GOWN WITH SECURE FIT AND COMFORT FEATURE |
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申请号 | US12164914 | 申请日 | 2008-06-30 | 公开(公告)号 | US20090320177A1 | 公开(公告)日 | 2009-12-31 |
申请人 | Brian Lin; Ajay Houde; | 发明人 | Brian Lin; Ajay Houde; | ||||
摘要 | A protective garment, such as a surgical gown, includes a garment body defining sleeves. A cuff may be secured at respective ends of the sleeves. A circumferentially extending coating is disposed on the sleeves beginning at the sleeve or cuff. The coating has a high friction surface such that an end of a glove pulled over the coating is inhibited from rolling or sliding back over the coating and down the sleeve. The coating may be formed of a low-tack surface modifier and may include a dye or colorant that may be used to indicate the fluid protection level of, for example, a surgical gown. Additionally, a second coating of a phase change and/or shape memory material may be applied to the protective garment. | ||||||
权利要求 | |||||||
说明书全文 | The present application is a continuation in part of application Ser. No. 11/096,580, filed Apr. 1, 2005, the entirety of which is herein incorporated by reference. Protective garments, such as coveralls and gowns, designed to provide barrier protection to a wearer are well known in the art. Such protective garments are used in situations where isolation of a wearer from a particular environment is desirable, or it is desirable to inhibit or retard the passage of hazardous liquids and biological contaminates through the garment to the wearer. In the medical and health-care industry, particularly with surgical procedures, a primary concern is isolation of the medical practitioner from patient fluids such as blood, saliva, perspiration, etc. Protective garments rely on the barrier properties of the fabrics used in the garments, and on the construction and design of the garment. Openings or seams in the garments may be unsatisfactory, especially if the seams or openings are located in positions where they may be subjected to stress and/or direct contact with the hazardous substances. Gloves are commonly worn in conjunction with protective garments, particularly in the medical industry. Typically, the gloves are pulled up over the cuff and sleeve of a gown or garment. However, the interface between the glove and the protective garment can be an area of concern. For example, a common issue with surgical gloves is glove “roll-down” or slippage resulting from a low frictional interface between the interior side of the glove and the surgical gown sleeve. When the glove rolls down or slips on the sleeve, the wearer is at greater risk of exposure to patient fluids and/or other contaminants. An additional problem associated with the use of surgical gloves is that as a result of the gloves being pulled up over the cuff and sleeve of the gown, a phenomenon known as “channeling” occurs. That is, the sleeve of the gown is bunched up under the glove as a result of pulling and rolling the glove up over the cuff and sleeve. Channels may develop along the wearer's wrist which may become accessible to patient fluids running down the outside of the sleeve of the gown. Such fluids may enter the channels and work down along the channels between the outer surface of the gown and inner surface of the surgical glove. The fluids may then contaminate the gown cuff, which lies directly against the wearer's wrist or forearm, particularly if the cuff is absorbent or fluid pervious. Surgeons and other medical personnel have attempted to address concerns with the glove and gown interface in different ways. For example, it has been a common practice to use adhesive tape wrapped around the glove portion extending over the gown sleeve to prevent channels and roll down of the glove on the sleeve. This approach unfortunately has some drawbacks. Many of the common adhesives utilized in tapes are subject to attack by water and body fluids and the seal can be broken during a procedure. Another approach has been to stretch a rubber coating around the glove and sleeve. This practice is, however, awkward to implement and difficult to adjust or to vary the pressure exerted by the rubber coating other than by using rubber coatings of different sizes and tensions, which of course necessitates having a variety of rubber coatings available for use. Yet another approach has been to incorporate a band of elastomeric polymer on the gown around the sleeve just above the cuff to provide a surface for the glove to cling to. This approach has also proved less than completely satisfactory. In addition to the problems encountered through the use of protective garments and glove together, there may be problems associated with the use of the protective garment by itself. In this regard, during medical procedures of extended length, the body temperatures of medical professionals may rise due to the physical characteristics of the protective garment and/or because of extensive