(A paper written by Calvin Woodings for the Insight Conference 2004)
Introduction
Toilet paper apart, the majority of disposable materials must be disposed of in the solid waste stream because their size, materials of construction, and methods of bonding make alternatives impractical. To date the convenience offered by disposability has been more than enough to offset the problems associated with disposal in distant landfills or incinerators. However the increasing demands for convenience has lead to the development of a wider range of disposable products. At the same time, an increasing awareness of the problems and hazards of landfill leads product developers to reconsider the use of the waste-water system as a more convenient hygienic, and environmentally-sound disposal route. The same thinking is evident in the development of liquid-stream medical disposables to aid the safe removal of contaminated waste from hospitals.With massive infrastructure already in place, most homes have a direct pipeline to an industrial biodegrader in the shape of a sewage farm, and many others have a local biodegrader or septic tank. Liquid waste system disposal of disposables is, superficially at least, attractive compared with the solid waste route where landfills are at best uncertain biodegraders and active composting of household waste is not an option for the majority of households in the majority of countries. So why does flushability remain a minority disposal route and why has disposability been the least important design feature for new disposable products?
A short History
Early disposable diapers came in two parts, a durable and washable plastic pant which could be reused many times, and an absorbent insert made, but for a few percent of latex holding the cover together, entirely of cellulose. This absorbent insert could be disposed of in the toilet after tearing in half longitudinally. For mothers who preferred the cloth diapers, flushable nonwoven liners were marketed which offered some protection from the wetness of the cotton and allowed faecal matter to be cleanly separated and disposed of down the toilet.One-piece diapers proved superior in use, the extra convenience and containment being achieved by integrating the plastic pant with the absorbent, the whole being “binnable” but not flushable. The later move from cellulosic to cheaper stronger drier synthetic fibre coverstocks, sometimes spun-laid, compounded the problems of disposal and increased their survival time in landfill. Similar trends affected the feminine hygiene industry, the increasing use of plastics either preventing flush-disposal or causing problems at the sewage farms.
Baby-wipes became a major market in the late-nineties, and these too were hard to flush and generally disposed of in solid waste with the diapers. For these products, and for the related fem-care wipes, the achievement of flushability appeared both desirable and more likely to be technically deliverable. There was however still the old puzzle to solve. The products had to be strong enough to be stored and/or used when wet, while being weak enough to fragment in the sewage system.
Flushability definition
EDANA confirm that a definition of flushability has yet to be developed by the nonwovens associations. However it was announced at January’s INDA Vision Conference in Las Vegas that EDANA and INDA were co-operating on developing both a definition of, and test-methods for, flushability. Task forces have now been set up and conclusions will emerge.The Water Environmental Research Foundation (WERF) published a flushability assessment manual in July 03 based on work with P&G and reported in July at the IDEA 2004 conference. The techniques described in this paper are are among those being considered by the trade association task forces.
The “Guiding Principles” of this assessment of flushability are:
a) No blockage of properly maintained household drainage systems under expected product usage.
b) Compatible with existing wastewater systems (collection, municipal, onsite)
c) Unrecognisable in the environment after a reasonable time.
d) Safe residuals in the relevant environment (soil, water)
All materials used would ideally have to be biodegradable within the sewage farm or septic tank system.
Existing Flushable Material Technologies
A search carried out for this update revealed 278 patents on the US Patent Database which refer to flushable nonwovens since 1976. 228 of these have appeared since Jan 1 1995 of which 93 are Kimberly-Clark patents and 87 are Procter and Gamble. Some of these refer to films, packaging and converted products as well as nonwovens. A complete patent analysis is beyond the scope of this review, but a selection of US patents, chosen to illustrate the variety of approaches, is given in the AppendixFrom these patents and the mechanisms of breakdown they cover, there appears to be a hierarchy of increasingly complex methods of achieving ever-stronger flushable nonwovens:
For Dry-to-wet flushability
a) Hydrogen-bonded cellulose without other bonding, achieved by wet laying. Dry bond strength increases as surface area and flexibility of the cellulosic fibres increases, hence refined pulps, fibrillated fibres and flat fibres give stronger (but stiffer) products, all being easily dispersible in flowing water.b) Hydrogen and friction-bonded cellulose achieved by carding, air-laying or wet-laying followed by low-pressure hydroentanglement. Strength/dispersibility balance would be achieved by varying the denier, length and surface area of the fibres as well as by varying the HE conditions.
c) Man-made fibres bonded with water soluble polymers such as starches, carboxymethyl celluloses, polyethylene oxides, polyvinyl alcohols, polyacrylates etc.
d) Polyolefin fibres or films loaded with water soluble polymers such as polyethylene oxide or derivatives engineered for better melt spinnability.
e) Biodegradable polymers (PLA etc) blended with water soluble polymers to make fibres/films and fabrics.
f) Fabrics made from, or pulp bonded with, water soluble fibres.
g) Fabrics bonded with cross-linked water soluble polymers , (e.g. superabsorbents) in fibre or powder form.
h) Fabrics bonded with bicomponent fibres , the sheath of which is a water-soluble or hydrolysable polymer.
i) Fabrics bonded with soft synthetic latexes – maybe incompletely cured.
j) Fabrics made from cellulose/synthetic blends bonded by heat . Here the poor cellulose/synthetic thermal bond is easily disrupted by cellulose swelling. Synthetic wood-pulps could give the right balance of strength/dispersibility.
k) Laminates with water soluble films or layers bonded with water soluble adhesives.
l) Very thin films extruded onto flushable nonwoven : waterproof when film side is wetted, but easily fragmented when both sides are wetted.
