The instant disclosure relates generally to a system, method and apparatus for producing a multi-layer, annular microcapillary product.
Polymers may be formed into films for separating, holding or containing items. Such films (or sheets) may be used, for example, as plastic bags, wraps, coatings, etc.
Polymeric material, e.g. polyolefins, may be formed into polymeric films via an extruder at increased temperatures and pressures. The extruder typically has one or more screws, e.g. single screw extruder or twin screw extruder. The polymer is forced out of the extruder through a die and formed into a film. The die may have a profile (or shape) used to define the shape of the extrudate or film as it exits the die.
Despite research efforts in film forming techniques, there is still a need for producing new microcapillary containing extrudate designs having improved properties. Furthermore, there is still a need for new die designs facilitating the production of microcapillary containing extrudate having improved properties.
In at least one aspect, the disclosure relates to a die assembly for producing a multi-layer, annular microcapillary product. The die assembly is operatively connectable to an extruder having a thermoplastic material passing therethrough. The die assembly includes a shell, an inner manifold, an outer manifold, and a die insert. The inner and outer manifolds are positionable in the shell with matrix flow channels thereabout to receive the thermoplastic material therethrough such that matrix layers of the thermoplastic material are extrudable therefrom. The die insert is disposable between the inner and outer manifolds, and has a distribution manifold with a tip at an end thereof defining microcapillary channels to pass a microcapillary material therethrough whereby microcapillaries are formed between the matrix layers.
In another aspect, the disclosure relates to an extruder assembly for producing a multi-layer, annular microcapillary product. The extruder assembly includes at least one extruder, at least one microcapillary material source, and a die assembly. The extruder includes a housing having an inlet for receiving a thermoplastic material and a driver positionable in the housing to advance the thermoplastic material through the housing. The die assembly is operatively connectable to an extruder to receive the thermoplastic material therethrough. The die assembly includes a shell, an inner manifold, an outer manifold, and a die insert. The inner and outer manifolds are positionable in the shell with matrix flow channels thereabout to receive the thermoplastic material therethrough such that matrix layers of the thermoplastic material are extrudable therefrom. The die insert is disposable between the inner and outer manifolds, and has a distribution manifold with a tip at an end thereof defining microcapillary channels to pass a microcapillary material therethrough whereby microcapillaries are formed between the matrix layers.
In yet another aspect, the disclosure relates to a method for producing a multi-layer, annular microcapillary product. The method involves passing a thermoplastic material through a die assembly. The die assembly includes a shell, an outer manifold and an inner manifold positioned in the shell with matrix flow channels thereabout, and a die insert positioned between the inner and outer manifolds. The die insert includes a distribution manifold with a tip at an end thereof defining microcapillary channels to pass a microcapillary material therethrough whereby microcapillaries are formed between the matrix layers. The method also involves extruding layers of the thermoplastic material through the matrix flow channels while passing a capillary material through the microcapillary channels and between the matrix layers. A multi-layer, annular microcapillary product may be produced by the method.
Finally, in another aspect, the disclosure relates to a multi-layer, annular microcapillary product. The product includes matrix layers of thermoplastic material extrudable into an annular microcapillary product shape. The matrix layers have channels disposed in parallel between the matrix layers of thermoplastic material, and microcapillary material disposable in the channels. In additional aspects, the disclosure relates to a multilayer structure comprising the annular microcapillary product and an article comprising the annular microcapillary product.
For the purpose of illustrating the disclosure, there is shown in the drawings a form that is exemplary; it being understood, however, that this disclosure is not limited to the precise arrangements and instrumentalities shown.
The description that follows includes exemplary apparatus, methods, techniques, and/or instruction sequences that embody techniques of the present subject matter. However, it is understood that the described embodiments may be practiced without these specific details.
The present disclosure relates to die assemblies and extruders for producing multi-layer, annular microcapillary products. The die assembly includes an annular die insert positioned between manifolds and defining material flow channels therebetween for extruding layers of the thermoplastic material. The die insert has a tip having microcapillary flow channels on an outer surface for insertion of microcapillary material in microcapillaries between the layers. The layers of thermoplastic material with microcapillaries therein may be extruded into multi-layer, annular microcapillary products having various configurations, such as multi-layer, annular microcapillary films (e.g., annular microcapillary blown co-extrusion films or air-filled microcapillary films), tubes or tubing (e.g., annular microcapillary co-extrusion pipes), bottles, molded shapes, blow molding parts, etc. The manifolds and die insert may have ends provided with configurations (e.g., asymmetric and symmetric) to define flow of the thermoplastic material through the channels.
Raw materials, e.g. thermoplastic materials, (117) are placed into the material hopper (107) and passed into the housing (105) for blending. The raw materials (117) are heated and blended by rotation of the screw (109) rotationally positioned in the housing (105) of the extruder (100). Motor (121) may be provided to drive the screw (109) or other driver to advance the material. Heat and pressure are applied as schematically depicted from a heat source H and a pressure source P (e.g., the screw (109)), respectively, to the blended material to force the material through the die assembly (111) as indicated by the arrow. The raw materials are melted and conveyed through the extruder (100) and die assembly (111). The molten thermoplastic material (117) passes through die assembly (111), and is formed into the desired shape and cross section (referred to herein as the ‘profile’). The die assembly (111) may be configured to extrude the molten thermoplastic material (117) into thin sheets of the multi-layer polymeric film (110) as is described further herein.
The multi-layer film (210) may also have an elongate profile as shown in
As shown, layers (250a,b) are made of a matrix thermoplastic material and channels (220) have a channel fluid (212) therein. The channel fluid may comprise, for example, various materials, such as air, gas, polymers, etc., as will be described further herein. Each layer (250a,b) of the multi-layer film (210) may be made of various polymers, such as those described further herein. Each layer may be made of the same material or of a different material. While only two layers (250a,b) are depicted, the multi-layer film (210) may have any number of layers of material.
Channels (220) may be positioned between one or more sets of layers (250a,b) to define microcapillaries (252) therein. The channel fluid (212) may be provided in the channels (220). Various numbers of channels (220) may be provided as desired. The multiple layers may also have the same or different profiles (or cross-sections). The characteristics, such as shape of the layers (250a,b) and/or channels (220) of the multi-layer film (210), may be defined by the configuration of the die assembly used to extrude the thermoplastic material as will be described more fully herein.
