Disclosed are multicomponent fibers wherein at least one component comprises a conventional, non-biodegradable synthetic polymer forming the exposed surface of the multicomponent fiber, thereby permitting thermal bonding of the multicomponent fiber to other fibers. The fibers also include at least one biodegradable component. The multicomponent fibers are useful in the manufacture of nonwoven structures, and in particular nonwoven structures used as a component in disposable absorbent products.

The present invention relates to heat bondable multicomponent fibers, and more particularly heat bondable multicomponent fibers having a biodegradable polymeric component, as well as articles incorporating the fibers as a component thereof
Synthetic fibers are widely used in a number of diverse applications to provide stronger, thinner, and lighter weight products. Synthetic fibers are typically heat adhesive (thermobondable) and thus are particularly attractive for the manufacture of nonwoven fabrics, either alone or in combination with other fibers (such as cotton, wool, and wood pulp). Nonwoven fabrics, in turn, are widely used as components of a variety of articles, including without limitation absorbent personal care products, such as diapers, incontinence pads, feminine hygiene products, and the like; medical products, such as surgical drapes, sterile wraps, and the like; filtration devices; interlinings; wipes; furniture and bedding construction; apparel; insulation; and others.
Nonwoven fabrics can be formed entirely of synthetic fibers or a mixture of synthetic and natural fibers (such as cellulosic fibers). For example, typically disposable absorbent products include an absorbent core formed of cellulosic fluff pulp. The absorbent core can also include thermobondable synthetic fibers to thermally bind the cellulose fibers together, thereby achieving an absorbent material with improved strength. The product can also be thinner and lighter weight than traditional products.
Conventional synthetic fibers, however, do not naturally degrade, thus creating problems associated with the disposal of products containing such fibers. In particular, recycling articles containing a blend of natural and conventional synthetic fibers is generally not cost effective, yet the disposal of these articles in landfills generates significant amounts of non-degradable waste. As landfills reach their capacity, the demand has increased for the incorporation of more degradable components in disposable products, as well as the design of products that can be disposed of by means other than by incorporation into solid waste disposal facilities.
To address concern over the issue of solid waste disposal, biodegradable polymers are increasingly used as a replacement for conventional synthetic polymers. Biodegradable polymers of interest include water-soluble polymers such as polyvinyl alcohol; naturally synthesized polymers such as sodium alginate and microbial polyesters; hydrolyzable aliphatic polyester and polyurethane polymers; and the like. Synthetic biodegradable aliphatic polyesters include polyglycolide and poly(lactic)acid polymers. See, for example, U.S. Pat. Nos. 5,166,231; 5,506,041; 5,759,569; and 5,171,309.
Of particular interest is the use of lactic acid to manufacture biodegradable resin. Poly(lactic) acid (hereinafterxe2x80x9cPLAxe2x80x9d) was initially introduced as a biodegradable polymer for medical products. U.S. Pat. Nos. 5,142,023 and 5,807,973 to Gruber et al. disclose processes by which a nonmedical grade of poly(lactic) acid may be produced and utilized in nonwoven fabrics. Examples of biodegradable fibers comprised entirely of polylactic acid polymers and/or copolymers are found in U.S. Pat. Nos. 5,010,145 and 5,760,144. See also U.S. Pat. Nos. 5,698,322 and 5,593,778 (directed bicomponent fibers which include poly(lactic acid) components).
The successful inclusion of biodegradable materials in disposable absorbent products provides several avenues by which these products may be discarded once their useful life has ended. Primarily, these articles may be easily and efficiently disposed of by composting. Alternatively, the disposable absorbent product may be easily and efficiently disposed of to a liquid sewage system wherein the disposable absorbent product is capable of being degraded.
Although biodegradable fibers are known, problems have been encountered with their use, for example, lack of control of the onset of polymer degradation. It is essential that the biodegradable fiber maintain its integrity until its useful life has ended. U.S. Pat. No. 5,593,778 is directed to a core/sheath bicomponent fiber comprised entirely of poly(lactic acid), wherein the core PLA component biodegrades at a faster rate than the sheath. Although such fibers can provide some benefits, such fibers merely delay the onset of degradation and do not provide means for proactively controlling or initiating degradation of biodegradable fibers.
The present invention provides multicomponent heat adhesive or thermobondable fibers which exhibit a number of desirable, yet contradictory, properties in a single fiber structure. The fibers of the invention include a biodegradable polymeric component, thereby providing advantages in the disposal of products made with such fibers. However, in contrast to prior biodegradable fiber constructions, the fibers of the invention are structured so that initiation of degradation can be readily controlled.
In this regard, in addition to a biodegradable component, the fibers of the invention also include a thermobondable non-biodegradable polymeric component. The non-biodegradable polymeric component forms the exposed outer surface of the fibers, completely encapsulating the biodegradable component. To control fiber degradation, the non-biodegradable polymer and biodegradable polymer can be selected so that the non-biodegradable polymer has a lower melting point (preferably at least about 10xc2x0 C. lower) than the melting point of the biodegradable polymer. The fibers can accordingly be thermally treated to melt away at least a portion of the non-biodegradable polymer component to expose the biodegradable component to conditions necessary to initiate decomposition or degradation thereof. Thus the fiber degradation process can be proactively initiated, rather than merely slowed or delayed, by protecting the biodegradable component from the environment until such a time as its degradation is purposefully triggered.
The present invention also provides fabrics formed of the multicomponent fibers of the invention, articles incorporating such fabrics as a component, processes for making the fibers and processes for controlling the degradation of articles made using the fibers.
The present invention will be described more fully hereinafter in connection with illustrative embodiments of the invention which are given so that the present disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art. However, it is to be understood that this invention may be embodied in many different forms and should not be construed as being limited to the specific embodiments described and illustrated herein. Although specific terms are used in the following description, these terms are merely for purposes of illustration and are not intended to define or limit the scope of the invention.
The multicomponent fibers of the invention include at least two structured polymeric components, a thermobondable non-biodegradable synthetic polymeric component and a biodegradable polymeric component. Multicomponent fibers are formed of two or more polymeric materials. For purposes of illustration only, the present invention will generally be described in terms of a bicomponent fiber comprising two components. However, it should be understood that the scope of the present invention is meant to include fibers with two or more components.
In general, the components are arranged in substantially constantly positioned distinct zones across the cross section of the multicomponent fiber and extend continuously along the length of the multicomponent fiber. A preferred configuration is a sheath/core arrangement, wherein a first component, the sheath, substantially surrounds a second component, the core. However, other structured fiber configurations as known in the art may potentially be used, such as but not limited to, xe2x80x9cislands-in-the-seaxe2x80x9d arrangements, and the like. Reference is made to U.S. Pat. No. 5,108,820 to Kaneko et al., U.S. Pat. No. 5,336,552 to Strack et al., and U.S. Pat. No. 5,382,400 to Pike et al. for a further discussion of multicomponent fiber constructions. The multicomponent fibers may also have unconventional shapes (such as multi-lobal) such as described in U.S. Pat. No. 5,277,976 to Hogle et al., and U.S. Pat. Nos. 5,057,368 and 5,069,970 to Largman et al.
The cross section of the multicomponent fiber is preferably circular, since the equipment typically used in the production of multicomponent synthetic fibers normally produces fibers with a substantially circular cross section. The configuration of the first and second components in a fiber of circular cross section can be either concentric or acentric, the latter configuration sometimes being known as a xe2x80x9cmodified side-by-sidexe2x80x9d or an xe2x80x9ceccentricxe2x80x9d multicomponent fiber.
The concentric configuration is characterized by the first component having a substantially uniform thickness, such that the second component lies approximately in the center of the fiber. In the acentric configuration, the thickness of the first component varies, and the second component therefore does not lie in the center of the fiber. In either case, the second component is substantially surrounded by the first component. Both the cross section of the fiber and the configuration of the components will depend upon the equipment which is used in the preparation of the fiber, the process conditions and the melt viscosities of the two components.
The thermobondable (or heat adhesive) non-biodegradable polymeric component and the biodegradable polymeric component of the fibers are selected so that the non-biodegradable component has a lower melting or softening temperature than the biodegradable component. Preferably the thermobondable non-biodegradable polymeric has a melting or softening point of at least 10xc2x0 C., more preferably at least about 20xc2x0 C., and most preferably at least about 25xc2x0 C., less than the melting point of the biodegradable polymeric component.
Because the non-biodegradable component has a lower melting point relative to the melting point of the biodegradable polymeric component, the non-biodegradable polymeric component can act as a latent adhesive in thermal bonding processes. Thermal bonding is a well-known method of nonwoven fabric formation in which synthetic fibers are heated to their glass transition point or beyond, causing the fibers to soften and adhere to adjoining fibers, thereby forming a nonwoven fabric. Thus, when the multicomponent fiber is subjected to an appropriate temperature, typically greater than the melting temperature of the first non-biodegradable component but less than the melting temperature of the second biodegradable component, the first component will soften or melt while the second component will generally maintain its rigid form. Thermal bonding conditions will vary depending upon factors such as polymers used, pressure, line speed and the like and can be readily determined by one of skill in the art.
Polymers suitable for use in the first component include polyolefins, polystyrenes, polyurethanes, acetal resins, polyethylene vinyl alcohol, and copolymers, terpolymers, and mixtures thereof. Polyester copolymers and polyamide copolymers are also acceptable for use in the first component. Olefinic resins, long-chain, synthetic polymers of at least 85 weight percent ethylene, propylene or other olefin unit, are of particular interest. Suitable polyolefins include polypropylene, polyethylene, polybutene, and copolymers and mixtures thereof. Specific examples of polyolefins suitable for use in the thermobondable non-biodegradable component include high density polyethylene, linear low density polyethylene, poly(1-butene), polypropylene, and copolymers, terpolymers, and mixtures thereof. In addition, the thermobondable non-biodegradable polymeric component may include mixtures of polyolefins with other polymers, such as but not limited to (ethyl vinyl acetate) copolymers, (ethylene acrylic acid) copolymers, and the like. In a preferred aspect of the invention, polyethylene is employed, in particular, high density polyethylene.
The second component of the fibers of the invention includes a biodegradable polymer as known in the art. As used herein, xe2x80x9cbiodegradablexe2x80x9d refers to a material that degrades under aerobic and/or anaerobic conditions in the presence of bacteria, fungi, algae, and other microorganisms to carbon dioxide/methane, water and biomass, although materials containing heteroatoms can also yield other products such as ammonia or sulfur dioxide. xe2x80x9cBiomassxe2x80x9d generally refers to the portion of the metabolized materials incorporated into the cellular structure of the organisms present or converted to humus fractions indistinguishable from material of biological origin. As a result, the biodegradable fiber, either in its initial form or after incorporation into a fabric, will begin to degrade when exposed to such microorganisms, even if such exposure occurs prior to the expiration of the fiber""s useful life. Exemplary biodegradable polymers include, without limitation, polyvinyl alcohol, hydrolyzable aliphatic polyesters, hydrolyzable aliphatic polyurethanes, cis-polyisoprene, cis-polybutadiene, poly(caprolactone), hydrolyzable poly(lactic acid), poly(hydroxy alkanoates), and the like and copolymers and blends thereof. The skilled artisan will appreciate that when poly(lactic acid) is used, the poly(lactic acid) polymer is first hydrolyzed before microorganisms can consume the hydrolysis products.
The biodegradable polymeric component can also be selected to provide strength or rigidity to the fiber and, thus, to nonwoven structures comprising the multicomponent fiber. Strength or rigidity of the fiber is generally achieved by selecting a biodegradable component having a thermal melting temperature greater than the thermal melting temperature of the thermobondable non-biodegradable component. Thus, as noted above, when the multicomponent fiber is subjected to an appropriate temperature, typically greater than the melting temperature of the first non-biodegradable component but less than the melting temperature of the second biodegradable component, the first component will soften or melt while the second component will generally maintain its rigid form.
