, household item, bedding, and/or packaging industries. However, it should be appreciated that the cited applications are not intended to be limiting, and the disclosed materials can be used with any application known in the art.

EXAMPLES

The following Examples have been included to provide guidance to one of ordinary skill in the art for practicing representative embodiments of the presently disclosed subject matter. In light of the present disclosure and the general level of skill in the art, those of skill can appreciate that the following Examples are intended to be exemplary only and that numerous changes, modifications, and alterations can be employed without departing from the scope of the presently disclosed subject matter.

EXAMPLE 1

Production of Meltblown Fabric Samples

Six samples of meltblown fabric were prepared on a Reicofil Exxon type meltblown system as set forth in Table 1 below. The die configuration used was: 35- hole per inch spinneret 1 .2 mm air gap/1 .2 mm setback. The throughput was 31 kg/hour/meter. Raw material was PLA (INGEO® PLA polymer 6202D, available from NatureWorks, LLC, Minnetonka, Minnesota). Table 1

Meltblown Fabric Samples Produced

EXAMPLE 2

PLA Meltblown/Cotton Nonwoven Lamination

Meltblowns from Table 1 were laminated to 150 gsm cotton hydroentangled fabric. Trial runs were performed on a laminator typical to Figure 2 (available from Klieverik Heli BV, Netherlands) using the conditions set forth in Table 2. The meltblown and cotton fabrics will be run through the Kieverik laminator, causing the PLA meltblown to "melt out" on the cotton fabric, resulting in a cotton fabric coated on one side by PLA.

Samples were tested using a simple method of placing fabric on top of a paper towel with cotton facing up and laminated meltblown layer down adjacent to the paper towel. 25 mL of water was poured onto the cotton side and allowed to wick to its maximum extent. Slight pressure was then applied to the fabric with the palm of the hand. The amount of water that bled through to the paper towel was then observed. Sample 26 from table 2 performed the best with no water bleeding through. Other samples had consistent pea-size to quarter-size wet spots on the paper towel. Further analysis will be made of porosity and moisture barrier properties.

Table 2

PLA/Nonwoven Lamination Trials

Run # Meltblown Speed Heat Press Laminator (bar) # Passes

Fabric (m/min) r)

Sample from

Table 1

#6 140 5 5 Not Used ¹

#3 140 5 5 Not Used ¹

#4 140 5 5 Not Used ¹

#5 140 5 5 Not Used ¹

#6 150 5 5 Not Used ¹

#3 150 5 5 Not Used ¹

#4 150 5 5 Not Used ¹

#5 150 5 5 Not Used ¹

#7 160 5 5 Not Used ¹

#3 160 5 5 Not Used ¹

#4 160 5 5 Not Used ¹

#5 160 5 5 Not Used ¹

#2 170 5 5 Not Used ¹

#5 170 5 5 Not Used ¹

#6 170 5 5 Not Used ¹

3 layers 170 5 5 Not Used

¹ of #6

#5 165 5 5 Not Used ¹

2 layers 165 5 5 Not Used

¹ of #6

2 layers 160 5 5 Not Used

¹ of #6

#5 160 5 5 Not Used ¹

#5 160 5 5 Not Used ¹

#5 155 5 5 Not Used ¹

2 layers 155 5 5 Not Used

¹ of #6

3 layers 155 5 5 Not Used

¹ of #4

2 layers 160 5 5 5 ¹ of #6

26 #5 160 5 5 5 1

PROPHETIC EXAMPLE 3

Wipes-Making Trial

About 1000 6.25" x 9" laminated fabric wipes will be prepared from run #26 in Table 2. The wipes will include 150 gsm cotton hydroentangled fabric laminated to an about 100 gsm PLA meltblown fabric. The best samples will then be selected and 1000- 2000 squares will be cut.