In all cases the rate of breakdown in water would be increased by fibres swelling, crimping or changing section as they wet out.
In many cases the addition of wet-strength additives would further boost wet strength and retard flushability, allowing the development of products suitable for the moist-to-wet flushability mentioned below.
For Flushability on a Moist-to-Wet change
Here the need for higher wet strength for storage and use in the moist state makes the disintegration in the sewage system harder to achieve. However the techniques would be broadly those listed above with additives to increase the wet strength. Ways of doing this which work only in storage and use, but not in the sewage system have been the subject of much recent development, but to date all appear to be carefully balanced compromises where performance in use appears to be sacrificed to achieve flushability claims.The main principle employed to date is the suppression of swelling of water sensitive polymeric binders with salts, and is similar in mechanism to the salt-effect on the absorbency of a superabsorbent. More specifically it involves:
a) Stabilising PVOH bonding with salts which wash out to allow them to dissolve in the sewage system. (Boric acid is a good stabiliser, but while it is harmless or even therapeutic in skin-contact, it is toxic by ingestion. Other salts are required in high percentages which spoil the lotion.)
b) Stabilising polyacrylic/methacrylic copolymers with calcium ions. When immersed in water with less calcium or an excess of sodium ions, the solubility of the binder increases.
Possibilities involving Packaging, Delivery or Disposal systems
Some innovations outside nonwoven manufacture could change the requirements for flushability:a) Wet-wipe dispensers can use rolls of dry wipe fabric, apply hot lotion, then cut and dispense wipes as a rolled hot-towel for immediate use. Binders that soften slowly in water or that lose wet-strength on cooling could be used for these materials.
b) Wet-toilet tissue dispensers moisten the sheets on withdrawal. Slow softening binders may work here also.
c) Using a pre-digester to degrade the bonding before flushing. (Storage in a bucket of bond- or fibre-solublising disinfectant solution prior to occasional flushing.)
d) The possibility of modifying toilets to fit “waste disposal units” on the outflow to allow a wider range of materials to be disposed of in the liquid stream. (Some toilet systems already have electric waste-macerators attached to allow waste disposal through small-bore pipes. Most short-fibre cellulosic nonwoven would be flushable in these systems)
e) The use of chemical additions to the toilet flush-water to trigger disintegration.
f) The use of oil-based lotions on wet wipes would protect water-sensitive bonds against attack until contacting the detergents in the toilet flush or sewage system.
g) The development of impregnated dry-wipes, to be wetted before use would increase the applicability of the dry techniques. (e.g. P&G launch of Olay Daily Facials for skin care. These are hydroentangled rayon products already sold as “flushable”.)
h) “Washing machines” with a “diaper disposal” cycle. (Disposal into the sewage stream via a washing machine rather than the toilet. A new “Detergent” provides the chemistry to destroy diapers the bonding system.)
Concluding Remarks
• 30 or more years ago when the International Nonwovens and Disposables Association, and the European Disposables and Nonwovens Associations rebranded as INDA and EDANA respectively, our industry was becoming aware of a disposable diaper growth opportunity with some unresolved disposability issues.• This growth opportunity has now been largely realised, and as a consequence the disposability issues are larger.
• Biodegradability alone is not the answer because biodegradation is too slow in landfill and while active composting could work, the infrastructure costs of this route will prove prohibitive.
• Biodegradation of flushable products after their disposal in the sewage system [1] could prove to be the option of choice now that the technology and materials are in place to allow it.
• Anaerobic biodegradation in sewage treatment generates natural gas making this route more energy efficient than composting. It also generates a range of other useful chemical intermediates, and compost, the use of which may become increasingly economic.
• The removal of excreta from dustbins; its transport in unsealed trucks and its disposal on the surface of landfill sites may even improve both air and groundwater quality.
• The problem which arose when consumers stopped flushing diaper waste to obtain the convenience of landfill-only disposables can however be solved.
• Recent patents and developments suggest the technology is now in place to allow progress on disposability issues via flushability.