Preferably the biodegradable polymeric component comprises poly(lactic acid). In addition to biodegradability, poly(lactic acid) can impart other desirable properties to the fibers of the invention. For example, the fibers of the invention which include poly(lactic acid) as a component can exhibit improved tensile strength, as compared to fibers including polyethylene terephthalate or a polyamides as a high temperature core.
Poly(lactic acid) polymer is a biodegradable polyester polymer generally prepared by the polymerization of lactic acid. However, it will be recognized by one skilled in the art that a chemically equivalent material may also be prepared by the polymerization of lactide. Therefore, as used herein, the term xe2x80x9cpoly(lactic acid) polymerxe2x80x9d is intended to represent the polymer that is prepared by either the polymerization of lactic acid or lactide. Reference is made to U.S. Pat. Nos. 5,698,322; 5,142,023; 5,760,144; 5,593,778; 5,807,973; and 5,010,145, the entire disclosure of each of which is hereby incorporated by reference.
Lactic acid and lactide are known to be an asymmetrical molecules, having two optical isomers referred to, respectively as the levorotatory (hereinafter referred to as xe2x80x9cLxe2x80x9d) enantiomer and the dextrorotatory (hereinafter referred to as xe2x80x9cDxe2x80x9d) enantiomer. As a result, by polymerizing a particular enantiomer or by using a mixture of the two enantiomers, it is possible to prepare polymers that are chemically similar yet which have widely differing properties. In particular, it has been found that by modifying the stereochemistry of a poly(lactic acid) polymer, it is possible to control the melting temperature of the polymer.
The degree of crystallinity of a PLA polymer is based on the regularity of the polymer backbone and its ability to line up with similarly shaped sections of itself or other chains. If even a relatively small amount of D-enantiomer (of either lactic acid or lactide), such as about 3 to about 4 weight percent, is copolymerized with L-enantiomer (of either lactic acid or lactide), the polymer backbone generally becomes irregularly shaped enough that it cannot line up and orient itself with other backbone segments of pure L-enantiomer polymer, thus reducing the crystallinity of the polymer, which in turn suppresses the melting point. Based on the foregoing, although a minimal amount of D-enantiomer can be tolerated, preferably the amount of D-enantiomer present in the instant invention is not such that it suppresses the melting point of the PLA component to the melting point of the first component, or to within 10xc2x0 C. thereof.
Advantageously the PLA polymer also exhibits residual monomer percents effective for the second component to exhibit desirable melt strength, fiber mechanical strength, and fiber spinning properties. As used herein, xe2x80x9cresidual monomer percentxe2x80x9d refers to the amount of lactic acid or lactide monomer that is unreacted yet which remains entrapped within the structure of the entangled PLA polymer chain. In general, if the residual monomer percent of a PLA polymer in a component is too high, the component may be difficult to process due to inconsistent processing properties caused by a large amount of monomer vapor being released during processing that cause variations in extrusion pressures. However, a minor amount of residual monomer in a PLA polymer in a component may be beneficial due to such residual monomer functioning as a plasticizer during a spinning process. Thus, the PLA polymer in the second component generally exhibits a residual monomer percent that is less than about 15 percent, preferably less than about 10 percent, and more preferably less than about 7 percent.
Each of the thermobondable non-biodegradable polymeric component and the biodegradable polymeric component can optionally include other components not adversely effecting the desired properties thereof. Exemplary materials which could be used as additional components would include, without limitation, pigments, antioxidants, stabilizers, surfactants, waxes, flow promoters, solid solvents, particulates, and other materials added to enhance processability of the first and the second components. For example, a stabilizing agent may be added to the biodegradable polymer to reduce thermal degradation which might otherwise occur during the poly(lactic) acid spinning process. The use of such stabilizing agents is disclosed in U.S. Pat. No. 5,807,973, hereby incorporated by reference. Further, additives which enhance the biodegradability of the poly(lactic) acid may optionally be included, as disclosed in U.S. Pat. No. 5,760,144, previously incorporated by reference. These and other additives can be used in conventional amounts.
The weight ratio of the thermobondable non-biodegradable polymeric component and the biodegradable polymeric component can vary. Preferably the weight ratio is in the range of about 10:90 to 90:10, more preferably from about 30:70 to about 70:30, and most preferably from about 40:60 to about 60:40.
As discussed above, the thermobondable non-biodegradable component generally provides the entire exposed surface on the multicomponent fiber, thereby permitting thermal bonding of the multicomponent fiber to other fibers (which may be the same or different from the multicomponent fiber of the present invention). In one preferred aspect of the invention, the thermobondable non-biodegradable polymeric component is the sheath of a sheath/core fiber. As a result, the multicomponent fiber is useful in the production of a wide variety of thermally bonded fibrous nonwoven structures, such as but not limited to carded webs, wet laid webs, dry laid webs, spunbonded webs, meltblown webs, and the like. While particularly useful in the production of nonwoven fabrics, the fibers of the invention can also be used to make other textile structures such as but not limited to woven and knit fabrics.
In addition, the onset of biodegradation in a multicomponent article containing a biodegradable polymer may be delayed until purposefully triggered, thereby extending the anticipated useful life of articles containing such biodegradable polymers. Therefore, in one aspect of the invention, fabric bonding occurs by simply softening the latent adhesive polymer without fully melting it, thereby leaving the latent adhesive polymer layer intact to protect the biodegradable polymer from the environment. Degradation of the fiber or article can then be initiated by a heat treatment of the fiber of the present invention, or article containing such fiber, prior to its disposal in the environment. This heat treatment is effected by exposing the fiber to sufficient energy to decrease the melt viscosity of the latent adhesive polymer so that it flows off of, or melts away from, the surface of the biodegradable polymer, thereby exposing the biodegradable polymer to the environment and triggering subsequent degradation.
The thermobondable non-biodegradable component comprises 100 percent of the surface of the fiber, thereby providing both thermal bonding properties and maximum protection to the biodegradable core. A core/sheath structure is preferred, as noted above. The core/sheath fiber can advantageously be incorporated into a thermally bonded nonwoven fabric, which can then be subjected to a heat treatment after the useful life of the fabric has ended.
In another aspect of this invention, the biodegradable polymer may be exposed to the environment during fabric formation. In this aspect, sufficient energy is supplied during the thermal bonding process to allow the latent adhesive polymer to flow off of the surface of the biodegradable polymer.
Methods for making multicomponent fibers are well known and need not be described here in detail. Generally, to form a multicomponent fiber, at least two polymers are extruded separately and fed into a polymer distribution system wherein the polymers are introduced into a segmented spinneret plate. The polymers follow separate paths to the fiber spinneret and are combined in a spinneret hole. The spinneret is configured so that the extrudant has the desired shape.
Following extrusion through the die, the resulting thin fluid strands, or filaments, remain in the molten state for some distance before they are solidified by cooling in a surrounding fluid medium, which may be chilled air blown through the strands. Once solidified, the filaments are taken up on a godet or another take-up surface. In a continuous filament process, the strands are taken up on a godet which draws down the thin fluid streams in proportion to the speed of the take-up godet. In the jet process, the strands are collected in a jet, such as for example, an air gun, and blown onto a take-up surface such as a roller or a moving belt to form a spunbond web. In the meltblown process, air is ejected at the surface of the spinnerette which serves to simultaneously draw down and cool the thin fluid streams as they are deposited on a take-up surface in the path of cooling air, thereby forming a fiber web. Regardless of the type of melt spinning procedure which is used, it is important that the thin fluid streams be melt drawn down in a molten state, i.e. before solidification occurs to orient the polymer molecules for good tenacity. Typical melt draw down ratios known in the art may be-utilized. Where a continuous filament or staple process is employed, it may be desirable to draw the strands in the solid state with conventional drawing equipment, such as, for example, sequential godets operating at differential speeds. See, for example, U.S. Pat. No. 5,082,899.
Following drawing in the solid state, the continuous filaments may be crimped or texturized and cut into a desirable fiber length, thereby producing staple fiber. The length of the staple fibers generally ranges from about 25 to about 50 millimeters, although the fibers can be longer or shorter as desired. See, for example, U.S. Pat. No. 4,789,592 to Taniguchi et al. and U.S. Pat. No. 5,336,552 to Strack et al.
The use of poly(lactic) acid in composite fibers is especially advantageous. Poly(lactic) acid develops tensile properties which are comparable or improved in comparison to the polyester and polyamide polymers traditionally employed in the core of bicomponent binder fibers.
The multicomponent fibers of the invention can be staple fibers, continuous filaments, or meltblown fibers. In general, staple, multi-filament, and spunbond fibers formed in accordance with the present invention can have a fineness of about 0.5 to about 100 denier. Meltblown filaments can have a fineness of about 0.001 to about 10.0 denier. Monofilament fibers can have a fineness of about 50 to about 10,000 denier.
As noted above, the multicomponent fibers can be incorporated into a fabric. Fibers other than the multicomponent fibers of the invention may be present as well, including any of the various synthetic and/or natural fibers known in the art. Exemplary synthetic fibers include polyolefin, polyester, polyamide, acrylic, rayon, cellulose acetate, thermoplastic multicomponent fibers (such as conventional sheath/core fibers, for example polyethylene sheath/polyester core fibers) and the like and mixtures thereof. Exemplary natural fibers include wool, cotton, wood pulp fibers and the like and mixtures thereof.
In a preferred embodiment, the multicomponent fiber of the instant invention is incorporated into a nonwoven fabric. Staple fibers of the present invention may be formed into nonwoven webs by any means known in the art, including dry laid processes, such as carding or airlaying, as well as wet laid processes. Wet laid webs are of particular interest in the present invention, and such a process is described in U.S. Pat. Nos. 5,167,765 and 5,456,982, both hereby incorporated by reference. In addition, continuous filament may be spun directly into nonwoven webs by a spunbonding process.
Alternatively, the multicomponent fibers of the invention may be incorporated, alone or in conjunction with other fibers, into a meltblown nonwoven fabric. The technique of meltblowing is known in the art and is discussed in various patents, e.g., Buntin et al., U.S. Pat. No. 3,987,185; Buntin, U.S. Pat. No. 3,972,759; and McAmish et al., U.S. Pat. No. 4,622,259.
The nonwoven webs thus formed are typically subsequently thermally bonded to transform them into nonwoven fabrics, using any thermal bonding technique known in the art.
Nonwoven fabrics which include the multicomponent fibers of the invention as a component are particularly suited for use in disposable products. Specific examples include without limitation disposable diapers, adult incontinent products, sanitary napkins, tampons, wipes, bibs, wound dressings, and surgical capes or drapes.
The nonwoven fabrics of the invention are particularly advantageous as components of a disposable diaper. Disposable diapers typically include a liquid-permeable topsheet, a backsheet attached to the liquid-permeable topsheet, and an absorbent structure positioned between the liquid-permeable topsheet and the backsheet. The nonwoven fabrics of the invention may be incorporated into any of the components which make up the disposable absorbent product, but are preferably included in the absorbent structure. Such absorbent structures are typically multilayered, comprising at least one acquisition/distribution layer and at least one storage layer. The nonwoven fabrics of the invention are particularly useful as a component of the storage layer. Exemplary disposable absorbent products are generally described in U.S. Pat. No. 4,710,187; U.S. Pat. No. 4,762,521; U.S. Pat. No. 4,770,656; and U.S. Pat. No. 4,798,603.
The fabrics of the invention can also be used as a layer in composite fabric laminate. By combining two or more nonwoven fabrics of different types, nonwoven fabric laminates have been developed for a variety of specific end use applications. Specific examples of such fabrics are described in U.S. Pat. Nos. 3,676,242; 3,795,771; 4,041,203; 4,766,029 and 4,863,785.
In an alternative embodiment, the concept of delaying the onset of polymer degradation by encapsulating the biodegradable polymer in conventional synthetic resin may be extended to other extruded articles, such as films or pultruded goods. For example, a film layer formed of a biodegradable polymer can be sandwiched between two layers of non-biodegradable polymer. The biodegradable film core typically has a melting temperature that is at least about 10xc2x0 C. greater than the melting temperature exhibited by the outer layers, congruent with the other embodiments of this invention. Similarly, a pultruded article can be prepared by sandwiching a higher melt temperature biodegradable core component between two outer layers comprised of one or more non-biodegradable synthetic polymers.


