MXPA00007496A - Cold seal package and method for making the same - Google Patents

Abstract

The present invention is directed to a cold seal package (10) that includes constructions wherein two substrates (12, 18) or two portions of one substrate, are sealingly engaged to one another using a substantially natural latex rubber-free contact adhesive (14, 16). The two substrates can be easily peeled apart without substantial damage to the substrates. Furthermore, the substrates cannot typically be resealed, or refastened, once peeled apart. That is, the cold seal formed by the adhesive between the substrates is substantially non-refastenable. Advantageously, a cold seal package of the present invention is particularly well suited for aseptic delivery of packaged goods, such as bandages, dressings, and the like.

Description

SEALING PACKAGING IN FRIÓ AND METHOD TO MANUFACTURE THE SAME Field of the Invention The present invention relates to cold seal gaskets that are sealed under the application of pressure without the need for the application of elevated temperatures. The cold seal packaging can be used to pack a variety of items, including groceries, pharmaceuticals, and medical supplies. They typically use adhesives for cold sealing such as natural rubber (also referred to as latex rubber). Such cold seal adhesives are differentiated from sealing adhesives with heating in that heat sealing adhesives typically require both temperatures and high pressures for activation. The adhesives for cold sealing are used as an alternative in the packaging because the adhesives for heat sealing have manufacturing limitations. For example, adhesives for sealing with heating require additional time for thermal diffusion for activation.

REF .: 121755 Background of the Invention Natural rubber (or latex rubber) has several disadvantages. It is of particular interest that it can initiate an allergic response in people. It is believed that certain people become sensitized to allergens in natural rubber during repeated exposure to natural rubber and, consequently, exhibit increasingly severe allergic responses during each exposure. This is particularly significant in the medical area where both health care workers and chronically ill patients are repeatedly and directly exposed to products, such as natural rubber gloves, pipes, and the like. To a lesser degree, medical packaging of bandages and wound dressings may also contain natural rubber in the cold-seal adhesives used in packaging. Other disadvantages of natural rubber include discoloration during aging and an unpleasant odor. Synthetic cold seal adhesives have been incorporated into the packaging or packing material to overcome the disadvantages associated with natural rubber. For example, U.S. Pat. No. 4.4, 2.599 (Isgur et al.) Describes the use of base polyurethanes aqueous in packaging applications with cold sealing. The U.S. Patent No. 5,616,400 (Zhang) discloses an adhesive for cold sealing for use in packaging formation. The cold seal adhesive is formed from a polyurethane ionomer, where the overlaying coatings of the cold seal adhesive are pressed together to form a wrapper enclosing a packaged article. That is, the seal is formed between the same substrates and the same adhesives with no difference in adhesion at the two interfaces between the adhesive layer and the substrates. Although these patents have described the adhesive characteristics of these materials for cold sealing, synthetic, the opening characteristics of the packaging remain an important consideration. This is of particular interest in pharmaceutical packaging and medical supplies to maintain sterility within the packaging. Evidence of misuse or cold seal violation are important characteristics of such packaging. However, a competitive interest is also emerging on the joint formed in a package with a cold sealing material. For example, it is desirable that the package be easily opened with a controlled force and predictable movement leading to a reduced likelihood of spillage of packaging contents. Accordingly, what is still necessary is a cold seal package which exhibits sufficient strength in the joint and is still easily opened and preferably provides evidence of the previous opening.