Calvin Woodings
2005
REFS:
The Anaerobic Biodegradation of Nonwoven Products by Angela Lindsay & Calvin Woodings, INDA “Disposing of the Disposables”Conference Baltimore 1990
Haynes and McAvoy, Procter and Gamble “Assessing Down the Drain Disposal of Flushable Products” IDEA 04 Miami Beach
Appendix: Patent References
USP 3,370,590: Feb 27 th 1968, George et al for Riegel Textile Corp:. Process for the prevention of undesirable loosening or matting of paper for use in sanitary disposables. Inflated/collapsed (i.e. smooth surfaced and flat) rayon fibres are wet-laid and bonded with CMC, starch, PVOH or polyvinylpyrrolidone. They exhibit high wet strength when moist but disintegrate in flowing water. Patent also covers a sanitary towel and diaper made using this coverstock.USP 3,616,797: Nov 2 nd 1971, Champaigne et al for K-C: Flushable wrapper for absorbent pads. Overall bonding a nonwoven web with water soluble binders e.g. CMC, PVOH and then overprinting with a pattern of water-insoluble binder in lines, the spacing of which is related to the fibre length, to obtain sufficient wet-strength in use. The lines also define the size of the fragments after dispersion.
USP 3,939,836: Feb 24 th 1976, Tunc et al for J&J: Water dispersible nonwoven fabric. The use of an alkali salt of a sulphated cellulose ester resin as a binder for viscose fibre creates a nonwoven strong enough for use with body fluids but which disintegrates in tap water. Sodium cellulose acetate sulphate had to be dissolved in acetone/water mixture before application to the fibres.
USP 3,950,578: Apr 13 th 1976, Laumann for Richard Keoseian: Water disintegratable sheet material. Water dispersible tissue or nonwoven is extrusion coated with an ultra-thin layer of polyethylene which is then reheated to destroy its physical properties before or during a second coating with microcrystalline wax to waterproof it. The product has high wet strength only when wetted from the film side. When immersed in flowing water the nonwoven reinforcement disperses and it disintegrates easily.
USP 4,755,421: Jul 5 th 1988, Manning et al for James River Corp.: Hydroentangled disintegratable fabrics. Binder-free wet-laid nonwoven made from cellulosic fibres where the HE conditions allow high wet tensile in packing and use while allowing disintegration when mildly agitated in a large volume of water. (The hydrodisentanglement phenomenum) The fibres are pulp reinforced with 5-30% viscose.
USP 5,137,600: Aug 11 th 1992, Barnes et al for K-C: Hydraulically needled nonwoven pulp fibre web. Hydroentangling long-fibre pulp in blend with cheaper pulps with optional addition of fillers and superabsorbents. For wipes and distribution layers in diapers. No claims to flushability but referred to in recent K-C patents.
USP 5,292,581: Mar 8 th 1994, Viazmenski et al for Dexter Corp.: Wet-Wipe. Wet-laid pulp reinforced with ~15% viscose, ~1% of a typical wet strength additive being added to the furnish to boost wet properties, followed by hydroentanglement. Said to overcome the weakness of HE-only wet-laid products while allowing disintegration in sewage system or septic tank.
USP 5,384,189: Jan 24 th 1995, Kuroda et al for LION Corp: Water decomposable nonwoven fabric. Acrylic/methacrylic copolymer binder used to bond biodegradable (ideally) fibres. Examples use carded, hydroentangled viscose or cellulose acetate fibres bonded with 6% of the binder, or viscose wet-laid with a PVOH bonding fibre, followed by hydroentanglement and spray-bonding with the binder. (The same binder is used in the recent K-C patents.)
USP 5,500,281: Mar 19 th 1996, Srinivasan et al to International Paper: Absorbent, flushable, biodegradable, medically safe nonwoven with PVA binder and process. 2-10% of PVOH fibres used to bond other fibres. Typically 92% rayon, 8% PVOH card webs are sprayed with water and the bonding of the PVOH is controlled by a 2 stage drying process, the first being ~60 oC and the second being ~80 oC. Hydroentanglement can be used instead of spraying to develop more strength and texture.
USP 5,667,635: Sept 16 th 1997, Win et al for K-C: Flushable pre-moistened personal wipe. Multi-ply, uncreped, through-air dried tissue-wipe where one or more layers is treated with wet-strength resin, the others being untreated to promote dispersion, the whole being pattern-embossed to weaken the sheets and bond them together. The wipe is strong enough in storage and use, but delaminates in excess water, the thin layers breaking up easily.
USP 5,763,065: June 9 th 1998, Patnode et al for 3M: Water dispersible multilayer microfibres. Multilayer nonwovens made from alternating layers of hydrolytically degradable polymer (eg PLA) and water soluble polymer (eg PVOH) either in fibre or film form. Used product (e.g medical gowns and drapes) is disposed of in a washing machine, where it dissolves in one laundry cycle and is pumped out into the sewers.
USP 5,905,046: May 18 th 1999, Takeda et al for Unicharm: Biodegradable and hydrolysable sheets. Aliphatic polyesters (e.g polylactic acid) blended with cellulosics and bonded with water soluble polymers listed as starch, alginates, natural gums and gelatins, polyethylene oxide, cellulose xanthate, polyacrylates or polymethacrylates, polyacrylamides, polyvinylpyrrolidone, carboxymethyl cellulose, carboxyethyl cellulose and their salts.