The present invention relates to specific methods of producing cleated rubber-backed floor mats (such as dust control or rubber mats) through the utilization of the combination of a perforated coated woven fabric article and a cushioned platen liner between the article and the metal platen of an in-line dust control mat manufacturing machine. Such a procedure permits a more efficient manner of producing cleated anti-creep dust control mats than previously followed. In particular, the fabric article is in the form of a conveyor belt and is preferably constructed from Teflon(copyright)-coated woven fiberglass which will not adhere to the tacky rubber component of the target mat and can withstand the extremely high vulcanization temperatures and pressures required during the production of a dust control mat. The cushioned platen liner, which is preferably comprised of or coated with silicon, is utilized as a separator between the metal platen of the manufacturing machine, as well as cushion for the molten rubber as it is pressed through the conveyor belt perforations during vulcanization. Such a cushioned liner material substantially eliminates any problems due to the force of the metal platen against the molten rubber as it passes through the article perforations. Further, a method for utilizing the conveyor belt to produce foam rubber cleated anti-creep mats is disclosed. The cleats of these mats have a thicker skin than the rest of the mat, thereby imparting enough strength and structural integrity so that the foam rubber mats may withstand the daily rigors of use, combined with periodic launderings. The produced mat as well as the woven fabric article/cushioned platen liner combination are also encompassed within this invention.

