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NEC Corporation of America-RCSD
NEC Unified Solutions Inc., is a leader in integrated communications solutions for the enterprise. We deliver an innovative suite of products; applications and services that help customers achieve their business goals. This includes a broad range of communications services and...
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Salesforce.com is the enterprise cloud computing company. The company's portfolio of Salesforce CRM applications has revolutionized the ways that companies collaborate and communicate with their customers across sales, marketing and service. The company's Force.com Platform enables...
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Agency Cadre
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Informed Design
We deliver custom websites. They are built to your specifications and adjust appropriately to the device your customer wants to use. Think mobile first and you will exceed your customer's expectations. Because our sites are built from the ground up they offer superior search engine...
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Automated Systems, Inc.
Since 1981, Automated Systems, Inc. has been focusing on providing core banking software solutions to community banks ranging from de novo to $500 M. The Insite Banking System is a complete in-house or hosted core data processing solution utilizing a 100% Microsoft Windows...
7 products
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Actuate Corporation provides a next-generation RIA-ready information platform for both customer and employee-facing applications. The Actuate platform boasts scalability, high-performance, reliability and security. Its proven RIA capabilities and highly collaborative development...
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Parasoft Corporation
Parasoft researches and develops software solutions that help organizations deliver defect-free software efficiently. By integrating development testing, API testing, and service virtualization, we reduce the time, effort, and cost of delivering secure, reliable, and compliant...
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Kronos Inc
At Kronos, we are experts who empower organizations to effectively manage their workforce. Kronos' vision is to be the universal experts in helping organizations effectively manage their workforce. As a global provider of human capital management solutions, we are solely focused on...
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Active Data, Inc.
Active Data Calendar
Active Data Exchange has been providing web-based calendaring, event marketing, event registration, and information broadcasting solutions since 1999. Our flagship product, Active Data Calendar, allows for events to be managed from initial marketing of the event, booking of...
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Converge Systems
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The present invention provides a web containing superfine microfibers. The web contains a blend of a first group of split microfibers which contains a first polymer component and a second group of split microfibers which contains a second polymer component, wherein at least one of the polymer components is hydrophilic. The invention additionally provides a meltblown fiber web having at least two groups of fibers, wherein each group of the fibers has a distinct cross-sectional configuration.
1. A multilayer laminate comprising:
a first layer, said first layer comprising a nonwoven web of continuous, molecularly oriented filaments; and
a second layer fixedly attached to said first layer, said second layer comprising a nonwoven web of meltblown fibers wherein said meltblown fibers comprise a mixture of first meltblown fibers and second meltblown fibers, said first meltblown fibers comprising a first polymer and said second meltblown fibers comprising a second polymer and further wherein said first polymer is immiscible with said second polymer and the first meltblown fibers and the second meltblown fibers are split from common unitary fibers.
2. The multilayer laminate of
3. The multilayer laminate of
4. The multilayer laminate of
5. The multilayer laminate of
6. The multilayer laminate of
7. The multilayer laminate of
8. A sterilization wrap comprising the multilayer laminate of
9. A surgical gown comprising the multilayer laminate of
10. A filter comprising the laminate of
11. A wipe comprising the laminate of
12. The wipe of
13. The multilayer laminate of
forming a nonwoven web of continuous molecularly oriented filaments;
forming a nonwoven web of multicomponent meltblown fibers, said multicomponent meltblown fibers comprising a first component of a first polymer and a second component of a second polymer and wherein said first and second polymers are immiscible with one another;
fixedly attaching said nonwoven web of meltblown fibers to said nonwoven web of molecularly oriented filaments; and
at least partially splitting said multicomponent meltblown fibers and separating said first and second components along a length-wise section of the multicomponent meltblown fibers.
14. The multilayer laminate of
15. The multilayer laminate of
16. The multilayer laminate of
17. The multilayer laminate of
This application is a continuation of application Ser. No. 09/256,377 filed Feb. 24, 1999 (now abandoned), which is a continuation of application Ser. No. 08/959,115 filed Oct. 23, 1997 (now U.S. Pat. No. 5,935,883), which is a continuation of application Ser. No. 08/565,466 filed Nov. 30, 1995 (now abandoned). The entirety of the aforesaid applications are hereby incorporated by reference.
The present invention is related to a microfiber nonwoven web. More specifically, the invention is related to a web containing superfine microfibers.
Microfiber webs, such as meltblown fiber webs, are well known, and meltblown fiber webs are described in various patents and publications, including Naval Research Laboratory Report 4364, "Manufacture of Super-Fine Organic Fibers" by V. A. Wendt et al.; Naval Research Laboratory Report 5265, "An improved Device for the Formation of Super-Fine Organic fibers" by K. D. Lawrence et al.; and U.S. Pat. No. 3,849,241 to Butin et al. Meltblown fiber webs, which contain thermoplastic microfibers generally having less than 10 μm in average diameter, are produced by heating a polymer resin to form a melt, extruding the melt through die orifices in a die head to form filaments, directing a stream of heated fluid, usually air, toward the filaments exiting the die orifice to attenuated the filaments, and collecting the filaments on a foraminous surface to form a nonwoven web. Because the filaments are still tacky when they are collected, they form autogenous interfiber bonds to produce an integrated web.
Although conventional meltblown fiber webs contain fine microfibers, there is a need for fiber webs containing finer microfibers. There have been various attempts to reduce the diameter of meltblown fibers. One example of such attempts is reducing the polymer through-put to the die head. However, this direct controlling approach for producing fine meltblown fibers can only be used to reduce the fiber size to a limited extent since after a certain limit the reduction in through-put interrupts the fiber production altogether. Another exemplary process for producing fine meltblown fibers involves the steps of producing bicomponent conjugate meltblown fibers of an island-in-sea configuration and then dissolving the sea component of the meltblown fibers, thereby producing microfibers of the island component. However, the dissolving process is disadvantageous in that it requires a cumbersome dissolving step and it removes substantial portions of the conjugate fibers to produce fine fibers. Consequently, the dissolving process tends to be uneconomical and inefficiently utilizes the component polymers.
Yet another group of exemplary processes known in the art for producing fine fibers is split fiber production processes. However, known split fiber production processes may not be suitable for splitting meltblown fibers. The most widely used split fiber production process is a hydro-needling process, which utilizes a pressurized stream of water to split multicomponent conjugate fibers. In general, the process simultaneously splits and entangles the fibers to form a bonded nonwoven web. However, the hydro-needling process has not been used to produce split meltblown fiber webs since the autogenously bonded meltblown fiber webs, which have very fine breakable fibers and contain substantially uniformly distributed numerous interfiber bonds that restrict fiber movements, are difficult to split with the mechanical splitting process.
There are other fine microfiber webs known in the art, and they include glass microfiber webs. Although superfine glass microfibers can be produced, the glass microfibers are brittle and, thus, are not suitable for applications in which strength properties of the fibers are important.
There remains a need for superfine microfiber webs and a production process for producing the webs.
The present invention provides a web containing superfine microfibers. The web contains a blend of a first group of split microfibers which contains a first polymer component and a second group of split microfibers which contains a second polymer component, wherein at least one of the polymer components is hydrophilic. The invention additionally provides a meltblown fiber web having at least two groups of fibers, wherein each group of the fibers has a distinct cross-sectional configuration.
The invention also provides a splittable meltblown conjugate fiber containing at least two incompatible polymer components that are arranged in distinct segments across the cross-section of the fiber along the fiber length. The fiber can be characterized in that at least one of the polymer components is hydrophilic. In addition, at least one of the component polymers forms distinct unocclusive cross-sectional segments along the length of the fiber such that the segments are dissociable.
The superfine split microfiber web of the present invention exhibits, over conventional meltblown fiber webs, improved properties including improved fiber coverage, strength and textural properties, barrier properties, filtration properties and the like.
The term "steam" as used herein refers to both steam and a mixture of steam and air, unless otherwise indicated. The term "aqueous medium" as used herein indicates a liquid or gaseous medium that contains water or steam. The term "fibers" as used herein refers to both staple length fibers and continuous filaments, unless otherwise indicated. The term "multicomponent conjugate fiber" as used herein refers to a fiber which contains at least two component polymers that are arranged to occupy distinct segments of the cross-section of the fiber along the fiber length.