USP 5,916,678: June 29 th 1999, Jackson et al for K-C: Water degradable multicomponent fibres and nonwovens. Bicomponent fibres with a sheath which is more water soluble than the core. e.g suphonated polyester from Eastman (AQ 38S) on a polyethylene core, or, PVOH from NSCC Japan on a polybutylene terephthalate core from Hulls GmbH. Films of National Starch 70-4442 copolyester are shown to be strong in ionic solutions but disperse like Kleenex toilet tissue in deionised water.
USP 5,935,880: Aug 10 th 1999, Wang, Pomplun et al for K-C: Dispersible nonwoven fabric and method of making the same. Water dispersible nonwoven made by hydroentangling wet or air-laid pulp or other fibres followed by partial drying, latex bonding and crepeing from both sides. The binder used is the LION SSB-3b with the Eastman AQ 29D as above, printed or sprayed on. It is stabilised with a solution of ~100pm Calcium either after bonding (for dry wipes) or in the lotion (for wet-wipes).
USP 5,986,004: Nov 16 th 1999, Pomplun, Jackson et al for K-C: Ion sensitive polymeric materials: Binder made from acrylic/methacrylic copolymer solutions (SSB-3b from LION in Japan) with sulphonated co-polyesters (e.g Eastman AQ 29D) as divalent ion inhibitors. When wetted with solutions containing more than ~50ppm of calcium ions they are stable, but dissolve in water with less than ~50ppm of calcium.
USP 6,117,438: Topolkaraev et al. September 12, 2000 for K-C Water degradable microlayer polymer film and articles including same: A microlayer polymer film comprising a plurality of coextruded microlayers including a non-degradable layer comprising a non-water degradable, melt-extrudable polymer and degradable layer comprising a water degradable, melt-extrudable polymer. The microlayer polymer film degrades when soaked in water and is suitable as a covering material for disposal items such as flushable diapers. The microlayer polymer film is also breathable and is a barrier to small amounts of water. A suitable non-water degradable, melt-extrudable polymer is linear low density polyethylene filled with a particulate filler. A suitable water degradable, melt-extrudable polymer is polyethylene oxide.
USP 6,127,593 Bjorkquist , et al. , October 3, 2000 for P&G: Flushable fibrous structures. The binder component of the fibrous structures comprises a salt and the condensation product of polyvinyl alcohol (hereafter referred to as “PVA”) and one or more substituted or unsubstituted C.sub.1 -C.sub.8 aldehydes. This condensation product is a polyvinyl alcohol-co-acetal (a “PVAA”). Preferred salts comprise anions such as citrate, sulfate, chloride, fluoride, bromide, thiosulfate, phosphate, nitrate, acetate, carbonate, and bicarbonate. Preferred salts include, but are ot limited to, sodium citrate, potassium citrate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, sodium phosphate, potassium phosphate, and magnesium chloride. Particularly preferred salts include potassium citrate and sodium sulfate.
USP 6,153,700: Wang , et al. , November 28, 2000 for K-C: Water-degradable flushable film of polyolefin and poly(ethylene oxide) and personal care article therewith. Film having greater than about 55 weight percent of a polyolefin and less than about 45 weight percent of poly(ethylene oxide) of weight average molecular weight of less than about 100,000. Preferably, the polyolefin is low density polyethylene.
USP 6,172,177: Jan 9 2001, Wang et al for K-C. Grafted Polyethylene Oxide compositions: A process for making PEO melt-spinnable into water soluble spunbonds, melt-blowns and films by grafting on 2-hydroxyethyl methacrylate or poly(ethyleneglycol methacrylate) .
USP 6,228,920 Topolkaraev , et al. , May 8, 2001 for K-C: Compositions and process for making water soluble polyethylene oxide films with enhanced toughness and improved melt rheology and tear resistance. The films composed of the PEO/latex blend have improved toughness, breathability, and tear resistance and are useful for the manufacture of disposable, flushable medical and personal care products, such as diapers, tampons, feminine napkins, and bladder control pads.
USP 6,258,427 : Kerins , et al. , July 10, 2001 for K-C: Flushable double-sided release liner. Formed by applying a release coating onto both surfaces of a water-sensitive film. The flushable double-sided release liner maintains its integrity and strength when in use, but disperses when placed in contact with water,
USP 6,296,914: Kerins , et al. , October 2, 2001 for K-C: Flushable release liners and methods of making the same. This comprises a thin discontinuous release coating on at least one surface of a water-sensitive film. The coated water-sensitive film functions like conventional release papers currently used.
USP 6,359,063 Wang , et al. , March 19, 2002 for K-C: Flushable personal care article with layer of monomer-grafted polyolefin and PEO. Contains a backing or barrier layer comprising a water degradable modified polyolefin-modified poly(ethylene oxide-containing film having greater than about 55 weight percent of a modified polyolefin and less than about 45 weight percent of a modified poly(ethylene oxide). The polyolefin and poly(ethylene oxide) polymers are modified by having grafted thereto from about 0.1 weight percent to about 30 weight percent of a monomer selected from 2-hydroxyethyl methacrylate or polyethylene glycol ethyl ether methacrylate.
