EP1468131A1 - Fibres de bande en polypropylene a faible retrait et procedes de production correspondants - Google Patents

Fibres de bande en polypropylene a faible retrait et procedes de production correspondants

Info

Publication number
EP1468131A1
EP1468131A1 EP02794092A EP02794092A EP1468131A1 EP 1468131 A1 EP1468131 A1 EP 1468131A1 EP 02794092 A EP02794092 A EP 02794092A EP 02794092 A EP02794092 A EP 02794092A EP 1468131 A1 EP1468131 A1 EP 1468131A1
Authority
EP
European Patent Office
Prior art keywords
polypropylene
fibers
article
polypropylene tape
ppm
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02794092A
Other languages
German (de)
English (en)
Inventor
Brian G. Morin
Martin E. Cowan
Kenneth B. Higgins
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Milliken and Co
Original Assignee
Milliken and Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US10/036,604 external-priority patent/US20030134118A1/en
Priority claimed from US10/027,626 external-priority patent/US6998081B2/en
Application filed by Milliken and Co filed Critical Milliken and Co
Publication of EP1468131A1 publication Critical patent/EP1468131A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
    • B32B5/24—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
    • B32B5/26—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it also being fibrous or filamentary
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
    • B32B5/06—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer characterised by a fibrous or filamentary layer mechanically connected, e.g. by needling to another layer, e.g. of fibres, of paper
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N7/00—Flexible sheet materials not otherwise provided for, e.g. textile threads, filaments, yarns or tow, glued on macromolecular material
    • D06N7/0063—Floor covering on textile basis comprising a fibrous top layer being coated at the back with at least one polymer layer, e.g. carpets, rugs, synthetic turf
    • D06N7/0068—Floor covering on textile basis comprising a fibrous top layer being coated at the back with at least one polymer layer, e.g. carpets, rugs, synthetic turf characterised by the primary backing or the fibrous top layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/732—Dimensional properties
    • B32B2307/734—Dimensional stability
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2471/00—Floor coverings
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N2201/00—Chemical constitution of the fibres, threads or yarns
    • D06N2201/02—Synthetic macromolecular fibres
    • D06N2201/0254—Polyolefin fibres
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
    • D06N2201/00—Chemical constitution of the fibres, threads or yarns
    • D06N2201/12—Fibres being in the form of a tape, strip or ribbon