and prolonged physical activity. This increase in body temperature may result in uncomfortable conditions in the surgical ward due to the production of excessive sweat and/or body odor. Therefore, a need exists for an improved device and method for providing an effective sealing interface between a glove and sleeve of a protective garment, wherein the device is easily incorporated with the protective garment and economically cost effective to implement. Additionally, a need exists for a mechanism to regulate body temperature to enhance comfort of medical professionals in the surgical ward. The present invention provides a protective garment incorporating an effective and economical mechanism for improving the interface area between the sleeves of the garment and a glove pulled over the sleeves. The improvement inhibits the proximal end of the glove from rolling or sliding back down the garment sleeves once the wearer has pulled the gloves on. In this way, the garment according to the invention addresses at least certain of the disadvantages of conventional garments discussed above. It should be appreciated that, although the present invention has particular usefulness as a surgical gown, the invention is not limited in scope to surgical gowns or the medical industry. The protective garment according to the present invention has wide application and can be used as a protective coverall, gown, robe, etc. All such uses and garments are contemplated within the scope of the invention. The present invention provides for a protective garment, desirably a surgical gown. The protective garment includes a garment body which defines a main body, a neck portion, and sleeves. The protective garment further includes a cuff secured at respective ends of the sleeves, and a circumferentially extending first coating of a first low-tack material on the sleeves. The low tack materials has a high friction surface and has a substantially uniform, flat profile. This high friction surface prevents material, when it is slides over the low tack material, from rolling back over the first coating. The protective garment also includes a second coating selected from a shape memory material, phase change material, or combinations thereof. The first coating may be continuous or discontinuous around the sleeeves and may by one continuous ring, a plurality of rings, or may exhibit a “Z” shape. The first coating may also further include a dye or colorant or may be an adhesive. The second coating may extend circumferentially and may be located on the surface of the garment opposite the surface containing the low-tack high friction coating; the surface overlapping the surface containing the low-tack high friction coating; and/or surfaces of the garment corresponding to the arm pit, neck, chest, and back of the wearer. Another aspect of the invention provides for protective garment. The protective garment includes a garment body which defines a main body, a neck portion, and sleeves. The protective garment further includes a circumferentially extending first coating of a first low-tack material on the sleeves. The low tack materials has a high friction surface and has a substantially uniform, flat profile. This high friction surface prevents material, when it is slides over the low tack material, from rolling back over the first coating. The protective garment also includes a second coating selected from a shape memory material, phase change material, or combinations thereof. Yet another aspect of the invention provides for a protective garment. The protective garment includes a garment body which defines a main body, a neck portion, and sleeves. The protective garment further includes a cuff secured at respective ends of the sleeves, and a circumferentially extending first coating of between about 10 and about 30 gsm of an amorphouspolyalphaolefin on the sleeves. The low tack materials has a high friction surface and has a substantially uniform, flat profile. This high friction surface prevents material, when it is slides over the low tack material, from rolling back over the first coating. The protective garment also includes a second coating selected from a shape memory material, phase change material, or combinations thereof. Embodiments of the protective garment according to the invention are described below in greater detail with reference to the appended figures. Reference will now be made in detail to one or more examples of the invention depicted in the figures. Each example is provided by way of explanation of the invention, and not meant as a limitation of the invention. For example, features illustrated or described as part of one embodiment may be used with another embodiment to yield still a different embodiment. Other modifications and variations to the described embodiments are also contemplated within the scope and spirit of the invention. The garment 10 is depicted as a surgical gown for illustrative purposes