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WO1999005986A1 - Fil dentaire ameliore - Google Patents

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Publication number
WO1999005986A1
WO1999005986A1 PCT/US1998/015356 US9815356W WO9905986A1 WO 1999005986 A1 WO1999005986 A1 WO 1999005986A1 US 9815356 W US9815356 W US 9815356W WO 9905986 A1 WO9905986 A1 WO 9905986A1
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WIPO (PCT)
Prior art keywords
dental floss
filaments
multipolymer
filament
dental
Prior art date
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PCT/US1998/015356
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English (en)
Inventor
Ira D. Hill
Dale G. Brown
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WhiteHill Oral Technologies Inc
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WhiteHill Oral Technologies Inc
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Filing date
Publication date
Application filed by WhiteHill Oral Technologies Inc filed Critical WhiteHill Oral Technologies Inc
Priority to AU85864/98A priority Critical patent/AU8586498A/en
Publication of WO1999005986A1 publication Critical patent/WO1999005986A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C15/00—Devices for cleaning between the teeth
    • A61C15/04—Dental floss; Floss holders
    • A61C15/041—Dental floss

Definitions

  • the present invention relates to improved dental flosses.
  • the improved dental flosses of the present invention are loaded, homopolymer and multipolymer, multifilament, high-tenacity dental flosses with improved elongation, gentleness and resistance to shredding.
  • the flosses of this invention are capable of releasing at least some of the "load” during flossing, while exhibiting improved gentleness on gums, resistance to shredding and a tendency to "give" rather than cut the user.
  • dental floss The purpose of dental floss is (1) to dislodge and remove any decomposing food material that has accumulated at the interproximal and subgingival surfaces that cannot be removed by brushing, and (2) to dislodge and remove as much as possible the growth of bacterial material (plaque) upon the teeth or the superimposed calculus that has accumulated interproximally since the previous cleaning.
  • dental floss marketed today are comprised of textile-type fibers including the polytetrafluoroethylene monofilament commercial dental flosses marketed under the trademarks Glide®, Easy Slide®, Precision®, etc.
  • the object of the present invention is to provide improved dental flosses based on innovative polymer and multipolymer, multifilament construction not used heretofore in the dental floss category.
  • Another object of this invention is to provide dental flosses with improvements in resistance to shredding, including improved tensile and tear strength, along with improved elongation.
  • a further object of this invention is to provide dental flosses with improvements in gentleness based on intrinsic self-activation (self-crimping) properties, improved elongation and filament construction, in combination with improved release of lubricating substances.
  • Still another object of this invention is to provide improved loaded dental floss that is shred resistant and capable of releasing at least a portion of said load during flossing into interproximal and subgingival areas with little or no shredding.
  • Figures 1-23 show greatly magnified cross sections, i.e., sections perpendicular to the filament axis of typical multipolymer filaments of this invention.
  • Figures 24A and 24B illustrate a test method using an Instron for helping to establish resistance to fraying.
  • Figure 25 is a schematic representation of equipment useful in practicing the spin-stretch process embodiment of the present invention.
  • the present invention is directed to improved dental flosses.
  • the present invention includes loadable polymer and multipolymer, multifilament, high-tenacity dental flosses having improved elongation, gentleness and resistance to shredding along with the capacity to release at least a portion of said load interproximally and subgingivally during flossing, where the floss tends to "give" rather than cut when encountering abrasive, sharp and /or tight spaces.
  • dental floss includes a broad array of filament type interdental devices, used to clean and remove plaque and tartar, material alba, food debris, etc. from interproximal and subgingival areas of the gums and/or to treat these areas with substances released during flossing.
  • Typical dental flosses for the purposes of the present invention include: (a) traditional waxed dental flosses such as described in U.S. Patent Nos.
  • the strength or tenacity of the polymer filaments and multipolymer multifilaments useful in the dental flosses of this invention can be defined in terms of tensile strength, i.e. the maximum tensile stress, expressed in force per unit cross sectional area of the multifilament, which the multifilament will withstand without breaking. See for example The American Society for Testing and Materials 1970 Annual Book of ASTM Standards, Part 24 at p. 41.
  • the strength of the polymer filaments and multipolymer multifilaments useful in the dental flosses of the present invention is dependent upon the strength of the extruded polymer and ⁇ rultipolymer, the degree of crystallinity of the multipolymers, the rate and temperature of the draw and the rate and temperature of self-activation of the multipolymer filaments.
  • the strength of homopolymer filaments which are useful in the improved dental flosses of the invention exhibit high-tenacity to elongation ratios, i.e. ratios from between 0.5:6 an 0.8:8.
  • the high-tenacity polypropylene filaments exhibit tensile strengths of 6g/ denier and above with elongations of about 40% or greater.
  • Preferred polypropylene filaments useful in the shred resistant dental flosses of this invention are spun from low melt flow index (MFI) resins which are generally considered non-spinning grade resins. .Spun at suitable temperatures using spin plates with low L/D (length/ diameter) ratios to reduce shear, these high molecular weight, low melt flow viscosity, generally narrow molecular weight range polypropylene polymers unexpectedly produce high tenacity yarns with high elongation properties.
  • MFI melt flow index
  • spin plates are typically constructed with low L/D ratios in an attempt to minimize shear and optimize polymer molecular weight during spinning.
  • Low denier/filament dental flosses are preferred for ease of floss fit between teeth and improved gentleness. This requires drawing the spun filaments under carefully controlled conditions with long residence time in heat controlled zones in order to promote polymer molecule orientation with corresponding high tenacity.
  • the high-tenacity polypropylene filaments of the present invention exhibit a distinct elongation advantage which allows the filaments to "give" rather than be cut when encountering abrasive, sharp or narrow spaces.
  • This combination of high tenacity and high elongation results in multifilament dental flosses with improved resistance to shredding which is further optimized by loading the floss with lubricants and the like such as MICRODENT®.
  • the improved elongation properties of the filaments of the present invention contributes to a perception of "gentleness" when these stretchable filaments are constructed into loaded dental flosses. Additionally, such improved elongation properties allow these filaments to be texturized with minimum loss of tenacity thereby allowing further improvements in gentleness of such high-tenacity loaded dental flosses. These improvements in elongation are particularly relevant to non round flosses of the present invention such as trilobal filament flosses.
  • the high-elongation/high-tenacity filaments of the present invention are particularly useful in the multicomponent flosses of the invention to impart improved strength, resistance to shredding and elongation.
  • the tensile strength of the finished loaded dental floss should be from about 5 to 25 lbs., although higher tensile strengths are acceptable.
  • the tensile strength of the floss is preferably from about 7 to 15 lbs. If a dental floss with a tensile strength of less than about 5 lbs. is prepared, it will break and /or fray easily and not be satisfactory for use as a floss. Dental floss with tensile strengths greater than 25 lbs. are satisfactory but offer few additional advantages and are less economical to produce.
  • the thickness of the dental floss should be from about 300 to 2,000 denier, preferably from about 500 to 1,500 denier.
  • a preferred embodiment of the present invention comprises a loaded dental floss formed of polymer multifilament or multipolymer multifilaments suitable for use as a dental floss.