In a given example, the film (210) may include (a) a matrix (218) comprising a matrix thermoplastic material; (b) at least one or more channels (220) are disposed in parallel in the matrix (218) along the microcapillary film or foam (210), wherein the one or more channels (220) are at least about 250 to about 500 μm apart from each other, and wherein each of the one or more channels (220) has a diameter (or width) in the range of at least about 100 to about 500 μm; and (c) a channel fluid (212) disposed in the one or more channels (220), wherein the channel fluid (212) is different than the matrix thermoplastic material (250a,b); and wherein said microcapillary film or foam (210) has a thickness in the range of from about 10 μm to about 2000 μm.
The microcapillary film or foam (210) may have a thickness in the range of from 10 μm to 2000 μm; for example, microcapillary film or foam (210) may have a thickness in the range of from 10 to 2000 μm; or in the alternative, from 100 to 1000 μm; or in the alternative, from 200 to 800 μm; or in the alternative, from 200 to 600 μm; or in the alternative, from 300 to 1000 μm; or in the alternative, from 300 to 900 μm; or in the alternative, from 300 to 700 μm. The film thickness to microcapillary diameter ratio is in the range of from 2:1 to 400:1.
The microcapillary film or foam (210) may comprise at least 10 percent by volume of the matrix (218), based on the total volume of the microcapillary film or foam (210); for example, the microcapillary film or foam (210) may comprise from 10 to 80 percent by volume of the matrix (218), based on the total volume of the microcapillary film or foam (210); or in the alternative, from 20 to 80 percent by volume of the matrix (218), based on the total volume of the microcapillary film or foam (210); or in the alternative, from 30 to 80 percent by volume of the matrix (218), based on the total volume of the microcapillary film or foam (210).
The microcapillary film or foam (210) may comprise from 20 to 90 percent by volume of voidage, based on the total volume of the microcapillary film or foam (210); for example, the microcapillary film or foam (210) may comprise from 20 to 80 percent by volume of voidage, based on the total volume of the microcapillary film or foam (210); or in the alternative, from 20 to 70 percent by volume of voidage, based on the total volume of the microcapillary film or foam (210); or in the alternative, from 30 to 60 percent by volume of voidage, based on the total volume of the microcapillary film or foam (210).
The microcapillary film or foam (210) may comprise from 50 to 100 percent by volume of the channel fluid (212), based on the total voidage volume, described above; for example, the microcapillary film or foam (210) may comprise from 60 to 100 percent by volume of the channel fluid (212), based on the total voidage volume, described above; or in the alternative, from 70 to 100 percent by volume of the channel fluid (212), based on the total voidage volume, described above; or in the alternative, from 80 to 100 percent by volume of the channel fluid (212), based on the total voidage volume, described above.
The inventive microcapillary film or foam (210) has a first end (214) and a second end (216). At least one or more channels (220) are disposed in parallel in the matrix (218) from the first end (214) to the second end (216). The one or more channels (220) may be, for example, at least about 250 μm apart from each other. The one or more channels (220) have a diameter in the range of at least about 250 μm; for example, from 250 μm to 1990 μm; or in the alternative, from 250 to 990 μm; or in the alternative, from 250 to 890 μm; or in the alternative, from 250 to 790 μm; or in the alternative, from 250 to 690 μm or in the alternative, from 250 to 590 μm. The one or more channels (220) may have a cross sectional shape selected from the group consisting of circular, rectangular, oval, star, diamond, triangular, square, the like, and combinations thereof. The one or more channels (220) may further include one or more seals at the first end (214), the second end (216), therebetween the first point (214) and the second end (216), and/or combinations thereof.
The matrix (218) comprises one or more matrix thermoplastic materials (250a,b). Such matrix thermoplastic materials (250a,b) include, but are not limited to, polyolefin, e.g. polyethylene and polypropylene; polyamide, e.g. nylon 6; polyvinylidene chloride; polyvinylidene fluoride; polycarbonate; polystyrene; polyethylene terephthalate; polyurethane and polyester. The matrix (218) may be reinforced via, for example, glass or carbon fibers and/or any other mineral fillers such talc or calcium carbonate. Exemplary fillers include, but are not limited to, natural calcium carbonates, including chalks, calcites and marbles, synthetic carbonates, salts of magnesium and calcium, dolomites, magnesium carbonate, zinc carbonate, lime, magnesia, barium sulphate, barite, calcium sulphate, silica, magnesium silicates, talc, wollastonite, clays and aluminum silicates, kaolins, mica, oxides or hydroxides of metals or alkaline earths, magnesium hydroxide, iron oxides, zinc oxide, glass or carbon fiber or powder, wood fiber or powder or mixtures of these compounds.
Examples of matrix thermoplastic materials (250a,b) include, but are not limited to, homopolymers and copolymers (including elastomers) of one or more alpha-olefins such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-hexene, 1-octene, 1-decene, and 1-dodecene, as typically represented by polyethylene, polypropylene, poly-1-butene, poly-3-methyl-1-butene, poly-3-methyl-1-pentene, poly-4-methyl-1-pentene, ethylene-propylene copolymer, ethylene-1-butene copolymer, and propylene-1-butene copolymer; copolymers (including elastomers) of an alpha-olefin with a conjugated or non-conjugated diene, as typically represented by ethylene-butadiene copolymer and ethylene-ethylidene norbornene copolymer; and polyolefins (including elastomers) such as copolymers of two or more alpha-olefins with a conjugated or non-conjugated diene, as typically represented by ethylene-propylene-butadiene copolymer, ethylene-propylene-dicyclopentadiene copolymer, ethylene-propylene-1,5-hexadiene copolymer, and ethylene-propylene-ethylidene norbornene copolymer; ethylene-vinyl compound copolymers such as ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-vinyl chloride copolymer, ethylene acrylic acid or ethylene-(meth)acrylic acid copolymers, and ethylene-(meth)acrylate copolymer; styrenic copolymers (including elastomers) such as polystyrene, ABS, acrylonitrile-styrene copolymer, α-methylstyrene-styrene copolymer, styrene vinyl alcohol, styrene acrylates such as styrene methylacrylate, styrene butyl acrylate, styrene butyl methacrylate, and styrene butadienes and crosslinked styrene polymers; and styrene block copolymers (including elastomers) such as styrene-butadiene copolymer and hydrate thereof, and styrene-isoprene-styrene triblock copolymer; polyvinyl compounds such as polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinylidene chloride copolymer, polyvinylidene fluoride, polymethyl acrylate, and polymethyl methacrylate; polyamides such as nylon 6, nylon 6,6, and nylon 12; thermoplastic polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyurethane, polycarbonate, polyphenylene oxide, and the like; and glassy hydrocarbon-based resins, including poly-dicyclopentadiene polymers and related polymers (copolymers, terpolymers); saturated mono-olefins such as vinyl acetate, vinyl propionate, vinyl versatate, and vinyl butyrate and the like; vinyl esters such as esters of monocarboxylic acids, including methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, n-octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, and butyl methacrylate and the like; acrylonitrile, methacrylonitrile, acrylamide, mixtures thereof; resins produced by ring opening metathesis and cross metathesis polymerization and the like. These resins may be used either alone or in combinations of two or more.