FIGS. 1-4 illustrate suitable conjugate fiber configurations for the present invention.
FIGS. 5-6 illustrate exemplary asymmetrical conjugate fiber configurations for the present invention.
FIG. 7 illustrates an exemplary superfine split microfiber web production process for the invention.
FIG. 8 illustrates an exemplary die head for producing meltblown fibers.
FIG. 9 is a microphotograph of a section of a split microfiber web of the present invention.
FIG. 10 is a microphotograph of a section of an untreated, unsplit microfiber web.
FIG. 11 illustrates a cut-away view of a two layer laminate of the present invention.
FIG. 12 illustrates a cut-away view of a three-layer laminate of the present invention.
The present invention provides a superfine microfiber web, and the superfine microfibers of the web are produced by splitting splittable conjugate meltblown fibers. The superfine split microfiber web contains at least two groups of fibers, and the polymers forming the two fiber groups are incompatible. In addition, at least one of the incompatible component polymers is hydrophilic. The term "hydrophilic" as used herein indicates affinity for water. The hydrophilicity of the hydrophilic component polymer can be measured in accordance with the ASTM D724-89 contact angle testing procedure on a film produced by melt casting the polymer at the temperature of the die head that is used to produce the split microfiber web. Desirably, the hydrophilic polymer has an initial contact angle equal to or less than about 80�, more desirably equal to or less than about 75�, even more desirably equal to or less than about 60�, most desirably equal to or less than about 50�. The term "initial contact angle" as used herein indicates a contact angle measurement made within about 5 seconds of the application of water drops on a test film specimen. In accordance with the present invention, the hydrophilic polymer component can be a naturally hydrophilic polymer or a hydrophilically modified polymer.
The splittable conjugate meltblown fiber of the present invention spontaneously splits without extraneous mechanical agitation or fibrillation when the fiber is contacted with a hot aqueous split-inducing medium. Aqueous split-inducing media suitable for the invention include hot water, desirably hot water having a temperature of at least about 60� C., more desirably a temperature between about 65� C. and 100� C. Additionally suitable split-inducing media are steam and mixtures of steam and air that have a temperature higher than 60� C. but lower than the melting point of the lowest melting polymer of the conjugate fiber in order to prevent inadvertent melting of the polymer component during the fiber splitting process. Desirably, the air-steam mixture has between about 0% and about 75% of air and between about 100% and about 20% of steam. When an air-steam mixture medium is utilized, the temperature of the air, which is mixed with steam, can be adjusted to change the temperature of the split-inducing medium. For example, the temperature of the air can be elevated to further increase the temperature of the steam-air mixture.
In accordance with the invention, the conjugate microfibers split in a time frame equal to or less than about 30 seconds; desirably equal to or less than about 10 seconds; more desirably equal to or less than 5 seconds; most desirably less than equal to or less than 1 seconds, e.g., nearly instantaneous, when contacted with the split-inducing medium. In addition, at least about 25%, desirably at least about 50%, more desirably at least about 75%, most desirably at least about 95% and up to 100% of the conjugate meltblown fiber splits with the present fiber splitting process.
The superfine split microfiber production process is highly advantageous over prior art fine microfiber production processes. Unlike the prior art dissolving production processes, the present split microfiber production process is simple and spontaneous and does not create significant amounts of byproducts that may need to be disposed of. In addition, the present splitting process does not remove portions of the fibers. Consequently, the splitting process does not reduce the weight and fiber coverage of the fiber web. In fact, the present splitting process, which increases the number of fiber strands in the nonwoven web without reducing its basis weight, improves the fiber coverage and textural and physical properties of the web. Furthermore, the superfine microfiber webs produced from the present process provide highly desirable properties including strength properties and drapability over glass fiber webs containing comparably sized superfine glass microfibers.
As stated above, the superfine split microfiber webs of the invention are produced from multicomponent conjugate meltblown fibers having at least two incompatible polymers that are placed to occupy distinct segments across the cross-section along the entire or substantially entire length of each fiber. In accordance with the present invention, each segment of the conjugate fiber is occupied by a polymer that is incompatible with the polymer or polymers of the adjacent segment or segments. For example, two incompatible polymer compositions are alternatingly placed to form a unitary conjugate fiber or a number of mutually incompatible polymers are placed to form the conjugate fiber.
The conjugate fiber should have a cross-sectional configuration that is amenable to partial or complete dissociation. Accordingly, at least one dissociable segment of the cross-section of the conjugate fiber, which is occupied by one of the component polymers of the fiber, forms a portion of the peripheral surface of the fiber and has a configuration that is not occluded by the adjacent segments such that the dissociable segment is not physically impeded from being separated.
Suitable configurations for the conjugate fibers include side-by-side configurations (FIG. 1), wedge configurations (FIG. 2), hollow wedge configurations is (FIG. 3) and sectional configurations (FIG. 4). It is to be noted that a suitable configuration does not need to have a symmetrical geometry provided that it is not occlusive or interlocking. Accordingly, suitable configurations also include asymmetrical configurations, for example, shown in FIGS. 5-6. Splittable conjugate fibers having an asymmetrical cross-sectional configuration, for example, FIG. 5 or FIG. 6, form a superfine microfiber web containing a mixture of at least two groups of fibers having different cross-sectional configurations, sizes or shapes. In addition, the splittable conjugate fibers need not be conventional round fibers. Other useful fiber shapes include rectangular, oval and multilobal shapes.
The different component polymers of the conjugate fiber need not be present in equal amounts. For example, a component polymer of the conjugate fiber may form a thin film-like section that merely acts as a divider between two adjacent component polymers, thus, providing a web that contains fine microfibers of mainly one polymer component.
Additionally, the splittable conjugate microfibers may be crimped or uncrimped. Crimped splittable microfibers of the present invention are highly useful for producing a lofty web since crimps increase the bulk or loft of the web.
In accordance with the invention, split microfibers having various thicknesses can be conveniently produced by adjusting the thickness of the conjugate fibers and/or adjusting the number of segments within the cross-section of the conjugate fibers. In general, a conjugate fiber having a finer thickness and/or a higher number of cross-sectional segments results in finer split microfibers. Correspondingly, the thickness of the split microfibers can be easily adjusted to have a wide variety of thicknesses. Of the suitable thickness controlling methods, the method of adjusting the number of cross-sectional segments is particularly desirable for the present invention. By adjusting the number of cross-sectional segments and the thickness of the conjugate microfibers, the split microfibers of the invention can even be produced to have a weight-per-unit-length of about 0.2 μm or less.
As indicated above, hydrophilic polymers suitable for the present splittable conjugate fiber include both hydrophilic and hydrophilically modified polymers. Suitable hydrophilic polymers desirably have a contact angle less than equal to about 80�. Inherently hydrophilic polymers suitable for the present invention include thermoplastic polymers having the above-described hydrophilicity. Such polymers include copolymers of caprolactam and alkylene oxide diamine, e.g., Hydrofil�, which are commercially available from AlliedSignal Inc.; copolymers of poly(oxyethylene) and polyurethane, polyamide, polyester or polyurea, e.g., absorbent thermoplastic polymers disclosed in U.S. Pat. No. 4,767,825 to Pazos et al.; ethylene vinyl alcohol copolymers; and the like. U.S. Pat. No. 4,767,825 in its entirety is herein incorporated by reference.
Hydrophilically modifiable polymers suitable for the present invention include polyolefins, polyesters, polyamides, polycarbonates and copolymers and blends thereof. Suitable polyolefins include polyethylene, e.g., high density polyethylene, medium density polyethylene, low density polyethylene and linear low density polyethylene; polypropylene, e.g., isotactic polypropylene, syndiotactic polypropylene, blends of isotactic polypropylene and atactic polypropylene, and blends thereof; polybutylene, e.g., poly(1-butene) and poly (2-butene); polypentene, e.g., poly(1-pentene) and poly(2-pentene); poly(3-methyl-1-pentene); poly(4-methyl-1-pentene); and copolymers and blends thereof. Suitable copolymers include random and block copolymers prepared from two or more different unsaturated olefin monomers, such as ethylene/propylene and ethylene/butylene copolymers. Suitable polyamides include nylon 6, nylon 6/6, nylon 4/6, nylon 11, nylon 12, nylon 6/10, nylon 6/12, nylon 12/12, copolymers of caprolactam and alkylene oxide diamine, and the like, as well as blends and copolymers thereof. Suitable polyesters include polyethylene terephthalate, polybutylene terephthalate, polytetramethylene terephthalate, polycyclohexylene-1,4-dimethylene terephthalate, and isophthalate copolymers thereof, as well as blends thereof.