Definitions

  • This invention relates to improvements in preventing heat- and moisture-shrink problems in specific polypropylene tape fibers.
  • Such fibers are basically manufactured through the initial production of polypropylene films or tubes which are then slit into very thin, though flat (and having very high cross sectional aspect ratios) tape fibers thereafter.
  • Such fibers (and thus the initial films and/or tubes) require the presence of certain compounds that quickly and effectively provide rigidity to the target polypropylene tape fiber after heat- setting.
  • these compounds include any structure that nucleates polymer crystals within the target polypropylene after exposure to sufficient heat to melt the initial pelletized polymer and allowing such an oriented polymer to cool.
  • the compounds must nucleate polymer crystals at a higher temperature than the target polypropylene without the nucleating agent during cooling.
  • the "rigidifying" nucleator compounds provide nucleation sites for polypropylene crystal growth.
  • the fiber is then exposed to sufficient heat to grow the crystalline network, thus holding the fiber in a desired position.
  • the preferred "rigidifying" compounds include dibenzylidene sorbitol based compounds, as well as less preferred compounds, such as sodium benzoate, certain sodium and lithium phosphate salts (such as sodium 2,2'- methylene-bis-(4,6-di-tert-butylphenyl)phosphate, otherwise known as NA-11). Specific methods of manufacture of such inventive tape fibers, as well as fabric articles made therefrom, are also encompassed within this invention.
  • Polypropylene tape fibers are utilized in various end-uses, including carpet backings, scrim fabrics, and other fabrics for article reinforcement or dimensional stability purposes.
  • prior applications utilizing standard polypropylene tape fibers have suffered from relatively high shrinkage rates, due primarily to the tape fiber constituents. Heat, moisture, and other environmental factors all contribute to shrinkage possibilities of the tape fibers (and yarns made therefrom), thereby causing a residual effect of shrinkage within the article itself.
  • shrinkage causes highly undesirable wa ⁇ ing or rippling of the final ca ⁇ et product.
  • ca ⁇ ets such as, for example, ca ⁇ et tiles
  • the production methods of forming ca ⁇ ets compensate for expected high shrinkage, thereby resulting in generation of waste materials, or, at least, the loss of relatively expensive amounts of finished ca ⁇ et material due to expected shrinkage of the ca ⁇ et itself, all the result of the shrinkage rates exhibited by the ca ⁇ et backing fibers themselves.
  • such previously manufactured and practiced tape fibers suffer from relatively low tensile strengths.
  • scrim fabrics such as in roofing articles, asphalt reinforcements, and the like
  • shrinkage rate problems are of great importance as well to impart the best overall reinforcement capabilities to the target article and permitting the reinforced article to remain flat.
  • Utilization of much more expensive polyesters and polyamides as constituent fibers has constituted the only alternative methods to such problematic high shrinkage, low tensile strength tape fibers in the past (for both ca ⁇ et backings and scrim applications).
  • polypropylene tape high aspect ratio fibers in various different products (as alluded to above), ranging from apparel to ca ⁇ et backings (as well as ca ⁇ et pile fabrics) to reinforcement fabrics, and so on.
  • Such polypropylene tape fibers exhibit excellent strength characteristics and do not easily degrade or erode when exposed to certain "destructive" chemicals.
  • polypropylene which is relatively inexpensive to manufacture and readily available as a petroleum refinery byproduct, such fibers are not widely utilized in products that are exposed to relatively high temperatures during use, cleaning, and the like.
  • the temperatures required for such a printing step are generated within a heated area, generally, attached to the printing assembly.
  • typical polypropylene tape fiber-containing backings exhibit the aforementioned high shrink rates (e.g., between 2-4% on average).
  • shrinkage unfortunately dominates the dimensional configuration of the printed tufted substrate as well and thus dictates the ultimate dimensions of the overall product prior to attachment of a secondary backing.
  • Such a secondary backing is thus typically cut to a size in relation to the expected size of the tufted component/primary backing article.
  • Nonuniformity in shrinkage, as well as the need to provide differently sized secondary backings to the primary and tufted components thus evince the need for low- shrink polypropylene tape fiber primary ca ⁇ et backings.
  • the reliable selection of a uniform, proper size for the secondary backing would be a clear aid in reducing waste and cost in the manufacture of such ca ⁇ ets.
  • tape fiber As noted above, the main concern with this invention is the production of low-shrink polypropylene tape fibers.