In selected embodiments, matrix thermoplastic materials (250a,b) may, for example, comprise one or more polyolefins selected from the group consisting of ethylene-alpha olefin copolymers, propylene-alpha olefin copolymers, and olefin block copolymers. In particular, in select embodiments, the matrix thermoplastic materials (250a,b) may comprise one or more non-polar polyolefins.
In specific embodiments, polyolefins such as polypropylene, polyethylene, copolymers thereof, and blends thereof, as well as ethylene-propylene-diene terpolymers, may be used. In some embodiments, exemplary olefinic polymers include homogeneous polymers; high density polyethylene (HDPE); heterogeneously branched linear low density polyethylene (LLDPE); heterogeneously branched ultra low linear density polyethylene (ULDPE); homogeneously branched, linear ethylene/alpha-olefin copolymers; homogeneously branched, substantially linear ethylene/alpha-olefin polymers; and high pressure, free radical polymerized ethylene polymers and copolymers such as low density polyethylene (LDPE) or ethylene vinyl acetate polymers (EVA).
In one embodiment, the ethylene-alpha olefin copolymer may, for example, be ethylene-butene, ethylene-hexene, or ethylene-octene copolymers or interpolymers. In other particular embodiments, the propylene-alpha olefin copolymer may, for example, be a propylene-ethylene or a propylene-ethylene-butene copolymer or interpolymer.
In certain other embodiments, the matrix thermoplastic materials (250a,b) may, for example, be a semi-crystalline polymer and may have a melting point of less than 110° C. In another embodiment, the melting point may be from 25 to 100° C. In another embodiment, the melting point may be between 40 and 85° C.
In one particular embodiment, the matrix thermoplastic materials (250a,b) include a propylene/α-olefin interpolymer composition comprising a propylene/alpha-olefin copolymer, and optionally one or more polymers, e.g. a random copolymer polypropylene (RCP). In one particular embodiment, the propylene/alpha-olefin copolymer is characterized as having substantially isotactic propylene sequences. “Substantially isotactic propylene sequences” means that the sequences have an isotactic triad (mm) measured by 13C NMR of greater than about 0.85; in the alternative, greater than about 0.90; in another alternative, greater than about 0.92; and in another alternative, greater than about 0.93. Isotactic triads are well-known in the art and are described in, for example, U.S. Pat. No. 5,504,172 and International Publication No. WO 00/01745, which refers to the isotactic sequence in terms of a triad unit in the copolymer molecular chain determined by 13C NMR spectra.
The propylene/alpha-olefin copolymer may have a melt flow rate in the range of from 0.1 to 500 g/10 minutes, measured in accordance with ASTM D-1238 (at 230° C./2.16 Kg). All individual values and subranges from 0.1 to 500 g/10 minutes are included herein and disclosed herein; for example, the melt flow rate can be from a lower limit of 0.1 g/10 minutes, 0.2 g/10 minutes, or 0.5 g/10 minutes to an upper limit of 500 g/10 minutes, 200 g/10 minutes, 100 g/10 minutes, or 25 g/10 minutes. For example, the propylene/alpha-olefin copolymer may have a melt flow rate in the range of from 0.1 to 200 g/10 minutes; or in the alternative, the propylene/alpha-olefin copolymer may have a melt flow rate in the range of from 0.2 to 100 g/10 minutes; or in the alternative, the propylene/alpha-olefin copolymer may have a melt flow rate in the range of from 0.2 to 50 g/10 minutes; or in the alternative, the propylene/alpha-olefin copolymer may have a melt flow rate in the range of from 0.5 to 50 g/10 minutes; or in the alternative, the propylene/alpha-olefin copolymer may have a melt flow rate in the range of from 1 to 50 g/10 minutes; or in the alternative, the propylene/alpha-olefin copolymer may have a melt flow rate in the range of from 1 to 40 g/10 minutes; or in the alternative, the propylene/alpha-olefin copolymer may have a melt flow rate in the range of from 1 to 30 g/10 minutes.
The propylene/alpha-olefin copolymer has a crystallinity in the range of from at least 1 percent by weight (a heat of fusion of at least 2 Joules/gram) to 30 percent by weight (a heat of fusion of less than 50 Joules/gram). All individual values and subranges from 1 percent by weight (a heat of fusion of at least 2 Joules/gram) to 30 percent by weight (a heat of fusion of less than 50 Joules/gram) are included herein and disclosed herein; for example, the crystallinity can be from a lower limit of 1 percent by weight (a heat of fusion of at least 2 Joules/gram), 2.5 percent (a heat of fusion of at least 4 Joules/gram), or 3 percent (a heat of fusion of at least 5 Joules/gram) to an upper limit of 30 percent by weight (a heat of fusion of less than 50 Joules/gram), 24 percent by weight (a heat of fusion of less than 40 Joules/gram), 15 percent by weight (a heat of fusion of less than 24.8 Joules/gram) or 7 percent by weight (a heat of fusion of less than 11 Joules/gram). For example, the propylene/alpha-olefin copolymer may have a crystallinity in the range of from at least 1 percent by weight (a heat of fusion of at least 2 Joules/gram) to 24 percent by weight (a heat of fusion of less than 40 Joules/gram); or in the alternative, the propylene/alpha-olefin copolymer may have a crystallinity in the range of from at least 1 percent by weight (a heat of fusion of at least 2 Joules/gram) to 15 percent by weight (a heat of fusion of less than 24.8 Joules/gram); or in the alternative, the propylene/alpha-olefin copolymer may have a crystallinity in the range of from at least 1 percent by weight (a heat of fusion of at least 2 Joules/gram) to 7 percent by weight (a heat of fusion of less than 11 Joules/gram); or in the alternative, the propylene/alpha-olefin copolymer may have a crystallinity in the range of from at least 1 percent by weight (a heat of fusion of at least 2 Joules/gram) to 5 percent by weight (a heat of fusion of less than 8.3 Joules/gram). The crystallinity is measured via DSC method. The propylene/alpha-olefin copolymer comprises units derived from propylene and polymeric units derived from one or more alpha-olefin comonomers. Exemplary comonomers utilized to manufacture the propylene/alpha-olefin copolymer are C2, and C4 to C10 alpha-olefins; for example, C2, C4, C6 and C8 alpha-olefins.