In accordance with the present invention, when a hydrophobic or less than sufficiently hydrophilic polymer is used as the hydrophilic component of the splittable conjugate fiber, the polymer must be hydrophilically or wettably modified. One useful means for modifying the polymer composition is adding a hydrophilic modifying agent or hydrophilic modifier. Suitable hydrophilic modifiers include various surfactants. Depending on the final use of materials containing the split microfibers, the surfactants can be fugitive or nonfugitive. Fugitive surfactants, i.e., surfactants that wash off from the fiber surface, are suitable if the split fibers are used in single exposure applications or applications in which nonwettable or hydrophobic properties are desired. When a fugitive surfatant is utilized, the split microfiber web can be subsequently washed such that the web and the split microfibers of the web become hydrophobic. Nonfugitive surfactants, i.e., surfactants that permanently or semipermanently adhere to the fiber surface, are suitable if the split fibers are used in applications in which more durably wettable or hydrophilic properties are desired. In addition, particularly suitable internally added surfactants are selected to have a low compatibility with the polymer of the hydrophilic component of the fiber since such surfactants readily migrate to the surface of the fiber during the fiber spinning process. When a surfactant having a slow migration characteristic is utilized, the fibers may need to be heat treated or annealed to facilitate the migration of the surfactant to the surface. Such heat treatment is known in the art as a "blooming" process. Illustrative examples of suitable surfactants include silicon based surfactants, e.g., polyalkylene-oxide modified polydimethyl siloxane; fluoroaliphatic surfactants, e.g., perfluoroalkyl polyalkylene oxides; and other surfactants, e.g., actyl-phenoxypolyethyoxy ethanol nonionic surfactants, alkylaryl polyether alcohols, and polyethylene oxides. Commercially available surfactants suitable for the present invention include various poly(ethylene oxide) based surfactants available under the tradename Triton, e.g., grade X-102, from Rohm and Haas Crop; various polyethylene glycol based surfactants available under the tradename Emerest, e.g., grades 2620 and 2650, from Emery Industries; various polyalkylene oxide modified polydimethylsiloxane based surfactants available under the tradename Masil, e.g., SF-19, which is available from Mazer; polyalkylene oxide fatty acid derivatives available under the tradename PEG, e.g. PEG 400, which is available from ICI; sorbitan monooleate, e.g., Span 80, which is available from ICI; ethoxylated hydroxylated castor oil, e.g., G1292, which is available from ICI; a mixture of sorbitan monooleate and ethoxylated hydroxylated castor oil, e.g., Ahcovel Base N62, which is available from ICI; polyoxyalkylene modified fluoroaliphatic surfactants which are available, e.g., from Minnesota Mining and Manufacturing Co.; and mixtures thereof.
The amount of surfactants required and the hydrophilicity of modified fibers for each application will vary depending on the type of surfactant and the type of polymer used. In general, fibers containing more hydrophilic or hydrophilically modified polymer or polymers result in more spontaneous splitting. Consequently, a high level of surfactant can be added to the polymer composition of the conjugate fibers provided that the surfactant level is not too high as to adversely affect the processability of the polymer composition. Typically, the amount of the surfactant suitable for the present fiber composition is in the range of from about 0.1% to about 5%, desirably from about 0.3% to about 4.5%, more desirably from about 0.5% to about 4%, by weight based on the weight of the polymer composition. The surfactant is thoroughly blended with the polymer composition before the composition is processed into fibers. For example, when a melt-extrusion process for producing fibers is utilized, the surfactant is blended and melt-extruded with the polymer compositions in extruders and then spun into fibers.
In accordance with the present invention, additional component polymers for the splittable conjugate fibers are selected from hydrophilic and hydrophobic thermoplastic polymers. Suitable polymers include the above-illustrated hydrophilic polymers and hydrophilically modifiable polymers. The additional component polymers do not have to hydrophilic, but need to be incompatible with the hydrophilic component polymer of the meltblown conjugate fibers.
The term "incompatible polymers" as used herein indicates the polymers that do not form a miscible blend when melt blended, i.e., immiscible. As a desirable embodiment of the present invention, differences in the polymer solubility parameter (δ) are used to select suitably incompatible polymers. The polymer solubility parameters (δ) of different polymers are well known in the art. A discussion of the solubility parameter is, for example, disclosed in Polymer: Chemistry and Physics of Modern Materials, pages 142-145, by JMG Cowie, International Textbook Co., Ltd., 1973. Desirably, the adjacently disposed component polymers of the present meltblown conjugate fiber have a difference in the solubility parameter of at least about 0.5 (cal/cm3)�, more desirably at least about 1 (cal/cm3)�, most desirably at least about 2 (cal/cm3)�. The upper limit of the solubility parameter difference is not critical for the present invention since the higher the difference, the more spontaneous the splitting of the fiber becomes.
Illustrative examples of particularly desirable pairs of incompatible polymers useful for the present conjugate microfibers include polyolefin-polyamide, e.g., polyethylene-nylon 6, polyethylene-nylon 6/6, polypropylene-nylon 6, polypropylene-nylon 6/6, polyethylene-a copolymer of caprolactam and alkylene oxide diamine, and polypropylene-a copolymer of caprolactam and alkylene oxide diamine; polyolefin-polyester, e.g., polyethylene-polyethylene terephthalate, polypropylene-polyethylene terephthalate, polyethylene-polybutylene terephthalate and polypropylene-polybutylene terephthalate; and polyamide-polyester, e.g., nylon 6-polyethylene terephthalate, nylon 6/6-polyethylene terephthalate, nylon 6-polybutylene terephthalate, nylon 6/6-polybutylene terephthalate, polyethylene terephthalate-a copolymer of caprolactam and alkylene oxide diamine, and polybutylene terephthalate-a copolymer of caprolactam and alkylene oxide diamine and polypropylene.
FIG. 7 illustrates an exemplary process for producing a superfine split microfiber nonwoven web of the present invention. A process line 10 is arranged to produce a split meltblown fiber nonwoven web of two polymer components (bicomponent). It is to be noted that conjugate meltblown fibers containing more than two polymer components can be produced. The process line 10 includes a pair of extruders 12 a and 12 b for separately melt-processing two incompatible component polymers. One or both of the component polymers are hydrophilic polymers or hydrophobic polymers blended with effective amounts of a hydrophilic modifier in accordance with the present invention, and they are fed into respective extruders. Alternatively, the hydrophilic modifier can be injected into the respective extruders. The polymers are melt-processed in the extruders and then fed to, for example, a side-by-side die head 14. Generally described, the die head 14 includes a housing containing a plurality of plates stacked one on top of the other with a pattern of openings arranged to create flow paths for directing polymer extrudates through the die 14 into die tip openings or orifices 16. The die head tip 22 which is shown in cross-section in FIG. 8, contains die openings 16. Each of the openings 16 receives predetermined amounts of the two extrudates in a side-by-side configuration, forming a side-by-side filament 24. Hot high-pressure fluid, usually air, is supplied to the die tip via pipes 18 and 20 which terminate in channels 26 and 28 adjacent the die openings 16. As the extrudates exit the die openings 16 to form filaments 24, the high-pressure fluid attenuates and carries the filaments 24 onto a moving foraminous belt 30. Alternatively, the high-pressure fluid can be used to attenuate filaments and to break up the filaments to form air-borne fine discontinuous fibers. The attenuated filaments or fibers 24, which are not fully quenched and still tacky, are randomly deposited to form an autogenously bonded nonwoven web 32. A vacuum is drawn underneath the foraminous belt 30 to assist the web formation. Once the fibers are deposited and the web is formed, the web 32 is drawn from the belt 30 by rolls 34 and 36. The conjugate meltblown fiber web 32 is then passed under a spray apparatus 38 that thoroughly and evenly applies a hot aqueous split-inducing medium, e.g., steam or hot water, to split the fibers of the web. As an alternative embodiment, the web 32 can be passed though a hot water bath. A vacuum apparatus (not shown) can be placed on the other side of the web under the spray apparatus 38 to remove the applied split-inducing medium. The spilt fiber web is then dried.