Brief Description of the Invention Methods for manufacturing a cold seal gasket and cold seal gaskets are provided by the present invention. A cold seal packaging generally includes constructions wherein the two substrates, which may be two discrete portions of a contiguous laminate, for example, are sealingly coupled together, preferably, to form a sealed enclosure for the placement of an article. in the same. The two sealing portions of the substrate (s) can generally be detached easily and cleanly without substantial damage to the substrate (s). In addition, the sealing portions of the substrate (s) typically can not be resealed, or resharpened, once they have been peeled off, whereby a "cold seal" is substantially formed. "reafianzable." By this it is understood that after the initial seal, the opening, and then again the engagement of the sealing portions of the substrate (s), a very small or non-existent force could be required to reopen the package. This non-assurance cold seal can be formed, for example, between two sealing portions of the substrate (s) and two layers of the contact adhesive, which can be the same or different. The two layers of the contact adhesive is typically a substantially permanent bond (referred to herein as a cold seal or an adhesive bond for cold sealing), that is, during the opening of the packaging of the present invention in the seal in cold, the layers of the adhesive are not separated from each other The joint formed at the interface of a layer of the contact adhesive and one of the substrates (ie, the anchoring substrate) is also typical A permanent bond is formed, while the joint formed in the interconnection of one layer of the contact adhesive and the other substrate (i.e., the transfer substrate) is a removable and nonrefurable bond. The bond at the interface of the contact adhesive layer and the transfer substrate is removable as a result of a layer of a release coating on the surface of the transfer substrate. Peeling ability can result from the release of the adhesive and the releasable coating of the transfer substrate, or portions thereof, or from the release of only the adhesive with the lyoration coating remaining on the transfer substrate. In one embodiment, the present invention provides a method for manufacturing a cold seal gasket comprising the steps of: applying a first substantially natural latex rubber-free contact adhesive to an anchoring surface to form a liquid contact adhesive coating. anchorage; applying a composition of the release coating to a transfer surface to form a coated transfer surface for release; applying a second, substantially natural latex rubber-free contact adhesive to the coated transfer surface for release, to form a coating of the contact adhesive for transfer; and contacting the anchor contact adhesive coating with the transfer contact adhesive coating, each of which are at a temperature of about 50 ° C or less, to form a cold seal substantially not reactance between the surface of anchor and the coated transfer surface for release; wherein during the separate detachment of the anchoring and transfer surfaces, substantially all of the anchor contact adhesive coating and the transfer contact adhesive coating that formed the cold seal remain on the anchoring surface. It will be understood that there may be other portions of the transfer contact adhesive that were not used in forming the cold seal that remain on the transfer substrate depending on the coating configurations of the contact adhesive layers and the release coating. The first rubber-free contact adhesive substantially natural latex and the second rubber-free contact adhesive substantially natural latex can be the same contact adhesive or the same can be different contact adhesives. Preferably, the contact adhesives have a free or unsealed time of at least about 24 hours at a temperature of about 50 ° C or less. The first and second rubber-free contact adhesives, substantially natural latex, preferably each comprise a material selected from the group of a polychloroprene, a polyurethane, a copolymer of styrene-isoprene, a styrene-butadiene copolymer, a polyimide, a polyvinyl chloride, a nitrocellulose, a polyisoprene, a terpolymer of acrylonitrile-butadiene-isoprene, a copolymer of butadiene-methacrylonitrile, a copolymer of vinyl acetate-polyethylene, a polyacrylate, and mixtures thereof. Preferably, at least one of the first and second rubber-free contact adhesives substantially of natural latex rubber is formed from an aqueous polyurethane dispersion. Preferably and advantageously for the improved adhesion of the contact adhesive, the anchoring surface is treated prior to the application of the first rubber-free contact adhesive substantially natural latex. This treatment step of the anchoring surface preferably involves the treatment with a crown arc of the anchoring surface, although other techniques can be used, such as a treatment with a flame or coating with a primer, for example. During the application of the release coating composition to a transfer surface, preferably and advantageously, a substantially continuous release coating is formed. By this it is understood that the release coating includes few voids or voids, if any, for example. This release coating substantially continuous can be coated by means of a template or coated by flood on the transfer surface, preferably, however, it is coated by a template. The release coating composition preferably comprises a release material selected from the group of an ethyl