The propylene/alpha-olefin copolymer comprises from 1 to 40 percent by weight of one or more alpha-olefin comonomers. All individual values and subranges from 1 to 40 weight percent are included herein and disclosed herein; for example, the comonomer content can be from a lower limit of 1 weight percent, 3 weight percent, 4 weight percent, 5 weight percent, 7 weight percent, or 9 weight percent to an upper limit of 40 weight percent, 35 weight percent, 30 weight percent, 27 weight percent, 20 weight percent, 15 weight percent, 12 weight percent, or 9 weight percent. For example, the propylene/alpha-olefin copolymer comprises from 1 to 35 percent by weight of one or more alpha-olefin comonomers; or in the alternative, the propylene/alpha-olefin copolymer comprises from 1 to 30 percent by weight of one or more alpha-olefin comonomers; or in the alternative, the propylene/alpha-olefin copolymer comprises from 3 to 27 percent by weight of one or more alpha-olefin comonomers; or in the alternative, the propylene/alpha-olefin copolymer comprises from 3 to 20 percent by weight of one or more alpha-olefin comonomers; or in the alternative, the propylene/alpha-olefin copolymer comprises from 3 to 15 percent by weight of one or more alpha-olefin comonomers.
The propylene/alpha-olefin copolymer has a molecular weight distribution (MWD), defined as weight average molecular weight divided by number average molecular weight (Mw/Mn) of 3.5 or less; in the alternative 3.0 or less; or in another alternative from 1.8 to 3.0.
Such propylene/alpha-olefin copolymers are further described in details in the U.S. Pat. Nos. 6,960,635 and 6,525,157, incorporated herein by reference. Such propylene/alpha-olefin copolymers are commercially available from The Dow Chemical Company, under the tradename VERSIFY™, or from ExxonMobil Chemical Company, under the tradename VISTAMAXX™.
In one embodiment, the propylene/alpha-olefin copolymers are further characterized as comprising (A) between 60 and less than 100, preferably between 80 and 99 and more preferably between 85 and 99, weight percent units derived from propylene, and (B) between greater than zero and 40, preferably between 1 and 20, more preferably between 4 and 16 and even more preferably between 4 and 15, weight percent units derived from at least one of ethylene and/or a C4-10 α-olefin; and containing an average of at least 0.001, preferably an average of at least 0.005 and more preferably an average of at least 0.01, long chain branches/1000 total carbons. The maximum number of long chain branches in the propylene/alpha-olefin copolymer is not critical, but typically it does not exceed 3 long chain branches/1000 total carbons. The term long chain branch, as used herein with regard to propylene/alpha-olefin copolymers, refers to a chain length of at least one (1) carbon more than a short chain branch, and short chain branch, as used herein with regard to propylene/alpha-olefin copolymers, refers to a chain length of two (2) carbons less than the number of carbons in the comonomer. For example, a propylene/1-octene interpolymer has backbones with long chain branches of at least seven (7) carbons in length, but these backbones also have short chain branches of only six (6) carbons in length. Such propylene/alpha-olefin copolymers are further described in details in the U.S. Provisional Patent Application No. 60/988,999 and International Patent Application No. PCT/US08/082599, each of which is incorporated herein by reference.
In certain other embodiments, the matrix thermoplastic material 11, e.g. propylene/alpha-olefin copolymer, may, for example, be a semi-crystalline polymer and may have a melting point of less than 110° C. In preferred embodiments, the melting point may be from 25 to 100° C. In more preferred embodiments, the melting point may be between 40 and 85° C.
In other selected embodiments, olefin block copolymers, e.g., ethylene multi-block copolymer, such as those described in the International Publication No. WO2005/090427 and U.S. Patent Application Publication No. US 2006/0199930, incorporated herein by reference to the extent describing such olefin block copolymers and the test methods for measuring those properties listed below for such polymers, may be used as the matrix thermoplastic materials (250a,b). Such olefin block copolymer may be an ethylene/α-olefin interpolymer:
(a) having a Mw/Mn from about 1.7 to about 3.5, at least one melting point, Tm, in degrees Celsius, and a density, d, in grams/cubic centimeter, wherein the numerical values of Tm and d corresponding to the relationship:
Tm>−2002.9+4538.5(d)−2422.2(d)2; or
(b) having a Mw/Mn from about 1.7 to about 3.5, and being characterized by a heat of fusion, ΔH in J/g, and a delta quantity, ΔT, in degrees Celsius defined as the temperature difference between the tallest DSC peak and the tallest CRYSTAF peak, wherein the numerical values of ΔT and ΔH having the following relationships:
ΔT>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g,
ΔT≧48° C. for ΔH greater than 130 J/g,
wherein the CRYSTAF peak being determined using at least 5 percent of the cumulative polymer, and if less than 5 percent of the polymer having an identifiable CRYSTAF peak, then the CRYSTAF temperature being 30° C.; or
(c) being characterized by an elastic recovery, Re, in percent at 300 percent strain and 1 cycle measured with a compression-molded film of the ethylene/α-olefin interpolymer, and having a density, d, in grams/cubic centimeter, wherein the numerical values of Re and d satisfying the following relationship when ethylene/α-olefin interpolymer being substantially free of a cross-linked phase:
Re>1481-1629(d); or
(d) having a molecular fraction which elutes between 40° C. and 130° C. when fractionated using TREF, characterized in that the fraction having a molar comonomer content of at least 5 percent higher than that of a comparable random ethylene interpolymer fraction eluting between the same temperatures, wherein said comparable random ethylene interpolymer having the same comonomer(s) and having a melt index, density, and molar comonomer content (based on the whole polymer) within 10 percent of that of the ethylene/α-olefin interpolymer; or
(e) having a storage modulus at 25° C., G′ (25° C.), and a storage modulus at 100° C., G′ (100° C.), wherein the ratio of G′ (25° C.) to G′ (100° C.) being in the range of about 1:1 to about 9:1.
Such olefin block copolymer, e.g. ethylene/α-olefin interpolymer may also:
(a) have a molecular fraction which elutes between 40° C. and 130° C. when fractionated using TREF, characterized in that the fraction having a block index of at least 0.5 and up to about 1 and a molecular weight distribution, Mw/Mn, greater than about 1.3; or
(b) have an average block index greater than zero and up to about 1.0 and a molecular weight distribution, Mw/Mn, greater than about 1.3.