The superfine split meltblown fiber web exhibits desirable properties, such as uniformity of the fabric, uniform fiber coverage, high barrier properties, high filtration properties and high fiber surface area. Webs containing the split microfibers that exhibit the above-illustrated desirable properties are highly suitable for various uses. For example, nonwoven webs containing the split microfibers are highly suitable for various uses including disposable articles, e.g., protective garments, sterilization wraps, wiper cloth and covers for absorbent articles.
As another embodiment of the present invention, the superfine microfiber web may be used as a laminate that contains at least one layer of the split microfiber web and at least one additional layer of another woven or nonwoven fabric or a film. The additional layer for the laminate is selected to impart additional and/or complementary properties, such as textural and strength properties. The layers of the laminate can be bonded to form a unitary structure by a bonding process known in the art to be suitable for laminate structures, such as a thermal, ultrasonic, adhesive, or hydroentangling process.
A laminate structure highly suitable for the present invention is disclosed in U.S. Pat. No. 4,041,203 to Brock et al., which is herein incorporated in its entirety by reference. In adapting the disclosure of U.S. Pat. No. 4,041,203, a pattern bonded laminate containing at least one layer of a continuous filament nonwoven web, e.g., spunbond fiber web, and at least one layer of the present superfine split microfiber nonwoven web can be produced, and such laminate combines the strength and textural properties of the spunbond web and the breathable barrier properties of the split microfiber web. The laminate structures are highly suitable for various uses including various skin-contacting applications, such as protective garments, covers for diapers, adult care products, training pants and sanitary napkins, various drapes, and the like.
Turning now to the drawings, FIG. 11 depicts a nonwoven material 50 in the form of a laminate having as a top layer an integrated mat 52 of thermoplastic microfibers 54 and, as a bottom layer, a web 56 of substantially continuous and randomly deposited, molecularly oriented filaments 58 of a thermoplastic polymer. As illustrated, in order to provide a unitary structure, ply attachment between the mat and web can be effected at the intermittent discrete bond regions 60 which are disposed over the surface of the material in a substantially regular pattern. While it is preferred that the discrete bond regions 60 be formed by the application of heat and pressure at the illustrated intermittent areas, other methods of ply attachment such as the use of independently applied adhesives or mechanical interlocking of the fibers such as by needling techniques or the like can also be used.
Turning now to the web 56 of substantially continuous filaments, the manner of preparing this web is also customary with illustrative techniques being set forth in the following patents: Kinney (U.S. Pat. Nos. 3,338,992 and 3,341,394); Levy (U.S. Pat. No. 3,276,944): Peterson (U.S. Pat. No. 3,502,538); Hartmann (U.S. Pat. Nos. 3,502,763 and 3,509,009); Dobo et al. (U.S. Pat. No. 3,542,615); and Harmon (Canadian Patent No. 803,714).
While many different methods are illustrated for initially preparing such continuous filament webs, the available methods generally have at least three common features. First, the methods of preparation involve continuously extruding a thermoplastic polymer (either from the melt or a solution) through a spinneret in order to form discrete filaments. Thereafter, the filaments are drawn (either mechanically or pneumatically) without breaking in order to molecularly orient the polymer filaments and achieve tenacity. Lastly, the continuous filaments are deposited in a substantially random manner onto a carrier belt or the like to form a web of substantially continuous and randomly arranged, molecularly oriented filaments. A preferred method for preparing such webs is described in U.S. Pat. No. 3,692,618.
Turning now,to FIG. 12, there is illustrated a further embodiment of the present invention wherein a material 80 is illustrated having, as outer plies, microfiber mats 82 and 84 and, as an inner ply a continuous filament web 86. Again, as illustrated in FIG. 11, ply attachment and integration of the continuous filament web is achieved by means of the regular pattern of intermittent bonds 88. Preparation of a material such as depicted in FIG. 12 can be accomplished by combining a second microfiber mat with a first microfiber mat and continuous filament web at the nip formed by a pair of rolls and thereafter passing the three ply composite through the rolls and bonding nip. Similarly, it will be understood that a microfiber mat can be formed on a wire and thereafter continuous filament webs can be disposed on one or both sides of the mat to form other constructions embodying the features of the present invention.
In addition to the illustrated desirable strength characteristics, the material possesses an overall opaque textile-like appearance, a desirable drape and full bodied hand, and is comfortable to the touch by appearing to equilibrate in moisture content with the surrounding atmosphere. In selecting the ratio of microfiber mat to continuous filament web, lower ratios are associated with uses where greater strength characteristics and less stringent barrier properties are required. As the microfiber mat content of the laminate is increased better barrier characteristics are noted but permeability is diminished. Preferred laminates are those wherein the mat to web ratio is less than about 1:1 (e.g., 7:1 to 0.9:1).
Laminates of the present invention are believed to be particularly useful as wipes for adding or removing water, polishes, and solvents and the like as well as for portable prewetted wash cloths for personal use. In addition, it has been found that certain laminates as herein described are exceptionally useful as sterile wrappers or containment fabrics for surgical and other health care procedures. As is well recognized, fabrics useful for these purposes must permit penetration of a sterilent (e.g. ethylene oxide, steam, gamma radiation, etc.), thereafter impede to a high degree passage of bacteria and like contaminants, be antistatic and preferably also fluid repellent. These applications include, among others, wraps for surgical instruments and packs, surgical caps, gowns and patient drapes, medical table covers, isolation gowns and scrub apparel.
Nonwoven materials are provided by the present invention which are fabric-like in drape, hand, and appearance. By employing the techniques illustrated herein, breathable, fluid repellent materials can be fashioned which are highly suitable for garment applications such as outwear lining, jackets, rainwear and the like. Furthermore, it has been found that those materials herein illustrated which have, as an exposed surface, a microfiber mat can be advantageously printed to provide decorative fabrics and, in addition, possess fluid retentive characteristics rendering them suitable as wipes as well as receptive to treatment with wetting agents and the like to impart absorbency characteristics.
Such uses may include: robe linings and facings; mattress pads, covers and ticking; shower curtains, drapes and drapery liners; pillow ticks, protectors and pillowcases; bedspreads and quilts; and, sleeping and slumber bags and liners. Similarly, with respect to the other strength characteristics, particularly grab tensile and trapezoid tear, a similar unexpected improvement in strength can be achieved which, as illustrated, is generally on the order of at least about 30% and generally at least about 50% compared with that theoretically predicted.
Yet another embodiment of the present innovation, the superfine split microfiber webs of the present invention is highly suitable for various filter media in that the webs have superfine fibers and uniform fiber coverage and provide highly desirable filtration properties. An example of microfiber filter media concept that can be adapted to use the present superfine microfiber webs is disclosed, for example, in U.S. Pat. No. 4,824,451 to Vogt et al., which patent is herein incorporated by reference.
The following examples are provided for illustration purposes and the invention is not limited thereto.
Testing Procedures
Frazier Permeability: The Frazier permeability, which expresses the permeability of a web in terms of cubic feet per minute of air per square foot of medium at a pressure drop of 0.5 inch of water, was determined utilizing a Frazier Air Permeability Tester available from the Frazier Precision Instrument Company and measured in accordance with Federal Test Method 5450, Standard No. 191A.
Contact Angle: The contact angle is an initial contact angle, i.e., measured within 5 seconds, that was measured on a 13 cm�13 cm cast film, which had a 3 mm thickness, with deionized water in accordance with ASTM D724-89.