  • tape fiber or fibers is intended to encompass a mono filament fiber exhibiting a cross sectional aspect ratio of at least 2:1, and therefore is a relatively wide and flat fiber.
  • such a tape fiber is generally produced through the initial creation of a film and/or tube of polypropylene from which the desired fibers are then slit (thereby according the desired flat configuration through such a slitting procedure with the slitting means, such as blades, situated at substantially uniform distances from each other during the actual slitting process to provide substantially uniform aspect ratios for the target fibers themselves).
  • a further object of the invention is to provide improved shrink rates without appreciably reducing tensile strengths for polypropylene tape fibers.
  • a further object of the invention is to provide a class of additives that, in a range of concentrations, will provide low shrinkage and/or higher tensile strength levels for such inventive tape fibers (and yarns made therefrom).
  • a further object of the invention is to provide a ca ⁇ et made with a polypropylene backing exhibiting very low heat shrinkage rates.
  • Another object of the invention is to provide a specific method for the production of nucleator-containing polypropylene tape fibers permitting the ultimate production of such low-shrink, high tensile strength, fabrics therewith.
  • Yet another object of the invention is to provide a ca ⁇ et article having a backing comprising a majority of relatively inexpensive polypropylene fibers that exhibits very low shrinkage.
  • this invention encompasses a polypropylene tape fiber comprising at least 10 ppm of a nucleator compound, and exhibiting a tensile strength of at least 3 grams/denier. Also encompassed within this invention is a polypropylene tape fiber comprising at least 10 ppm of a nucleator compound and exhibiting a shrinkage rate after exposure to 150°C hot air of at most 2%, wherein said fiber further exhibits a tensile strength of at least 2.5 grams/denier. Also, this invention encompasses a polypropylene tape fiber exhibiting an x-ray scattering pattern such that the center of the scattering peak is at most 0.4 degrees. Certain yarns and fabric articles comprising such inventive fibers are also encompassed within this invention.
  • a ca ⁇ et article having a top side and a bottom side, wherein a fiber substrate of either tufted fiber, berber fiber, or like type is attached to said top side and a backing comprising a majority of poylpropylene fibers wherein said fibers comprise at least 10 ppm of a nucleator compound, is attached to said bottom side.
  • a ca ⁇ et article exhibits very low shrinkage rates on par with those noted above.
  • this invention also concerns a method of producing such fibers comprising the sequential steps of a) extruding a heated formulation of polypropylene comprising at most about 2000 ppm, preferably at most about 1500 ppm, more preferably at most about 1000 ppm, and most preferably below about 800 ppm, of a nucleator compound into a film or tube; b) immediately quenching the film or tube of step "a" to a temperature which prevents orientation of polypropylene crystals therein; c) slitting said film or tube with cutting means oriented longitudinally to said film or tube thereby to produce individual tape fibers therefrom; d) mechanically drawing said individual tape fibers at a draw ratio of at least 5:1 while exposing said fibers to a temperature of at between 250 and 360°F, preferably between 260 and 330°F, and most preferably between 270 and 300°F , thereby permitting crystal orientation of the polypropylene therein.
  • step "b" will be performed at a temperature of at most 95°C and at least about 5°C, preferably between 5 and 60°C, and most preferably between 10 and 40°C (or as close to room temperature as possible for a liquid through simply allowing the bath to acclimate itself to an environment at a temperature of about 25-30°C).
  • a temperature is needed to ensure that the component polymer (being polypropylene, and possibly other polymeric components, such as polyethylene, and the like, as structural enhancement additives therein that do not appreciably affect the shrinkage characteristics thereof) does not exhibit orientation of crystals.
  • the drawing speed to line speed ratio should exceed at least five times that of the rate of movement of the film to the cutting means.
  • a drawing speed is from 400-700 feet/minute, while the prior speed of the film to the cutting means from about 50-400 feet/minute, with the drawing speed ratio between the two areas being from about 3:1 to about 10:1, and is discussed in greater detail below, as is the preferred method itself.
  • the final heat-setting temperature is necessary to "lock" the polypropylene crystalline structure in place after extruding and drawing.
  • Such a heat-setting step generally lasts for a portion of a second, up to potentially a couple of minutes (i.e., from about 1/10 l of a second, preferably about !/_ of a second, up to about 3 minutes, preferably greater than V ⁇ of a second).