In one embodiment, matrix (218) may further comprise a blowing agent thereby facilitating the formation a foam material. In one embodiment, the matrix may be a foam, for example a closed cell foam. In another embodiment, matrix (218) may further comprise one or more fillers thereby facilitating the formation a microporous matrix, for example, via orientation, e.g. biaxial orientation, or cavitation, e.g. uniaxial or biaxial orientation, or leaching, i.e. dissolving the fillers. Such fillers include, but are not limited to, natural calcium carbonates, including chalks, calcites and marbles, synthetic carbonates, salts of magnesium and calcium, dolomites, magnesium carbonate, zinc carbonate, lime, magnesia, barium sulphate, barite, calcium sulphate, silica, magnesium silicates, talc, wollastonite, clays and aluminum silicates, kaolins, mica, oxides or hydroxides of metals or alkaline earths, magnesium hydroxide, iron oxides, zinc oxide, glass or carbon fiber or powder, wood fiber or powder or mixtures of these compounds.
The one or more channel fluids (212) may include a variety of fluids, such as air or other gases and channel thermoplastic material. The channel thermoplastic materials may be, but are not limited to, polyolefin, e.g. polyethylene and polypropylene; polyamide, e.g. nylon 6; polyvinylidene chloride; polyvinylidene fluoride; polycarbonate; polystyrene; polyethylene terephthalate; polyurethane and polyester. The matrix (218) may be reinforced via, for example, via glass or carbon fibers and/or any other mineral fillers such talc or calcium carbonate. Exemplary fillers include, but are not limited to, natural calcium carbonates, including chalks, calcites and marbles, synthetic carbonates, salts of magnesium and calcium, dolomites, magnesium carbonate, zinc carbonate, lime, magnesia, barium sulphate, barite, calcium sulphate, silica, magnesium silicates, talc, wollastonite, clays and aluminum silicates, kaolins, mica, oxides or hydroxides of metals or alkaline earths, magnesium hydroxide, iron oxides, zinc oxide, glass or carbon fiber or powder, wood fiber or powder or mixtures of these compounds.
Examples of channel fluids (212) include, but are not limited to, homopolymers and copolymers (including elastomers) of one or more alpha-olefins such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-hexene, 1-octene, 1-decene, and 1-dodecene, as typically represented by polyethylene, polypropylene, poly-1-butene, poly-3-methyl-1-butene, poly-3-methyl-1-pentene, poly-4-methyl-1-pentene, ethylene-propylene copolymer, ethylene-1-butene copolymer, and propylene-1-butene copolymer; copolymers (including elastomers) of an alpha-olefin with a conjugated or non-conjugated diene, as typically represented by ethylene-butadiene copolymer and ethylene-ethylidene norbornene copolymer; and polyolefins (including elastomers) such as copolymers of two or more alpha-olefins with a conjugated or non-conjugated diene, as typically represented by ethylene-propylene-butadiene copolymer, ethylene-propylene-dicyclopentadiene copolymer, ethylene-propylene-1,5-hexadiene copolymer, and ethylene-propylene-ethylidene norbornene copolymer; ethylene-vinyl compound copolymers such as ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-vinyl chloride copolymer, ethylene acrylic acid or ethylene-(meth)acrylic acid copolymers, and ethylene-(meth)acrylate copolymer; styrenic copolymers (including elastomers) such as polystyrene, ABS, acrylonitrile-styrene copolymer, α-methylstyrene-styrene copolymer, styrene vinyl alcohol, styrene acrylates such as styrene methylacrylate, styrene butyl acrylate, styrene butyl methacrylate, and styrene butadienes and crosslinked styrene polymers; and styrene block copolymers (including elastomers) such as styrene-butadiene copolymer and hydrate thereof, and styrene-isoprene-styrene triblock copolymer; polyvinyl compounds such as polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinylidene chloride copolymer, polyvinylidene fluoride, polymethyl acrylate, and polymethyl methacrylate; polyamides such as nylon 6, nylon 6,6, and nylon 12; thermoplastic polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyurethane; polycarbonate, polyphenylene oxide, and the like; and glassy hydrocarbon-based resins, including poly-dicyclopentadiene polymers and related polymers (copolymers, terpolymers); saturated mono-olefins such as vinyl acetate, vinyl propionate, vinyl versatate, and vinyl butyrate and the like; vinyl esters such as esters of monocarboxylic acids, including methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, n-octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, and butyl methacrylate and the like; acrylonitrile, methacrylonitrile, acrylamide, mixtures thereof; resins produced by ring opening metathesis and cross metathesis polymerization and the like. These resins may be used either alone or in combinations of two or more.
In selected embodiments, the channel fluid (212) may, for example, comprise one or more polyolefins selected from the group consisting of ethylene-alpha olefin copolymers, propylene-alpha olefin copolymers, and olefin block copolymers. In particular, in select embodiments, the channel fluid (212) may comprise one or more non-polar polyolefins.
In specific embodiments, polyolefins such as polypropylene, polyethylene, copolymers thereof, and blends thereof, as well as ethylene-propylene-diene terpolymers, may be used. In some embodiments, exemplary olefinic polymers include homogeneous polymers; high density polyethylene (HDPE); heterogeneously branched linear low density polyethylene (LLDPE); heterogeneously branched ultra low linear density polyethylene (ULDPE); homogeneously branched, linear ethylene/alpha-olefin copolymers; homogeneously branched, substantially linear ethylene/alpha-olefin polymers; and high pressure, free radical polymerized ethylene polymers and copolymers such as low density polyethylene (LDPE) or ethylene vinyl acetate polymers (EVA).
In one embodiment, the ethylene-alpha olefin copolymer may, for example, be ethylene-butene, ethylene-hexene, or ethylene-octene copolymers or interpolymers. In other particular embodiments, the propylene-alpha olefin copolymer may, for example, be a propylene-ethylene or a propylene-ethylene-butene copolymer or interpolymer.
In certain other embodiments, the channel fluid (212) may, for example, be a semi-crystalline polymer and may have a melting point of less than 110° C. In another embodiment, the melting point may be from 25 to 100° C. In another embodiment, the melting point may be between 40 and 85° C.
In one particular embodiment, the channel fluid (212) is a propylene/α-olefin interpolymer composition comprising a propylene/alpha-olefin copolymer, and optionally one or more polymers, e.g. a random copolymer polypropylene (RCP). In one particular embodiment, the propylene/alpha-olefin copolymer is characterized as having substantially isotactic propylene sequences. “Substantially isotactic propylene sequences” means that the sequences have an isotactic triad (mm) measured by 13C NMR of greater than about 0.85; in the alternative, greater than about 0.90; in another alternative, greater than about 0.92; and in another alternative, greater than about 0.93. Isotactic triads are well-known in the art and are described in, for example, U.S. Pat. No. 5,504,172 and International Publication No. WO 00/01745, which refer to the isotactic sequence in terms of a triad unit in the copolymer molecular chain determined by 13C NMR spectra.