The present invention relates to specific methods of producing cleated rubber-backed floor mats (such as dust control or rubber mats) through the utilization of the combination of a perforated coated woven fabric article and a cushioned platen liner between the article and the metal platen of an in-line dust control mat manufacturing machine. Such a procedure permits a more efficient manner of producing cleated anti-creep dust control mats than previously followed. In particular, the fabric article is in the form of a conveyor belt and is preferably constructed from Teflon(copyright)-coated woven fiberglass which will not adhere to the tacky rubber component of the target mat and can withstand the extremely high vulcanization temperatures and pressures required during the production of a dust control mat. The cushioned platen liner, which is preferably comprised of or coated with silicon, is utilized as a separator between the metal platen of the manufacturing machine, as well as cushion for the molten rubber as it is pressed through the conveyor belt perforations during vulcanization. Such a cushioned liner material substantially eliminates any problems due to the force of the metal platen against the molten rubber as it passes through the article perforations. Further, a method for utilizing the conveyor belt to produce foam rubber cleated anti-creep mats is disclosed. The cleats of these mats have a thicker skin than the rest of the mat, thereby imparting enough strength and structural integrity so that the foam rubber mats may withstand the daily rigors of use, combined with periodic launderings. The foam rubber mats described herein are also encompassed within this invention.
All U.S. patent cited herein are hereby fully incorporated by reference.
Floor mats have long been utilized to facilitate the cleaning of the bottoms of people""s shoes, particularly in areas of high pedestrian traffic such as doorways. Moisture, dirt, and debris from out of doors easily adhere to such footwear, particularly in inclement weather and particularly in areas of grass or mud or the like. Such unwanted and potentially floor staining or dirtying articles need to be removed from a person""s footwear prior to entry indoors. As will be appreciated, such outdoor mats by their nature must undergo frequent repeated washings and dryings so as to remove the dirt and debris deposited thereon during use. These mats are generally rented from service entities which retrieve the soiled mats from the user and provide clean replacement mats on a frequent basis. The soiled mats are thereafter cleaned and dried in an industrial laundering process (such as within rotary washing and drying machines, for example) and then sent to another user in replacement of newly soiled mats. Furthermore, it is generally necessary from a health standpoint to produce floor coverings on which persons may stand for appreciable amounts of time which will provide comfort to such persons to substantially lower the potential for fatigue of such persons by reducing the stress on feet and leg joints through cushioning.
Typical carpeted dust control mats comprise solid and/or foam rubber backing sheets which must be cleated in some manner to prevent slippage of the mat from its designated area. Such cleats are formed during a vulcanization step and have required a time-consuming procedure of placing the green (unvulcanized) rubber sheet on a molded, perforated silicone pad which is itself placed by hand on the conveyor belt of a dust control manufacturing apparatus. The finished mat is then removed after vulcanization from the non-stick silicon pad. The resultant mat product possesses cleats formed through the melting and forcing of part of the rubber backing through the pad perforations during vulcanization. Such cleats provide anti-slip or anti-creep characteristics to the finished mat when placed upon a surface to be protected. Various types, shapes, and arrangements of cleats have been utilized in the past for such anti-creep benefits with dust control mats. Examples include U.S. Pat. No. 4,741,065 to Parkins, U.S. Pat. No. 5,170,526 to Murray, and U.S. Pat. No. 5,227,214 to Kerr et al.
Heretofore, attempts to use a foam rubber backing on cleated floor mats or carpets have been mostly unsuccessful because the foam rubber is rather weak, with poor abrasion resistance, which leads to the cleats being quickly worn away. The foam rubber is too soft to withstand the daily rigors of wear and tear in combination with the periodic laundering process. However, it would be desirable to provide a rubber floor mat or carpet having a foam rubber, cleated backing because of the reduced, weight and improved frictional characteristics imparted by the foam rubber.
As noted above, previous methods of providing such cleat features to rubber-backed mats are generally produced through the utilization of a perforated silicon pad which is placed by hand on a conveyor belt on in in-line vulcanization apparatus. A rubber article is then placed on top of silicon pad, and optionally a fabric pile (such as a carpet) is then placed, again by hand, on top the rubber article. The conveyor belt then transports the entire composite to a vulcanization chamber wherein it is pressed at a pressure of from about 25 to about 50 psi at a temperature of from about 300 to about 400xc2x0 F. for anywhere between about 30 seconds and 20 minutes. After vulcanization, the conveyor belt transports the finished composite (floor mat plus silicon pad) out of the chamber. The floor mat is then removed from the pad and allowed to cool and the pad is moved, by hand, back to a location on the conveyor belt, prior to the chamber, in order for another rubber article to be placed thereon. Such a procedure is labor-intensive and inefficient. However, until now, there have been no disclosures of proper methods to reduce the time and labor required to effectively and efficiently produce rubber-backed cleated floor mats. There have been developments in conveyor belts, particularly those covered with Teflon(copyright) coatings, for utilization in other rubber molding processes. However, there has been no discussion or suggestion regarding the problems associated with cleat-forming perforated conveyor belts in the past. In light of the above, it will be appreciated that there is a need for a process and apparatus to efficiently produce cleats within the rubber backing of an anti-creep floor mat. Further, there exists a need to produce a foam rubber, cleated mat or carpet that includes thick-skinned cleats, which are resistant to wear and tear during use, as well as during periodic laundering. The present invention thus represents a useful advancement over prior practice.
In view of the foregoing, it is a general object of the present invention to provide an in-line method for the production of cleats in a rubber or rubber-backed floor mat. Furthermore, it is an object of this invention to provide a novel conveyor belt system for an in-line floor mat manufacturing apparatus. Additionally, an object of this invention is to provide a cleated anti-creep floor mat which is more easily and efficiently produced than standard cleated floor mats. Still another object of this invention is to provide an anti-creep floor mat which exhibits not only cleats to provide anti-slip characteristics, but also intermittent patterned areas within the rubber on the underside of the rubber floor mat component which mirrors the woven structure of the perforated fabric article. Another object of the present invention is to provide a foam rubber floor mat having a relatively thin skin of dense rubber on an outer layer thereof, and further having cleats that include a thick skin of dense rubber on at least the bottom portions of the cleats. Yet another object of the present invention is to provide a foam rubber floor mat as described above, which further includes a carpet pile secured to one side thereof.
Accordingly, this invention encompasses a method of producing a cleated anti-creep floor mat comprising a rubber mat component with a mat producing apparatus comprising the steps of:
(a) providing a perforated woven fabric article, which is coated or comprised of a material which will not adhere to said rubber mat component after a vulcanization step, wherein said perforated woven fabric article is optionally separated from the metal platen of said apparatus by a cushioned platen liner;
(b) placing said rubber mat component on top of said perforated woven fabric article of step xe2x80x9caxe2x80x9d and optionally placing thereon a fabric pile;
(c) transporting the rubber mat component/perforated woven fabric article composite to a vulcanization chamber; and
(d) vulcanizing said rubber mat component as it remains on top of the perforated woven fabric article, thereby forming cleats through the perforations of said perforated woven fabric article;
wherein said woven fabric article and said optional platen liner are comprised of or coated with materials which can withstand the temperatures and pressures associated with vulcanization. Also, this invention concerns a floor mat manufacturing apparatus having a metal platen wherein said apparatus further comprises a perforated conveyor belt positioned on top of a cushioned platen liner which is positioned on top of said metal platen. Additionally, this invention encompasses floor mat article comprising at least a rubber sheet component wherein said rubber comprises a plurality of cleats formed integrally on the surface and at least a portion of the surface of said rubber sheet also comprises a weave pattern of molded rubber.
Also, a method for-making a foam rubber cleated floor mat or carpet is described, including the steps of:
providing a mold having at least one recess to form at least one protrusion on said floor covering article;
providing a temperature differential between a bottom portion of the recess and other portions of the mold, so that the bottom portion of the recess maintains a higher temperature than other portions of the mold;
placing an unvulcanized foam rubber compound onto the mold; and
vulcanizing the floor covering article.
The term xe2x80x9cperforatedxe2x80x9d or xe2x80x9cperforationsxe2x80x9d is intended to encompass any configuration of holes within the woven fabric article structure through which molten rubber may be forced during vulcanization. Thus, any shape hole, any orientation of holes, and any depth of such holes is encompassed within such a term. Preferably, the holes (perforations) are circular in shape ultimately to produce cylindrically shaped cleats in the target mat article. Also, the diameter of such perforations are preferably from about {fraction (1/64)} inch to about xc2xc inch; more preferably from about {fraction (1/32)} inch to about xe2x85x9 inch; and most preferably from about {fraction (3/32)} to about {fraction (1/16)} inch.
Preferably, the perforated woven fabric article of the instant invention exhibits a modulus of from about 70 to 100 on the Shore A Hardness Scale and is present in the form of a conveyor belt which thereby permits an in-line mat production procedure. In such a form, the platen liner must be utilized under the conveyor belt in order to reduce off-quality cleat production, as discussed below. However, if desired, the woven fabric article may also be a separate article that is cut from a web of fabric which can be placed by hand on a cushioned platen liner and/or on a standard conveyor belt within a mat a manufacturing apparatus. After vulcanization, the finished mat can easily be removed from the fabric article and the fabric article can then be transported to a pre-vulcanization location for placement of another rubber mat component thereon. The preferred conveyor belt of the instant invention must be constructed of material which not only can withstand continuous and/or repeated movement around a rotating drum and through a standard in-line floor mat manufacturing apparatus; such materials (including the cut-out forms of such woven fabric articles) must also be able to withstand the high temperatures and pressures associated with rubber vulcanization. The core material of such a belt or cut-out is thus preferably fiberglass although other materials, such as polyaramids, silicon, and the like, may also be utilized. The belt or cut-out should also be coated with a covering which can also withstand vulcanization temperatures and pressures and not appreciably adhere to molten rubber. Silicon may be utilized for this purpose as well; however, the preferred coating is polyfluoroethylene, also known as Teflon(copyright), available from DuPont. The preferred conveyor belt (or cut-out fabric) is first produced by taking a woven (or non-woven) fiberglass fabric and coating it with a certain number of Teflon(copyright) layers. Perforations are then cut into the coated fabric to conform with the desired shape and orientation of ultimately formed cleats on the target floor mat article. Then, the cut fabric is coated with a few more layers of Teflon(copyright) in order to insure the potentially frayed fibers of the cut fiberglass will not interfere with the eventual removal of the target floor mat article from the belt surface. If such frayed fiber ends were not coated themselves, they could adhere to the mat and produce aesthetically displeasing results. The coated fabric, and thus the belt itself, may have a thickness of from about {fraction (1/64)} inch to about xc2xc inch, depending on the desired size of the ultimately formed cleats. The thickness of the fabric (belt) dictates the length of the projected cleats from the rubber surface of the mat article since, upon melting during vulcanization, the rubber will become forced through the perforations of the belt a distance roughly the same as the belt thickness. Preferably, the cleat lengths are from about {fraction (1/64)} to xc2xc inch, more preferably from about {fraction (1/32)} inch to about xe2x85x9 inch; most preferably about {fraction (3/32)} inch.
Prior to incorporating the aforementioned preferred conveyor belt to a floor mat manufacturing apparatus (which generally comprises a metal platen over which the conveyor belt would be placed directly), a cushioned platen liner is placed over the metal platen. A platen liner may be placed beneath the cut-out woven fabric article as well; however, since the hand-placed fabric article would most likely be placed on a conveyor belt itself, or placed within a shelf-type vulcanization chamber, some degree of cushioning would already be provided which could render the utilization of such a platen liner unnecessary.
In general, it has been discovered that the platen liner should be present to avoid the creation of xe2x80x9cflaredxe2x80x9d cleats in the final mat product. Such a problem is caused by both the lack of adhesion between the molten rubber and the Teflon(copyright)-coated fabric surface as well as the force of the metal platen on the molten rubber forced through the fabric perforations. Without a cushioning platen liner, when the vulcanization chamber presses down on the mat article, the rubber, upon melting, is forced through the perforations into the metal platen. The force of the stationary metal platen then forces the rubber back toward the belt and rubber article; however, the molten rubber will seek the path of least resistance rather than returning through the perforation it came originally. Without the adhesion between the fabric and the rubber, the rubber will easily move between the fabric and the platen. In such an instance, upon exiting the vulcanization chamber, the mat article is not easily removed from the belt (since the rubber forms xe2x80x9chooksxe2x80x9d on the underside of the belt). The resultant mat article thus exhibits aesthetically displeasing cleat formations which themselves possess suspect effectiveness as preventing slippage or creeping of the mat when placed on a protected surface. Hence, it was discovered that in order to provide such an efficient procedure of in-line cleat forming for floor mat articles, a cushioned platen liner was required to separate the fabric article (belt) from the metal platen and to provide cushioning of the rubber to prevent re-forcing back toward the belt itself during vulcanization. However, such a platen liner may not be required when a cut-out article is utilized to produce the desired cleats, most notably when the conveyor belt itself (which may be coated rubber, or other fabric, for example) within the mat manufacturing apparatus provides the necessary cushioning effect; but, other times there will be a need to utilize such a cushioned article to reduce the production of off-quality cleats.
When present, the platen liner preferably covers the entire area of the metal platen over which mat articles will be placed. Preferably, the platen liner will possess a modulus of from about 40 to 70 on the Shore A Hardness Scale in order to provide the necessary cushioning effects for proper cleat formation. Preferably, the modulus is about 50 on the same scale. Furthermore, the platen liner must be able to withstand the high temperatures and pressures associated with rubber vulcanization. Thus, the liner must be constructed from material that possesses both characteristics. The preferred material is a rubber coated silicon (available from Taconic, for example), which exhibits a Shore Hardness of about 50. However, the liner may also be constructed from other heat-resistant materials which have been incorporated within flexible fabrics, rubber, and the like, and/or alternatively coated with a heat-resistant material, such as Teflon(copyright), silicon, and the like. The thickness of such a liner is not of great importance, although, the thicker the better (for cushioning purposes). The utilization of too thick a liner will not seriously impact the effectiveness of the perforated conveyor belt in producing the desired cleats; however, as silicon liners are rather expensive, the thickness should be dictated primarily by cost versus available cushioning characteristics. As such, a thickness of from about {fraction (1/64)} inch to about xc2xd inch is preferred; {fraction (1/64)} to about xe2x85x9 inch more preferred; and {fraction (1/64)} inch to about {fraction (1/32)} inch most preferred.
In an alternate embodiment, foam rubber is used to form a cleated floor mat or carpet that is strong enough to withstand the normal, day to day wear and tear, as well as the periodic launderings and washings that are commonly performed on these articles. The method and apparatus for mat manufacture disclosed herein may be used to advantageously produce a foam rubber cleated floor mat or carpet in accordance with the present invention.