only. The garment 10 may be any type or style of protective covering that is generally worn about the body and includes sleeves. The terms “lower” or “distal” are used herein to denote features that are closer to the hands of the wearer. The terms “upper” or “proximal” are used to denote features that are closer to the shoulder of the wearer. It should be appreciated that the type of fabric or material used for garment 10 is not a limiting factor of the invention. The garment 10 may be made from a multitude of materials, including nonwoven materials suitable for disposable use. For example, gown embodiments of the garment 10 may be made of a stretchable nonwoven material so that the gown is less likely to tear during donning or wearing of the gown. A material particularly well suited for use with the present invention is a three-layer nonwoven polypropylene material known as SMS. “SMS” is an acronym for Spunbond, Meltblown, Spunbond, the process by which the three layers are constructed and then laminated together. See for example U.S. Pat. No. 4,041,203 to Brock et al. One particular advantage is that the SMS material exhibits enhanced fluid barrier characteristics. It should be noted, however, that other nonwovens as well as other materials including wovens, films, foam/film laminates, and combinations thereof may be used to construct the garment of the present invention. It is also contemplated that the garment may be coated with a liquid impervious coating to prevent fluid absorption into the garment material. The sleeves 16 may incorporate a cuff 26 attached to the distal end 22 thereof. The cuff 26 also has a distal end 28 and a proximal end 30. The configuration and materials used in the cuff 26 may vary widely. For example, short, tight-fitting cuffs made from a knitted material may be provided. The cuff 26 may be formed with or without ribs. The cuff may be formed of a liquid repellant material or a liquid retentive material. Cuffs suitable for use with garments according to the present invention are described in U.S. Pat. Nos. 5,594,955 and 5,680,653, both of which are incorporated herein in their entirety for all purposes. As shown for example in Many types of protective gloves, particularly elastic synthetic or natural rubber surgical gloves, have a thickened bead or region at the open proximal end 36. This thickened portion or bead is intended to strengthen the glove 32 and provide an area of increased elastic tension to aid in holding the glove 32 up on the sleeve 16. According to one embodiment of the invention, the garment 10 includes a circumferentially extending first coating 40 formed on the sleeves 16 from the proximal end 30 of the cuff 26 ( The first coating 40 may extend up the sleeve 16 a distance greater than the proximal end 36 of the glove 32 extends when the glove is normally donned. The dimensions of the coated area may vary as the size of the gown may also vary. As shown in any of It should be appreciated that the first coating 40 can take on many different configurations. If the first coating 40 interferes with the bonding or seaming process about a half inch (1.25 cm) border 56 along the edges 50, 52, 54 may be kept uncoated. If the first coating 40 does not interfere with the bonding process, the half inch border 56 need not be present. The first coating may alternatively be discontinuous around the sleeve 16, such as a “Z” shape arrangement ( The first coating 40 may be formed on the sleeve in various known ways and from a variety of materials. For example, a surface modifier compatible with the sleeve material may be applied directly to the sleeve in a spraying, printing, slot coating, or other conventional process. The first coating 40 may be formed of an inherently low-tack material with high frictional characteristics, such as a low-tack hot melt adhesive. This type of material increases slip resistance between the glove and sleeve 16 and may be applied directly onto the exterior surface 24 of the sleeve to form the first coating 40. In general, the surface modifier could be any polymer that is sufficiently soft and pliable so as to cling to the inside surface of the glove 32. At the same time, the polymer should not have too high a tack level so as to cause the garment sleeve 16 to stick to the garment body 12 when the garment 10 is folded, hence the term “low-tack”. The term “high frictional characteristics” means that the coefficient of friction of the coated fabric is higher than the same, uncoated fabric. Polymers such as metallocene based polyolefins are suitable examples of acceptable first coatings. Other suitable surface coatings include, for example, ethylene vinyl acetate copolymers, styrene-butadiene, cellulose acetate butyrate, ethyl cellulose, synthetic rubbers including, for example, Krayton® block copolymers, natural rubber, polyethylenes, polyamides, flexible polyolefins, and amorphous polyalphaolefins (APAO). A suitable commercial hot melt adhesive