acrylate-acrylonitrile copolymer, a copolymer of acrylic acid-alkyl acrylate, a polyvinyl chloride resin, a polyvinyl N-octadecyl carbamate, a polyethylene-based wax, a polyamide-based wax, a polysiloxane, a fluorocarbon polymer, a polyvinyl ester, a polyethylene imine, an alkyl substituted amine, a chromium complex, a fatty acid-based wax, and mixtures thereof. The release coating composition may also optionally include a rubber-free contact adhesive substantially natural latex. In certain embodiments of the method, the anchoring surface and the transfer surface are on two separate substrates, as for example, when each comprises a first major surface of laminate material or separate sheets. In other embodiments, however, the anchoring surface and the transfer surface are on two different portions of the same substrate, such as, for example, a laminate or of contiguous sheets. When both surfaces are part of a laminated material or of adjacent sheets, the anchoring surface and the transfer surface may each be on a different portion of a first major surface of the laminate or sheet material. Alternatively, the anchoring surface may be on a portion of a first major surface of the laminate or sheets and the transfer surface may be on a second major surface of the laminate or sheet material. Typically, in the formation of a package, the step of contacting the adhesive coatings to form a substantially non-recoverable cold seal produces an enclosure within the package. An article, preferably, a medical product such as a bandage, for example, is placed in the enclosure before sealing completely in packing. Typically, when a medical product is placed inside the package, after sealing the package, the method includes a step of sterilizing the medical pro-gas. The method of the invention may also optionally include a step of printing a signal or graphic indication on a substrate, such as one of the separated sheet materials. The present invention also provides a cold seal gasket comprising: a substrate of an anchor having a first main surface and a second main surface; a transfer substrate having a first main surface and a second main surface, wherein the first main surface of the transfer substrate has a release coating thereon to form a coated surface for release; and a rubber-free contact adhesive substantially of natural latex placed between the first main surface of the anchoring substrate and the release coating of the coated surface for the release of the transfer substrate forming a substantially non-reafiable cold seal between the substrate of anchoring and the transfer substrate; wherein the adhesion between the contact adhesive and the first main surface of the anchoring substrate is greater than the adhesion between the contact adhesive and the coated transfer substrate for the release. Preferably, substantially the entire free adhesive rubber contact substantially natural latex remains on the first major substrate surface anchoring during opening of a package cold seal removing by peeling the substrate anchor and the transfer substrate . More preferably, at least a portion of the release coating substantially continuous also remains on the rubber-free, substantially natural latex contact adhesive, during the opening of a cold pack by the removal by detachment of the anchoring substrate and the transfer substrate. Preferably, a cold seal gasket has a Release Force T between the coated transfer substrate for release and the natural latex rubber free contact adhesive of approximately 600 g / 2.5 cm or less. Preferably, in the package the anchoring substrate and the transfer substrate each comprise a laminate or sheet material. Alternatively, the anchoring substrate and the transfer substrate form different portions of the same substrate, such as a laminate or adjacent sheet material. The anchoring substrate and the transfer substrate can each have the same rubber-free contact adhesive substantially of natural latex or a different one, coated thereon. Preferably, the natural latex rubber-free contact adhesive can include two layers of different contact adhesives, one coated on each of the anchoring substrate and the transfer substrate at a coating weight of about 4. 0 g / m2 or less. Each may be coated with a template or flooded, preferably, however, the contact adhesive layer adjacent to the release coating is substantially contiguous to the transfer substrate. In this case, the substantially continuous release coating is coated by means of a template on the transfer substrate. Another embodiment of the present invention is a cold seal gasket comprising: an anchoring substrate having a first main surface and a second main surface; a transfer substrate having a first main surface and a second main surface, wherein the first main surface has a substantially continuous release coating thereon to form a coated surface for release; and a rubber-free contact adhesive substantially of natural latex having a free or unsealed time of at least about 24 hours placed between the first main surface of the anchoring substrate and the coated surface for release of the transfer substrate, wherein a cold seal, substantially non-refundable, is formed between the first main surface of the anchoring substrate and the release coating of the coated surface for the release of the transfer substrate in such a way that the adhesion between the contact adhesive and the first main surface of the anchoring substrate is greater than the adhesion between the contact adhesive and the coated transfer substrate for liberation.