Cleat-forming woven fabric article for the manufacture of anti-creep floor mats


Provided herein are kits, compositions and methods for cancer diagnosis, research and therapy, including but not limited to, cancer markers. In particular, the present invention relates to recurrent gene fusions (e.g., recurrent translocations involving TYK2) as diagnostic markers and clinical targets for cutaneous CD30-positive lymphoproliferative disorders (e.g., lymphomatoid papulosis; primary cutaneous anaplastic large cell lymphoma).

Lymphoproliferative disorders (LPDs) refer to several conditions in which lymphocytes are produced in excessive quantities. They typically occur in patients who have compromised immune systems. Examples of LPDs include, but are not limited to, follicular lymphoma, chronic lymphocytic leukemia, acute lymphoblastic leukemia, hairy cell leukemia, lymphomas, multiple myeloma, Waldenstrom's macroglobulinemia, Wiskott-Aldrich syndrome, post-transplant lymphoproliferative disorder, autoimmune lymphoproliferatieve syndrome (ALPS), lymphoid interstitial pneumonia, and CD30-positive lymphoproliferative disorders. Examples of CD30-positive lymphoproliferative disorders include lymphomatoid papulosis and primary cutaneous anaplastic large cell lymphoma.
Lymphomatoid papulosis (LYP) is characterized by multiple papules and nodules, which regress spontaneously. Three histologic subtypes have been described, which represent a spectrum with overlapping features and do not carry prognostic significance. Type A lesions have a few tumor cells in a background of inflammatory cells including neutrophils, eosinophils, and histiocytes. Type B lesions are characterized by epidermotropic lymphocytes with cerebriform nuclei mimicking mycosis fungoides. Type C lesions have sheets of large atypical lymphoid cells with only a few admixed inflammatory cells. The large atypical lymphoid cells are thought to be of T cell origin. Various histologic types may be present in individual patients at the same time. In LYP types A and C the large atypical cells express CD30, CD3, and CD4. CD2 and CD5 are usually expressed. These cells also express the cytotoxic markers TIA-1 and granzyme. The large atypical cells do not express CD8, CD7, or CD56. The cells may lose expression of CD3. In LYP type B the atypical cells are usually CD30 negative. Five year survival rates for LYP are 100%; however up to 20% of patients develop LYP-associated malignant lymphomas (e.g., mycosis fungoides, Hodgkin lymphoma, systemic or cutaneous CD30+ large T-cell lymphoma), which result in a fatal outcome of 2% of patients.
Primary cutaneous anaplastic large cell lymphoma (ALCL) is composed of large atypical to anaplastic appearing lymphoid cells. This disease mainly affects adults with a peak in the sixth decade, but cases have been reported in children. It usually presents as a solitary rapidly growing nodule. The skin overlying the lesion may ulcerate. Histologically the cells grow in sheets. Mitotic figures are frequent. Clusters of small reactive lymphocytes are found within and around the tumor cells. The malignant cells express CD2, CD3, CD4, CD30, and cytotoxic markers including TIA-1, granzyme, and perforin. Loss of T-cell antigen expression is not infrequent. The malignant cells do not express EMA or ALK. Five year survival rates approach 90%. Interestingly, up to 40% of C-ALCL show spontaneous regression similarly to LYP.
Improved methods for detecting, investigating, and treating CD30-positive lymphoproliferative disorders (e.g., lymphomatoid papulosis; primary cutaneous anaplastic large cell lymphoma) are needed.

Recurrent gene fusions in cutaneous CD30-positive lymphoproliferative disorders

The Regents of the University of Michigan


An aluminum-polymer composite is made by coating a surface portion of an aluminum alloy body with a primer composition comprising a vinylphosphonic acid-acrylic acid copolymer to form a primer layer, coating the primer layer with a radiation curable polymer precursor, and irradiating the polymer precursor with ultraviolet or electron beam radiation. The process of the invention is particularly suitable for making polymer coated aluminum alloy sheet that is shaped into container end panels for food and beverage containers.

