of a cotton cloth or similar and then over wrapping the cover and the extremity with a woven cloth impregnated with Paris plaster that has been wetted by immersing it in water immediately before application. This practice is still in widespread use but it has several significant disadvantages. For example, the application procedure described above is dirty and time consuming. Several components are required and considerable skill is required. In order to alleviate the aforementioned disadvantages of the conventional method of applying castings and gypsum boards of paris, unitary splints materials have been contemplated and are described, for example, in U.S. Patent Nos. 3,900,024; 3,923,049 and 4,235,228. All of these patents describe a filling material with a plurality of layers of cloth impregnated with Paris plaster. These unitary splint materials are not so dirty and can be applied more quickly but still suffer from several disadvantages inherent in plaster cast materials of Paris. All paris gypsum boards have a relatively low weight-to-weight ratio, which results in a finished board that is very heavy and bulky. Paris plasterboards are slow to harden, requiring 24 to 72 hours to reach maximum strength. Since Paris plaster is destroyed in water, it is difficult to bathe and shower. Even if moisture can be avoided due to these causes, perspiration for a prolonged period of time can destroy the plaster of paris and create a significant problem with odor and itching. US Patent Nos. 4,411,262 and 4,502,479 disclose a significant advantage in the molding and splinting art. The molding materials described in these patents comprise a flexible fabric impregnated with a moisture-curable resin encased in a moisture-impermeable, moisture-free package. Compared to Paris plaster, these products are extremely light in weight, have a very high weight-to-weight ratio and can be made relatively porous, allowing the flow of air through the molded material. Moisture cure systems of the prior art include a package within which a plurality of layers of fabric, such as glass fiber, impregnated with a moisture curing resin are contained. No provision is made for the re-closure of the package, so that the entire material should be used very quickly after the removal of the package, since these moisture-curing resins will cure in a relatively short period of time due only to contact with atmospheric humidity. U.S. Patent Nos. 4,770,299 and 5,003,970, among others owned by the applicant, each describe synthetic, roll-shaped bandage products that include the ability to distribute desired stretches of bandage material when necessary, while sealing the remaining stretch of material for later use. These products have proven to be very successful in many applications, since they include a filling material on both sides, thus allowing a quick and easy application. Similar products are also sold in pre-cut sections sealed in a moisture-proof wrapping for individual use. From the above analysis, it can be seen that both the conventional Paris plaster molding method and the latest molding method with moisture curable resins have advantages and disadvantages. On the one hand, paris gypsum moldings are bulky, heavy and difficult to apply, while moldings of moisture curable resin are light in weight, durable and relatively easy to apply. Paris plaster can be stored very easily and is used as needed since it has a relatively long shelf life as long as it does not get completely wet. On the other hand, moisture-curable resins are very sensitive to the presence of even lower amounts of moisture, which requires that either the materials are packed in a wide variety of different shapes and sizes or the unused portions are discarded, generating a substantial amount of waste and increasing the effective cost of the product. However, the synthetic, roll-shaped, fillings, current, are relatively expensive and limit the option to the practitioner to use less filling or filling in different densities or thicknesses from one point in the tablet to another. The invention combines the advantages of both paris gypsum and moisture curable resin systems, while avoiding their respective disadvantages. This is achieved by providing a unitary splinting system with improved strength and convenience. Conventional splinting and molding products have been generally manufactured by incorporating textile substrates that have been impregnated with moisture curable resin. These products generally require a weaving process that is often the largest part of the manufacturing process. It has now been determined that an improved immobilization or fracture support product can be manufactured using a polymer foam either independent of, or in conjunction with, a textile substrate formed by knitting, sewing, punching, lamination or adhesion. Preferably, at least part of the yarns or fabrics are reached in the substrate through the polymer foam thereby creating a reinforcing matrix.