USP 6,362,277 Wang , et al. , March 26, 2002 for K-C: Personal care article with layer of monomer-grafted polyolefin and unmodified PEO. The polyolefin is modified by grafting thereto a monomer selected from 2-hydroxyethyl methacrylate and polyethylene glycol ethyl ether methacrylate in an amount ranging between about 0.1 weight percent and about 30 weight percent, based on the total weight of the polymer blend. The polyolefin-containing film, when immersed in water for about 30 seconds, loses at least 10% in two or more of the tensile properties: percent strain-to-break, peak stress, energy-to-break and modulus when compared to the dry or pre-immersion values.
USP 6,372,850 Wang , et al. , April 16, 2002 for K-C: Melt processable flushable poly (ethylene oxide) fibers. The poly(ethylene oxide) is modified by grafting polar vinyl monomers, such as poly(ethylene glycol) methacrylate and 2-hydroxyethyl methacrylate, onto poly(ethylene oxide). The modified poly(ethylene oxide) has improved melt processability and can be used to melt process poly(ethylene oxide) fibers of thinner diameters.
USP 6,433,245 Bjorkquist , et al. , August 13, 2002 for P&G: Flushable fibrous structures. The fibrous structures comprises a salt and the condensation product of polyvinyl alcohol (hereafter referred to as “PVA”) and one or more substituted or unsubstituted C.sub.1 -C.sub.8 aldehydes. This condensation product is a polyvinyl alcohol-co-acetal (referred to herein as a “PVAA”). The PVA should be acetalized to such a degree that the cloud point of the PVAA (as determined turbidimetrically by measuring a change in light transmittance) is higher than the temperature of tap water (i.e. greater than about 25.degree. C.) and is depressed by the addition of salts. The binder is typically applied to wet-laid cellulose.
USP 6,495,080: Tsai , et al. , December 17, 2002 for K-C: Methods for making water-sensitive compositions for improved processability and fibers including same. The compositions comprise a blend of at least one water-sensitive polymer and at least one polymer selected from polylactide (PLA), polyolefin-grafted with one or more polar groups, such as maleic anhydride (MA), and other aliphatic polyesters. Desirably, the water-sensitive polymer comprises one or more copolyesters. The compositions may be spun into monocomponent or multicomponent fibers through conventional processes, such as spunbonding and meltblowing processes. The compositions may also be extruded to form films and other thermoformable articles
USP 6,500,897 Wang , et al. , December 31, 2002 for K-C Modified biodegradable compositions and a reactive-extrusion process to make the same. In a preferred embodiment, the invention is a method of grafting polar groups onto biodegradable polymers and modified biodegradable polymer compositions produced by the method. The polymer compositions are useful as components in flushable and degradable articles. Water-sensitive polymer blends and method of making those polymer blends are also disclosed.
USP 6,514,602: Zhao , et al. , February 4, 2003 for P&G: Water-flushable and biodegradable film useful as backsheets for disposable absorbent articles. The film comprises: (1) a relatively thin water-impervious biodegradable layer to maintain the integrity of the film during use and to minimize or prevent aqueous liquids from penetrating through the film; (2) a relatively thick substantially water-soluble layer adjacent the water-impervious layer to cause the film to lose integrity after the film is flushed; and (3) a relatively thin substantially water-permeable layer adjacent the water-soluble layer to control the rate at which water and other aqueous liquids contact, dissolve and disintegrate the water-soluble layer.
USP 6,530,910 Pomplun et al. , March 11, 2003 for K-C: Flushable release film with combination wiper. The flushable release liner/wiper combination is formed by applying a release coating onto a first surface of a water-sensitive film and an absorbent fibrous material onto an opposite surface of the water-sensitive film. The flushable release liner/wiper combination maintains its integrity and strength when in use, but loses its integrity and strength when placed in contact with water.
USP 6,552,124 Wang , et al. , April 22, 2003 for K-C: Method of making a polymer blend composition by reactive extrusion. Poly(.beta.-hydroxybutyrate-co-valerate), poly(butylene succinate), poly(ethylene succinate) and polycaprolactone are biodegradable polymers which are commercially viable and, in general, thermally processable. By grafting polar monomers onto one or more of poly(.beta.-hydroxybutyrate-co-valerate), poly(butylene succinate) and polycaprolactone, the resulting modified polymer is more compatible with polar polymers and other polar substrates. For flushable material development, the modified polymer compositions of this invention have enhanced compatibility with water-soluble polymers, such as polyvinyl alcohol and polyethylene oxide, than the unmodified biodegradable polymers.
USP 6,552,162 Wang , et al. , April 22, 2003 for K-C: Water-responsive, biodegradable compositions and films and articles comprising a blend of polylactide and polyvinyl alcohol and methods for making the same. The water-responsive blends and films and fibers disclosed in this invention have the unique advantage of being biodegradable so that the blends, films, fibers and articles made from the blends and films can be degraded in aeration tanks, by aerobic degradation, and anaerobic digesters, by anaerobic degradation, in waste water treatment plants. Therefore, articles comprising the blends of this invention will not significantly increase the volume of sludge accu mulated at waste water treatment plants.