for the coating application is REXtac® 2115 APAO from Huntsman Polymers Corp. of Odessa, Tex. Another suitable commercial hot melt adhesive for this application is REXtac® 2215 APAO (Amorphous PolyAlpha Olefin) also from Huntsman Polymers. The polymer may be applied to the sleeve at an amount between about 5 and 50 gsm, more particularly between 10 and 30 gsm or still more particularly about 20 gsm. Other materials may be added to the first coating to provide particular characteristics. These optional materials may include, for example, dyes, pigment or other colorants to give the coated area a visually perceptible color such as yellow, green, red or blue (e.g. Sudan Blue 670 from BASF). These colors may be used to indicate the protection level accorded by the gown according to, for example, the standards of the Association for the Advancement of Medical Instrumentation (AAMI), e.g., ANSI/AAMI PB70:2003. A user would thus be able to select a gown for a surgical procedure where the sleeve color corresponded to or indicated the fluid protection level of the gown. In order to validate the superiority of the inventive garment sleeve coating in the retention of gloves, testing was carried out on a variety of coatings and an uncoated “control” sleeve. The control was a sleeve made from 1.7 osy (58 gsm) SMS made from polypropylene. Two samples of sleeves of the same 1.7 osy SMS material were coated with REXtac® 2115 APAO for comparison; one at an add-on rate of 10 gsm for a distance of 4 inches (10 cm) from the cuff (sample 1) and one at an add-on rate of 20 gsm for a distance of 6 inches (15 cm) from the cuff (sample 2). The sleeves were coated by a spraying process. The three sleeves were tested using human subjects and an experimental protocol designed to simulate tasks performed by medical personnel in an operating room. During and after the protocol, measurements of glove location were taken for comparison. The subjects' opinions were also solicited for a qualitative indication of gown preference. A total of 47 subjects tested the three types of gowns. The protocol was as follows:
1 pump of triangle lotion soap 15 second lather 15 second rinse dry until there are no visible signs of moisture
Ask the subject to handle the following items (dry): at the wrist, flex hands palm down, up and down 10 times using both hands at the wrist, flex hands palm up, up and down 10 times using both hands rotate wrists to the outside 10 times using both hands rotate wrists to the inside 10 times using both hands. remove and replace stopper in test tube 5 times using each hand turn stop cock clockwise a full rotation 5 times using each hand wrap gauze 5 wraps around an artificial arm and cut gauze with scissors—unwrap, then re-wrap gauze and unwrap using other hand twist wrist to remove and replace top on a water bottle 5 times using each hand (exaggerate movements) pass a block back and forth from right hand to left hand 5 times twist the length of a long threaded rod 2 times using each hand twist the length a rope 2 times using each hand to the knot
Results of the testing protocol were as follows: Average movement (slip-down) measured from the starting point was, for the control: 42 mm, for sample 1: 17 mm and for sample 2: 13 mm. This indicates a significant advantage for either of the coated sleeves over the uncoated sleeve. Qualitative survey responses were also gathered. The areas of inquiry were “cuff stays in place”, “acceptability of glove slip-down”, “how well to protect from fluid”, “gown acceptability”. The three gown sleeves were preferred by the subjects in the same order as their finish in the slip-down measurements. In addition to the above testing, the control and sample 2 sleeves were tested for breathability using a TEXTEST FX 3300 air permeability machine from Schmid Corporation of Spartanburg, S.C., using a 38 cm2 head at a test pressure of 125 Pa using 20 samples. According to the testing, the control sleeve fabric had a breathability of about 21.985 cubic feet per minute (CFM) (0.6225 cubic meter/min) and the sample 2 (coated) sleeve fabric had a breathability of about 21.020 CFM (0.5952 cubic meter/min). This indicates that, despite having a relatively heavy polymeric coating of 20 gsm, the breathability was not reduced by even 10 percent, and more particularly not even 5 percent. This indicates almost no change in the degree of comfort felt by a wearer of the coated sleeve. Testing in order to quantify to some degree the coefficient of friction (COF) of the coated sleeve was also carried out. The control and sample 2 sleeves were tested using test method ASTM D1894 using both a glass surface and a steel surface. The data is given in the following table: The glass and steel in the previous test were replaced with a commercial, market leading latex glove (Biogel Surgical glove by Regent) in order to gain a more realistic picture of the sleeve's performance. A number of commercially available gowns