When used herein, "non-recoverable cold seal" means a seal formed between two substrates, which may be two portions of the same substrate such as two different portions of a laminate or adjacent sheets, using an adhesive or combination of adhesives which can form a bond or bond at room temperature (i.e., about 20 ° C to about 30 ° C). The resistance to detachment of the non-recoverable cold seal of a package of the present invention is at least about 20 grams / 2.5 centimeters (20 g / 2.5 cm). Preferably, the non-recoverable cold seal has a peel strength of at least about 80 g / 2.5 cm and is stable (ie, the seal does not fail) at temperatures typically encountered during transportation and delivery, which may be up to about 70 ° C. This non-reafiable cold seal includes the bonds or bonds formed at an interface number, for example, between an adhesive and a anchoring substrate (typically, a permanent bond), between two adhesive layers (typically, a permanent "cold seal"), between a release coating and a transfer substrate (optionally, a release bond), and between an adhesive and a release coating (optionally, a release link). When used herein, "natural latex rubber" or "natural rubber" means a milky fluid obtained primarily from the Heavea brasiliensis tree (also known as the rubber tree). Typically, the milky fluid contains small particles of substances that are naturally present, such as cis-1,4-polyisoprene, stabilized by proteins and dispersed in an aqueous medium. When used herein, "free of substantially natural latex rubber" refers to a contact adhesive composition to which natural rubber is not intentionally added. Preferably, the contact adhesive composition contains about 1 part per million (ppm) or less, and more preferably about 1 part per billion (ppb) or less, of a natural latex rubber and exhibits characteristics of a contact adhesive, as defined later.

When used herein, "contact adhesive" (also known as a cold-seal adhesive) is one that preferably adheres to itself or a chemically similar material under pressure or force without the need for significantly elevated temperatures (e.g. without the need for temperatures above 50 ° C). Unlike pressure-sensitive adhesives, the contact adhesives are typically non-adherent or only lightly adhere to chemically different surfaces at temperatures of about 15 ° C to about 50 ° C. Accordingly, a contact adhesive preferably not blocked, does not reseal, or sticks to the contents placed inside the package. When placed against each other, contact adhesives typically require moderate pressure (such as that exerted by finger tip pressure) to achieve a bond without the application of significantly elevated temperatures. That is, the packages can be sealed at room temperature (ie, approximately 20 ° C to approximately 30 ° C) and even lower (for example, 15 ° C), as well as temperatures up to approximately 50 ° C, if the product Packed is not sensitive to such temperatures. The use of crosslinking or thermal curing agents in a contact adhesive is typically unnecessary to form a bond when it is required in the formation of a "sealing with heating". Sealing adhesives with heating typically require the application of elevated temperatures, generally at least about 100 ° C, and often in a range of about 138 ° C to about 205 ° C, to form a seal when the substrates are brought together. Accordingly, a contact adhesive (i.e., the cold seal adhesive) as used herein, is one that does not require high temperatures (i.e., above about 50 ° C) for the activation of its adhesive characteristics. This includes, however, contact adhesives that can be hot-melt coated, but do not require the application of heat to form a seal. Actually, some suitable contact adhesives can be melt-coated with heating. When the contact adhesive is hot melt coated, it is tacky in the molten state (eg, at a temperature of about 90 ° C to about 150 ° C) but is non-sticky or is very lightly adherent to the surfaces chemically unequal at a temperature of about 50 ° C or lower, preferably at room temperature. Once the hot-melt adhesive is cooled, A package is typically formed by carrying two adhesive coated surfaces, which may be on two separate substrates or on the same substrate, together under moderate pressure, preferably at room temperature. A contact adhesive is to be distinguished from a pressure sensitive adhesive (P? A). A P? A is typically sticky at room temperature, requires moderate pressure to achieve a bond (such as that exerted by the pressure of the finger tip), but which adheres to a wide variety of different substrates. A pressure sensitive adhesive is understood to refer conventionally to an adhesive that exhibits a permanent and aggressive tack to a wide variety of substrates after applying only light pressure. An accepted quantitative description of a pressure-sensitive adhesive is given by the Dahlquist criteria line, which indicates that materials having a storage modulus (G ') of less than about 3 x 105 Pascals (measured at 10 radians) / sec at room temperature, about 20 ° C to about 22 ° C) have pressure-sensitive adhesive properties while materials having a G 'in excess of this value do not.