Brief Description of the Invention Therefore, it is an object of the invention to provide a medical bandage product having a foam substrate material coated and impregnated with a moisture curable resin that hardens the material on exposure to moisture to form a rigid structure of self-support. It is another object of the invention to provide a medical bandage product that can be distributed to any desired length while preventing the hardening of the remaining material until use is desired. It is another object of the invention to provide an orthopedic immobilization bandage that can be used as a splint or molded tape that allows a wide variety of filler applications, included with, or applied as an integral part of the bandage or to be applied from separate way. According to the present invention, the foam is a flexible type polymer that is formed either chemically or by physical means. The foam used in the invention can be formed of acrylics, nitriles, polyurethane, styrene-butadiene rubber, EVA, PVAC, neoprene, PVDC, PVC, polyolefins such as PE or combinations and mixtures thereof. The structure of the foam can be of open cells, closed cells or cross-linked cells with a rigid, semi-rigid or flexible hardness. The preferred structure is an open cell foam with between 40-120 pores / aperture per inch. The main function of the textile reinforcement is to provide increased stiffness and durability to the substrate and the final immobilization product. Additionally, the reinforcement helps to reduce the weight fraction of the resin needed to achieve the desired strength and stiffness. These and other objects and advantages of the present invention are achieved in the preferred embodiment described below by providing a medical bandage product in the form of a roll to be distributed in predetermined lengths or lengths suitable for a given medical use, and comprising a sleeve elongate formed from a moisture impermeable and sealable material to prevent the ingress of moisture, and an elongated medical bandage material of substantially the same length as the sleeve and placed in the sleeve at an individual length along the length of the sleeve and sealing it against the entry of moisture until use. The medical bandage material comprises a substrate formed of a foam layer and a textile reinforcement layer with a reactive system impregnated in or coated on the substrate. The system remains stable when maintained in substantially moisture-free conditions and hardens on exposure to sufficient moisture to form a rigid self-supporting structure. A liner protective sheet encloses the substrate along its length and forms a barrier between the substrate and the sleeve during storage, and can optionally be removed after removal of the medical bandage material from the sleeve and prior to application to a patient. The substrate is applied to have a protective filler material interposed between the substrate and the patient. A means of pre-sealing is provided to re-seal the sleeve against moisture entry after a predetermined length or length has been distributed in the bandage product for use to prevent hardening of the substrate remaining in the sleeve. According to a preferred embodiment of the invention, the sleeve comprises an aluminum foil laminate having an outer tear-resistant layer, a central layer of aluminum foil and an inner layer of heat-sealable plastic. According to another preferred embodiment of the invention, the foam substrate comprises a polymer foam. According to yet another preferred embodiment of the invention, the reactive system comprises a mixed polyisocyanate, polyol, catalyst and stabilizer. According to still another preferred embodiment of the invention, the re-sealing means for re-sealing the sleeve is selected from the group consisting of tape, a clamp, a clip to retain a folded end of the closed sleeve and a restricted opening through which the sleeve extends. According to still another preferred embodiment of the invention, the roll comprises the sleeve with the medical bandage material therein and the sleeve formed in a spiral. Preferably, the invention includes a dispenser within which the spiral of bandage material is contained. According to still another preferred embodiment of the invention, the dispenser comprises a container into which the roll is placed, the container defining a slot therein in which the leading end of the spiral can be placed and through which it is distributed as the product is needed. According to still another preferred embodiment of the invention, a medical bandage product is provided to be packaged in predetermined lengths suitable for a given medical use, and comprises a sleeve formed of moisture impermeable and sealable material to prevent moisture ingress and a medical bandage material placed in the sleeve and sealed therein against moisture entry until use. The medical bandage material comprises a substrate, a reactive system impregnated in or coated on the substrate, the system which remains stable when maintained under substantially moisture-free conditions and which hardens exposure to sufficient moisture to form a rigid, self-supporting structure . A liner protective sheet encloses the substrate and forms a barrier between the substrate and the sleeve during storage and can optionally be removed after removal of the medical bandage material from the sleeve and prior to application to the patient. The substrate is adapted to have a protective filler material interposed between the substrate and the patient. According to still another preferred embodiment of the invention, there is provided a medical bandage product having a predetermined length suitable for a given medical use, and comprises a closure formed of a sealable moisture impervious material to prevent the ingress of moisture. The enclosure includes an elongated re-sealable dispensing sleeve with a medical bandage material placed in the enclosure and sealed therein against moisture entry until use. The medical bandage material comprises a substrate formed of a plurality of layers of woven or knitted fabric, a reactive system impregnated in or coated on the substrate, the system remaining stable when maintained under substantially moisture-free and hardening conditions on exposure to sufficient moisture to form a rigid self-supporting structure comprising a mixed polyisocyanate, polyol, catalyst and stabilizer. One embodiment of the method for constructing a medical bandage product according to the invention comprises the steps of providing an elongated sleeve, impermeable to moisture and an elongate medical bandage material comprised of a substrate enclosed within a filling layer, impregnated in or coated on the substrate, a reactive system which remains stable when kept under substantially moisture-free conditions and hardens exposure to sufficient moisture to form a rigid self-supporting structure, and placing a bundle of elongated medical bandage material into the elongated sleeve that in general it is of the same length as the sleeve and extends along the length of the sleeve in a single layer. The sleeve is sealed to prevent moisture ingress until use.