The propylene/alpha-olefin copolymer may have a melt flow rate in the range of from 0.1 to 500 g/10 minutes, measured in accordance with ASTM D-1238 (at 230° C./2.16 Kg). All individual values and subranges from 0.1 to 500 g/10 minutes are included herein and disclosed herein; for example, the melt flow rate can be from a lower limit of 0.1 g/10 minutes, 0.2 g/10 minutes, or 0.5 g/10 minutes to an upper limit of 500 g/10 minutes, 200 g/10 minutes, 100 g/10 minutes, or 25 g/10 minutes. For example, the propylene/alpha-olefin copolymer may have a melt flow rate in the range of from 0.1 to 200 g/10 minutes; or in the alternative, the propylene/alpha-olefin copolymer may have a melt flow rate in the range of from 0.2 to 100 g/10 minutes; or in the alternative, the propylene/alpha-olefin copolymer may have a melt flow rate in the range of from 0.2 to 50 g/10 minutes; or in the alternative, the propylene/alpha-olefin copolymer may have a melt flow rate in the range of from 0.5 to 50 g/10 minutes; or in the alternative, the propylene/alpha-olefin copolymer may have a melt flow rate in the range of from 1 to 50 g/10 minutes; or in the alternative, the propylene/alpha-olefin copolymer may have a melt flow rate in the range of from 1 to 40 g/10 minutes; or in the alternative, the propylene/alpha-olefin copolymer may have a melt flow rate in the range of from 1 to 30 g/10 minutes.
The propylene/alpha-olefin copolymer has a crystallinity in the range of from at least 1 percent by weight (a heat of fusion of at least 2 Joules/gram) to 30 percent by weight (a heat of fusion of less than 50 Joules/gram). All individual values and subranges from 1 percent by weight (a heat of fusion of at least 2 Joules/gram) to 30 percent by weight (a heat of fusion of less than 50 Joules/gram) are included herein and disclosed herein; for example, the crystallinity can be from a lower limit of 1 percent by weight (a heat of fusion of at least 2 Joules/gram), 2.5 percent (a heat of fusion of at least 4 Joules/gram), or 3 percent (a heat of fusion of at least 5 Joules/gram) to an upper limit of 30 percent by weight (a heat of fusion of less than 50 Joules/gram), 24 percent by weight (a heat of fusion of less than 40 Joules/gram), 15 percent by weight (a heat of fusion of less than 24.8 Joules/gram) or 7 percent by weight (a heat of fusion of less than 11 Joules/gram). For example, the propylene/alpha-olefin copolymer may have a crystallinity in the range of from at least 1 percent by weight (a heat of fusion of at least 2 Joules/gram) to 24 percent by weight (a heat of fusion of less than 40 Joules/gram); or in the alternative, the propylene/alpha-olefin copolymer may have a crystallinity in the range of from at least 1 percent by weight (a heat of fusion of at least 2 Joules/gram) to 15 percent by weight (a heat of fusion of less than 24.8 Joules/gram); or in the alternative, the propylene/alpha-olefin copolymer may have a crystallinity in the range of from at least 1 percent by weight (a heat of fusion of at least 2 Joules/gram) to 7 percent by weight (a heat of fusion of less than 11 Joules/gram); or in the alternative, the propylene/alpha-olefin copolymer may have a crystallinity in the range of from at least 1 percent by weight (a heat of fusion of at least 2 Joules/gram) to 5 percent by weight (a heat of fusion of less than 8.3 Joules/gram). The crystallinity is measured via DSC method. The propylene/alpha-olefin copolymer comprises units derived from propylene and polymeric units derived from one or more alpha-olefin comonomers. Exemplary comonomers utilized to manufacture the propylene/alpha-olefin copolymer are C2, and C4 to C10 alpha-olefins; for example, C2, C4, C6 and C8 alpha-olefins.
The propylene/alpha-olefin copolymer comprises from 1 to 40 percent by weight of one or more alpha-olefin comonomers. All individual values and subranges from 1 to 40 weight percent are included herein and disclosed herein; for example, the comonomer content can be from a lower limit of 1 weight percent, 3 weight percent, 4 weight percent, 5 weight percent, 7 weight percent, or 9 weight percent to an upper limit of 40 weight percent, 35 weight percent, 30 weight percent, 27 weight percent, 20 weight percent, 15 weight percent, 12 weight percent, or 9 weight percent. For example, the propylene/alpha-olefin copolymer comprises from 1 to 35 percent by weight of one or more alpha-olefin comonomers; or in the alternative, the propylene/alpha-olefin copolymer comprises from 1 to 30 percent by weight of one or more alpha-olefin comonomers; or in the alternative, the propylene/alpha-olefin copolymer comprises from 3 to 27 percent by weight of one or more alpha-olefin comonomers; or in the alternative, the propylene/alpha-olefin copolymer comprises from 3 to 20 percent by weight of one or more alpha-olefin comonomers; or in the alternative, the propylene/alpha-olefin copolymer comprises from 3 to 15 percent by weight of one or more alpha-olefin comonomers.
The propylene/alpha-olefin copolymer has a molecular weight distribution (MWD), defined as weight average molecular weight divided by number average molecular weight (Mw/Mn) of 3.5 or less; in the alternative 3.0 or less; or in another alternative from 1.8 to 3.0.
Such propylene/alpha-olefin copolymers are further described in details in the U.S. Pat. Nos. 6,960,635 and 6,525,157, incorporated herein by reference. Such propylene/alpha-olefin copolymers are commercially available from The Dow Chemical Company, under the tradename VERSIFY™, or from ExxonMobil Chemical Company, under the tradename VISTAMAXX™.
In one embodiment, the propylene/alpha-olefin copolymers are further characterized as comprising (A) between 60 and less than 100, preferably between 80 and 99 and more preferably between 85 and 99, weight percent units derived from propylene, and (B) between greater than zero and 40, preferably between 1 and 20, more preferably between 4 and 16 and even more preferably between 4 and 15, weight percent units derived from at least one of ethylene and/or a C4-10 α-olefin; and containing an average of at least 0.001, preferably an average of at least 0.005 and more preferably an average of at least 0.01, long chain branches/1000 total carbons. The maximum number of long chain branches in the propylene/alpha-olefin copolymer is not critical, but typically it does not exceed 3 long chain branches/1000 total carbons. The term long chain branch, as used herein with regard to propylene/alpha-olefin copolymers, refers to a chain length of at least one (1) carbon more than a short chain branch, and short chain branch, as used herein with regard to propylene/alpha-olefin copolymers, refers to a chain length of two (2) carbons less than the number of carbons in the comonomer. For example, a propylene/1-octene interpolymer has backbones with long chain branches of at least seven (7) carbons in length, but these backbones also have short chain branches of only six (6) carbons in length. Such propylene/alpha-olefin copolymers are further described in details in the U.S. Provisional Patent Application No. 60/988,999 and International Patent Application No. PCT/US08/082599, each of which is incorporated herein by reference.