USP 6,579,934: Wang , et al. June 17, 2003 for K-C, Reactive extrusion process for making modified biodegradable compositions Biodegradable polymers that are useful in the present invention include poly(.beta.-hydroxy alkanoates) (“PHA”), such as poly(.beta.-hydroxybutyrate) (“PHB”), poly(.beta.-hydroxybutyrate-co-.beta.-hydroxyvalerate) (“PHBV”); poly(alkylene succinates) (“PAS”), such as poly(ethylene succinate) (“PES”) and poly(butylene succinate) (“PBS”); and polycaprolactones (“PCL”) that are hydrolytically degradable.
USP 6,585,922: Wang , et al. , July 1, 2003 for K-C: Flushable fiber compositions comprising modified polypropylene and modified poly(ethylene oxide) and process for making the same. These fibers have good ductility with a tensile strain-at-break value which is higher than such value for the polypropylene used in these compositions and substantially higher than the poly(ethylene oxide) used in the fiber compositions of this invention. The present invention also provides a reactive blending process for the manufacture of such fiber compositions in which polypropylene and poly(ethylene oxide) are modified with a polar vinyl monomer and a free radical initiator in an extrusion apparatus. This process is also referred to as “reactive extrusion”.
USP 6,607,819: Wang , et al. August 19, 2003 for K-C: Polymer/dispersed modifier compositions have improved melt processability and properties and may be used to thermally process films, fibers, and articles having improved properties. In one embodiment, the polymer resin/dispersed modifier compositions are further grafted with one or more monomers, which graft onto the polymer resin and/or the dispersed modifier. In a further embodiment, the polymer resin is a water-soluble or water-dispersible polymer, such as polyethylene oxide; the modifier is a styrene butadiene polymer, a carboxylated acrylonitrile-butadiene-styrene polymer, or a combination thereof; and the grafted monomer is poly(ethylene glycol) ethyl ether methacrylate, poly(ethylene glycol) ethyl ether acrylate, 2-hydroxyethyl methacrylate (HEMA), poly(ethylene glycol) methacrylate (PEG-MA), or a mixture thereof. The grafted PEO/dispersed modifier compositions have improved properties compared to unmodified polyethylene oxide compositions, and modified polyethylene oxide compositions.
USP 6,623,466: Richardson , September 23, 2003 Absorbent article having detachable components. The detachable topsheet can be removed from the article and flushed in a toilet together with the human waste. A binding allows the pouch to be opened to flush the absorbent contents and human waste inside the pouch, in segments to avoid clogging a toilet.
USP 6,673,446: Wang , et al. , January 6, 2004 for K-C, Flushable fiber compositions comprising modified polypropylene and modified poly (ethylene oxide) and process for making the same. These fibers are comprised of multiple filaments (i.e., microfibers) of modified polypropylene with a diameter of about one micron or less dispersed in a continuous matrix of modified poly(ethylene oxide). Since modified poly(ethylene oxide) is water-soluble, when the fiber is placed in water the continuous matrix of modified poly(ethylene oxide) dissolves, leaving modified polypropylene microfibers which are wettable because they are grafted with a polar vinyl monomer (i.e., a hydrophilic vinyl monomer). These types of fibers are especially useful in the production of flushable personal care products.
USP 6,746,766, Bond et al for P&G, June 8, 2004 Multicomponent fibers comprising starch and polymers The present invention is directed to multicomponent fibers. The fibers may be in a side-by-side, sheath-core, segmented pie, islands-in-the-sea configuration, or any combination of configurations. Each component of the fiber will comprise destructurized starch and/or a thermoplastic polymer. The present invention is also directed to nonwoven webs and disposable articles comprising the multicomponent fibers. The nonwoven webs may also contain other synthetic or natural fibers blended with the multicomponent fibers of the present invention.
USP 6,743,506, Bond et al for P&G, June 1, 2004 High elongation splittable multicomponent fibers comprising starch and polymers Splittable multicomponent fibers, to split fibers made from such splittable fibers, to a processes for making such splittable and split fibers, and to nonwovens and other substrates made form the split fibers. The splittable multicomponent fibers can comprise one component comprising thermoplastic starch and another component comprising a non-starch thermoplastic polymer, wherein: (i) said second component is capable of being split or removed from said first component to provide at least one split fiber consisting essentially of said first component; and (ii) wherein the split fiber of said first component can have good elongation properties. The splittable multicomponent fibers can also provide split fibers of the thermoplastic starch component. The split fibers corresponding to the thermoplastic polymer component will have a greater elongation than directly spun thermoplastic fibers which have an equivalent mass through put as the thermoplastic polymer component of the multicomponent fiber and which have the same diameter as the split fiber
USP 6,730,057, Zhao et al for P&G, May 4,2004 Flushable tampon applicators Disclosed are flushable tampon applicators which comprise a combination of thermoplastic materials that readily disintegrate in water such as toilet water for improved disposal and reduced environmetal concerns regarding the destruction of these applicators. The flushable tampon applicators comprise a combination of high molecular weight polyethylene oxides, low molecular weight polyethylene glycols, and biodegradable polymers, wherein this combination of water-dispersible and biodegradable thermoplastic polymers provide flushable tampon applicators that are readily disposed of and that are smooth, soft, flexible, and non-sticky or non-slimy to the touch before and during use.