were used for comparison testing and their fabric was tested against the inside surface of the glove. The testing was done according to ASTM D1894 using the outside surface of each gown fabric, with the fabric oriented in the machine direction, as it would be orientated on a wearer. In the table below, gown A is a commercially available gown with sleeves made from two 1.0 osy (33.9 gsm) SMS layers glued together. Gown B has a 0.6 osy (20.3 gsm) spunbond layer over a film and SMS fabric with the spunbond on the outside. Gown C has a 0.75 mil film on an SMS fabric with the film on the outside. Gown D has 1.6 osy (54.3 gsm) SMS sleeves. Gown E has 2.1 osy (71.1 gsm) spunlace sleeves. The following table shows the test results. This data shows that the sample 2 fabric had a much higher coefficient of friction in all areas than any of the competitive, commercially available gowns. Gowns having the coating according to the invention thus have a much higher ability to retain gloves and avoid slip down and roll down, and they do so without sacrificing comfort and breathability. In addition to the low tack, high friction first coating materials described above, various materials forming a second coating may be used in conjunction with the first coating on the protective garment. These materials include phase change materials and shape memory materials. Similar to the first coating, the second coating may be present in a variety of geometric configuations including a single continuous ring, plurality of rings, discontinuous shapes, and “Z” shapes as discussed previously. Phase change materials may be added to one or more surfaces of the protective garment to enhance the comfort of the wearer by regulating the wearer's body temperature at the surface site. As shown Generally speaking, regardless of the location of the phase change material, the phase change material is a material or combination of materials capable of providing or absorbing heat at a given temperature, for example, at ambient temperature or at normal human body temperature. By absorbing or releasing thermal energy, the phase change material can temporarily reduce or eliminate heat transfer at a given temperature or temperature range and provide a heating or cooling sensation to the gown wearer. Thus, a phase change material may be used as thermal moderator or barrier to heat, because a quantity of thermal energy must be absorbed by the phase change material until most or all of the material has undergone solid-to-liquid phase change, before its temperature can begin to increase. When placed next to the skin of a wearer, this absorption of heat from the wearer's skin and into the phase change material provides a cooling effect to the user. Alternatively, a phase change material may provide a thermal moderating effect as a barrier to chilling where the phase change material is substantially in a liquid phase and must release a quantity of thermal energy or heat to undergo the liquid-to-solid phase change, and before its temperature can begin to decrease. Such phase change material thermal regulating additives may be incorporated into a thermoplastic melt from which fibers included in an extensible fibrous layer, such as an extensible nonwoven layer, are produced. Alternatively, or in addition, such phase change material thermal regulating additives may be added to the extensible fibrous layer via topical coating or impregnation of the extensible fibrous layer with the phase change material thermal regulating additive in powder form or in liquid forms such as suspensions or emulsions, etc. As an example, U.S. Pat. No. 6,689,466 to Hartmann describes phase change compositions which, as described therein, are temperature stabilized and therefore suitable for, among other things, melt extrusion processes such as melt spinning of fibrous materials. The phase change material compositions described therein include phase change materials and a stabilizing agent such as antioxidants and thermal stabilizers. Exemplary phase change materials include, by way of non-limiting example only are waxes, oils, fatty acids, fatty acid esters, dibasic acids, dibasic esters, 1-halides, primary alcohols, anhydrides (e.g., stearic anhydride), ethylene carbonate, polyhydric alcohols (e.g., 2,2-dimethyl-1,3-propanediol, 2-hydroxymethyl-2-methyl-1,3-propanediol, ethylene glycol, polyethylene gylcol, pentaerythritol, dipentaerythrital, pentaglycerine, tetramethylol ethane, neopentyl glycol, tetramethylol propane, monoaminopentaerythritol, diaminopentaerythritol, and tris(hydroxymethyl)acetic acid), polyethylene glycol, polypropylene, polypropylene glycol, polytetramethylene glycol, and copolymers, such as polyacrylate or polymethacrylate with alkyl hydrocarbon side chain or with polyethylene glycol side chain and copolymers comprising polyethylene, polyethylene glycol, polypropylene, polypropylene glycol, or polytetramethylene glycol), and mixtures thereof. It should be