  • the heat- setting temperature must be well in excess of the drawing temperature and must be at least 265°F, more preferably at least about 290°F, and most preferably at least about 300°F (and as high as 380°F).
  • the term "mechanically drawing” is intended to encompass any number of procedures which basically involve placing an extensional force on fibers in order to elongate the polymer therein. Such a procedure may be accomplished with any number of apparatus, including, without limitation, godet rolls, nip rolls, steam cans, hot or cold gaseous jets (air or steam), and other like mechanical means.
  • Such tape yarns may also be produced through extruding individual fibers of high aspect ratio and of a sufficient size, thereby followed by drawing and heatsetting steps in order to attain such low shrinkage rate properties. All shrinkage values discussed as they pertain to the inventive fibers and methods of making thereof correspond to exposure times for each test (hot air and boiling water) of about 5 minutes. The heat-shrinkage at about
  • 150°C in hot air is, as noted above, at most 2.0% for the inventive fiber; preferably, this heat- shrinkage is at most 1%; more preferably at most 0.5%; and most preferably at most 0.1%.
  • the amount of nucleating agent present within the inventive fiber is at least 10 ppm; preferably this amount is at least 50 ppm; and most preferably is at least 100 ppm, up to a preferred maximum (for tensile strength retention) of about 700-800 ppm. Any amount within this range should suffice to provide the desired shrinkage rates after heat-setting of the fiber itself; again, however, excessive amounts (e.g., above about 2,000 ppm) should be avoided, primarily due to costs and tensile strength problems.
  • nucleator compound(s) may be desired, up to about 2000 ppm, for instance, in order to provide faster crystallization rates at such high drawing speeds.
  • any low-shrink ca ⁇ et backing component comprising a majority of polypropylene fibers including such nucleator compound (in the requisite amounts, preferably between 200 and 800 ppm, and most preferably between about 400 and 700 ppm), provides the necessary low shrinkage properties.
  • Fibers and/or yarns of the inventive tape type, as well as polypropylene staple, multifilament, and monofilament, types, are available in such capacity for such improved, low-shrink ca ⁇ et articles.
  • polypropylene is intended to encompass any polymeric composition comprising propylene monomers, either alone or in mixture or copolymer with other randomly selected and oriented polyolefins, dienes, or other monomers (such as ethylene, butylene, and the like). Such a term also encompasses any different configuration and arrangement of the constituent monomers (such as syndiotactic, isotactic, and the like). Thus, the term as applied to fibers is intended to encompass actual long strands, tapes, threads, and the like, of drawn polymer.
  • the polypropylene may be of any standard melt flow (by testing); however, standard fiber grade polypropylene resins possess ranges of Melt Flow Indices between about 2 and 50.
  • fibers Contrary to standard plaques, containers, sheets, and the like (such as taught within U.S. Pat. No. 4,016,118 to Hamada et al., for example), fibers clearly differ in structure since they must exhibit a length that far exceeds its cross-sectional area (such, for example, its diameter for round fibers). Fibers are extruded and drawn; articles are blow- molded or injection molded, to name two alternative production methods. Also, the crystalline mo ⁇ hology of polypropylene within fibers is different than that of standard articles, plaques, sheets, and the like. For instance, the dpf of such polypropylene fibers is at most about 5000; whereas the dpf of these other articles is much greater.
  • Polypropylene articles generally exhibit spherulitic crystals while fibers exhibit elongated, extended crystal structures. Thus, there is a great difference in structure between fibers and polypropylene articles such that any predictions made for spherulitic particles (crystals) of nucleated polypropylene do not provide any basis for determining the effectiveness of such nucleators as additives within polypropylene fibers.
  • nucleators are intended to generally encompass, singularly or in combination, any additive to polypropylene that produces nucleation sites for polypropylene crystals from transition from its molten state to a solid, cooled structure.
  • the polypropylene composition including nucleator compounds
  • the nucleator compound will provide such nucleation sites upon cooling of the polypropylene from its molten state.
  • the only way in which such compounds provide the necessary nucleation sites is if such sites form prior to polypropylene recrystallization itself.
  • any compound that exhibits such a beneficial effect and property is included within this definition.