Brief Description of the various views of the Drawings Figure 1 is an exploded view of a disassembled cold seal package according to the invention. Figure 2 is a cross-sectional view of a portion of a cold seal gasket partially assembled according to the invention. Figure 3 is a cross-sectional view of a partially open cold seal gasket according to the invention showing a product within an enclosure. Figures 4A and 4B are cross-sectional views of alternative embodiments of the cold seal gaskets assembled according to the invention.

Figure 5 is a representation of a preferred orientation of a rotogravure cylinder and a doctor blade.

Description of the Preferred Modalities A cold seal gasket according to the invention generally includes two substrates or substrates surfaces, which may be two portions of a substrate such as two distinct portions of a material laminate or contiguous sheets, sealed together with a rubber-free contact adhesive substantially of natural latex (ie, a cold-seal adhesive), including a mixture of adhesives, whereby a cold seal is formed. Preferably, the two substrates and the seal form an enclosure for a product. The two sealed surfaces of the substrate (s) can be removed by detachment in a generally easy and clean manner without substantial damage to the substrate (s) for removal of the product from the enclosure. further, the sealing portions of the substrate (s) typically can not be resealed or reaffirmed, once they have been removed by detachment. Surprisingly, the cold seal is formed with a release coating as part of the sealed portion of the package. That is, a release coating is placed between a portion of a substrate and the contact adhesive. Typically, such release coatings are used on the back side of a substrate coated with a contact adhesive to prevent blocking when the substrate is stored in a roll or cylinder form. As a result of the release coating that is part of the sealed portion (i.e., cold sealing) of the package, it can be opened by peeling off the sealed surfaces of the package. (of) the substrate (s) without breaking the integrity of the substrate (s). Referring to Figure 1, a schematic view of an embodiment of a non-assembled cold seal gasket 10 according to the invention is shown. In a preferred embodiment, a cold seal gasket 10 includes a first substrate 12, also referred to herein as an "anchoring substrate", in the form of a laminate or sheet material. Coated thereon is a first rubber-free contact adhesive substantially of natural latex 14 (also referred to herein as the "anchor coating contact adhesive"). The first rubber-free natural latex-free contact adhesive 14 can be coated in any desired pattern or pattern onto the anchoring substrate, including the entire surface of the substrate such that the adhesive layer is substantially contiguous with the substrate, as shown in FIG. shown in Figure 1. In cold seal packaging 10 it includes a second substrate 18, also referred to herein as a "transfer substrate", in the form of a laminate or sheet material. Coated thereon is a second rubber-free contact adhesive substantially of natural latex 16 (also referred to herein as "contact adhesive of the coating of "The second rubber-free contact adhesive substantially natural latex 16 can be coated on any desired template or pattern on the transfer substrate The contact adhesive layer 16 is coated on a layer of a release coating. in a substantially contiguous manner on the substrate 18. Alternatively, the contact adhesive of the anchor coating can be coated with a template on the anchoring substrate in the same template or configuration as the release coating is on the transfer substrate with the contact adhesive of the coated transfer coating on the entire surface of the substrate When they are brought together, the surfaces coated with the adhesive of the anchoring substrate and the transfer substrate form the cold seal of a package. of the interface of the two substrates (or two per of a substrate) which are respectively coated with the adhesive or the adhesives are typically adhesively connected. These surfaces form the internal walls of a cold seal gasket. Preferably, the space within a cold seal gasket which does not correspond to the contact area between the first and second adhesives of rubber-free contact, substantially natural latex, is the space available for the placement of an article in a cold-seal packaging. Accordingly, only typically one of the layers of the contact adhesive can be coated on substantially the entire surface of one of the substrates with the other which is a peripheral coating on the other substrate, for example, although both layers of the adhesive can be coated. by a template or configuration on the periphery of the two substrates. For example, as shown in Figure 1, the first rubber-free contact adhesive substantially of natural latex 14 is coated substantially on the entire surface of the first substrate 12, while the second rubber-free contact adhesive is substantially natural latex. 16 is coated as a peripheral coating on the second substrate 18. Accordingly, the article to be sealed within a cold seal gasket lies within the area 15 traced by the contact adhesive 16. The substrate or substrates ( for example, the first substrate 12 and the second substrate 18 of Figure 1) are each preferably in the form of a laminate or sheet material (eg, a film), although the substrate (s) may be in other ways.