noted that although the phrases “phase change” and “phase transition” are commonly employed, phase change materials may undergo either a solid/liquid (liquid/solid) phase transition or a solid/solid transition. In a solid/solid transition, the phase change material undergoes a phase transition that is between two solid states, such as a crystalline/mesocrystalline phase transition. As mentioned above, the thermal regulating additive may desirably be coated onto or impregnated into the extensible fibrous layer, instead of (or in addition to) being incorporated into the polymer used in producing the fibers. Such coatings may be applied as a powder or liquid form. Liquid forms include aqueous or other liquid dispersions, suspensions and/or emulsions, may be foamed, and may include components other than the thermal regulating additive or phase change material in the composition such as, for example, thickeners, adhesives or binders, including polymeric binders. Exemplary thermal regulating additive coatings for fabrics are disclosed, for example, in U.S. Pat. Nos. 6,207,738 and 6,514,362 to Zuckerman et al. Such coating compositions may be applied to the extensible fibrous layer by spraying, brushing, dipping or immersion, or, more particularly, by slot coating or applying as a foam and spreading with a knife or doctor blade, or the like. The coated fabric layer may then be air dried or dried by heat, heated air, oven drying, or other means. The phase change material may be included within or applied to the substrate in an amount between about 0.1 to about 100% of the weight of the final substrate. In addition to the phase change materials described above, shape memory materials may may be added to one or more surfaces of the protective garment to enhance barrier protection of the protective garment wearer. As shown in Generally speaking, shape memory materials are polymeric materials which may be returned from their deformed state to their original state or permanent configuration via an external stimulus. This external stimulus is usually temperature, as in the case of phase change materials, but may also be the application of an electric or magnetic field, light, or a change in pH. In this regard, the application of shape memory materials to gowns may enhance comfort, fit, barrier, and safety by elimination of fluid wicking channels at the glove gown interface as discussed earlier, and maintenance of the gown's original configuation during use. The shape memory materials of the present invention desirably contain at least one shape deformable matrix material. These materials include, but are not limited to polymers. In an embodiment, the shape deformable matrix material contains at least one polymer, and more preferably two polymers. Suitable polymers include, but are not limited to, segmented block copolymers comprising one or more hard segments and one or more soft segments; polyester-based thermoplastic polyurethanes; polyether-based polyurethanes; polyethylene oxide; poly(ether ester) block copolymers; polyamides; poly(amide esters); poly(ether amide) copolymers; polyvinyl alcohol; polyvinyl pyrolidone; polyvinyl pyridine; polyacrylic acid; polymethacrylic acid; polyaspartic acid; maleic anhydride methylvinyl ether copolymers of varying degrees of hydrolysis; polyvinyl methyl ether copolymers of polyacrylic acid and polyacrylic esters; and mixtures thereof. Desirably, the shape deformable matrix material contains a segmented block copolymer comprising one or more hard segments and one or more soft segments, where either the soft segment, the hard segment, or both contain functional groups or receptor sites that are responsive to an external stimulus. More desirably, the segmented block copolymer is an elastomer. Suitable shape deformable elastomers for use in the present invention include, but are not limited to, polyurethane elastomers, polyether elastomers, poly(ether amide) elastomers, polyether polyester elastomers, polyamide-based elastomers, thermoplastic polyurethanes, poly(ether-amide) block copolymers, thermoplastic rubbers such as uncrosslinked polyolefins, styrene-butadiene copolymers, silicon rubbers, synthetic rubbers such as nitrile rubber, butyl rubber, ethylene-vinyl acetate copolymer, styrene isoprene copolymers, styrene ethylene butylene copolymers and mixtures of thereof. Some non-elastomeric polymers may be used. These polymers can provide some degree of recovery when exposed to an external stimulus. Examples of non-elastomeric polymers useful in the present invention include, but are not limited to, polyethylene oxide, copolymers of polylactic acid, blends and mixtures thereof. In one embodiment of the present invention, the shape deformable matrix material contains a polyurethane. Suitable polyurethanes for use in the present invention include, but are not limited to, polyester-based aromatic polyurethanes, polyester-based aliphatic polyurethanes, polyether-based aliphatic and