The present invention relates to radiation curable coatings for aluminum alloy bodies. More specifically, the invention relates to an improved primer composition for coatings containing radiation curable polymer precursors. The product is preferably polymer coated aluminum alloy sheet suitable for shaping into end panels for food and beverage containers. Another aspect of the invention relates to polymer coated aluminum alloy extrusions for architectural uses.
Aluminum alloy sheet coated with a polymeric composition on one or more surfaces is commonly used for shaping into end panels for food and beverage containers. The coating can be applied by processes such as reverse roll coating, gravure coating, electrocoating, spraying, powder coating, and forward roll coating. Coatings are applied to the sheet to better preserve foods and beverages stored in metal containers produced from the coated sheet, and to improve their taste characteristics. Coatings also improve the corrosion resistance, formability and appearance of the metal.
Commonly used commercial coating processes involve the use of solvent based systems that generate volatile organic compounds (VOC""s) into the air. To reduce or eliminate the generation of such volatile organics during the coating process, solids coating systems have been proposed for application to the metal surface during the coating process. Examples of solids coating systems are those known as ultraviolet (UV) or electron beam (EB) curable coatings. Such coating systems generally contain monomers and oligomers so that they can be applied to substrates in a fluid state. Some coating systems may also contain small amounts of a solvent to improve fluidity during application. The monomers and oligomers react to form 100% solids coatings.
However, UV and EB curable coatings often separate from the metal substrate during end formation operations.
Accordingly, a need exists for a polymer coated metal sheet which is produced using coatings that do not generate VOC""s after being cured and which has sufficient polymer adhesion to adhere to the metal during subsequent fabrication of the metal sheet into ends for beverage or food containers.
Thus, an objective of the present invention is to provide an improved primer composition for making aluminum alloy sheet using coatings that do not generate VOC""s during curing and which have sufficient adhesive strength to adhere to the metal surface during subsequent fabrication of the sheet into ends for beverage or food containers.
Although aluminum and aluminum alloys protect themselves against corrosion by forming a natural oxide coating, the protection is not complete. In the presence of moisture and certain electrolytes, aluminum and its alloys may corrode very quickly. Such moisture and electrolytes may originate in acid rain water, water puddles on roadways, salted winter roads, or food materials, among others. Coatings, such as organic polymer and silicone coatings, may protect aluminum substrates to a limited extent by themselves, but are usually poorly adherent without an intermediate treatment or layer. Also, thin coatings are frequently porous, and therefore require an intermediate coating or layer to enhance corrosion resistance of the aluminum substrate.
Accordingly, there is a need to treat aluminum substrates with primers or other chemicals that provide improved corrosion resistance as well as strong bonding affinity for subsequent coatings. Suitable aluminum substrates for practice of the present invention include sheet, plate, castings, and wrought products such as forgings and stampings.
In the prior art, chemical conversion coatings have been formed on aluminum by xe2x80x9cconvertingxe2x80x9d a surface of the metal into a tightly adherent coating, part of which consists of an oxidized form of aluminum. Chemical conversion coatings provide high corrosion resistance and improved bonding affinity for polymer coatings. A chromate conversion coating is typically provided by contacting aluminum with an aqueous solution containing hexavalent or trivalent chromium ions, phosphate ions and fluoride ions. In recent years, concerns have arisen regarding the pollution effects of chromates and phosphates discharged into waterways by such processes. Because of the high solubility and strongly oxidizing character of hexavalent chromium ions, expensive waste treatment procedures must be employed to reduce the hexavalent chromium ions to trivalent chromium ions for waste disposal.
Attempts have been made in the prior art to produce acceptable chromate-free conversion coatings for aluminum. For example, some chromate-free conversion coatings contain zirconium, titanium, hafnium and/or silicon, sometimes combined with flourides, surfactants and polymers such as polyacrylic acid. In spite of the extensive efforts that have been made previously, there is still no entirely satisfactory non-chromate conversion coating or primer for improving the adhesion and corrosion resistance of coated aluminum. Two of the major problems are that the chromate free conversion coatings usually provide weaker adhesion of the subsequent coating to the substrate, or the chromate free conversion coatings usually provide less corrosion resistance in aggressive environments, or both.
A principal objective of our invention is to provide aluminum with a chromium free primer layer which provides better corrosion resistance and better adhesion of subsequent coatings than a chromate conversion coating.
A related objective of our invention is to provide coated aluminum having a primer layer comprising a reaction product of a vinylphosphonic acid-acrylic acid copolymer and an aluminum oxide or hydroxide layer on the sheet.
Additional objectives and advantages of our invention will become apparent to persons skilled in the art from the following detailed description of some particularly preferred embodiments.
In accordance with the present invention there is provided a process for making an aluminum-polymer composite. The composite comprises an aluminum alloy body coated with a radiation cured coating composition. The aluminum alloy body may be a casting, extrusion, plate, wrought product, or sheet and is preferably a sheet having a thickness of about 0.008 to 0.015 inch. Some aluminum alloys suitable for the present invention include aluminum-manganese alloys of the AA 3000 series, aluminum-magnesium alloys of the AA 5000 series, and aluminum-magnesium-silicon alloys of the AA 6000 series. For making polymer coated sheet suitable for shaping into food container bodies or food or beverage container end panels, we prefer aluminum-magnesium alloys of the AA 5000 series and particularly the AA 5042 and AA 5182 alloys. For making polymer coated sheet suitable for use on vehicle bodies we prefer aluminum-magnesium-silicon alloys of the AA 6000 series.
Aluminum alloys suitable for container end panels such as AA5182 are provided as an ingot or billet or slab by casting. Before working, the ingot or billet is subjected to elevated temperature homogenization. The alloy stock is then hot rolled to provide an intermediate gauge sheet. For example, the material may be hot rolled at a metal entry temperature of about 700-950xc2x0 F. to provide an intermediate product having a thickness of about 0.130 inch to about 0.190 inch. This material is cold rolled to provide a sheet ranging in thickness from about 0.007 to 0.014 inch. A preferred metal sheet is AA5182 aluminum alloy sheet in either the H19 or H39 temper.
Aluminum alloys such as AA5042 are provided as an ingot that is homogenized. This procedure is followed by hot rolling to an intermediate gauge of about 0.125 inch. Typically, the intermediate gauge product is annealed, followed by cold rolling to a final gauge of about 0.007 to 0.014 inch. A preferred metal sheet is AA5042 aluminum alloy sheet in the H2E72 temper.
The aluminum alloy sheet is generally cleaned with an alkaline surface cleaner to move any residual lubricant adhering to the surface, and then rinsed with water. Cleaning may be avoided if the residual lubricant content is negligible.
The cleaned sheet surface is then primed with a primer composition comprising an aqueous solution of about 1-20 g/L of a vinyl phosphonic acid-acrylic acid copolymer VPA-AA copolymer). Solutions containing about 4-10 g/L of the copolymer are preferred. The copolymer usually comprises about 5-50 mole % vinylphosphonic acid, preferably about 20-40 mole %. A particularly preferred VPA-AA copolymer contains about 30 mole % VPA and about 70 mole % AA. The solution has a temperature of about 100-200xc2x0 F., more preferably about 120-180xc2x0 F. A particularly preferred solution has a temperature of about 170xc2x0 F.
The sheet surface may be dipped into the primer composition or the composition may be roll coated or sprayed onto the sheet surface. A preferred continuous cleaning and pretreating line is operated at about 1000-1500 feet per minute. A contact time of about 6 seconds between the sheet surface and the primer composition is sufficient when the line is operated at 1000 feet per minute. The VPA-AA copolymer reacts with the oxide or hydroxide coating to form a primer layer on the sheet surface.
Optionally, the primed sheet may be rinsed with water to remove a portion of the VPA-AA copolymer unreacted with the oxide or hydroxide coating. The rinse water preferably has a temperature of about 170-180xc2x0 C. The rinse water is concentrated by removing excess water so that the VPA-AA copolymer can be recycled. Some preferred concentrating techniques include reverse osmosis and membrane filtration.