In certain other embodiments, the channel fluid 12, e.g. propylene/alpha-olefin copolymer, may, for example, be a semi-crystalline polymer and may have a melting point of less than 110° C. In preferred embodiments, the melting point may be from 25 to 100° C. In more preferred embodiments, the melting point may be between 40 and 85° C.
In other selected embodiments, olefin block copolymers, e.g., ethylene multi-block copolymer, such as those described in the International Publication No. WO2005/090427 and U.S. Patent Application Publication No. US 2006/0199930, incorporated herein by reference to the extent describing such olefin block copolymers and the test methods for measuring those properties listed below for such polymers, may be used as the channel fluid (212). Such olefin block copolymer may be an ethylene/α-olefin interpolymer:
(a) having a Mw/Mn from about 1.7 to about 3.5, at least one melting point, Tm, in degrees Celsius, and a density, d, in grams/cubic centimeter, wherein the numerical values of Tm and d corresponding to the relationship:
Tm>−2002.9+4538.5(d)−2422.2(d)2; or
(b) having a Mw/Mn from about 1.7 to about 3.5, and being characterized by a heat of fusion, ΔH in J/g, and a delta quantity, ΔT, in degrees Celsius defined as the temperature difference between the tallest DSC peak and the tallest CRYSTAF peak, wherein the numerical values of ΔT and ΔH having the following relationships:
ΔT>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g,
ΔT≧48° C. for ΔH greater than 130 J/g,
wherein the CRYSTAF peak being determined using at least 5 percent of the cumulative polymer, and if less than 5 percent of the polymer having an identifiable CRYSTAF peak, then the CRYSTAF temperature being 30° C.; or
(c) being characterized by an elastic recovery, Re, in percent at 300 percent strain and 1 cycle measured with a compression-molded film of the ethylene/α-olefin interpolymer, and having a density, d, in grams/cubic centimeter, wherein the numerical values of Re and d satisfying the following relationship when ethylene/α-olefin interpolymer being substantially free of a cross-linked phase:
Re>1481-1629(d); or
(d) having a molecular fraction which elutes between 40° C. and 130° C. when fractionated using TREF, characterized in that the fraction having a molar comonomer content of at least 5 percent higher than that of a comparable random ethylene interpolymer fraction eluting between the same temperatures, wherein said comparable random ethylene interpolymer having the same comonomer(s) and having a melt index, density, and molar comonomer content (based on the whole polymer) within 10 percent of that of the ethylene/α-olefin interpolymer; or
(e) having a storage modulus at 25° C., G′ (25° C.), and a storage modulus at 100° C., G′ (100° C.), wherein the ratio of G′ (25° C.) to G′ (100° C.) being in the range of about 1:1 to about 9:1.
Such olefin block copolymer, e.g. ethylene/α-olefin interpolymer may also:
(a) have a molecular fraction which elutes between 40° C. and 130° C. when fractionated using TREF, characterized in that the fraction having a block index of at least 0.5 and up to about 1 and a molecular weight distribution, Mw/Mn, greater than about 1.3; or
(b) have an average block index greater than zero and up to about 1.0 and a molecular weight distribution, Mw/Mn, greater than about 1.3.
In one embodiment, the channel fluid (212) may further comprise a blowing agent thereby facilitating the formation of a foam material. In one embodiment, the channel fluid (212) may be formed into a foam, for example a closed cell foam. In another embodiment, the channel fluid (212) may further comprise one or more fillers. Such fillers include, but are not limited to, natural calcium carbonates, including chalks, calcites and marbles, synthetic carbonates, salts of magnesium and calcium, dolomites, magnesium carbonate, zinc carbonate, lime, magnesia, barium sulphate, barite, calcium sulphate, silica, magnesium silicates, talc, wollastonite, clays and aluminum silicates, kaolins, mica, oxides or hydroxides of metals or alkaline earths, magnesium hydroxide, iron oxides, zinc oxide, glass or carbon fiber or powder, wood fiber or powder or mixtures of these compounds.
The films or foams according to the present disclosure may be used in packaging (e.g. reinforced thermoformed parts for trays, tape wrap, buckets, beakers, boxes); thermoformed boat hulls, building panels, seating devices, automotive body parts, fuselage parts, vehicle interior trim, and the like.
One or more inventive films or foams may form one or more layers in a multilayer structure, for example, a laminated multilayer structure or a coextruded multilayer structure. The films or foams may comprise one or more parallel rows of microcapillaries (channels as shown in
Inventive film 1 was prepared according to the following process.
The matrix material comprised linear low density polyethylene (LLDPE), available under the tradename DOWLEX™ 2344 from THE DOW CHEMICAL COMPANY™, having a density of approximately 0.933 g/cm3, according to ASTM-D792 and a melt index (I2) of approximately 0.7 g/10 minutes, according to ISO 1133 at 190° C. and 2.16 kg, formed into microcapillary films via the inventive die having a width of 24 inches (60.96 cm) and 530 nozzles thereby forming a microcapillary film having a target thickness of approximately 2 mm having microcapillaries having a target diameter of about 1 mm, the film has a width in the range of about 20 inches (50.80 cm) and 530 capillaries parallel therein. The channel fluid disposed in microcapillaries was ambient air, approximately 25° C.
Inventive film 2 was prepared according to the following process.
The matrix material comprised of polypropylene homopolymer, available under the tradename Braskem PP H110-02N™ available from BRASKEM AMERICA INC.™, a melt flow rate of approximately 2.0 g/10 min (230 C/2.16 Kg) according to ASTM D1238, formed into microcapillary films via the inventive die having a width of 24 inches (60.96 cm) and 530 nozzles thereby forming a microcapillary film having a target thickness of approximately 2 mm having microcapillaries having a target diameter of about 1 mm, the film has a width in the range of about 20 inches (50.80 cm) and 530 capillaries parallel therein. The channel fluid disposed in microcapillaries was ambient air, approximately 25° C.
The present disclosure may be embodied in other forms without departing from the spirit and the essential attributes thereof, and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the disclosure.