A bicomponent meltblown fiber web was formed in accordance with the process described in U.S. Pat. No. 3,978,185 to Butin et al., except a side-by-side die head was used and two single screw extruders were used to process the two component polymers. The meltblown fibers of the web had 50 wt % of polypropylene and 50 wt % of nylon 6, based on the total weight of the fibers. The polypropylene was Himont's HH441, and the nylon 6 used was custom polymerized polycaprolactam, which was produced by Nyltech, Manchester, NH, and had a formic acid relative viscosity of 1.85. The solubility parameter difference of the two polymers is larger than 5 (cal/cm3)�. The nylon component additionally contained 2 wt % of ethyoxylated polysiloxane, SF-19, which is available from Mazer. The polymer components were fed into the extruders and were processed to 455� F. (235� C.) extrudates. The extrudates were fed into the die and processed into a meltblown bicomponent fiber web. The meltblown web was removed from the forming surface and placed in boiling water for 5 seconds. The treated web was then dried, and the web studied under a microscope. In addition, the modified nylon component composition was tested for its hydrophilicity and had a contact angle of about 40�.
The observation under the microscope indicated that a large portion of the fibers of the meltblown fiber web was split during the water treatment.
Comparative Example 1 is the meltblown bicomponent fiber web of Example 1 before the web was treated in boiling water. The nonwoven web did not contain apparently visible split fibers.
The visual observation of the webs of Example 1 and Comparative Example 1 demonstrates that the conjugate microfibers containing a hydrophilic component polymer split when treated with a split-inducing medium of the present invention.
A meltblown bicomponent fiber web was produced in accordance with Example 1 except the nylon component contained 4 wt % of the ethoxylated polysiloxane. The contact angle of the modified nylon component was about 10�. The treated nonwoven web was tested for its permeability, and the result is shown in Table 1.
Comparative Example 2 is the meltblown bicomponent fiber web of Example 2 before the web was treated in boiling water. The permeability result is shown in Table 1.
The significant decrease in permeability of Example 2 clearly demonstrates that the hydrophilically modified conjugate microfibers split to form a web containing increased number of fiber strands when treated with a hot aqueous fibrillation-inducing medium, thereby improving the barrier property of the web.
Turning to the figures, FIG. 9 is a scanning electron microphotograph of a representative section of the web of Example 2, and FIG. 10 is a scanning electron microphotograph of a representative section of the web of Comparative Example 2. FIG. 9 shows semicircular split fibers produced from round side-by-side meltblown fibers, whereas FIG. 10 shows unsplit bicomponent fibers of the web of Comparative Example 2.
As can be seen from the above examples, the present superfine split microfiber production process provides a spontaneously split superfine microfiber web. In addition, the superfine split microfiber web produced from the process provides a highly desirable combination of textural and physical properties, including desirable softness, uniform fiber coverage, desirable strength properties, drapability, high barrier properties, high filtration properties and the like.
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That our 17th century palazzo inspires romance is no surprise. It was originally built as a wedding gift from Pope Alexander VII to his niece Olimpia and her fiancée Giulio de' Gori, and the spirit of love and celebration is imbued in the very soul of the building and expressed in its elaborate interiors.
Through the centuries, the famous walls of our ceremonial hall, the Salone delle Feste, has witnessed noble weddings, grand ceremonies and lavish banquets. Today, the hotel and our passionate event team, welcome you with open arms and promise you an unforgettable occasion. The hall perpetually captivates guests with its precious trompe-l'œil; stunning marble floors; sparkling Murano glass chandeliers; and exquisite finishes of gilded wood, aqua velvet and golden damask.
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Noble weddings, meetings of heads of state, gatherings of celebrities: the Salone delle Feste has hosted many important events in Siena's long history. Any event in this grand hall, enriched
with precious 16th century tromp l'oeils, stunning Murano glass chandeliers and marble floors, has a unique allure. The hall can host up to 100 guests seated theatre style
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The ceilings are high and frescoed, the fine furniture includes carefully chosen antiques and the overall atmosphere is refined. At 30m², the Sala Olimpia can host up to 20 guests
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banquets to functional meetings and parties, boasts warm hues, graceful high ceilings and precious chandeliers. Sala Gori measures some 70m² and can host up to 40 guests for cocktails.
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make it ideal for small private meetings. Wide range proposals of wedding menus, business lunches, buffets are available. Every event may be tailored according to preferences and requirements.
Since mastering the delicate art of homemade pasta in his grandparent's restaurant, Luca Ciaffarafà has been driven by a deep love of traditional Tuscan cooking. Today, after years of experimentation and experience, his recipes are certainly unique but remain pure in their homage to his regional roots.
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Some more icons from the Vector Scout Merit Badge icon set. A preview of the full set is attached. I'm so close to done with the pack. Making the push to have it available tomorrow!
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38 year old man | Plain City, OH, USA | Seeking women 27-42 within 50 miles
I'm often referred to as a "high energy"...
I'm often referred to as a "high energy" person. Extrovert all the way. I'm seeking that person that has the same passion for life that I do. Somebody that lets themselves live in the moment. Somebody that can enjoy some spontaneity from time to time. Life is too short to waste it not doing what makes you happy. You only get one spin, so make the most of it. Now, that being said, I still live in the real world. I have a job, bills, and a few other responsibilities, but I'm always looking for that next adventure. Things you should possess 1) a sense of humor 2) compassion for those less fortunate 3) a desire to try/see new things 4) a good taste in music and art 5) a valid passport 6) the innate ability to choose the proper footwear for the activity at hand Deal breakers 1) Republicanism 2) Being anti-equal rights for EVERYONE 3) An unhealthy obsession with cats (owning 3 or more) 4) Steelers fans, unless you are from Pennsylvania
Camping , Cooking , Dining out , Gardening/Landscaping , Museums and art , Music and concerts , Exploring new areas , Political interests , Travel/Sightseeing , Watching sports , Wine tasting
Bowling, Cycling, Dancing, Golf, Running, Walking / Hiking, Weights / Machines
I exercise 3-4 times per week.
I like Dogs, Fish
Not a big fan of cats
Very Liberal
Short North, Grandview, Yellow Springs
Beating you at Jeopardy, local brews,(I have a penchant for hops) non-chain restaurants, quality conversation, political debate...
I really enjoy seeing live music of almost any kind. Rock, Blues, Jazz, Bluegrass or Electronic are some of my favorites. I usually see at least 20 concerts a year.
100 Years of Solitude
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|6'0" (182cms)
|5'2" (157cms) to 5'10" (177cms)
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|Black, Blue, Brown, Grey, Green, Hazel
|Light brown
|Auburn / Red, Black, Light brown, Dark brown, Blonde, Salt and pepper, Silver, Dark blonde, Grey, Platinum
|No Way
|No Way, Occasionally
|Social Drinker, Regularly, Moderately
|Architecture / Interior design
|No preference
Design Implementation
|$35,001 to $50,000
|$25,001 to $35,000, $35,001 to $50,000, $50,001 to $75,000, $75,001 to $100,000, $100,001 to $150,000, $150,001+
|Never Married, Widow / Widower, Currently Separated, Divorced
|Have kids:
|Yes, and they sometimes live at home, No, Yes, and they live away from home, Yes, and they live at home
|Wants kids:
|Probably not
|Probably not, No
|White / Caucasian
|Asian, Black / African descent, East Indian, Latino / Hispanic, Middle Eastern, Native American, Pacific Islander, White / Caucasian, Other
|Agnostic, Atheist, Spiritual but not religious
|Associates degree
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A Covert Affair: When Julia and Paul Child Joined the OSS They Had No Way of ...By Jennet Conant
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Jadience Slimming Patch™ -- 12 Patches
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Jadience Herbal Formulas combines the science of herbology and the power of jade with tightly guarded internal and external formulations, which feed and detoxify the skin and body to the core. The Jadience Slimming Patch contains powerful herbs such as Bladderwrack, Dandelion, and Green Tea known to increase your body's circulation, chi (energy), and metabolism by removing toxins and improving the function of your internal organs. The Slimming Patches will help decrease appetite, reduce cravings for sweets, and remove stress.
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River splits with East Miss
POPLARVILLE --- Pearl River Community College split with East Mississippi in MACJC non-division softball action here Friday, winning the first game 5-4 before falling 9-1 in the nightcap contest of the doubleheader.