The polymer is applied to the primer layer on the aluminum alloy sheet as a radiation curable polymer precursor. Radiation curable polymer precursors are monomeric and/or oligimeric materials such as acrylics, methacrylates, epoxies, polyesters, polyols, glycols, silicones, urethanes, vinyl ethers and combinations thereof which have been modified to include functional groups and optionally photoinitiators that trigger polymerization upon the application of ultraviolet (UV) or electron beam (EB) radiant energy. Such polymer precursors include acrylated aliphatic oligomers, acrylated aromatic oligomers, acrylated epoxy monomers, acrylated epoxy oligomers, aliphatic epoxy acrylates, aliphatic urethane acrylates, aliphatic urethane methacrylates, allyl methacrylate, amine-modified oligoether acrylates, amine-modified polyether acrylates, aromatic acid acrylate, aromatic epoxy acrylates, aromatic urethane methacrylates, butylene glycol acrylate, silanes, silicones, stearyl acrylate, cycloaliphatic epoxides, cyclohexyl methacrylate, ethylene glycol dimethacrylate, epoxy methacrylates, epoxy soy bean acrylates, glycidyl methacrylate, hexanediol dimethacrylate, isodecyl acrylate, isoctyl acrylate, oligoether acrylates, polybutadiene diacrylate, polyester acrylate monomers, polyester acrylate oligomers, polyethylene glycol dimethacrylate, stearyl methacylate, triethylene glycol diacetate, and vinyl ethers.
The polymer coatings for use in this invention are thermosetting polymers that cross link and cure when exposed to suitable radiation sources.
The preferred polymer precursors are acrylated epoxy monomers and oligomers polyester acrylates, and silicone monomers.
Photoinitiators suitable for use in this invention are materials which absorb UV and EB radiant energy and form reactive free radicals, cations, or anions which initiate polymerization of monomeric and oligomeric materials. Such materials include acryloins, ketones, substituted benzoquinones, substituted polynuclear quinones, halogenated aliphatic, alicyclic and aromatic hydrocarbons, and mixtures thereof. In an embodiment of our invention illustrated in the Examples, UV radiation interacts with a cationic photoinitiator to addition polymerize an epoxy precursor.
Photoinitiators may not be necessary for use with polymeric precursors that contain function groups that are sufficiently reactive to polymerize upon irradiation particularly with EB radiation.
Preferred polymer resins precursor systems are sold commercially by Sun Chemical Company under the registered trademarks Sunbeam and Suncure.
The polymer coating composition may also optionally contain additives such as dyes, pigment particles, anticorrosion agents, antioxidants, adhesion promoters, light stabilizers, lubricants, and mixtures thereof.
The polymer precursor coating composition may be applied to the sheet by any of several techniques, including gravure coating, slot coating, forward roll coating, reverse roll coating, spraying, powder coating, and electrostatic coating. Reverse roll coating is particularly preferred. The polymer precursor coating is preferably applied onto the metal sheet as a single layer. Preferably, both sides of an aluminum alloy sheet are coated with a polymer precursor coating leaving a thickness of about 0.01-0.5 mils (1-13 microns).
To cure the polymer precursor coating composition, the aluminum-polymer composite sheet is irradiated with an electron beam. The electron beam polymerizes and cross links the coating. The radiation dose is about 2-20 megarads, preferably about 5-15 megarads. Electron beam radiation is the preferred energy for curing the polymer precursor coatings used for this invention, however, alternatively, UV radiation may also be used. The radiation curing step does not result in any substantial temperature increase in the coating. The coating temperature is less than about 250xc2x0 F. (121xc2x0 C.) after curing.
Optionally the composite sheet may then be heated by convection or induction heating to temperatures between 350-450xc2x0 F. The exposure time needed for this heating step will depend upon the thickness of the substrate being coated, and the speed at which the substrate (e.g., coil stock) traverses through the convection or induction heating units. A typical exposure time may range from 10-15 seconds.
The inventors believe the polymer precursor coating applied to the metal sheet is sufficiently viscous to bridge peaks in the irregular microsurface of the metal sheet. When the precursor coating is polymerized by radiant energy, the polymer networks across the metal surface peaks. By networking across the peaks, the polymer does not adhere as strongly to the metal as if the polymer inhabited the pockets, grooves, and other features of the metal microsurface. Heating of the metal-polymer composite sheet causes the polymer to flow into the metal surface irregularities. Upon cooling of the sheet, the polymer hardens within the irregularities in the metal surface thereby increasing the strength of the polymer adherence to the metal sheet.
The irradiated and heat treated composites sheets are shaped into container end panels for food and beverage containers. Easy open end panels for carbonated beverages are generally shaped by stamping metal blanks between shaping dies.
In a preferred embodiment of the invention, sheets of metal coated with a polymer precursor are exposed to EB radiation and heated before the sheets are formed into container ends. However, heating of a metal sheet coated with a polymer precursor prior to irradiation with EB energy is also within the scope of this invention. Also, sheets of metal coated with a polymer precursor can be exposed to EB radiation, formed into container ends and heated within the scope of this invention.
The invention will now be further described with reference to a number of specific examples which are to be regarded solely as illustrative and not as restricting the scope of the present invention.
In accordance with the present invention there is provided an AA5182 aluminum alloy sheet in the H19 temper having a sheet thickness of about 0.0080-0.0090 in (0.20-0.23 mm) and preferably about 0.0084 in (0.21 mm).
The natural oxide coating on aluminum surfaces is generally sufficient for practice of the invention. The natural oxide coating ordinarily has a thickness of approximately 30-50 angstroms. Also, the oxide coating resulting after cleaning, cleaning and etching, or cleaning, etching, and desmutting the aluminum is sufficient for practice of our invention. It is not necessary to grow the oxide coating by treatments such as anodic oxidation or hydrothermal treatment in water, water vapor or aqueous solutions, although this is possible.
The aluminum to be coated is cleaned with alkaline or acid surface cleaner to remove any residual organic contaminants adhering to the surface, and then rinsed with water. Cleaning might be avoided if the organic contamination is negligible.
The cleaned aluminum is then primed with a primer composition comprising an aqueous solution of about 0.1-200 g/L of a vinyl phosohonic acid-acrylic acid copolymer (VPA-AA copolymer). Solutions containing about 1-20 g/L of the copolymer are preferred. The copolymer usually comprises about 5-50 mole % vinylphosphonic acid, preferably about 20-40 mole %. A particularly preferred VPA-AA copolymer contains about 30 mole % VPA and about 70 mole % AA. The solution has a temperature of between 50xc2x0 F. and 200xc2x0 F. There is an inverse relationship between time and temperature required: the lower the temperature, the longer the time required, or the shorter the time available, the higher the temperature required. A xe2x80x9cRoom Temperaturexe2x80x9d of 65xc2x0 F. to 85xc2x0 F. is preferred with an immersion time of 15 seconds to 2 minutes, which minimizes equipment and heating requirements. Where speed is critical, a temperature of 170xc2x0 F. and a time of 15 seconds is preferred. Many different combinations of time and temperature are possible.
The aluminum surface may be dipped into the primer composition or the composition may be roll coated or sprayed onto the sheet surface. The VPA-AA copolymers reacts with the oxide or hydroxide coating to form a primer layer on the sheet surface.
Optionally, the aluminum may be rinsed with water to remove a portion of the VPA-AA copolymer unreacted with the oxide or hydroxide coating. The rinse water may have temperature of 35xc2x0 F. to 200xc2x0 F. Room temperature water is preferred, unless quick drying is required, in which case heated water speeds the water drying process. The rinse water may be concentrated by removing excess water so that the VPA-AA copolymer can be recycled. This improves the economics of the process, but does not affect the invention. Some preferred concentrating techniques include reverse osmosis and membrane filtration.
The roll coating apparatus applies to the aluminum sheet a coating of a polymer precursor having a thickness of approximately 0.0001-0.0005 in (2.5-13 microns), thereby to form an aluminum-polymer composite.
The polymer coating in the composite is irradiated by an electron beam. A suitable electron beam generator is commercially available from Energy Sciences, Inc. of Wilmington Mass. under the trade designation ESI xe2x80x9cELECTROCURExe2x80x9d EB SYSTEM.
Optionally, the surface coated with the UV or EB coatings may then be subjected to thermal or induction heating by raising the metal temperature to a range of 350-450xc2x0 F.
Finally, the aluminum-polymer composite is cooled (preferably with water) and dried.