  • the plurality of individual filaments are formed together to give a larger thread of a sufficiently small diameter to permit working into the interproximal areas between the teeth.
  • the filaments of yarn can be colored utilizing any compatible and accepted color dye such as FD&C Blue No. 1 , FD&C Yellow No. 5, FD&C Red No. 40, mixtures thereof and the like.
  • Dental floss can be made without twisting the individual filaments.
  • Dental tape is usually made with little or no filament twist.
  • the twist of the filaments can be from about 0.5 to 3.0 turns per inch, with a preferred twist of about 1.5 to 2.0 turns per inch.
  • dental flosses have contained wax and/or flavor with various "active ingredients” such as fluoride as described in several of the traditional waxed flosses cited above.
  • U.S. Patent Nos. 4,91 1 ,927; 5,098,711 ; 5, 165,913 and pending patent application 08/240, 149 described various substances being loaded throughout these flosses at levels from a few milligrams to over 100 milligrams yd., with the release of a substantial quantity of this load occurring during flossing.
  • the "load” described in the foregoing references is incorporated in this disclosure by reference.
  • the load of the present invention can include various chemotherapeutic agents, antiplaque, anticalculus, antigingivitis ingredients including stannous fluoride, chlorhexidene, cetylpyridinium chloride and triclosan.
  • Therapeutics such as tetracycline, metronidazole, antibiotics, coagulants such as described in U.S. Patent No. 5,033,488, as well as anti- plaque substances such as MICRODENT® and ULTRAMULSION®, are suitable and useful in the present invention.
  • Coagulants suitable for inclusion in the load in the flosses of the present invention include: K vitamins ( 1-4), calcium ions in the form of a soluble (water) calcium salt and blood factors that initiate the coagulation cascade.
  • Additional coagulants useful in the flosses of the present invention include: aminocaproic acid, tranexamic acid, adrenaline, alum, noradrenaline, iron salts, zinc salts, and calcium alginate. See also Martindale (The Extra Pharmacopeia), the Pharmaceutical Press, London Ed. 5. EF Reynolds.
  • actives which may be loaded or otherwise incorporated into the flosses of this invention which promote oral hygiene, include fluoride, quaternary salts, hexachlorophene, soluble pyrophosphate salts with hydrolysis inhibiting agent(s), as well as compounds that assist in wound healing such as allantoin, zinc sulphate and similar astringents.
  • the load of this invention can optionally contain at least one humectant selected from the group consisting of glycerine, xylitol, sorbitol, hydrogenated glucose syrup and propylene glycol.
  • humectants are utilized in the proportion of about 0.1 percent to about 25 percent by weight based upon the total weight of the composition.
  • the humectant is utilized in an amount of about 3 to 15 percent by weight, see Examples below.
  • Flavors, colorants, sweeteners, non-cariogenic sugars and humectants are also used to impart optimum cosmetic characteristics to the compositions of the present invention.
  • the flavoring component is present as an oil, emulsified into the composition by the surfactant component.
  • the conventional flavoring components are exemplified by the following materials, menthol, anise oil, benzaldehyde, bitter almond oil, camphor, cedar leaf oil, cinnamic aldehyde, cinnamon oil, citronella oil, clove oil, eucalyptol, heliotropin, lavender oil, mustard oil, peppermint oil, phenyl salicylate, pine oil, pine needle oil, rosemary oil, sassafras oil, spearmint oil, thyme oil, thymol, wintergreen oil, lemon and orange oils, vanillin, spice extracts and other flavoring oils generally regarded as safe (GRAS) by health authorities.
  • GRAS safe
  • Additional adjuvants can be added to provide color, flavor, or sweetening effects, as desired.
  • suitable sweetening agents include sorbitol, sodium cyclamate, saccharine, commercial materials such as NutraSweet brand of aspartame and xylitol.
  • Citric acid or acetic acid is often utilized as a flavor additive. All types of flavoring materials are generally used in amounts of about 1.0 to about 20 percent by weight, preferably about 2.0 percent to about 15 percent by weight.
  • a buffering ingredient may also be added to the load of this invention in order to prevent natural degradation of the flavoring components or therapeutically active ingredients.
  • the pH of these compositions is adjusted from about 3.5 to about 8, depending on the chemistry of the active ingredient most requiring protection.
  • the buffering ingredients such as alkali metal salt of a weak organic acid, for instance, sodium benzoate, sodium citrate, sodium phosphate, sodium bicarbonate or potassium tartrate is generally added in an amount of about 0.1 to about 1.0 percent by weight.
  • Other buffering agents such as weak organic acids or salts of weak bases and strong acids such as boric acid, citric acid, ammonium chloride, etc. can also be used in similar concentrations.
  • Stabilizers are often added to the compositions for additional control, such as:
  • chemical oxidative control substances such as ethylene- diaminetetraacetic acid, BHA, BHT, propyl gallate and similar substances approved for ingestion. Concentration levels of these stabilizers comply with industry and regulatory standards.
  • compositions of this invention are loaded throughout the floss in concentrations ranging from about 10% to over 100% by weight of the floss. This translates to from between about 10 mg and about 100+ mg per yard of floss. These loaded substances are then controflably released into the oral cavity during flossing at from between about 10 and about 80% of the load.
  • a floss containing 40 mg/yd of load will generally release between about 20 and about 32 mg of load during flossing. Note, the rate of release of these loaded actives is easily controlled by varying the floss construction, the process of loading, and the composition of the loaded material, providing additional novelty and utility to the present invention.
  • homopolymers means one polymer, such as polypropylene, preferably made from low MFI resins.
  • multipolymers means two or more synthetic polymers made from relatively low molecular weight compounds (monomers) generally by addition or condensation, polymerization, methods.
  • Preferred multipolymers include various nylon polymers with high RV values.
  • suitable, preferred multipolymers include: polyamides, polyesters, polyethers, polycaprolactones, polyolefins, polyester amides, etc. such as described in U.S. Patent Nos. 2,071 ,250; 2,071 ,253; 2, 130,523; 2, 130,948; 2, 190,770; 2,465,319; 3,399, 108; 3,418, 1 19; 3,526,802; 3,803,453; 4,019,31 1 ; 4,202,854; 4,244,907 and 4,271 ,233, wherein each of these polymers includes two or more polymers of the same type or different types with different molecular weights and/ or different melt viscosities, wherein at least one of said polymers is fully oriented and said polymers exhibit differential linear behavior when spun into filaments.
  • Homologous polymers for example, a combination of the same kind of polyesters having different intrinsic viscosities, a combination of the same kind of polyolefins having different melt indexes; a combination of different kinds of homopolyamides, such as, polycapramide/polyhexamethylene adipamide, polycapramide/polyhexamethylene sebacamide, polyhexamethylene/adipamide polyamino-undecanoic acid; a combination of homopolyester and homopolyester ether, such as polyethylene terephthalate/polyethylene- paraoxybenzoate; a combination of homopolyolefins, such as polyethylene having a high density/ polyethylene having a low density, polyethylene having a high density/ isocactic polypropylene; a combination of homologous homopolymer and copolymer, such as polycapramide/polycapramide- polyhexamethylene isophthalamide copolymer, polyhexamethylene- a
  • thermoplastic synthetic linear polymers such as polyurethane, polyoxymethylene, polypivalolactone and polychlorotrifluoroethylene can be used properly by combining with the above mentioned various kinds of polymers.