Both squads are now even on the year with the Lady Wildcats at 2-2 and the Lady Lions at 3-3.
In the first game, EMCC went up 1-0 in the top of the first before PRCC rebounded in the bottom of the second to take the lead off a two-run homer by Kelsea Lewis of Oak Grove High.
Lady Wildcats split with ASCC in season-opening twin bill
POPLARVILLE --- Pearl River Community College opened its 2014 softball season with a doubleheader split against Alabama Southern here Friday, falling 7-2 in the first game before rebounding with a 5-3 victory in the nightcap.
Both squads are now 1-1 overall.
In the first game, the Lady Wildcats fell behind 1-0 in the top of the opening inning when ASCC's Rebekah Blackstock drilled a one-out single down the first base line and Kayla Jordan drove her home an out later with a double to left.
MACJC softball post-season format sees dramatic change
POPLARVILLE --- Dramatic post-season changes are set for the Mississippi Association of Community & Junior Colleges (MACJC) for the 2014 season.
The state's 14 community colleges have adopted a new playoff format identical to baseball's with an initial best-of-three series (North No. 1 hosting South No. 4, South No. 1 hosting North No. 2, North No. 2 hosting South No. 3, South No. 2 hosting North No. 3) set for April 25-26.
Pearl River wraps season with 8-0 semi-final setback to top-ranked LSU-Eunice
CLINTON — Pearl River's Lady Wildcats wrapped their 2013 softball season with an 8-0 (five innings) loss to top-ranked LSU-Eunice (La.) Saturday in semi-final action of the Region 23 Tournament underway at Traceway Park.
River eliminated by Jones in MACJC semi-final match
PERKINSTON — The South No. 4 Pearl River Lady Wildcats were eliminated from the MACJC State Softball Tournament here Monday with a 3-2 semi-final loss to reigning state champion and South No. 2 Jones County.
The victorious Lady Bobcats, ranked No. 8 in the latest NJCAA Division II softball poll, went on to defeat South No. 1 host Mississippi Gulf Coast 9-6 with another comeback victory to repeat as MACJC champs. Seventh-ranked MGCCC defeated South No. 3 East Central 7-3 in Monday's other semi-final contest.
Pearl River wallops Itawamba 15-0 in five in opening round of MACJC Softball Tournament
PERKINSTON — Brittany LeBlanc pitched a one-hit shutout to propel Pearl River's Lady Wildcats to a lopsided 15-0 (five innings) softball victory over Itawamba here Sunday in opening-round action of the MACJC State Tournament underway at Mississippi Gulf Coast CC.
The Lady Wildcats, the South Division No. 4 seed, will now face South No. 2 and eighth-ranked Jones County, a 7-1 winner over North No. 3 Holmes to open Sunday's tournament play, at 12 noon Monday. The winner of that contest will earn a berth in the state championship bout at 5 p.m.
MACJC Softball Bracket/Webcast
PLEASE NOTE: The 2013 MACJC State Softball Tournament has been rescheduled for a second time due to wet field conditions at host MGCCC. It was originally scheduled for Thursday and Friday, rescheduled for Saturday and Sunday due to rain forecasts, then rescheduled for a second time to Sunday and Monday due to wet field conditions. Hopefully, this is the last "reschedule" of the tournament.
River opens rescheduled MACJC Tournament play Sunday against North Division champ Itawamba
PLEASE NOTE: The 2013 MACJC State Softball Tournament has been rescheduled for a second time due to wet field conditions at host MGCCC. It was originally scheduled for Thursday and Friday, rescheduled for Saturday and Sunday due to rain forecasts, then rescheduled for a second time to Sunday and Monday due to wet field conditions. Hopefully, this is the last "reschedule" of the tournament.


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A catheter having at least two lengths of tubular material axially joined together by a welded joint with no perceptible change in diameter at the welded joint; the welded joint including a substantial axially oriented seam between the two lengths of material.
1. An intravascular catheter having an external peripheral surface and a lumen extending therethrough and along a longitudinal axis, which catheter comprises:
a flexible, plastic inner tube; a fibrous, tubular reinforcement member carried by said inner tube; and an outer tube of substantially constant diameter including
a first axial section comprising a first plastic material overlying said inner tube and reinforcement member;
a second axial section comprising a second plastic material overlying said inner tube and reinforcement member, wherein said first and second axial sections are substantial mirror images of each other; and
a welded joint between said first and second axial sections, said welded joint including a seam along said external peripheral surface at least 0.5 cm. in axial length extending at an acute angle to said longitudinal axis.
2. The catheter of claim 1 wherein said external peripheral seams have an axial length of between 0.5 cm. and 10 cm.
3. The catheter of claim 1 wherein a ratio of seam axial length to radial depth is between 3:1 and 40:1.
4. The catheter of claim 1 wherein said first and second plastic materials have different compositions and different properties.
5. The catheter of claim 1 wherein said first and second plastic materials have substantially identical compositions but different durometers.
This is a continuation of application Ser. No. 08/570,941, filed Dec. 12, 1995, now U.S. Pat. No. 5,772,641.
This invention relates generally to catheter constructions, and more particularly to welded joints between adjacent lengths of catheter material.
Currently, both diagnostic and therapeutic catheters are manufactured by forming braided tubes of stainless steel fibers or strands, over a mandrel. More specifically, the braided tube may be formed about an inner Teflon� liner or tube initially carried on a supporting mandrel. An outer plastic layer may then be extruded about the braided material to create the catheter body. Current catheter constructions also utilize a transition tip which is not reinforced with braid in order that the tip be softer and more flexible than the remaining portions of the catheter. In some catheter designs, an even more flexible tip is bonded to the free end of the tubular transition tip.
Catheters which incorporate multiple axial sections typically employ butt or lap weld joints to secure the axial sections of the catheter together. See, for example, U.S. Pat. Nos. 5,254,107; 4,861,337; 4,793,351; 4,662,404; and 4,391,302.
Catheters incorporating either butt or lap type welded joints are not completely satisfactory however, and it is thus the object of this invention to improve upon prior catheter constructions by incorporating unique weld configurations which have a substantial axial seam component extending along the axis of the catheter. In other words, adjacent catheter sections are cut and welded in such a way that they overlap in the longitudinal direction, but without altering the outer diameter of the catheter. This arrangement not only increases surface area at the weld joints and thereby also increases bond integrity, but also creates a more desirable transition between the same materials of different durometer or different materials with or without the same durometer, than other more conventional welds such as lap or butt welds.
The unique weld configurations of this invention also permit alteration of properties or characteristics of the catheter material in the area of the weld, and this feature is particularly advantageous in areas of the catheter that will be curved, in that different stiffness or hardness materials can be used on the inside and outside of the curve.
Examples of the unique weld configurations in accordance with this invention include step joints, taper joints, and combinations of the two.
Thus, in accordance with its broader aspects, the present invention relates to a catheter having at least two lengths of tubular material axially joined together by a welded joint with no perceptible change in outer diameter at the welded joint; the welded joint including a substantial axially oriented seam between the two lengths of material.
In another aspect, the invention relates to a catheter having at least two lengths of tubular material axially joined by a welded joint, the welded joint having an axial length component of at least 0.5 cm. in length, and preferably in the range of 0.5-10 cm.
Other objects and advantages of the subject invention will become apparent from the detailed description which follows.
FIG. 1 is a side elevation, partly broken away, of a conventional catheter construction;
FIG. 2 is a side section of the distal end of the catheter shown in FIG. 1;
FIG. 3 is a section taken along the line 3--3 of FIG. 2;
FIG. 4 is a cross section of a conventional lap weld in a catheter;
FIG. 4A is a partial side section of the welded joint illustrated in FIG. 4;
FIG. 5 is a side elevation of a catheter incorporating a step weld in accordance with the present invention;
FIG. 5A is a section taken along the line 5A--5A of FIG. 5;
FIG. 6 is a side elevation of a catheter incorporating a multi-step weld in accordance with the invention;
FIG. 7 is a side elevation of a catheter incorporating a shallow angle weld in accordance with the invention;
FIG. 8 is a side elevation of a catheter incorporating a steep angle weld in accordance with the invention;
FIG. 9 is a side elevation of a catheter incorporating a combination step/angle weld in accordance with the invention;
FIG. 10 is a side elevation of a catheter incorporating a combination step, angle and butt weld in accordance with the present invention; and
FIG. 11 is a partial side elevation illustrating a catheter with multiple sections including a curved section incorporating a weld in accordance with the subject invention.