USP 6,713,414 Pomplun et al for K-C, March 30, 2004 Ion-sensitive, water-dispersible polymers, a method of making same and items using same The present invention is directed to ion-sensitive, water-dispersible polymers. The present invention is also directed to a method of making ion-sensitive, water-dispersible polymers and their applicability as binder compositions. The present invention is further directed to fiber-containing fabrics and webs comprising ion-sensitive, water-dispersible binder compositions and their applicability in water-dispersible personal care products .
USP 6,713,140 McCormack et al. March 30, 2004 for K-C Latently dispersible barrier composite material The disclosure describes a latently dispersible barrier composite material including an exposed low strength barrier component, an internal water sensitive layer, and a water permeable, inextensible, water dispersible support layer. When exposed to aqueous conditions on the barrier side, the composite prevents it from passing through to the other layers. When exposed to aqueous conditions on the opposite side, the composite readily disperses and may be disposed of by flushing in a toilet, for example. Uses are many and include numerous containment applications such as commode liners, containers for bodily and animal wastes, components of personal care products and the like. Examples of barrier layers include polylactic acid. Examples of water sensitive layers include polyvinyl alcohol. Examples of support layers include low stretch grades of toilet tissue.
USP 6,683,143 Mumick et al. January 27, 2004 for K-C , Ion-sensitive, water-dispersible polymers, a method of making same and items using same. The present invention is directed to ion-sensitive, water-dispersible polymers. The present invention is also directed to a method of making ion-sensitive, water-dispersible polymers and their applicability as binder compositions. The present invention is further directed to fiber-containing fabrics and webs comprising ion-sensitive, water-dispersible binder compositions and their applicability in water-dispersible personal care products.
USP 6,713,140 McCormack et al. March 30, 2004 for K-C Latently dispersible barrier composite material The disclosure describes a latently dispersible barrier composite material including an exposed low strength barrier component, an internal water sensitive layer, and a water permeable, inextensible, water dispersible support layer. When exposed to aqueous conditions on the barrier side, the composite prevents it from passing through to the other layers. When exposed to aqueous conditions on the opposite side, the composite readily disperses and may be disposed of by flushing in a toilet, for example. Uses are many and include numerous containment applications such as commode liners, containers for bodily and animal wastes, components of personal care products and the like. Examples of barrier layers include polylactic acid. Examples of water sensitive layers include polyvinyl alcohol. Examples of support layers include low stretch grades of toilet tissue.
USP 6,713,414 Pomplun et al for K-C, March 30, 2004 Ion-sensitive, water-dispersible polymers, a method of making same and items using same The present invention is directed to ion-sensitive, water-dispersible polymers. The present invention is also directed to a method of making ion-sensitive, water-dispersible polymers and their applicability as binder compositions. The present invention is further directed to fiber-containing fabrics and webs comprising ion-sensitive, water-dispersible binder compositions and their applicability in water-dispersible personal care products .
USP 6,730,057, Zhao et al for P&G, May 4,2004 Flushable tampon applicators Disclosed are flushable tampon applicators which comprise a combination of thermoplastic materials that readily disintegrate in water such as toilet water for improved disposal and reduced environmetal concerns regarding the destruction of these applicators. The flushable tampon applicators comprise a combination of high molecular weight polyethylene oxides, low molecular weight polyethylene glycols, and biodegradable polymers, wherein this combination of water-dispersible and biodegradable thermoplastic polymers provide flushable tampon applicators that are readily disposed of and that are smooth, soft, flexible, and non-sticky or non-slimy to the touch before and durng use.
USP 6,743,506, Bond et al for P&G, June 1, 2004 High elongation splittable multicomponent fibers comprising starch and polymers Splittable multicomponent fibers, to split fibers made from such splittable fibers, to a processes for making such splittable and split fibers, and to nonwovens and other substrates made form the split fibers. The splittable multicomponent fibers can comprise one component comprising thermoplastic starch and another component comprising a non-starch thermoplastic polymer, wherein: (i) said second component is capable of being split or removed from said first component to provide at least one split fiber consisting essentially of said first component; and (ii) wherein the split fiber of said first component can have good elongation properties. The splittable multicomponent fibers can also provide split fibers of the thermoplastic starch component. The split fibers corresponding to the thermoplastic polymer component will have a greater elongation than directly spun thermoplastic fibers which have an equivalent mass through put as the thermoplastic polymer component of the multicomponent fiber and which have the same diameter as the split fiber
USP 6,746,766, Bond et al for P&G, June 8, 2004 Multicomponent fibers comprising starch and polymers The present invention is directed to multicomponent fibers. The fibers may be in a side-by-side, sheath-core, segmented pie, islands-in-the-sea configuration, or any combination of configurations. Each component of the fiber will comprise destructurized starch and/or a thermoplastic polymer. The present invention is also directed to nonwoven webs and disposable articles comprising the multicomponent fibers. The nonwoven webs may also contain other synthetic or natural fibers blended with the multicomponent fibers of the present invention.