  • Such nucleator compounds more specifically include dibenzylidene sorbitol types, including, without limitation, dibenzylidene sorbitol (DBS), monomethyldibenzylidene sorbitol, such as l,3:2,4-bis(p-mefhylbenzylidene) sorbitol (p-MDBS), dimethyl dibenzylidene sorbitol, such as l,3:2,4-bis(3,4-dimethylbenzylidene) sorbitol (3,4-DMDBS); other compounds of this type include, again, without limitation, sodium benzoate, NA-11, and the like.
  • DBS dibenzylidene sorbitol
  • p-MDBS monomethyldibenzylidene sorbitol
  • p-MDBS dimethyl dibenzylidene sorbitol
  • 3,4-DMDBS dimethyl dibenzylidene sorbitol
  • other compounds of this type include,
  • the concentration of such nucleating agents (in total) within the target polypropylene fiber is at least 10 ppm, preferably at least 50 ppm.
  • concentration of such nucleating agents (in total) within the target polypropylene fiber is at least 10 ppm, preferably at least 50 ppm.
  • inventive tape fibers must be produced by basically the slitting of extruded films or tubes as outlined above.
  • the shrink- reducing nucleators which perform the best are those which exhibit relatively high solubility within the propylene itself.
  • compounds which are readily soluble such as 1,3:2,4- bis(p-methylbenzylidene) sorbitol provides the lowest shrinkage rate for the desired polypropylene fibers.
  • the DBS derivative compounds are considered the best shrink- reducing nucleators within this invention due to the low crystalline sizes produced by such compounds.
  • Other nucleators, such as NA-11 also provide acceptable low-shrink characteristics to the target polypropylene fiber and thus are considered as potential nucleator compound additives within this invention.
  • the selection criteria required of such nucleator compounds are particle sizes (the lower the better for ease in handling, mixing, and inco ⁇ oration with the target resin), particle dispersability within the target resin (to provide the most effective nucleation properties), and nucleating temperature (e.g., crystallization temperature, determined for resin samples through differential scanning calorimetry analysis of molten nucleated resins), the higher such a temperature, the better.
  • particle sizes the lower the better for ease in handling, mixing, and inco ⁇ oration with the target resin
  • particle dispersability within the target resin to provide the most effective nucleation properties
  • nucleating temperature e.g., crystallization temperature, determined for resin samples through differential scanning calorimetry analysis of molten nucleated resins
  • nucleator compounds that exhibit good solubility in the target molten polypropylene resins (and thus are liquid in nature during that stage in the fiber- production process) provide effective low-shrink characteristics.
  • low substituted DBS compounds including DBS, p-MDBS
  • p- MDBS is preferred, however, any of the above-mentioned nucleators may be utilized within this invention as long as the x-ray scattering measurements are met or the low shrink requirements are achieved through utilization of such compounds. Mixtures of such nucleators may also be used during processing in order to provide such low-shrink properties as well as possible organoleptic improvements, facilitation of processing, or cost.
  • sodium benzoate and NA-11 are well known as nucleating agents for standard polypropylene compositions (such as the aforementioned plaques, containers, films, sheets, and the like) and exhibit excellent recrystallization temperatures and very quick injection molding cycle times for those pu ⁇ oses.
  • the dibenzylidene sorbitol types exhibit the same types of properties as well as excellent clarity within such standard polypropylene forms (plaques, sheets, etc.). For the pu ⁇ oses of this invention, it has been found that the dibenzylidene sorbitol types are preferred as nucleator compounds within the target polypropylene fibers.
  • the shrink rate for each is dominated by the other polypropylene fiber components which do not have the benefit of the nucleating agent.
  • the internal layer being polypropylene without the aid of a nucleating agent additive, dictates the shrink rate for this structure. Furthermore, the patentees do not expose their yarns and fibers to heat-setting procedures in order to permanently configure the crystalline fiber structures of the yarns themselves as low-shrink is not their objective.
  • a higher SAXS long period corresponds to thicker lamellae (which are the plate-like polymer crystals characteristic of semi-crystalline polymers like PP), and which is evidenced by a SAXS peak centered at a lower scattering angle than for comparative unnucleated polypropylene tape fibers.
  • the higher the crystallization temperature of the average crystal the thicker the measured SAXS long period will be.
  • higher SAXS long periods are characteristic of more thermally stable polymeric crystals. Crystals with shorter SAXS long periods will "melt", or relax and recrystalhze into new, thicker crystals, at a lower temperature than those with higher SAXS long periods. Crystals with higher SAXS long periods remain stable to higher temperatures, requiring more heat to destabilize the crystalline structure.