For example, a substrate may be molded to form a sheet of connected but individual compartments which, when sealed, may be used as packets of ampoules to pack individually forms of pills or tablets of pharmaceutical or nutripharmaceutical substances, batteries, and the like. The preferred sheet or laminate material can be made of a polymeric material, a woven material, or a non-woven material. The materials used to form a sheet or sheet are preferably selected from the group of polyolefins such as polyethylene (including high density, low density, linear low density polyethylene, metallocene catalyzed polyethylene, etc.) and polypropylene, as well as polyethylene. poly (vinyl acetate), poly (vinyl alcohol-co-ethylene), polyvinyl chloride, polyester, poly (ethyl acrylate), acrylic acid / ethylene copolymer (such as that commercially available under the registered designations NUCREL of EI du Pont de Nemours, Wilmington, DE, and PRIMACOR of Dow Chemical Co., Midland, MI), ethylene / methacrylic acid copolymer, vinyl acetate / ethylene copolymer (such as that commercially available under the registered designation NA 443-021 of Quantum Chemical Co., Cincinnati, OH), polychlorotrifluoroethylene, polycarbonate, polytetrafluoroethylene (such as that available commercially under the TEFLON registered designation of E.l. du Pont de Nemours, Wilmington, DE), polystyrene, polyacrylonitrile, ionomers of ethylene / methacrylic acid copolymers (such as those commercially available under the trade designation SURLYN from El Du Pont de Nemours, Wilmington, DE), polyamide, poly (chloride) vinylidene), paper, and laminates or compounds thereof. A particularly preferred material is high density polyethylene (HDPE) because it is typically stable under sterilization conditions, and is cost less than many other suitable materials. A coextruded HDPE laminate and a metallocene catalyzed polyethylene layer is desirable because a backside coating of an anti-blocking composition is typically not required when a roll of such a substrate is stored with a contact adhesive coated thereon. When the two substrates are used, the two substrates can be identical or different materials. The transfer substrate 18 (Figure 1) includes at least one main surface that has been coated with a release coating 19. The main modified surface of the substrate is the surface having the rubber-free contact adhesive substantially natural latex 16 on the same.

The release coating 19 is preferably substantially continuous without considering the surface area of the coated substrate. This means that substantially preferably there are no voids or fibrils in the coating. This does not mean that the substrate has to be continuously coated on its entire surface with the release coating. Accordingly, preferably, the substantially continuous release coating is coated with a template on the substrate 18. Typically, the release coating 19 and the transfer contact adhesive 16 are coated on the same templates or patterns and substantially contiguous with each other; however, the transfer contact adhesive 16 can be coated on the entire transfer surface 18. The release coating 19 (Figure 1) includes a polymeric material or a mixture of materials with release properties. Preferably, the release material is selected from the group of an ethyl acrylate-acrylonitrile copolymer, a copolymer of acrylic acid-alkyl acrylate (e.g., ethyl acrylate-acrylic acid copolymer), a polyvinyl chloride resin, a N-octadecyl polyvinyl carbamate, a polyethylene-based wax, a wax based on polyamide, a polysiloxane, a fluorocarbon polymer, a polyvinyl ester (eg, vinyl stearate, vinyl palmitate, etc.), a polyethylene imine, an alkyl substituted amine, a fatty acid based wax (e.g. fatty acid condensate), a chromium complex (eg, chromic chloride stearate), and mixtures thereof. Examples of such release coating compositions include those commercially available under the registered designations MICROMID 321RC (a polyamide dispersion) from Union Camp Corp., Jacksonville, FL, FC270 (a fluorochemical) from Minnesota Mining & Manufacturing Co., St. Paul, MN, and NORPEL 7465 (a fatty acid condensate) from Northern Products, Inc. Woonsocket, IR. A particularly preferred release coating is formed from a dispersion of aqueous polyamide. The release coating can be completely coated with a composition comprising a dispersion or aqueous solution or a dispersion or solution of an organic solvent. Alternatively, the release coating can be hot melt coated or coated from a 100% solids composition. For ease and environmental reasons, the coating of the release coating with water (typically, distilled or deionized water) is preferred.