USP 6,750,163, Wang et al for K-C, June 15 th 2004 Melt processable poly (ethylene oxide) fibers To overcome the disadvantages of the prior art, this invention teaches fibers comprising PEO coplymers comprising grafted polar functional groups. Such modification of PEO reduces the melt viscosity and melt pressure of the PEO. The modified PEO resins can be solidified for later thermal processing into fibers or processed directly into fibers. The fibers are water soluble and are useful as components in personal care products.
USP 6,764,477, Chen et al for K-C, July 20, 2004 Center-fill absorbent article with reusable frame member A composite absorbent article comprises a reusable frame member for shaping and leakage control onto which a single-use absorbent device can be detachably connected and repeatedly replaced without the need to replace the reusable frame member. A low-cost, high-performance composite absorbent article can thus be provided from low-cost single-use absorbent devices by virtue of the reusable frame member. A wicking barrier lining a central void or depression helps provide leakage containment for the overall composite absorbent article.
USP 6,770,356, O’Donnell et al for P&G Fibers and webs capable of high speed solid state deformation The present invention relates to an intermediate web comprising of high glass transition polymer fibers. The fibers are spun at low to moderate speeds and have a relative crystallinity of from 10% to 75% of the maximum achievable crystallinity. The intermediate web is a low crystallinity web that exhibits shrinkage of more than 30% and elongation to break of more than 80% at high strain rates. This web can be heat treated to reduce shrinkage to less than 15% while the web is capable of at least about 60% elongation at a strain rate of at least about 50 second.sup.-1.
USP 6,782,589 Ngai for PGI, Aug 31 2004 Method for forming laminate nonwoven fabric A method for creating a nonwoven laminate fabric has steps of depositing a first nonwovne layer on a moving support, depositing a second nonwoven layer over the first layer, and conveying the layers under a manifold. The manifold has a plurality of jet clusters separated from one another by a distance. Water is directed form the jet clusters onto the underlying layers to thereby create a laminated fabric. Because the jet clusters are separated from one another, the laminate fabric is “pattern entangled”. Bundling occurs along substantially linear lines, with much lighter bundling in regions between the linear bundling regions. The result is a fabric with regions of relative strong entanglement and other regions of much lighter entanglement. When three layers are laminated, with top and bottom layers of thin veneer and a center layer of pulp the method of the invention has been discovered to result in a laminate fabric with particular utility as a flushable wipe product.
USP 6,783,826 Sherrod et al for K-C, Aug 31 2004 Flushable commode liner The disclosure describes a commode liner made from a first and a second opposing member defining a top with an opening, a bottom, and a pair of opposing sides. The pair of opposing sides includes a separation distance D, which varies from the top to the bottom, and the distance D is larger at the top than at the bottom. The opposing members can be formed from a latently dispersible barrier composite material including an exposed low strength barrier component, an internal water sensitive layer, and a water permeable, inextensible, water dispersible support layer. When exposed to aqueous conditions on the barrier side, the composite prevents it from passing through to the other layers. When exposed to aqueous conditions on the opposite side, the commode liner readily disperses and may be disposed of by flushing in a toilet, for example. Examples of barrier layers include polylactic acid. Examples of water sensitive layers include polyvinyl alcohol. Examples of support layers include low stretch grades of toilet tissue.
USP 6,783,854, Bond for P&G, Aug 31 2004 Bicomponent fibers comprising a thermoplastic polymer surrounding a starch rich core A bicomponent fiber comprising one thermoplastic polymer component comprising nonstarch, thermoplastic polymer and one thermoplastic starch component comprising a destructured starch and a plasticizer. The thermoplastic polymer component surrounds the thermoplastic starch component. Also provided are nonwoven webs and disposable articles comprising the bicomponent fibers.
USP 6,790,519, Johnson et al for K-C, Sept 14 th 2004 Moisture-induced poly(ethylene oxide) gel, method of making same and articles using same A method for making modified poly(ethylene oxide) by graft polymerizing thereto organic monomers containing a trialkoxy silane functional group or a moiety that reacts with water to form a silanol group, such as methacryloxypropyl trimethoxy silane, onto the poly(ethylene oxide) is disclosed. The graft polymerization is accomplished by mixing the poly(ethylene oxide), the silane-containing monomer(s) and an initiator and applying heat. Preferably, the method is a reactive-extrusion process. After graft polymerization, the modified poly(ethylene oxide) may be exposed or subjected to relatively high moisture conditions, thereby causing crosslinking and formation of a structure that is capable of absorbing relatively large amounts of saline. The resulting modified poly(ethylene oxide) has improved properties over articles similarly processed from unmodified poly(ethylene oxide).