FIGS. 1 and 2 represent a known catheter construction of the type disclosed in U.S. Pat. No. 5,254,107. The catheter assembly 10 includes a conventional hub 12 at its proximal end, and a tubular catheter 14 extending from the hub 12 to a distal end 16. The catheter may have a first axial section 18, a second axial section 20 and a distal tip section 22.
The catheter 14 comprises an inner tubular plastic layer 24, which may be made of fluoro polymers such as PTFE, FEP or other similar polymers. A second layer 26 comprises a braided stainless steel tube applied by a conventional braiding machine. An outer, third layer 28 of plastic is then applied by suitable means over the braided layer. As disclosed in the '107 patent, this outer layer may include two or more axial sections. For example, the first axial section 18 may be made of a plastic material such as nylon 12 with a Shore D durometer of about 65-70. The second axial section 20 may be Pebax, but may have a Shore D durometer of about 35-55. The transition tip 22 may be Pebax and may or may not be reinforced by the braided layer 26. In the '107 patent, the adjacent axial sections are butt welded or fused together, such that the joints describe circles C1 and C2 perpendicular to the longitudinal axis of the catheter.
The present invention relates to new and unique weld configurations for joining axial sections of the outer plastic layer of a catheter as generally described above.
Conventional welds used in catheter constructions are either of the butt type shown in FIGS. 1 and 2, or of the overlapping variety, typically known as "lap" welds as shown in FIGS. 4 and 4A (inner layer and braided layer removed for the sake of clarity). Thus, one tubular portion 30 is received over a second tubular portion 32 and welded thereto, such that, in the weld area, a double thickness is created, as best seen in FIG. 4A.
In accordance with this invention, welds are used to connect lengths of catheter tubing, which welds are designed to have substantial axial length, but without altering the outer diameter of the catheter. In FIG. 5, for example, a first catheter length 34 is connected to a second catheter length 36 by a step weld 38 which includes radial seam portions 40 and 42 and extended axial seam portions 44, 44A (see FIG. 4A). Note there is no double thickness of material and no change in outside diameter. Here again, internal layers have been omitted simply for the sake of clarity.
In FIG. 6, a multi-step weld 46 axially joins catheter lengths 48 and 50, with the weld having three radial seam portions 52, 54 and 56 and two extended axial seam portions 58 and 60.
In FIG. 7, a shallow angle weld 62 axially joins catheter lengths 64 and 66. While no purely radial weld seam portions are formed in this arrangement, a single extended axial portion 68 gradually transitions along a shallow angle α.
FIG. 8 illustrates a variation in the weld configuration of FIG. 7, in that the weld 70 axially joining catheter lengths 72, 74 axially along a seam 76 which makes a relatively steep angle β.
FIG. 9 illustrates a hybrid weld 78 axially joining catheter lengths 80, 82 along a pair of angled seams 84, 86 connected by an extended axial seam 88.
FIG. 10 illustrates yet another hybrid weld 90 axially joining catheter lengths 92, 94. The weld includes a radial seam portion 96 and an angled seam portion 98 connected by an extended axial seam portion 100.
In each instance, the above described welds axially join two lengths of catheter with a significant axial seam portion (at least about 0.5 cm. in axial length and preferably 0.5-10 cm.) but without altering the outside diameter (OD) of the catheter. In other words, the OD of the outer plastic layer does not change and, in no case are there double thicknesses as in lap welds. At the same time, unlike butt welds, the weld seams extend axially along the length of the catheter. These extended axial portions of the various weld configurations (the longitudinal or axial extent of which may be varied) allow the catheter to be constructed with certain desired properties or characteristics as explained below.
The overall increased surface area of the welded joints increases the bond integrity between the two joined sections. The various weld configurations also create more desirable transitions between materials of different durometers, resins, etc. than typical butt or lap welded joints.
It is also possible to vary the characteristics of the catheter along its length by means of the overlapping welds described herein. For example, for the catheter shown in FIGS. 5 and 5A, with an axially extended overlap of from, e.g., 0.5 to 10 cm., a unique section of catheter is created where section 34 might be a hard durometer (e.g., 60-70 D Scale) and section 36 a soft durometer (e.g., 25-50 D Scale or even a very soft shore A hardness), the combined axial section along the axial length of the weld has a stiffness which is the average of the two durometers. This ability to create lengths of catheter with different properties or characteristics is most advantageous in areas of the catheter which will incorporate (or be bent into) curved areas. With reference now to FIG. 11, which illustrates the catheter sections 34 and 36 in a curved state through the weld area 38, the length 34 has a harder durometer--on the outside of the curve; while the length 36 has a softer durometer--on the inside of the curve. As a result, not only does the weld overlap area have a desirable stiffness which falls between the stiffness of the materials used to form sections 34 and 36, but in addition, unique curve retention properties are created by reason of the dominance of the harder durometer over the softer durometer. This is merely one example of the many possible applications of the concept. It is quite possible, for example, that for a similar curved area with a different purpose, the softer durometer may be on the outside and the harder durometer on the inside of the curve. By altering the radial location of the axial seam of the weld, different percentages of harder and softer durometers can be employed. As a visual aid to distinguish catheter sections having different properties, the axially overlapping sections may be color coded.
It should also be pointed out that the different catheter lengths can be of the same material (e.g., suitable resins) but have different durometers, or they can be of different materials of the same or different durometer. Suitable resins include Nylon 11 and Nylon 12; Pebax (25D to 70D); Nylon/Pebax blends; polyurethanes (large Durometer--infinite range); polyethylenes (high and low density); PVC; and other medical grade resins and various combinations of same.
Typical catheter constructions as shown and described herein may be in the size range of 1-15 French (0.013" to about 0.200" I.D.).
One or more inner layers (omitted from FIG. 5A but similar to FIG. 3) may include, for example, a conventional PTFE, FEP or similar liner reinforced by stainless steel braid. The invention here is applicable, however, to a wide range of catheter types. For example, both diagnostic (angiography) and therapeutic (guiding) catheters (and other catheter technologies such as PTA, PTCA, electrophysiology, casing leads, etc.) are suitable candidates for incorporation of the welds of this invention. Such catheters, as indicated above, may or may not include woven or braided reinforcements. Such reinforcements, if used, may comprise metal or synthetic materials including stainless steel, Kevlar�, etc. The catheters may be of single or multi-lumen design and may or may not have a Teflon� or other friction reducing lining. The catheters may or may not have a tapered distal portion and may or may not have side ports. While the catheter constructions illustrated herein show only a single weld per catheter, i.e., two axial sections, it should be understood that each catheter may have more than one welded area and may incorporate two or more different resins with the same or varying durometers.
With regard to the weld areas per se, the transition portions, i.e., the axially extending portions of the weld, may have an axial length to radial depth ratio of from about 3:1 to about 40:1. For purposes of discussion herein, a short transition weld has a ratio of about 3:1 to about 12:1, whereas a long transition weld has a ratio of about 12:1 to about 40:1. Short transition welds provide increased surface areas which strengthens the welded joints, and provide longer, less abrupt transition areas than simple butt welds. Such welds minimize the tendency of kinking and provide better torque transmission characteristics than conventional butt welds.
Long transition welds also provide increased surface area for strengthening the welded joints. In addition, long transition welds produce more desirable feel and/or handling characteristics in use. The orientation of different materials in long transition welds provides ease of straightening and permits unique properties to be established within one or more curved areas of the catheter. Long transition welds also allow for greater differences in durometer.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Patent Citations
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FCPA Compliance and Ethics Report-Episode 171-FCPA Enforcement in the Energy Industry
Cyber Risks Facing Businesses Today
Private Equity Fees and Expenses
Stephanie Pindyck Costantino Talks Domestic Oil and Gas M&A with The Deal
The Water Values Podcast: Rolling Out AMI in San Francisco with Alison Kastama and Heather Pohl (Part 1)
A Focus on Energy: Royalty Trusts
What Are the Important Issues for Investor-Owned Water Utilities?