  • copolymers, graft polymers and mixtures thereof or the above described polymers added with viscosity stabilizer, dye-stuff, pigment, plasticizer and other organic or inorganic additives can, of course, be used.
  • Multipolymers suitable for the purposes of the present invention in addition to hexamethylene adipamide include other polyamides, including copolymers, whether prepared by the reaction of diamines and dibasic acids, and their derivatives, amino acids, or other compounds (e.g., caprolactam, which yields a polyamide under proper reaction conditions).
  • This invention is applicable similarly to other fiber-forming polymers that may contain amine groups, including polyureas derived, for example, from a diisocyanate and a diamine, as shown by Rinke et al. in U.S. Patent No. 2,51 1 ,544; polyurethanes; polythioureas; polythioamides; polysulfonamides, as taught by Jones et al.
  • Copolyesteramides also can be used.
  • the amine content of the core polymer may arise from a blend of a polymer containing amine groups and another polymer with few or no amine groups as, for example, a blend of a polyamide and a polyester, such as polyethyleneterephthalate.
  • an N-amino-alkyl morpholine can be used as a viscosity stabilizer in the preparation of polyamides, as taught by Watson in U.S. Patent No. 2,585, 199, in order to obtain polymers with tertiary amine end-groups, having increased dyability with acid dyes.
  • Other means of forming amine end- groups by polymerization or after-treatment of a polymer will be obvious to those skilled in the art.
  • Polyamides having an intrinsic viscosity of at least about 0.4 can be converted into self-supporting filaments by extrusion of the molten polymer through fine orifices ("melt-spinning"). Tenacity and other properties of the product being enhanced subsequently by cold-drawing it to increased length. Sometimes an excess of one or the other of the polymerizing reactants is employed in the polymerization of diamines and dicarboxylic acids or their amide-forming derivatives, or some other "viscosity stabilizer" is used with these reactants or in the polymerization of aminocarboxylic acids, with the objective of terminating growth of the polymer molecules.
  • Residual unreacted amine and carboxyl end-groups are determinable by microtitration methods, as described by Waltz and Taylor in Analytical Chemistry, 19, 448 ( 1947); neutral (e.g., alkyl) and end-group content can be calculated from the amount of stabilizer (e.g., acetic acid) reacted with the polymer or its polymerizable components.
  • stabilizer e.g., acetic acid
  • polymers having fewer than 50 amine equivalents per 10" grams of polymer is considered essentially free of amine end-groups because at that content melt-spinning of the polymer is commercially feasible, despite degradation (attributal to amine content) that occurs upon exposure of the polymer to the atmosphere. Spinning of polymer containing more than this amount has not been commercial, and a content of 10 ⁇ equivalents of amine end-groups per 10" grams of polymer is termed high in degradable amine. Although the usual terminal amine group is primary, secondary and tertiary amine groups are included also. Filaments of high average amine end-group content are dyable to deep fast colors with acid dyes.
  • Polyhexamethylene adipamide (nylon 66) and polycaprolactam (nylon 6) are preferred polyamides for use in this invention.
  • the other suitable polyamides include those formed by the polycondensation of one or more diamines of the formula NH2"(-CH2-)- n NH with one or more diacids of the formula HOOC-(-CH 2 -)- COOH and/or HOOC-Ar -COOH, where n is an integer from 4 to 12 and Ar is:
  • polyamides include nylon 6TA/6IA, nylon 66/6TA, nylon 66/6TA/6IA and the like.
  • the polyamides from which the multifilaments are produced may contain additives or modifiers such as those commonly employed in textile and carpet yarns.
  • orientation of the homopolyamides' filaments should take place to a substantial degree by the end of the filament drawing step in order to avoid substantial shrinkage in the subsequent self crimping step.
  • another polymer as a melt blend is acceptable including other homopolyamides such as: polyheptanamide, polyundecanamide, polyoctamethylene oxamide, polytetramethylene suberamide, polyhexamethylene suberamide, polyxylylene azelamide and poly-2-methyl-hexamethylene terephthalamide.
  • Crystallizable isomorphic copolymers such as the copolymer of polyhexamethylene adipamide and polyhexamethylene terephthalamide may be used in place of the homopolyamide component.
  • Acrylonitrile multipolymers are also viable for the dental flosses of the present invention such as those described in U.S. Patent Nos. 2,837,500; 2,988,420; 3,038,236; 3,038,240; 3,039,237; 3,039,524; 3,092,892; 3,864,447; 4,284,598 and 4,309,475.
  • Suitable comonomers useful in preparing the desired acrylonitrile polymers may be selected from, but are not limited to, for example, methyl acrylate; ethyl acrylate; butyl acrylate; methoxymethylacrylate; beta-chloro- ethyl acrylate and the corresponding esters of methacrylic and chloracrylic acids; vinyl chloride; vinyl fluoride; vinyl bromide; vinylidene chloride; vinylidene bromide; allyl chloride; 1 -chloro- 1 -bromo-ethylene; methacrylonitrile; methyl vinyl ketone; vinyl formate; vinyl acetate; vinyl propionate; vinyl stearate; vinyl benzoate; N-vinyl phthalimide; N-vinyl succinimide; methylene malonic esters; itaconic esters; diethyl citraconate; diethyl mesaconate; styrene; dibromostyrene; vinyl
  • Synthetic addition polymers and linear polyesters suitable for the multipolymers of the present invention include, in addition to polyethyleneterephthalate, the corresponding copolymers containing sebacic acid, adipic acid, isophthalic acid as well as the polyesters containing recurring units derived from glycols with more than two carbons in the chain, e.g., diethylene glycol, butylene glycol, decamethylene glycol and trans-bis- 1 ,4- (hydroxymethyl)-cyclohexane.
  • Polymers derived from acrylonitrile and particularly those containing 80% or more of acrylonitrile combined in the polymer molecule are particularly useful in the practice of this invention.
  • Polymers containing 80% or more of acrylonitrile combined in the polymer molecule are especially preferred in the practice of this invention because of the chemical inertness, general water insensitivity, high modulus, high tensile strength and especially the pleasing handle, etc. that are characteristics of filament formed from these polymers.
  • both components will be preferably made of similar polymers (e.g., both acrylonitrile polymers) in order that optimum adhesion be obtained between the two components.
  • the necessary differential reversible length change between the components is readily obtained by altering the content of ionizable groups in the two polymers.
  • Such ionizable groups are readily obtained by copolymerizing acrylonitrile, for example, with monomers containing acid groups such as carboxylic, sulfonic or phosphonic in either the salt or free-acid form.
  • carboxylic monomers suitable for use in this invention are: acrylic acid, alpha-chloroacrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, citraconic acid, crotonic acid, vinyl benzoic acid and the like.