Brief Description of the Figures Some of the objects of the invention have been discussed above. Other objects and advantages of the invention will appear as the description of the invention continues when taken in conjunction with the following figures, in which: Figure 1 is a perspective view of one embodiment of a medical bandage product including a cuff waterproof sheet moisture; Figure 2 is a perspective view of a bundle of medical bandage material; Figure 3 is a vertical cross-sectional view of the medical bandage material shown in Figure 2, - Figure 4 is a perspective view of a medical bandage product, including one embodiment of a dispensing box; Figure 5 is a perspective view of the medical bandage product shown in Figure 5, showing the manner to close the leaf sleeve after use; Figures 6 and 7 illustrate a preferred way to prepare and apply the medical bandage material according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT AND BEST MODE With reference now specifically to the figures, Figure 1 illustrates a medical bandage product according to the present invention and is generally shown in the reference number 10. The product 10 ' The medical bandage is comprised of a substrate 12, impregnated or coated with a moisture curable resin as more specifically described below, enclosed within a soft filler 15, such as non-woven polypropylene. The substrate 12 and the filling 15 together comprise a medical bandage material 16. The medical bandage material 16 is enclosed within a sheet / plastic sleeve 18 laminated under moisture-free conditions and sealed within the sleeve 18 to maintain moisture-free conditions until the product is ready for use. The substrate 12 is preferably manufactured using a layer 13 of polymer foam, either by itself or with a superimposed textile reinforcement layer 14 formed of fabric, punching, lamination or adhesion. Preferably, in the substrate 12 at least part of the yarns or fibers of the textile reinforcement layer 14 penetrate through the polymer foam layer 14, thereby creating a reinforcing matrix. The reinforcing layer may also serve as a liner sheet to separate the inside of the sleeve 18 from the foam layer 13. According to the present invention, the polymer foam layer 13 is a flexible polymer that is formed either chemically or by physical means. The foam used in the invention can be formed of acrylics, nitriles, polyurethane, styrene-butadiene rubber, EVA, PVAC, neoprene, PVDC, PVC, polyolefins such as PE or combinations and mixtures thereof. The structure of the foam can be of open cells, closed cells or cross-linked cells with a rigid, semi-rigid or flexible hardness. The preferred structure is an open cell foam with between 40-120 pores / aperture per inch. The main function of the textile reinforcement layer 14 is to provide increased stiffness and durability to the substrate 12 and the final immobilization product. Additionally, the reinforcement provided by the reinforcing layer 14 helps reduce the weight fraction of the resin needed to achieve the desired strength and stiffness. The fibers or yarns used for sewing, knitting, punching, laminating or adhering to the foam layer 13 can be any suitable organic or inorganic fiber such as polyester, polypropylene, polyethylene, cotton, nylon, aromatic polyamide yarns or fibers, wool, linen, jute and glass or any other synthetic material. The fiber count should be in the range of 100 to 2000 dtex, preferably 250-1500 dtex. The construction of the substrate reinforced with knitting, stitching or punching should allow a spacing of yarns in the longitudinal or warp direction of between 5 and 50 per inch, more preferably between 12 and 24 per inch. The weight of the total substrate 12 is not limited but must be in the range of 20-500 g / m2, preferably 20-250 g / m2. The foam layer 12 should preferably have a thickness between 0.5 mm to 6 mm, more preferably 4 mm. Foams in excess of this value tend to be too thick to conform to the human anatomy and create a bulky device for immobilization. In this regard, an open cell foam is the