A Focus on Energy: M&A Trends in the Energy Sector
A Focus on Energy: Traditional MLPs vs. Variable MLPs
PV Project Finance in Latin America is Easy, Right?
The Water Values Podcast - How Can We Resolve Water Conflicts?
The Water Values Podcast: Water as a Business Risk. And Opportunity. With Will Sarni
The Water Values Podcast - The Economics of Water with David Zetland, Ph.D.
Las Reformas Constitucionales Transcendentales en México: Oportunidades y Retos para el Inversionista Privado
Mexico's Historic Energy Reform: Opportunities and Challenges for Investors
How to Avoid Corruption Risks in China
Polsinelli Podcast - Hot Energy Trends in 2014 by Polsinelli
Bill on Bankruptcy: LightSquared, the Battle among Hedge Funds
California Commercial Building Owners Must Disclose Energy Usage of the Building During Sale, Lease or Financing after July 1, 2013
Transbay Tower Groundbreaking
On May 15, 2015, China's Ministry of Industry and Information Technology ("MIIT") released a latest Draft for Comments ("May 2015 Draft") of the "Management Methods for the Restriction of the Use of Hazardous Substances in...more
This week, the California Attorney General's Department of Justice sent letters to a large number of retailers, notifying those retailers that they may be subject to California's Transparency in Supply Chains Act (the "Act"...more
The Federal Energy Regulatory Commission has ordered the New York Independent System Operator, Inc. to reopen and resettle billings for electricity it supplied during the November/December 2012 billing periods, and to refund...more
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On July 31, 2013, United States Senators Elizabeth Warren and Edward J. Markey submitted a letter to Federal Energy Regulatory Commission ("FERC") Chairman Jon Wellinghoff, expressing serious concern over the apparent...more
On April 12, 2013, the N.C. Supreme Court stepped into the ongoing dispute regarding the 7.2 percent rate increase sought by Duke Energy and approved by the North Carolina Utilities Commission (NCUC) in January 2012. Duke...more
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With a population of roughly 1.3 million people, Maine is a small player in national markets. At the same time, Maine legislators have attempted to have an out-sized voice in the national marketplace of legislative policy by...more
Solar power panels on residential rooftops are an increasingly common sight these days. But the legal mechanics behind the development and delivery of solar power to consumers can be complex.
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Homeowners and renters in California may soon be able to access solar or other renewable energy from community based self-generation programs as an alternative to the power grids offered by the state's three major public...more
Attorney Steven Getman reports that Chesapeake Appalachia, L.L.C. will allow over 4,400 landowners who were locked into potentially unfavorable natural gas leases the opportunity to renegotiate with the energy company.
On October 11, 2009, Governor Schwarzenegger signed Senate Bill (SB) 695, the Ratepayer Protection Act (the "Act"), into law. The bill, authored by Senator Kehoe, represents a compromise between utilities, consumer groups and...more
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NFL - Page 17
Which NFL Team Has The Most Unstable Fans?
Groundbreaking Delayed at New Minnesota Vikings Stadium
Former South Dakota Lineman Tom Compton Praised for Pre-Season Play with Washington Redskins
Minnesota Vikings Shariff Floyd Out for Rest of Preseason
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Bud Grant Says He was Offered Minnesota Vikings Head Coaching Job in 2004
Greg Jennings Takes Another Jab At His Former Team
5-Year-Old Cancer Survivor Scored 40-yd Touchdown
At the Cleveland Browns family practice on Sunday, 5 year-old Ryan Encinas, a 5-year-old cancer survivor, finished off the night with a long touchdown run with Richardson directing him the whole way.
Minnesota Vikings Receiver Greg Jennings Now Says His Aaron Rodgers Comments Were Just a 'Joke'
Minnesota Vikings' Greg Jennings Jabs at Green Bay Packers' Aaron Rodgers
Minnesota Vikings new wide receiver Greg Jennings hasn't had the best things to say about his former quarterback this off-season since signing with the Green Bay's rival.


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text: I'm sorry that I haven't kept you guys in the loop on Liana's bulging soft spot ... but so much has happened this week, it was hard to keep up with it all, let alone blog about it!On Monday, I took her back to the pedi for a follow-up, and I could tell she was concerned. She also felt that Liana's head was maybe growing a little too fast, which could further indicate that something is causing extra cerebral pressure. However, she said the next tests would all be quite invasive (MRI, for which she'd need to be sedated or a spinal tap), and she wasn't quite ready to do that to an otherwise healthy child. She suggested to wait another couple of weeks and see what happened. Bjorn and I talked it over that night and decided we really didn't feel safe waiting for 2 more weeks. After the pediatrician had mentioned on Monday that it could possibly be a vascular issue, we were specifically concerned that her bulging soft spot was in some way related to the TTTS, (which is a vasucalar disease) or the other complications she had in-utero. So I called back the pediatrician and ask for a referral to a pediatric neurologist, which she was more than happy to make.In the mean time, Liana had a helmet adjustment, and when I told the cranial cap technician about her bulging soft spot, she was also concerned and didn't think Liana should be wearing her helmet at all. I had taken it off after we got back from the CT last week and she didn't wear it all weekend, and had also called the cranial cap doctor about it but not yet heard back from him. So as of yesterday, Liana is completely helmet-free, at least until we figure out what to do next.Then, this morning, we had the neurologist appointment down at Children's - and oh my gosh, what a chore!We were with the doctor for maybe 30 minutes but the whole thing turned into an almost 5 hour ordeal! What should have been a 45 minute drive there took TWO WHOLE HOURS! I just about died! And the roads weren't even that bad ... but I guess there'd been a few accidents and the whole metro area was a parking lot. For the last half hour of my drive there, I had DH on the phone who found me all these back roads online, because I swear, otherwise I might have never gotten there.Thankfully, the crazy receptionist lady told me to be there 45 minutes early to "fill out papers" (which turned out to be exactly ONE form that needed to be signed), so I was technically "only" half hour late to see the doctor. Liana was such a trooper and hardly made a peep the entire 2 hours there.About the appointment: It went okay and I guess she's fine. I was a little concerned that the appointment was so early in the day, because the bulging varies greatly depending on the time of day and is always worst at night. So of course, this morning, it was hardly bulging, just kind of "full". But the doctor was very thorough, both in taking her history and in examining her. Which reminds me: At some point as I am relaying the details of their TTTS and NICU stay to him he asks me if I work in the medical field - LOL! When you spent an entire year only thinking and talking about that stuff, I guess you kind of pick up the lingo. About the TTTS: It's always frustrating to me because often I feel I know more about the disease than many doctors do. I know it is relatively rare, but it does claim more lives each year than SIDS! At some point, the neurologist asked me if Liana's twin was a boy or a girl. TTTS ONLY happens in identical twin pregnancies, so yes, she'd have to be a girl. But also, there are just so many unanswered questions still - basically no one knew what exactly was going on for the last 7 weeks of the girls' pregnancy ... and in the same fashion, no one can tell me exactly if this could at all be related to the TTTS or not.But all this to say: The neurologist is not sure if there really is a problem. He's not saying there isn't - but there might not be. He thinks her head growth is fine ... it was a little aggressive for a while but is actually tapering of. Again, he didn't see the bulging at its worst, but he didn't think it was anything to worry about at this point. He did mention (and I didn't know this) that preemies can have issues in regards to the production and subsequent absorption of spinal fluids, and that usually resolves on its own. So at least that's a theory ... and certainly one I could live with! He gave me some very specific neurological symptoms to look for in case her cerebral pressure was increasing ... and at this point I feel very confident that I would know right away if something was getting worse. On the other hand, I still don't like the feeling of constantly having to assess her, if you know what I mean.For now, the plan is to take her back in 6 weeks for another check-up. I don't feel all of our questions have been answers and worries alleviated, but at least it's nothing serious right now and for that I'm very thankful!