  • sulfonated polymerizable monomers and their salts are eminently suited for use in this invention: o- and m-styrene sulfonic acid, allyloxyethylsulfonic acid, methallyloxyethylsulfonic acid, allyloxypropanolsulfonic acid, allylthioethylsulfonic acid, allylthiopropanolsulfonic acid, isopropenylbenzenesulfonic acid, vinylbromobenzenesulfonic acid, vinylfluorobenzenesulfonic acid, vinylmethylbenzenesulfonic acid, vinylethylbenzenesulfonic acid, isopropenylisopropylbenz
  • Salts of diacids such as of disulfonic acids may also be used, for example, salts of 3,4- disulfobutene(l), vinylbenzenedisulfonic acid, vmylsulfophenylmethanesulfonic acid, allylidinesulfonic acid, etc.
  • Sulfonic acid groups can be introduced as end groups in polyesters by using metallic salts of sulfomonocarboxylic esters such as sodium p- carbomethoxy benzene sulfonate and dipotassium 5-carbomethoxy benzene- 1,3-disulfonate and sulfomonohydric alcohols, such as sodium-3-hydroxy propane- 1 -sulfonate as chain terminators.
  • sulfomonocarboxylic esters such as sodium p- carbomethoxy benzene sulfonate and dipotassium 5-carbomethoxy benzene- 1,3-disulfonate and sulfomonohydric alcohols, such as sodium-3-hydroxy propane- 1 -sulfonate as chain terminators.
  • Sulfonate acid groups can be placed in mid-chain units of a polyester by using as a monomer, a dicarboxylic acid compound or its derivative containing a metallic salt of a sulfonate, such as sodium l ,8-di(carbomethoxy)naphthalene 3-sulfonate, potassium 2,5-di(carbomethoxy) benzene sulfonate, and sodium 4,4-dicarbomethoxy butane- 1 -sulfonate.
  • a sulfonate such as sodium l ,8-di(carbomethoxy)naphthalene 3-sulfonate, potassium 2,5-di(carbomethoxy) benzene sulfonate, and sodium 4,4-dicarbomethoxy butane- 1 -sulfonate.
  • Carboxy groups and their salts in a polyester are also useful in this invention although sulfonic acid is preferred. They can be introduced as end groups by using an excess of a dibasic acid or by degrading a polymer by various means. Chain terminators such as potassium monomethyl terephthalate, potassium hydroxybutyrate, or potassium monomethyl sebacate can be used in ester exchange polymerizations.
  • Carboxy groups can also be introduced to midchain units of a polyester.
  • Metallic salts of carboxylic acids do not enter into an ester exchange polymerization, so that compounds such as potassium dimethyltrimesate, or the potassium salt of desoxycholic acid
  • Mid-chain carboxy groups can also be introduced by melt blending a polyester having predominately hydroxyl end-groups with a dianhydride such as pyromellitic anhydride followed by extrusion of the modified polyester into shaped articles, the holding time at the high temperature of melt-blending and extrusion being of short duration.
  • a dianhydride such as pyromellitic anhydride
  • the required ionizable groups can also be obtained by the use of basic comonomers, such as 2-vinyl pyridine, 2-methyl-5-vinyl pyridine and others of that type as disclosed in U.S. Patent No. 2,491,471 , issued to Arnold, p- dimethylaminomethyl styrene (see U.S. Patent No.
  • vinyl ethers of amino alcohols such as betadiethyl aminoethyl vinyl ether, esters of acrylic and methacrylic acid with amino alcohols such as N,N-diethylaminoethyl acrylate, and polymerizable quaternary ammonium compounds, such as allyltriethylammionium chloride, vinyl pyridinium chloride, allylpyridinium bromide, methallylpyridinium chloride, and others as disclosed in Price, U.S. Patent No.
  • polymers containing basic groups are preferably made by copolymerization, it will be obvious to those skilled in the art that such basic groups can arise from the after- treatment of the polymer or of the fiber, as for example, the reduction-amination of polymers containing ketone groups made from such monomers as methyl vinyl ketone, isopropenyl methyl ketone and the like as disclosed in Ham, U.S. Patent No. 2,740,763 issued April 3, 1956, or by the quaternization of a nitrogen group in a solution of a copolymer such as a copolymer of acrylonitrile and 2-vinyl pyridine as shown in Ham, U.S. Patent No.
  • the required ionizable groups can be incorporated into a polymeric component by the blending of 2 or more polymers.
  • the polymers should preferably be compatible.
  • acidic modifiers in a copolymer are preferred since in general they afford better polymerizations, such as less tendency to form insoluble gels than basic modifiers.
  • Polymers, their spinning solutions and spun fibers containing acid groups (especially sulfonic), are more resistant to discoloration by heat than are the basic modified polymers.
  • Suitable monomers may be found among ethyl methacrylate, butyl methacrylate, octyl methacrylate, methoxyethyl methacrylate, phenyl methacrylate, cyclohexyl methacrylate, dimethyl amidoethyl methacrylate, and the corresponding esters of acrylic acid; acrylamides and methacrylamides or alkyl substitution products thereof; unsattirated ketones such as phenyl vinyl ketone, methyl isopropenyl ketone and the like; vinyl carboxylates such as vinyl formate, vinyl propionate, vinyl butyrate, vinyl thiolacetate, vinyl benzoate, esters of ethylene alpha, betacarboxylic acids such as maleic, fumaric, citraconic, mesaconic, aconic acids, N-vinyl succinimide, vinyl ethers.
  • the multifilament dental flosses of the present invention include:
  • unitary filaments comprised of high-tenacity homopolymers spun from low MFI resins, which filaments exhibit high-elongation properties.
  • unitary filaments comprised of multipolymers having different melt viscosities and different physical properties, wherein the filament is comprised of at least two of such polymers while having a uniform multipolymer composition throughout, and 3. composite filaments wherein each of the multipolymers comprises a distinct component in the filament construction. See Figures 1 to 23. These latter are referred to as:
  • the multipolymers suitable for the dental flosses of the present invention may differ from one another with respect to, for example, their chemical structure. See U.S. Patent Nos. 3,399, 108; 3,418, 1 19 and 4,019,31 1. Or, the polymers may have the same structure and be different because of a difference in relative viscosity. See U.S. Patent No. 3,536,802. Or, because one polymer contains an additive that changes its morphology and the other polymer does not undergo such change. See U.S. Patent No. 4,271 ,233.
  • a single polymer of two distinct molecular weights is extruded to form a multipolymer filament comprised of this two molecular weight polymer mixture.
  • This latter is not considered a composite filament, rather a "unitary filament" construction for the purposes of the present invention.
  • Composite molecularly-oriented multipolymer filaments suitable for this invention are described in Chemical Processing of Fibers and Fabrics, Fundamentals and Preparation, Part A, Handbook of Fiber Science and Technology, Vol. 1 , pp. 1-33, Marcel Dekker Inc. , New York, NY and the references cited therein at pp. 30-33, all of which is incorporated herein by reference.
  • Particularly preferred multipolymer filaments contain at least two polymers wherein the polymer components have different linear behavior properties suitable for supporting self-crimping such as described in U.S. Patent No. 5, 162,074 and the 86 patents cited therein which are included herein by reference. See also U.S. Patent Nos. 2,439,814; 3,038,237; 3,039,524; 3,092,892; 3,094, 174; 3,399, 108; 3,536,802; 4,019,31 1 ; 4,244,907; 4,309,475; 4,601,949 and 5, 130, 195.