For those release materials available in the form of 100% solids in pills, granules, or blocks, conventional hot melt coating techniques can be used to apply a release coating on a substrate. Significantly, the release coating may include a rubber-free contact adhesive substantially of natural latex or a mixture of adhesives in addition to the release material. This improves the adhesion of the transfer contact adhesive to the coated surfaces for release. The release material and the contact adhesive are preferably used in a ratio of at least about 2 parts of the release material to about 1 part of the contact adhesive, more preferably, at least about 5 parts of the release material to about 1 part. of the contact adhesive, and even more preferably, at least about 10 parts of the release material to about 1 part of the contact adhesive. The contact adhesives described below can be used for this purpose. For example, a mixture or combination of a polyamide dispersion as the release material and a polyurethane dispersion as the contact adhesive can be combined in a ratio of about : 1 in water, preferably deionized water, to form a coating composition for release. Optional additives for the release coating composition may include ultraviolet light absorbers, antioxidants, viscosity modifiers, and other additives as are known in the art of the release compositions. In addition, the transfer substrate can optionally include at least one major surface that has been treated to modify the adhesion of the release coating. This can be done using a number of techniques well known to those skilled in the art depending on the chosen substrate, as described below for the anchoring substrate. The anchoring substrate 12 (Figure 1) can include at least one main surface that has been treated to modify the adhesion of the contact adhesive. The main modified surface of the substrate is preferably the surface having the rubber-free contact adhesive substantially natural latex on it. This main surface can be modified to ensure that the contact adhesive adheres firmly to the substrate. This can be done using a number of techniques well known to those skilled in the art depending on the substrate chosen one. Suitable techniques include, for example, chlorinating the substrate, oxidizing the substrate with agents such as chromic acid, treating the substrate with steam, treating the substrate with a surface treatment technique of the active gas, and / or coating the substrate with a primer coating composition (eg, an alkyl titanate, a primer of the epoxy type, melamine-formaldehyde, etc.). The treatment of the anchoring substrate with an active gas treatment technique to improve the adhesion of the contact adhesive to the substrate is preferred. Treatment of the release substrate with an active gas treatment technique to improve adhesion of the release coating to the substrate is preferred. Examples of treatment techniques with an active gas include the processes of treatment with a corona arc, with a flame, with ozone, and with plasma. The corona discharge treatment of the polymeric films to impart certain surface characteristics, for example, adhesive properties, generally involves the electrostatic treatment of the surface of the film. Specifically, the treatment with a corona arc involves the exposure of the material to be treated to a gaseous electric discharge in the which the ionization regions are confined around the active electrodes. The specific type of the crown arc used to modify the polymeric surfaces is the corona arc of alternating current discharge (bipolar), which is characterized by two metal electrodes at least one of which is covered with a dielectric material. The material to be treated is typically located on the grounded electrode. The corona treatment processes suitable for use in the present invention can be any typical crown arc treatment process, for example, a nitrogen corona arc, an air corona arc, a corona arc oxygen, a halogen corona arc, etc. The preferred corona treatment process, however, involves the air corona arc treatment. Methods for standard corona arc treatment processes are described, for example, in U.S. Pat. Nos. 3,705,844 (Haas); 3,546,065 (Ostermeier); 3,503,859 (Goncarovs et al.); and 3,754,117 (Walter). Typically, at least about 0.1 Joules / cm2 of energy can be used, although 0.3-1.0 Joules / cm2 are preferred. Crown arch systems are commercially