  • the nucleating additive is used in conjunction with a thermal treatment to create fibers exhibiting a center of the SAXS scattering peak of at most 0.4 degrees, which corresponds to thicker lamellae that in turn are very stable and exhibit low shrinkage up to very high temperatures.
  • fibers may also be colored to provide other aesthetic features for the end user.
  • the fibers may also comprise coloring agents, such as, for example, pigments, with fixing agents for lightfastness pu ⁇ oses. For this reason, it is desirable to utilize nucleating agents that do not impart visible color or colors to the target fibers.
  • Other additives may also be present, including antistatic agents, brightening compounds, clarifying agents, antioxidants, antimicrobials (preferably silver-based ion-exchange compounds, such as ALPHASAN® antimicrobials available from Milliken & Company), UN stabilizers, fillers, and the like.
  • any fabrics made from such inventive fibers may be, without limitation, woven, knit, non-woven, in-laid scrim, any combination thereof, and the like.
  • Such fabrics may include fibers other than the inventive polypropylene fibers, including, without limitation, natural fibers, such as cotton, wool, abaca, hemp, ramie, and the like; synthetic fibers, such as polyesters, polyamides, polyaramids, other polyolefms
  • non-low-shrink polypropylene polylactic acids, and the like
  • inorganic fibers such as glass, boron-containing fibers, and the like
  • any blends thereof include non-low-shrink polypropylene, polylactic acids, and the like, inorganic fibers such as glass, boron-containing fibers, and the like; and any blends thereof.
  • FIG. 1 is a schematic of the potentially preferred method of producing low-shrink polypropylene tape fibers.
  • FIG. 2 is a side view of a preferred ca ⁇ et article comprising the inventive fibers within a backing.
  • FIG. 1 depicts the non-limiting preferred procedure followed in producing the inventive low-shrink polypropylene tape fibers.
  • the entire fiber production assembly 10 comprises a mixing manifold 11 for the inco ⁇ oration of molten polymer and additives (such as the aforementioned nucleator compound) which then move into an extruder 12.
  • the extruded polymer is then passed through a metering pump 14 to a die assembly 16, whereupon the film 17 is produced.
  • the film 17 then immediately moves to a quenching bath
  • the drawing speed of the film at this point is dictated by draw rolls and tensioning rolls 20, 22, 24, 26, 28 set at a speed of about 100 feet/minute, preferably, although the speed could be anywhere from about 20 feet/minute to about 200 feet/minute, as long as the initial drawing speed is at most about l/5 th that of the heat-draw speed later in the procedure.
  • the quenched film 19 should not exhibit any appreciable crystal orientation of the polymer therein for further processing.
  • Sanding rolls 30, 31, 32, 33, 34, 35 may be optionally utilized for delustering of the film, if desired.
  • the quenched film 19 then moves into a cutting area 36 with a plurality of fixed knives 38 spaced at any distance apart desired.
  • such knives 38 are spaced a distance determined by the equation of the square root of the draw speed multiplied by the final width of the target fibers (thus, with a draw ratio of 5:1 and a final width of about 3 mm, the blade gap measurements should be about 6.7 mm).
  • a last tensioning roll 52 leads to a spool (not illustrated) for winding of the finished tape fibers 54.
  • an inventive ca ⁇ et article 110 comprising a pile layer 112 comprising tufted fibers 114 tufted through a primary backing layer or tufting substrate comprising the inventive fibers 113 (which could be woven, knit, or non- woven in structure and comprise, as additional fibers, any type of natural fibers, such as cotton, and the like, or synthetic fibers, such as polyamide, and the like; preferably, it is a woven substrate comprising polyamide fibers), and embedded within one or more adhesive layers 115, to which is attached a stabilizing layer 116 (such as a glass mat), and a foam or cushion layer 118 (which may be a fabric, such as a felt, or resin, such as polyvinyl chloride other like compound; preferably, it is polyurethane foam).
  • inventive fibers 113 which could be woven, knit, or non- woven in structure and comprise, as additional fibers, any type of natural fibers, such as cotton, and the like, or synthetic fibers, such as polyamide, and the like;
  • the stabilizing layer 116 is adhered to both the pile layer 112 and a cushion layer 118 to form the desired ca ⁇ et article 110.
  • the inventive primary backing layer 113 comprising such low-shrink polypropylene tape fibers, thus accords the desired low-shrink characteristics to the entire ca ⁇ et article 110 itself.
  • backing layers such as an increase or decrease in the number required
  • types of fibers such as berber, short pile, and the like