  • the multipolymer composition is continuous along the entire fiber length and with at least two of the polymer components permanently joined at an interface form, a side-by-side arrangement such as described in U.S. Patent Nos. 3,038,237; 3,038,239; 4,019,31 1 ; 4,309,475 and 4,601 ,949. See also Figures 1 to 23 of the drawings.
  • the self-activating, multipolymer, multifilaments suitable for use in the dental flosses of the present invention are generally referred to as self- crimping, since their "bi-metallic" type of behavior causes them to curl when exposed to heat and/or moisture, resulting in a more fibrous mass. Sheath- core composites will behave similar to side-by-side composites although their curling forces are not as great.
  • the differential linear behavior of the multipolymer filaments of the dental flosses of the present invention is attributed to the differential polymer orientation obtained by stretching a bicomponent filament comprised of two different polymers to beyond the classic limit of one of the components.
  • the self-activating, self-crimping, multipolymer, multifilament dental flosses of the present invention can be produced by spinning two or more polymers differing from one another in their linear behavior in the form of individual filaments and combining them to form a yarn or spinning them in the form of bicomponent or so-called composite filaments or fibers. Since, in both cases, the combined components form a homogeneous length of filament, the "longer" component is forced by the different linear behavior of the components to wrap itself in turns around the "shorter” component. This provides the resulting yarn with crimp, bulkiness and voluminosity.
  • differential linear behavior is caused by the type of polymers used (for example Austrian Patent No. 228,919, French Patent No. 1 ,416,022 or U.S. Patent No. 3,099, 174), by the viscosity of the spinning melts (British Patent No. 969, 1 10), by additives (British Patent No. 1 , 128,536) and various other treatments (for example British Patent No. 1 ,087,823 or British Patent No. 1,028,873).
  • the differential linear behavior can be produced simply by stretching the yarn or the bicomponent filament (for example as disclosed by Austrian Patent No. 228,919) or by subsequent shrinkage treatment carried out in the absence of tension (British Patent No.
  • the shrinkability of one component should be at least 1% greater than the shrinkability of the other component, that is, said component has at least 1% greater loss of the original length upon shrinkage than the other component.
  • the shrinkability of a component is determined by measuring the shrinkage, upon immersion in boiling water under no tension, of a monocomponent filament made from the component polymer (spun and otherwise processed under substantially the same conditions as the composite filament). If a component cannot be spun into a monocomponent filament, e.g., because its molecular weight is too low, its shrinkability is determined by extrapolation from a graph of the shrinkage characteristics of monocomponent filaments of the same polymer (in different, spinnable molecular weights).
  • spontaneous crimp means crimp observed upon release at ambient temperatures of the tension applied to the filaments during the drawing thereof;
  • latent crimp means crimp which is not observed even upon release of the drawing tension until the filaments are subjected to heat while relaxed;
  • crimp means crimp res ilting from the additive effect of both spontaneous and latent crimps.
  • U.S. Patent No. 3,832,435 describes a melt spinning process for producing partially drawn polyester filaments having latent crimp.
  • Latent crimp is imparted to the filaments after they leave the spinneret by cooling the freshly spun filaments on one side before they completely solidify. The cooling is accomplished by passing the individual filaments over a cooled roll (quench roll) driven at a given peripheral speed. The yarn is passed from the quench roll over a second cooled roll of smaller diameter which is normally stationary or substantially stationary when compared to the speed of the first roll. The filaments are pulled from the second roll at a speed such that they are partially drawn as they leave the second roll. The partially drawn filaments prepared by this process must be further drawn in a separate operation and then heated to develop the latent crimp.
  • the bicomponent dental floss contains bilaminar (or side-by-side) and multilaminar filaments.
  • bilaminar filament is to be understood as meaning a continuous filament comprising two different components which have a surface of contact with one another and with the outside over substantially the whole length of the filaments.
  • multilaminar filament is to be understood as meaning a filament in which at least one of the components is present more than once in its cross-section of over substantially the whole of its length.
  • preferred multipolymer multifilaments for the dental flosses of the present invention can be described as "conjugate filaments".
  • the term "eccentric” as used herein includes both side-by-side and asymmetrical sheath- core structures. By differing in “longitudinal dimensional change characteristics” is meant that when the filament is structurally relaxed, as evidenced by the filament assuming a helical configuration.
  • Conjugate filaments having segments differing from each other in longitudinal dimensional change characteristics can be produced by methods well known in the art, such as, by using polymers having different relative viscosities (e.g., see U.S. Patent No. 3,536,802). There may be a distinct line of demarcation between the segments at their interface or, in some instances, merely a gradient change in composition of the filament across its cross-section.
  • Conjugate filaments and their preparation are well known in the art. Typically, their preparation comprises two completely separate and discontinuous operations; a melt spinning operation in which two different polymers are co-extruded to form as-spun filaments which are wound onto a bobbin to form a package, and a stretching operation in which the as- spun filaments are withdrawn from the bobbin, stretched and then wound onto a second bobbin to once again form a package.
  • Composite filaments prepared for use in accordance with the present invention may be subjected to a drawing (permanent stretching) operation in order to impart to the filaments the desired physical properties as tenacity, elongation and initial modulus.
  • drawing permanent stretching
  • crimped filaments with a reversible crimp have been made from dry-spun filaments withovit a drawing treatment.
  • the conditions applied to drawing the spun multi-component filaments may vary in wide limits. The drawing characteristics of the components can readily be determined from those of mono-component filaments of each of the component polymers of the composite filaments.
  • the drawing can be accomplished in accordance with known principles applicable to the particular polymers of the composite filaments and, in general, the composite filaments are drawn at least 50% (i.e., to 150% of original undrawn length) and preferably about 2-8 times the original lengths.
  • the extent of drawing will, of course, also depend somewhat upon the nature of the particular polymers used in the composite filaments and upon the type of eccentric relationship between those polymers in the composite filament. In considering the extent of drawing, one should take into consideration the amount of draw which may be effected during the spinning of the filaments, and, in fact, the desired amount of drawing may be effected during spinning rather than as a separate drawing step following the windup of the filaments from the spinning operation.
  • the shrinkage of the composite filaments in order to affect crimping may be carried out by the use of any suitable known shrinking agent.
  • Shrinking will ordinarily be carried out by the use of hot aqueous media such as hot or boiling water, steam, or hot highly humid atmosphere, or by the use of hot air or other hot gaseous or liquid media chemically inert to the polymers of the composite filaments.
  • the shrinking temperature is generally in the neighborhood of 100°C, but may be higher or lower, e.g. , 50°C up to about 150°C or even up to a temperature not exceeding the melting point of the lowest melting polymeric component of the fiber.
  • This invention is particularly directed to filaments and yarns (i.e., bundles of filaments) having deniers of the magnitude used in textiles. It is preferred that the filaments of this invention have a denier of 1 to 10 (inclusive) and that the yarns of this invention have a denier of 30 to 8,000 (inclusive) .