The die insert (353) is provided in the die assembly (311a) to combine the thermoplastic material (117) from the extruders (100a,b,c) into the annular microcapillary product (310a). As shown in
While
The die assemblies (311a,b) may be operatively connected to the extruders (100a,b,c) in a desired orientation, such as a vertical upright position as shown in
As shown in
In the example of
The materials used to form the annular microcapillary products as described herein may be selected for a given application. For example, the material may be a plastic, such as a thermoplastic or thermoset material. The thermoplastic material (117) forming the matrix (418) and/or the microcapillary material (117) may be made of the material used to form the film (210) as previously described. For example, the annular microcapillary products may be made of various materials, such as polyolefins, polyethylene, and polypropylene. In the example of
The annular microcapillary products provided herein may be defined for use in various applications, such as agricultural films, packaging bags, stretch film, laminating films, and barrier films. The annular microcapillary products may also be produced, for example, for lightweighting, reinforcing, toughening, and/or other applications. The annular microcapillary products may be provided with structure and/or materials defined to provide desired mechanical properties, such as tensile strength, flexural strength, and/or toughness in multiple directions (e.g., in transverse and machine directions). The annular die assembly (311a,b) may be used to generate various dimensions (e.g., widths and sizes) of the annular microcapillary products. The dimensions may be defined with or without a given amount of trimming and/or scrap material.
The multi-layer, annular microcapillary product (310a) generated by the die assembly (311a) may be extruded from the annular die assembly (311a) into various shapes. As shown in
Referring back to
As also shown by
As shown in
The die insert (768) is positioned between the outer manifold (762) and the inner manifold (760). The inner manifold (760) has the cone (764) at an end thereof extending through the die insert (768) and the outer manifold (762) and into the shell (758). The die assembly (711) may be provided with connectors, such as by bolts (not shown) to connect portions of the die assembly (711).
Annular matrix channels (774a,b) are defined between the shell (758) and the outer manifold (762) and between the die insert (768) and the inner manifold (760), respectively. The thermoplastic material (117) is depicted passing through the matrix channels (774a,b) as indicated by the arrows to form the layers (450a,b) of the multi-layer, annular microcapillary product (710). The multi-layer, annular microcapillary product (710) may be any of the multi-layer, annular microcapillary products described herein, such as (310a,b).
A microcapillary channel (776) is also defined between the die insert (768) and the outer manifold (762). The microcapillary channel (776) may be coupled to the microcapillary material source for passing the microcapillary material (117,312b) through the die assembly (711) and between the layers (450a,b) to form the microcapillaries (303) therein. The fluid channel (778) extends through the inner manifold (760) and the cone (764). Annular fluid (312a) from fluid source (319a) flows through the fluid channel (778) and into the product (710a,).
The die insert (768) may be positioned concentrically between the inner manifold (760) and the outer manifold (762) to provide uniform distribution of polymer melt flow through the die assembly (711). The die insert (762) may be provided with a distribution channel (781) along an outer surface thereof to facilitate the flow of the microcapillary material (117/312b) therethrough.
The matrix channels (774a,b) and the microcapillary channel (776) converge at convergence (779) and pass through an extrusion outlet (780) such that thermoplastic material flowing through matrix channels (774a,b) forms layers (450a,b) with microcapillary material (117/312b) from microcapillary channel (776) therebetween. The outer manifold (762) and die insert (768) each terminate at an outer nose (777a) and an insert nose (777b), respectively. As shown in
The die assemblies (811, 911) of
The tip (986) is an annular member at a flow end of the tubular manifold (984). An inner surface of the tip (986) is inclined and shaped to receive an end of the cone (764). The tip (986) has a larger outer diameter than the annular microcapillary manifold (984) with an inclined shoulder (990) defined therebetween. An outer surface of the tip (986) has a plurality of linear, parallel microcapillary flow channels (992) therein for the passage of the microcapillary material (117/312b) therethrough. The outer manifold 762 terminates in a sharp edge (938a) along nose (977a) and tip (968) terminates in a sharp edge (983b) along nose (977b).
The annular microcapillary manifold (984) is an annular member extending between the base (982) and the tip (986). The annular microcapillary manifold (984) is supportable between a tubular portion of the inner manifold (760) and the outer manifold (762). The annular microcapillary manifold (984) has a passage (988) therethrough to receive the inner manifold (760).
The distribution channel (781) may have a variety of configurations. As shown in
A small gap may be formed between the die insert (768) and the outer manifold (762) that allows the microcapillary material (117/312b) to leak out of the distribution channel (781) to distribute the microcapillary material (117/312b) uniformly through the die assembly (311). The distribution channel (781) may be in the form of a cavity or channel extending a desired depth into the die insert (768) and/or the outer manifold (760). For example, as shown in
As illustrated in
Referring to the extruder configuration of
As shown in
As shown in
The experimental protocol for making microcapillary films was given as follows: Firstly, the extruder (100a,b) and die assembly (311b) were heated to the operating temperatures with a “soak” time. As the thermoplastic material (e.g., polymer pellets) passed through the extruder screw (109) the thermoplastic material was melted to form a melt (e.g., a polymer melt). The extruder screw (109) fed the melt to a gear pump which maintained a substantially constant flow of melt towards the die assembly (311b). Then, the two polymer melt streams of each extruder (100a,b) passed through the die assembly (311b) and over the microcapillary channels (992a,b) and met with streamlines of microccapillary fluid (e.g., air flow) (312b) from the microcapillary material source (319b). As shown in
As also shown in
As shown in
The final dimension of the multi-layer, annular microcapillary tubings (310a) was determined by sizing and cooling operations downstream of the die assembly (311a). The thickness of the multi-layer, annular microcapillary pipe (310a,a′) was about 30 mils. Thicker samples could be achieved by increasing the extrusion rate or defining the dimensions of the die assembly (311a). Microcapillaries (303) could be also filled with microcapillary fluid (312b) (e.g., air) to achieve voided multi-layer, annular microcapillary tubing (310b) usable in even lightweighting applications.
The method may also involve shaping (1099) the multi-layer film into a multi-layer, annular microcapillary shape, and/or selectively adjusting a profile of the multi-layer film by manipulating one of temperature, flow rate, pressure, material properties and combinations thereof of the thermoplastic material. The multi-layer film may be formed by manipulating flow properties of the thermoplastic material (temperature, flow rate, pressure, etc.) The multi-layer film may be formed by extruding one or more thermoplastic materials through the plurality of film channels.
The method may be performed in any order and repeated as desired. A film may be produced by the method as described.
Filing Document | Filing Date | Country | Kind |
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PCT/US15/27957 | 4/28/2015 | WO | 00 |
Number | Date | Country | |
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61993341 | May 2014 | US |