  • the ca ⁇ et backing slit film fibers were made on the standard production equipment as described above at a drawing rate of 600 ft/min as follows: A 3.5-3.8 melt flow homopolymer polypropylene resin (P4G32-050, from Huntsman) was blended with an additive concentrate consisting of 10% 4-methyl-DBS and 90% 4 MFI homopolypropylene resin. The blending ratio was changed to adjust the final additive level, as shown in the table below. This mixture, consisting of PP resin and the additive, was extruded on a single screw extruder through a film dye approximately 72 inches wide. The PP flow was adjusted to give a final tape thickness of approximately 0.002 inches.
  • the molten film was quenched in room temperature (about 25°C) water, then transferred by rollers to a battery of knives, which cut it into parallel strips.
  • An approximately 100 ppm concentration of 4-methyl-DBS (aka, p- methyl-DBS) was utilized.
  • the film appeared clear.
  • the film, having been slit into strips, was run across three large rolls all running at 110 ft/min, and then into an oven, approximately 14 ft long and set a temperature of about 330°F, where it was drawn. After leaving the oven, the film strips were transferred to three more rolls, running at speeds of 600, 500 and 500 ft/min, respectively. The first two rolls were heated by hot oil to temperatures of 367°F. These film strips were then traversed to winders where they were individually wound up. These final film strips are thus referred to as the polypropylene tape fibers.
  • tape fibers were made in this manner, adjusting the concentrated additive-PP mixture level to adjust the final additive level.
  • These tape fibers were tested for tensile properties on an MTS Sintech 10/G instrument. They were also tested for shrinkage at 150°C and 155°C in hot air by measuring 5 10" strips, exposing them in an oven for 5 minutes at the aforementioned temperatures, and then removing the strips and measuring the resultant length. Shrinkage was calculated as the average shrinkage of the five strips in relation to the initial lengths thereof.
  • the concentration level of 4-methyl-DBS in the tape fiber was also measured by gas chromatograhy. All of these results are reported in the table below for different nucleator compound levels in different fibers (with the denier measured at
  • the inventive fibers provided excellent low shrinkage rates and very good physical characteristics as well.
  • the long period spacing of several of the above yarns was tested by small angle x-ray scattering (SAXS).
  • SAXS small angle x-ray scattering
  • the small angle x-ray scattering data was collected on a Bruker AXS (Madison, WI) Hi-Star multi-wire detector placed at a distance of 105 cm from the sample in an Anton-Paar vacuum chamber where the chamber was evacuated to a pressure of not more than 100 mTorr.
  • the entire system generator, detector, beampath, sample holder, and software
  • the detector was calibrated per manufacturer recommendation using a sample of silver behenate.
  • a typical data collection was conducted as follows. To prepare the sample, the yarn was wrapped around a 3 mm brass tube with a 2 mm hole drilled in it, and then the tube was placed in an Anton-Paar vacuum sample chamber on the x-ray equipment such that the yarn was exposed to the x-ray beam through the hole. The path length of the x-ray beam through the sample was between 2-3 mm. The sample chamber and beam path was evacuated to less than 100 mTorr and the sample was exposed to the X-ray beam for one hour. Two- dimensional data frames were collected by the detector and unwa ⁇ ed automatically by the system software. The data were smoothed within the system software using a 2-pixel convolution prior to integration.
  • intensity scattering data [I(q)] as a function of scattering angle [20] the data were integrated over ⁇ with the manufacturer's software set to give a 20 range of 0.2° - 2.5° in increments of 0.01° using the method of bin summation.
  • the data was collected upon exposure to such high temperatures for one-half hour, and subtracting the baseline obtained by taking similar data with no tape fiber sample in place.
  • the center of the scattering peak is obtained by integrating a 60 degree wedge above the sample, said wedge centered on the axis that defines the tape fiber direction.
  • the peak is defined in two ways: either as the position of maximum counts near the center of the peak, or as the average of the positions of the left half maximum and the right half maximum of the peaks. The position of the maximum counts and the center are shown in the table below.
  • Yarns of the tape fibers above were then woven into a primary ca ⁇ et backing component for ca ⁇ et tiles.
  • Such tape fibers were made with knives set to cut the tape to different widths, such that yams of both approximately 1100 and 600 denier measurements were made.
  • the 600 denier yams were wa ⁇ ed at 24 yams/inch and a full width of about 168 inches. These wa ⁇ ed yarns were then woven with the wider, 1100 denier yarns on a rapier loom at approximately 12 picks per inch to provide a backing substrate.