  • Distinguishing features of the polymer and multipolymer filament flosses of the present invention include:
  • the physical strength properties of the resultant dental flosses' tenacity are substantially improved over traditional filament flosses.
  • the dental floss filaments of the invention exhibit exceptional elongation properties.
  • the polymers of the multipolymer flosses exhibit differential linear behavior which intrinsically provides the basis for "self-activation” and release during flossing of "loaded” substances from the gentler flosses of this invention.
  • bicomponent fibers Of the multipolymer filament loaded dental flosses of the present invention, those comprised of bicomponent fibers are preferred.
  • the major types of bi-component fibers are:
  • Side-by-side bicomponent fibers are produced as the name implies by spinning two fiber components together so that they are joined longitudinally.
  • the main reason for manufacturing these fibers is to provide helical crimp caused by differences in the expansion or shrinkage of the two components of the fibers.
  • the two fiber components may differ in chemical composition or differ in some property such as molecular weight or degree of crystallization which provides differential expansion or shrinkage.
  • the polymer components may differ in degree of hydrophilicity; for example, both polymers may be copolymers of polyacrylonitrile but contain different amounts of sulfonic acid groups.
  • Some bicomponent fibers develop crimp when they are heated in a relaxed state. Crimp can also be produced in bicomponent side-by- side fibers by a water-quenching or a hot knife-edge treatment.
  • the non-water reversible crimp fibers are visually composed of two nonionic polymers which have different shrinkage properties.
  • the crimp produced in these bicomponent fibers is usually not affected by subsequent wetting.
  • one of the polymers used in the bicomponent fibers with water-reversible crimp in side- by-side fibers contains water-ionizable groups, which allow that polymer component to swell in water.
  • the second polymer may contain no water- ionizable groups or fewer groups so that differential shrinkage can occur.
  • Crimp in this fiber develops when the fiber is dried after hot-wet treatment. This crimp decreases when the fiber is wet; it exhibits "squirming" and the crimp increases upon drying.
  • the spinning equipment used to produce bicomponent fibers can be summarized as follows: Side-by-side bicomponent fibers can be spun by vising a bilateral spinneret. Sheath/core fibers can be prepared with a pipe-in-pipe spinneret. Islands-in-the-sea fibers can be produced by pipe-in-pipe spinnerets with several small pipes in a large pipe or small pipes can be used to inject several core polymer streams into one sheath stream pipe. Islands-in-the-sea fibers can also be made with merged streams spinning vising static or similar mixers. The cross sections of commercial islands-in-the-sea fibers show great variation in the number, shape, size and distribution of the islands.
  • Citrvis type bicomponent fibers can be made by spinneret modifications to allow the bicomponent fibers to be produced in various configurations.
  • the cross sections of commercial citrvis type bicomponent fibers vary considerably. Additional spinning methods for bicomponent fibers can be found in the patents cited previously.
  • the physical properties of the spinning solution are very important in producing suitable bicomponent fibers. Much that is known abovit the rheological properties of dopes for spinning the standard fibers of single polymers is applicable to bicomponent fibers.
  • bicomponent dope compatibility is a very important factor in satisfactorily spinning bicomponent fibers. Individual viscosities, under the conditions of spinning, must be (1) high enough to prevent turbulence after the spinneret and (2) not too dissimilar. If the viscosities are not similar, the flow patterns designed to give the required fiber cross section may not be stable. Also, unstable extrusion may occur leading to flickering filaments and interfilament coalescence in the molten thread line.
  • Viscosities of the individual dopes can be changed by modifying the polymer concentration or molecular weight, although these changes may affect the resulting fiber properties. See Encyclopedia of Textiles, Fibers and Non-woven Fabrics, pp. 152- 172, 1984.
  • Another compatibility problem is adhesion of the individual polymers in the bicomponent fiber.
  • adhesion of the components is satisfactory if similar classes of polymers such as (1) polypropylene (PP) and polyethylene (PE), (2) nylon 6 and nylon 66 and (3) polyethylene terephthalate (PET) and copolymers of polyethylene terephthalate (coPET) are vised together.
  • PP polypropylene
  • PE polyethylene
  • PET polyethylene terephthalate
  • coPET copolymers of polyethylene terephthalate
  • a preferred embodiment of this invention comprises stretching a fresh filament at a stretch ratio greater than 1.0 and less than that which would cause the filament to break, said filament being melt spun at a spinning speed of at least 1829 mpm (meters per minute) and comprising a first longitudinal polyamide segment and a second longitudinal polyamide segment arranged in an eccentric configuration along the length of the filament and differing from each other in dimensional change characteristics, said difference and said stretch ratio being selected to provide a filament having a high-load crimp test value.
  • fresh filament is meant a filament which has not been allowed to age under conditions such that when stretched, no substantial improvement is obtained as compared to characteristics obtained when a filament spun under the same conditions is aged for four (4) hours at 70% relative humidity and at a temperature of 25°C prior to stretching to the same stretch ratio.
  • Fresh filament characteristics can, in some instances, be preserved at least temporarily by collecting and maintaining the filament under anhydrous conditions until it is drawn.
  • the process is a spin-stretch process wherein the stretching of the filament is accomplished inline during melt spinning after the filament is formed and before it is collected.
  • the process is a spin-stretch process comprising co-extruding two molten fiber-forming polyamides having different terminal velocity distances to form a molten stream in which the polyamides are arranged in an eccentric configuration along the length thereof, cooling and solidifying said molten stream in a quenching zone to form a filament (solidified molten stream), attenviating and accelerating said molten stream by withdrawing the filament from the qvienching zone at a speed (i.e., spinning speed) of at least 1829 mpm and then stretching the filament at a stretch ratio greater than 1.0 in-line before it is collected and, preferably, as soon as possible after the molten stream has solidified, the processing conditions and polyamides being selected to provide a filament having a high- load crimp test value.
  • a speed i.e., spinning speed
  • solidified means the molten stream has cooled sufficiently so that it no longer sticks (i.e. fuses) to other filaments or to yarn guide surfaces.
  • Polyamides having "different terminal velocity distances" are characterized in that under the particular spin-stretch conditions employed to form the molten stream the polyamides solidify at different distances from their point of extrvision (i.e. at different distances from the spinneret). The measurement of terminal velocity distances is hereinafter described.
  • the highest high-load crimp test values are attained by selecting highly crystalline homopolyamides, svich as nylon 66 and nylon 6.
  • both homopolyamides are of the same chemical structure, that is, consist of recurring structural units of the same chemical formula.
  • Most preferably each polyamide is Nylon 66.
  • the polyamide conjugate filaments of the present invention have little or not torque (i.e., are substantially torque-free) and, therefore, offer certain advantages over false-twist textured filaments which contain substantial torque (i.e., are torque-lively).
  • the polyamide conjugate filaments of the present invention have a high- load crimp test value.
  • Conjugate filaments of the present invention when subjected to mild conditions, develop adequate crimp having characteristics of the type required for "activation".
  • the process is carried out using the equipment arrangement shown in FIG 25.
  • polyamides A and B of different terminal velocity distances are coextruded at about the same melt temperature at a given speed (extrusion speed) in molten form through circular capillaries 2 and 3, respectively, of spinneret 1.