Primer for radiation curable coating compositions


It is desirable for interrupt handling routines to be aware of the interrupt latency—the time between a interrupt request is received and the time when the interrupt service routine begins executing. A method is shown wherein the latency is measured by a dedicated counter and is available to the interrupt service routine. Alternately, a threshold may be set indicating the maximum acceptable latency and the interrupt service routine is signaled when said maximum is reached.

In systems programming, an interrupt is a signal to the processor emitted by hardware or software indicating an event that needs immediate attention. An interrupt alerts the processor to a high-priority condition requiring the interruption of the current code the processor is executing (the current thread). The processor responds by suspending its current activities, saving its state, and executing a small program called an interrupt handler (or interrupt service routine, ISR) to deal with the event. This interruption is temporary, and after the interrupt handler finishes, the processor resumes execution of the previous thread. There are two primary types of interrupts:
A hardware interrupt is an electronic alerting signal sent to the processor from an external device, either a part of the computer itself such as a disk controller or an external peripheral. For example, pressing a key on the keyboard or moving the mouse triggers hardware interrupts that cause the processor to read the keystroke or mouse position. Unlike the software type, hardware interrupts are asynchronous and can occur in the middle of instruction execution, requiring additional care in programming. The act of initiating a hardware interrupt is referred to as an interrupt request (IRQ).
A software interrupt is caused either by an exceptional condition in the processor itself, or a special instruction in the instruction set which causes an interrupt when it is executed. The former is often called a trap or an exception and is used for errors or events occurring during program execution that are exceptional enough that they cannot be handled within the program itself. For example, if the processor's arithmetic logic unit is commanded to divide a number by zero, this impossible demand will cause a divide-by-zero exception, perhaps causing the computer to abandon the calculation or display an error message. Software interrupt instructions function similarly to subroutine calls and are used for a variety of purposes, such as to request services from low level system software such as device drivers. For example, computers often use software interrupt instructions to communicate with the disk controller to request data be read or written to the disk.
Each interrupt has its own interrupt handler. The number of hardware interrupts is limited by the number of interrupt request (IRQ) lines to the processor, but there may be hundreds of different software interrupts.
Interrupts are a commonly used technique for computer multitasking, especially in real-time computing. Such a system is said to be interrupt-driven.

Method of providing timing information for interrupts


An accessory (26,28) for selectively coupling with an orthopedic table (A) supports a patient""s leg during surgery. The accessory includes a unitary support member (42) formed from a radiolucent material, such as carbon fiber. A joint assembly (40) pivotably and removably mounts the accessory to a side rail (24) of the table.

The present invention relates to the surgical table arts. It finds particular application in connection with a removable accessory with a radiolucent support surface for the positioning of a patient""s legs during surgery, and will be described with particular reference thereto. It should be appreciated, however, that the accessory is also suited to the support of a patient""s arms or for use in forensic or veterinary applications.
For performing many modern surgical procedures, a support, such as a table, is used for positioning the patient on whom the procedures are to be performed. The table preferably provides unrestricted access by a surgeon to the parts of the patient""s body on which the surgical procedures are to be performed. The table should also permit positioning of image-amplification apparatus proximate those parts of the patient""s body on which the surgeon is to perform surgical procedures.
Conventional surgical tables include a horizontal support for the upper body of the patient, a base for supporting the upper body support a suitable distance from the floor, and a leg support, connected to the upper body support, for supporting the legs. For certain types of surgery, such as laparoscopic surgery, where the surgeon requires access to the pelvic region of the patient, or where the surgeon is operating on the legs, such as knee arthroscopy, vascular surgery, and orthopedic surgery, the table includes abductor bars, rather than a leg support, for maintaining the patient""s legs in a spaced position. This allows the surgeon to stand between the patient""s legs to conduct the surgery. The abductor bars are usually mounted to the base for horizontal pivotal movement and include foot supports which are clamped to the bars. The foot supports are moved along the abductor bars to accommodate patients of different sizes. U.S. Pat. Nos. 4,872,656; 4,989,848; and Des. 287,625 provide examples of such tables.
Some surgical procedures employ image-amplification apparatus to provide the surgeon with a picture of the operation in progress. Examples include fluoroscopic imaging and x-ray imaging. It is desirable for the surgical table to provide the source of radiation with 360 degree access to the site of the operation in such procedures. Typically, leg supports and abductor bars are formed from materials which are not radiolucent, i.e. they limit access to x-rays and other radiation used to monitor the surgical procedures. Additionally, such supports are often only pivotable in a horizontal direction and thus the image amplification equipment is not able to encircle completely one of the legs.
There remains a need for a leg support which provides access to the patient for surgery while providing all-round access to monitoring equipment. The present invention provides a radiolucent split-leg accessory for a surgical table which overcomes the above-referenced problems and others.
In accordance with one aspect of the present invention, a surgical table for supporting a patient during the performance of a surgical procedure is provided. The table includes a base and a table top mounted on the base for supporting an upper portion of the patient""s body. The table includes at least one leg support sub-assembly, pivotally mounted to the table top. The leg support sub-assembly includes a support member for supporting a patient""s leg. The support member includes a support surface formed from a radiolucent material. A mounting member pivotally connects the support member to the table top.
In accordance with another aspect of the present invention, an accessory for a surgical table is provided. The accessory includes a support member for supporting a patient""s leg. The support member includes a support surface formed from a radiolucent material, which supports upper and lower portions of the patient""s leg. A mounting member selectively mounts the support member to the surgical table and enables selective pivoting of the support member relative to the table.
In accordance with another aspect of the present invention, an accessory for a surgical table is provided. The accessory includes a support member which defines a trough configured for receiving upper and lower portions of a patient""s leg. A mounting assembly, connected with the support member, is provided for selectively locking the support member in a plurality of positions relative to the table. The mounting assembly is selectively releasable to enable free motion of the support member.
One advantage of the present invention is that it provides a support for a patient""s legs during surgery.
Another advantage of the present invention is that it is radiolucent.
Yet another advantage of the present invention is that it cradles a patient""s legs.
A further advantage of the present invention is that it permits independent horizontal and vertical positioning of a patient""s legs.
A yet further advantage of the present invention is that it is readily connected to the side rail of a conventional surgical table.
A still further advantage of the present invention is that it permits a conventional surgical table to be readily converted to a split-leg table.
Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiment.

Radiolucent split-leg accessory for a surgical table


During a process of migrating a source system into a standardized virtual environment, virtual machine instances of the source system executing in a hypervisor are snapshotted as virtual machine images in an operational repository of the hypervisor. The virtual machine images in the operational repository are short-term snapshots. From time to time during the migration process, long-term snapshots of the source system are created by checking given ones of the virtual machine images from the hypervisor operational repository into an image library as image objects.

In an Infrastructure as a Service (IaaS) cloud, the capability provided to the consumer is to provision processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, deployed applications, and possibly limited control of select networking components (e.g., host firewalls).

Use of snapshots to reduce risk in migration to a standard virtualized environment

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