Landscapes

  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Artificial Filaments (AREA)
  • Nonwoven Fabrics (AREA)
  • Laminated Bodies (AREA)
  • Carpets (AREA)
  • Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
  • Woven Fabrics (AREA)

Abstract

L'invention concerne des améliorations dans la prévention de problèmes liés au thermoretrait et au retrait provoqué par l'humidité dans des fibres de bande en polypropylène. De telles fibres sont généralement fabriquées par le biais de la production initiale de tubes ou de films en polypropylène qui sont ensuite fendus en fibres de bande très fines, bien que plates (et à rapports d'aspects transversaux très élevés). Ces fibres (et donc les tubes et/ou films d'origine) nécessitent la présence de certains composés qui confèrent rapidement et efficacement une rigidité à la fibre de bande de polypropylène cible, après thermofixation. En général, ces composés possèdent une structure quelconque qui nucléée des cristaux de polymère au sein du polypropylène cible, après une exposition thermique suffisante destinée à faire fondre le polymère aggloméré initial et après avoir laissé une telle matière fondue refroidir. Ces composés doivent nucléer des cristaux polymères à une température plus élevée que celle du polypropylène cible, sans utilisation d'agents de nucléation au cours du refroidissement. Ainsi, les composés nucléants de rigidification engendrent des sites de nucléation pour la croissance de cristaux de polypropylène. Une fois le tube et/ou le film initial fendu, la fibre est exposée à suffisamment de chaleur pour croître à travers le réseau cristallin, ce qui permet de maintenir la fibre à une position souhaitée. Lesdits composés de rigidification préférés renferment des composés à base de sorbitol de dibenzylidène, ainsi que des composés moins préférés, tels que le benzoate de sodium, certains sels de phosphate de sodium et de lithium (tels que sodium 2,2'-méthylène-bis-(4,6-di-tert-butylphényl)phosphate, connu sous la dénomination NA-11). Ladite invention a également trait à des procédés spécifiques de fabrication des fibres de bande susmentionnées, ainsi que des articles en tissu fabriqués à partir de ces fibres.
EP02794092A 2001-12-21 2002-12-02 Fibres de bande en polypropylene a faible retrait et procedes de production correspondants Withdrawn EP1468131A1 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US36604 1987-04-10
US27626 2001-12-21
US10/036,604 US20030134118A1 (en) 2001-12-21 2001-12-21 Low-shrink polypropylene tape fibers
US10/027,626 US6998081B2 (en) 2001-12-21 2001-12-21 Method of producing low-shrink polypropylene tape fibers
PCT/US2002/038322 WO2003057956A1 (fr) 2001-12-21 2002-12-02 Fibres de bande en polypropylene a faible retrait et procedes de production correspondants

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EP1468131A1 true EP1468131A1 (fr) 2004-10-20

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JP (1) JP2005533932A (fr)
CN (1) CN100562613C (fr)
AU (1) AU2002359546A1 (fr)
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WO (1) WO2003057956A1 (fr)

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US9376766B2 (en) 2008-09-02 2016-06-28 Interface, Inc. Low weight-hardback carpet tile
MX2011002083A (es) * 2008-09-02 2011-03-29 Interface Inc Alfombra de bajo peso y mosaico de alfombra y metodos de manufactura, dimensionamiento e instalacion.
US20170037567A1 (en) * 2015-08-05 2017-02-09 Milliken & Company Washable Multi-Component Magnetic Floor Mat

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JPS5122740A (fr) * 1974-08-16 1976-02-23 Kenzo Hamada
JPS5947418A (ja) * 1982-09-07 1984-03-17 Chisso Corp 熱収縮性改良フラツトヤ−ン
US4522857A (en) * 1984-09-24 1985-06-11 Milliken Research Corporation Carpet tile with stabilizing material embedded in adhesive layer
US5366786A (en) * 1992-05-15 1994-11-22 Kimberly-Clark Corporation Garment of durable nonwoven fabric
US6203905B1 (en) * 1995-08-30 2001-03-20 Kimberly-Clark Worldwide, Inc. Crimped conjugate fibers containing a nucleating agent

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See references of WO03057956A1 *

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AU2002359546A1 (en) 2003-07-24
BR0215059A (pt) 2005-11-01
WO2003057956A1 (fr) 2003-07-17
JP2005533932A (ja) 2005-11-10
CN100562613C (zh) 2009-11-25
CN1599813A (zh) 2005-03-23

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