  • the molten polymers converge below the spinneret face to form molten stream 4 in which polyamides A and B are arranged, as segments, in a side-by-side configuration.
  • the formation of only one filament is shown in FIG 25.
  • the spinneret will normally have provisions for forming a plurality of molten streams; that is, the spinneret will have a plurality of capillary pairs 2 and 3.
  • Molten stream 4 is then qvienched by conventional means to form a filament (i.e., solidified molten stream).
  • the filament is then passed into contact with finish applicator means 5 which applies a liquid finish to the filament. Where there is a plurality of filaments, the filaments are conveniently converged on applicator means 5.
  • the filament is then passed around feed roll 6 with a partial wrap, around stretch roll 7 with a partial wrap, heated by heating means 8 (e.g., a heated tube through which the filament passes) and finally collected by collecting means 9 (e.g., a bobbin on which the filament is wound).
  • Heating means 8 e.g., a heated tube through which the filament passes
  • collecting means 9 e.g., a bobbin on which the filament is wound.
  • Roll 6 is rotated at a peripheral speed of at least 1829 mpm.
  • Roll 7 is rotated at a peripheral speed greater than that of roll 6 but usually no greater than twice that of roll 6.
  • the partial wraps are of an angle sufficient to prevent slippage of the filament on the rolls.
  • the filament When the filament is collected on a bobbin, it should be collected at a speed less than the peripheral speed of roll 7, thereby permitting the filament to relax (retract) before it is collected: otherwise, difficulty is encountered in removing the bobbin from the chuck on which it is rotated, particularly, where the filament or yarn makes a large number of wraps on the bobbin to form the package. In instances where the filament makes only a small number of wraps on the bobbin, heating of the filament by means 8 may be omitted.
  • the filament collected on the bobbin normally has both original crimp (visible crimp) which manifests itself when the spinning tension is released and latent crimp which can be developed by subsequent treatment of the yarn.
  • the spin- stretch process is carried out under processing conditions and using polyamides so as to provide a filament having a high-load crimp test value.
  • One segment of the conjugate filament is preferably formed from a rapidly crystallizable fiber-forming polyamide and the other from a less rapidly crystallizable fiber-forming polyamide.
  • This difference in crystallizability may be achieved by selecting polyamides having different terminal velocity distances. In general as the difference between their terminal velocity distances increases, the high-load crimp test value increases to or approaches a maximum value and thereafter remains substantially the same. In general, polymers become less crystallizable as the ratio of homopolymeric segments to copolymeric segments increases, for example, the crystallizability of nylon 66>nylon 66-6 (95:5)>nylon 66-6 (90: 10)>nylon 66-6 (85: 15).
  • nylon 66 and nylon 6 are preferred, with nylon 66 giving the highest high-load crimp test values and, therefore, being the preferred polyamide for use in practicing this invention.
  • Nylon copolymers are designated herein in a conventional manner, for example, "nylon 66-6" means the copolymer consisting of randomly occurring 66 units, -NH(CH 2 )6NHCO(CH2) 4 CO-, and 6 units, -NH(CH 2 ) 5 CO-, formed, for example, by copolymerizing hexamethylene diammonium adipate and caprolactam. Mole ratios when given are given in parenthesis following the copolymer designation, for example, (95:5) means a mole ratio of 95:5, respectively.
  • the polyamide used to form one of the segments of the conjugate filament is composed of strvictural repeating units of the same chemical formula as the polyamide used to form the other segment, selection of polyamides differing from each other in relative viscosity values will provide the desired result in this process.
  • nylon 66 polyamides of different relative viscosities (RV) are used to form the segments, the difference in RV between the two nylon 66's should be at least 5, preferably at least 15 and most preferably at least 30 with the RV of the low RV nylon 66 being at least 20 and, preferably, at least 50 and most preferably at least 65.
  • nylon 66 is the preferred polyamide
  • other polyamides may be used in practicing this invention.
  • suitable homopolyamides include nylon 6 and nylon 610.
  • suitable copolyamides include, but are not limited to, those described in U.S. Patent Nos. 3,399, 108; 3,418, 199; 3,558,760 and 3,667,207. Examples of such copolyamides are: nylon 6-66, nylon 66-610: nylon 66-610 61 1-612; nylon 66-612; nylon 66-61, where 61 is:
  • nylon 66-6T where 6T is:
  • nylon 66-6-612 nylon 6-66-610 and nylon 6-612.
  • the spinneret may be designed so that in forming a molten stream each of the molten polymers may be extruded through a separate capillary in such a manner that the molten polymers converge at the spinneret face to form the molten stream or the polymers may be combined and then extruded through a common spinneret capillary to form the molten stream.
  • each of the molten polymers be extruded though a separate capillary and converge below the spinneret face to form the molten stream as shown in FIG 25.
  • the one segment e.g., the low RV segment
  • the other segment e.g., high RV segment
  • the filament may be of any desired cross-section, e.g., circular, trilobal, etc. Filaments having a cross-section resulting from the use of various capillaries are shown in FIGS 1-23.
  • the volume ratio of the polyamide segments can vary over a wide range.
  • the segment system normally will be within the range of 3: 1 to 1 :3.
  • a ratio of 1 : 1 to 1 :3 (high to low relative viscosity) is preferred with the greatest amount of crimp being obtained with a ratio of about 30:70 (high to low relative viscosity).
  • Cooling of the molten streams normally occurs in a quench chamber, commonly referred to as a chimney.
  • the term "quench” as used herein means the cooling of the molten streams sufficiently to provide solidified streams (i.e., filaments). Although cooling of the streams may be assisted by a transverse (or concurrent) stream of flowing air, such a stream is not required in order to provide filaments having high levels of high-load crimp.
  • the filaments are passed from the quenching chamber through what is called a "steam conditioning" tube. Steam is circulated through the tube and comes into intimate contact with the filaments. The purpose of the steam is to facilitate subsequent processing of the filament.
  • conditioning steam should not be used with the process when high-load crimp is desired or, if it is used, it should be used very sparingly.
  • the molten streams are attenviated and accelerated from the spinneret (or, when formed below the spinneret, from their point of formation) by a feed roll which withdraws the quenched streams (filaments) from the quenching zone at a spinning speed greater than the extrusion speed.
  • the extrusion speed is the linear speed at which the molten polyamide is theoretically traveling through the spinneret capillary or capillaries and is calculated from the dimensions of the capillary, the extrusion rate and the density of the polyamide. When more than one capillary is used to form the filament, the linear speeds are averaged and the average speed is used as the extrusion speed.
  • the filaments are stretched in-line before being collected, for example, before being wound onto a bobbin.
  • the filaments will not possess a significant level of high-load crimp even thovigh they may possess a moderate level of low-load crimp. It has been discovered, however, that if the filaments are spun and collected under anhydrous conditions and kept under anhydrous conditions for a limited period of time until subsequently stretched, it is possible to obtain filaments having a high-load crimp level in excess of 8% even though the stretching of the filaments is accomplished in an operation subsequent to and separate from the spinning operation. However, such conditions are usually not practical from the standpoint of commercial operations.