preferred option with approximately 20-150 pores per inch, more preferably 65-85 pores per inch. In another embodiment, the foam layer 13 can be reinforced by adding an organic or inorganic filler during the manufacture of the foam, or an external organic or inorganic filler such as wood flour, chopped fibers, glass, silica, microfibers, microspheres in the foam substrate to achieve the desired levels of strength and rigidity. The addition of fillers may also help to improve the transpiration and porosity of the foam substrate. The addition of fibers or microspheres of lower density will also help in reducing the weight of the final product. The filler loading will depend on the type of filler chosen and the desired final stiffness value. The preferred filler loading may vary in the range of 15-85 volume percent. The reinforced foam substrate 12 which has been woven through, punched into, laminated or adhered with the textile fibers or yarns, or loaded with fillers, will be impregnated with a curable resin, more preferably a resin of isocyanate that can be cured by air or water. The substrate 12 is impregnated or coated with a reactive system which remains stable when maintained under conditions substantially free of moisture but which hardens the exposure to sufficient moisture to form a rigid self-supporting structure. A typical formulation of the reaction system is set forth in the following table:
Typical formulation Isonate 143L or Mondur CD or Polysiocyanate 50.0% Carbowax PEG 600 Carbowax PEG 4600 22.0% Carbowax PEG 8000 Voranol 230-238 Voranol 220-110 18% Irganox 1010 2% Antiespuma 1400 4% Methane sulfonic acid 1% DMDEE 3%
A complete analysis of the parameters of the reactive system, the manner of production and the variables that apply are found in U.S. Patent No. 4,411,262. The polyisocyanate resin remains in a viscous state, so long as the resin is not exposed to moisture. This allows the substrate to remain flexible and moldable so long as the resin does not over-expose to moisture, and for a short period of time after which the exposure occurs. The rate at which the resin cures can be controlled to some degree by the amount of water to which the resin is exposed. Briefly immersing the resin in water will cause the resin to cure quickly. In contrast, by only exposing the resin to open air, it will result in a curing process having a significantly slower reaction rate that will be proportional to the amount of moisture in the air to which the resin is exposed. The medical bandage product 10 can be sold in any convenient length, such as in pre-cut sections, see Figure 2, or in long stretches, such as 24 feet, which are wound in a spiral and placed in a box 25 Proper distribution, as shown in Figures 4 and 5. The dispensing box 25 is provided with a slot 26 in a lower corner through which the bandage product 10 extends. As shown in Figures 6 and 7, a section of the medical bandage material 16, after it has been dispensed from the box 25, is removed from the leaf sleeve 18 and wetted as described above, applied to the end which it will be treated and molded in the conformable form. An elastic bandage "B" is then applied on the material 16 to retain the material 16 in its shaped form during curing. This occurs over a period of several minutes, depending on the amount of moisture at which the resin was exposed. In the hardening, the medical bandage material 16 forms a splint which is held at the extremity with the "B" bandage during healing, but which can be removed as needed for bath or splint replacement. A medical bandage product and material formed from a moisture curable plastic material, a method for building this improved medical bandage, and a method for building and applying an improved bandage product are described above. Various details of the invention can be changed without departing from its scope. Additionally, the above description of the preferred embodiment of the invention and the best mode for practicing the invention are provided for the purpose of illustration only and not for the purpose of limitation.