aromatic polyurethanes, and blends and mixtures of these polyurethanes. Such polyurethanes may be obtained, for example, from Huntsman Polyurethanes (Chicago, Ill.). Examples of specific polyurethanes, which can be used in the present invention include, but are not limited to, MORTHANE® PS370-200, MORTHANE® PS79-200, MORTHANE® PN3429, and MORTHANE® PE90-100. Other thermoplastic polyurethanes applicable for the present invention can be obtained from BF Goodrich Performance Materials under the trade name ESTANE® polyurethanes. In a further embodiment of the present invention, the shape deformable matrix material includes a poly(ether amide) elastomer. Poly(ether amide) elastomers, which may be used in the present invention, may be obtained, for example, from Arkema, Inc. (Philadelphia, Pa.). Examples of such poly(ether amide) elastomers include PEBAX® series elastomers which may include, but are not limited to, PEBAX® 2533, PEBAX® 3533, and PEBAX® 4033. Polyurethane elastomers and poly(ether amide) elastomers are particularly useful as the shape deformable matrix material in the present invention because they structurally consist of soft and hard segments, which contain groups having high dipole moments (i.e., isocyanate, amide, and ester groups) which are sensitive to external stimuli. The hard segments in these elastomers typically act as physical cross-linking points for the soft segments, enabling an elastomeric performance. Both hard and soft segments may contribute to the shape deformation during a number of pre-activation treatments described below, such as stretching, which provides “locked-in” shape deformation, which may be recoverable by exposure to an external stimulus. In yet another embodiment of the present invention, the shape deformable matrix material includes a blend of an elastomeric polymer and a non-elastomeric polymer. These blends may either be co-extruded together, or may be formed into multi- or micro-layer structures. Alternatively, the multi-layer or micro-layer structure may be formed from separate layers of the elastomeric polymer and non-elastomeric polymer. These layers may or may not be alternating layers. Blends are advantageous since blending or multi-layering/micro-layering of a shape deformation elastomer with another non-elastomeric shape deformation polymer can improve latent deformation properties, especially at lower stretching temperatures, and can significantly increase recoverable deformation as a result of activation by an external stimulus. The shape memory materials of the present invention may possess a variety of shapes and sizes. The shape memory materials of the present invention may be in the form of blends, films, multi-layered or micro-layered films, laminates, filaments, fabrics, foams, nonwovens or any other three-dimensional form. In some embodiments, a desirable substrate is nonwoven material. Similar to the phase change materials, and as discussed above, the shape memory materials may be formed by any method known to those of ordinary skill in the art including, but not limited to, extrusion, coating, foaming, etc. When used as a coating, the coatings may be applied as a powder or liquid form. Liquid forms include aqueous or other liquid dispersions, suspensions and/or emulsions, may be foamed, and may include components other than the shape memory materials in the composition such as, for example, thickeners, adhesives or binders, including polymeric binders. Such coating compositions may be applied to the substrate by spraying, brushing, dipping or immersion, or, more particularly, by slot coating or applying as a foam and spreading with a knife or doctor blade, or the like. The coated fabric layer may then be air dried or dried by heat, heated air, oven drying, or other means. The shape memory material may be included within or applied to the substrate in an amount between about 0.1 to about 100% of the weight of the final substrate. Regardless of the size and shape of the shape memory material, the shape memory material of the present invention exhibits a change in at least one spatial dimension when subjected to an external stimulus. Typically, the shape memory material of the present invention exhibits a change in one, two, or three dimensions. For example, when the shape memory material is in the form of a fiber, the shape deformation material exhibits a change in the fiber length and/or fiber diameter. When the shape memory material is in the form of a film, the shape deformation material exhibits a change in the film length and/or film width and film thickness. It should be appreciated by those skilled in the art that various modifications and variations can be made to the embodiments of the present invention described and illustrated herein without departing from the scope and spirit of the invention. The invention includes such modifications and variations coming within the meaning and range of equivalency of the appended claims. |