  • the stretching is preferably accomplished using a roll arrangement as shown in FIG 25 wherein roll 6 is a feed roll and roll 7 is a stretch roll.
  • the stretch roll is operated at a peripheral speed higher than the peripheral speed of the feed roll.
  • the filaments are stretched as they leave feed roll 6.
  • the stretch ratio is increased from 1
  • the level of high-load crimp imparted to the filaments increases through a maximum level and thereafter decreases slightly.
  • maximum high- load crimp test values are attained when the filaments are stretched at a ratio greater than 1.0. In many instances, use of a stretch ratio greater than 2.0 can not be used without breaking filaments.
  • the stretching of the filaments may occur downstream of the feel roll; for example, between two pairs of rolls where the first pair is rotating at the same peripheral speed as that of the feed roll and the second pair at a higher peripheral speed.
  • the filaments are stretched as soon as possible after being quenched.
  • PE (HDPE, LDPE AND LLDPE) */PP PP/PET
  • the multipolymer, multifilament dental flosses of the present invention can be loaded with various substances, described above, generally according to the teachings of U.S. Patent Nos. 4,91 1,927; 5,033,488; 5,098,71 1; 5, 165,913 and U.S. Patent Application Serial No. 08/240, 149 filed 10 May 1994.
  • Preferred loadable substances include MICRODENT® and ULTRAMULSION® as described in U.S. Patent Nos. 5,032,387 and 5,538,667, respectively.
  • the loaded, self-active dental flosses of this invention can be "activated" as follows:
  • the floss is wound around middle fingers leaving about 4 inches of floss between them. See FIG 1.
  • the floss is then stretched. When pressure on this 4 inch section is relaxed, the floss expands and is thereby activated.
  • the load is prepared for release. (See FIG 2.) See "Tips on using R ⁇ MICROSTANTM Gentle Dental Floss” ⁇ 1997, IDS.
  • the differential linear behavior of the respective polymers in the multipolymer, multifilament dental floss of this invention is responsible for the floss filament expansion and the release (and/or breaking up) of the load prior to flossing. See also Pending Application Serial No. 08/240, 149.
  • the “activation step” also expands the dental floss dramatically as shown in FIG 2. This expansion feature allows the floss to be stretched during flossing and to fit into tighter spaces without “snapping” onto gum surfaces, while also covering substantially larger tooth surface areas while it is being worked between the teeth and below the gum line.
  • this activation feature of the flosses of the present invention is attributable to the multipolymer construction of the floss. Activation is accomplished when one of these polymers is stretched beyond their limit. See U.S. Patent No. 2,439,814.
  • the gentleness features of the dental flosses of the present invention are influenced by:
  • the gentleness of the dental flosses of the present invention which is far superior to that of traditional dental flosses, may be dvie to a more effective distribution of the flossing pressvire across the multipolymer, multifilament, with their multiple gum contact points as illustrated in FIGS 1 1 to 23 in the drawings.
  • the dental floss multifilaments of the present invention have irregular shaped cross- sections featuring ribs and channels and/ or lobes rather than the smooth round surfaces of commercial flosses.
  • the improved gentleness featv re of preferred dental flosses of the present invention is attributed in part to the non-round cross-section construction of the multipolymer multifilament flosses of the present invention.
  • These gentle filaments are characterized by multiple gum surface contact points/filament.
  • These filaments include multilobal filaments with cross- sections such as shown in FIGS 9, 10, 12, 19, 22 and 23. Pentalobal and hexalobal cross-sections may in fact offer the optimum number of contact points/filament.
  • the gentleness property of the flosses of the present invention is also attributed in part to the lower coefficient of friction characteristic of the self- activated flosses of the present invention with the release of various "lubricantlike" compositions contained in the load.
  • the coefficient of friction of standard commercial flosses i.e. about 0.2 and about 0.08 for PTFE flosses (see U.S. Patent No. 5,033,488) and 0.15 for wax coated PTFE flosses.
  • This lower coefficient of friction of the flosses of the present invention results in less force being reqv ired during flossing to pull these flosses between "contact points", thereby generally avoiding snapping the floss into the gums after the floss passes through the contact point.
  • SV shredding value
  • activation which expands the flosses of this invention and presents distinct multipolymer, multifilament elements to the fraying surface.
  • This can be distinguished from presenting the complete 800+ denier dental floss to said fraying surface.
  • the net is the loaded activatable multipolymer, multifilament dental flosses of the present invention tend to resist fraying more effectively than commercial flosses, particularly when polyethylene or polypropylene polymers are included in the multipolymer, multifilament construction of the flosses of the present invention.
  • Preferred dental flosses of the present invention with high resistance to fraying are the composite multifilament flosses, particularly those of sheath and core construction as shown in FIGS 1-3, 5, 1 1-20, 22 and 23 and side-by- side construction as illustrated in drawing FIGS 2, 6- 10 and 21.
  • a series of multipolymer, self- activatable, composite, multifilament fibers were spun from various polymer chips including: polyamides, polyesters, polyolefins and mixtures thereof.
  • the resulting filaments were generally drawn to dental floss deniers, i.e. from between about 3 and about 6 dpf.
  • Table 4 below illustrates various high-tenacity, high-elongation, polypropylene, loaded dental flosses of the invention.

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Abstract

Fils dentaires constitués d'homopolymères et de mélanges de polymères, multifilaments, chargés, très résistants, qui possèdent des propriétés améliorées d'élongation, de douceur et de résistance à la dilacération, qui sont capables de libérer au moins une partie de leur charge durant leur utilisation, tout en présentant une plus grande douceur pour les gencives, une résistance accrue à la dilacération et une tendance à se détendre plutôt qu'à couper.
PCT/US1998/015356 1997-07-29 1998-07-24 Fil dentaire ameliore Ceased WO1999005986A1 (fr)

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AU85864/98A AU8586498A (en) 1997-07-29 1998-07-24 Improved dental floss

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US5408697P 1997-07-29 1997-07-29
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EP3587630A1 (fr) * 2018-06-26 2020-01-01 Profil Indústria e Comércio de Fios Ltda. Fils trilobés pour application dans les fils dentaires, fil dentaire les comprenant et utilisation de fils trilobés dans la fabrication de fil dentaire
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EP1372523A4 (fr) * 2001-04-05 2006-11-02 Peri Dent Ltd Rubans dentaires monofilaments elastomeres
JP2009160380A (ja) * 2007-11-08 2009-07-23 Mcneil Ppc Inc 多リブ付きデンタルテープ
EP3587630A1 (fr) * 2018-06-26 2020-01-01 Profil Indústria e Comércio de Fios Ltda. Fils trilobés pour application dans les fils dentaires, fil dentaire les comprenant et utilisation de fils trilobés dans la fabrication de fil dentaire
US12065766B2 (en) 2018-06-26 2024-08-20 Profil Industria E Comercio De Fios Ltda Trilobal yarns for application on dental floss, dental floss including the same and use of trilobal yarns in the manufacture of dental floss
CN112535546A (zh) * 2019-09-23 2021-03-23 普罗菲尔工贸有限公司 用于牙线的三叶形纱、包括其的牙线以及三叶形纱在制造牙线中的用途

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