available from Pillar Technology Ltd. Partnership (Hartland, Wl). Treatment with a flame of polymeric films it is also well known in the art as a surface modification treatment. Representative flame treatment processes are described in U.S. Pat. Nos. 2,746,084 (Kreidl); 2,704,382 (Kreidl); 2,684,097 (Kritchever); 2,683,394 (Kritchever); and 2,632,921 (Kreidl). Referring to Figure 1, the first rubber-free contact adhesive substantially natural latex 14 and the second rubber-free contact adhesive substantially natural latex 16 are preferably adhesives that do not adhere or lightly adhere to the touch at temperatures of about 15 ° C to about 50 ° C and require moderate pressure (such as that exerted by the pressure of the finger tip) to achieve a cold seal connection. That is, the contact adhesives are considered not sensitive to pressure because the materials that lack chemical similarity with the adhesive do not have a significant adhesion to the adhesive; however, the contact adhesives adhere tenaciously to each other or to other materials that have chemical similarities. Preferably, they have a vitreous transition temperature of about 15 ° C or less and have sufficient plasticity to bind themselves or similar materials chemically under a single pressure and a hardness sufficient to resist bonding to different substrates under pressure; Preferred contact adhesives particularly for use in the present invention have a free or unsealed time (ie, the time during which the characteristics of the adhesive are available to form a joint during the application of a single pressure or force) of at least about 24 hours, and more preferably, of at least about 3 weeks, and even more preferably, of at least about one year, at a temperature of about 50 ° C or less. In this way, a substrate, such as a laminate or sheet material, can be coated with a contact adhesive and stored for a period of time prior to the manufacture of the package. The first rubber-free contact adhesive substantially natural latex 14 and the second rubber-free contact adhesive substantially natural latex 16 may be different or they may be the same contact adhesive, or mixtures of the contact adhesives. Accordingly, the first rubber-free contact adhesive substantially natural latex 14 and the second rubber-free contact adhesive substantially natural latex 16 may possess the same adhesive characteristics or they may possess different adhesive characteristics. If it is the same adhesives, once a cold seal is formed, the two layers of the contact adhesive may appear as one layer of the adhesive. Preferred polymeric materials for use in the natural latex rubber-free contact adhesive include, for example, a polymeric material selected from the group of polychloroprene; polyurethane (including aqueous polyurethanes such as those described in US Pat. No. 4,442,259 (Isgur et al.) and those commercially available under the registered designations WD 4007 and 4008-M of HB Fuller Co., St. Paul, MN, and BR-4620 from Basics Adhesives, Inc., Brooklyn, NY); styrene-isoprene copolymers (including terpolymers, tetrapolymers, etc.), such as commercially available series under the registered designation KRATON, of Shell Chemical Co., Chicago, IL; styrene-butadiene copolymers; polyimide; polyvinyl chloride; nitrocellulose; polyisoprene; acplonitrile-butadiene-isoprene terpolymers, such as commercially available series under the registered designation ZEON (1201L, 1022, 1072), from Zeon Chemical, Inc., Louisville, KY; the butadiene / methacrylonitrile copolymer as described in U.S. Pat. No. 5,145,929 (Ou-Yang); polyethylene vinyl acetate; polyacrylates, including an emulsion acrylic modified with carboxyl, such as those commercially available under the registered designation BFG1858, from B.F. Goodrich, Cleveland, OH, ethyl acrylate / vinyl acetate / methacrylic acid terpolymers described in Pat. U.S. No. 4,898,787 (Min et al.), And those described in Pat. U.S. No. 5,070,164 (Min et al.); and the mixtures thereof. The most preferred polymeric materials for use in the natural latex rubber-free contact adhesive are those which have a relatively long free time and are selected from the group of polyurethane, styrene-butadiene, terpolymers of acrylonitrile-butadiene-isoprene, polyacrylates , styrene-isoprene copolymers, polyisoprene, and mixtures thereof. A particularly preferred contact adhesive is formed from an aqueous polyurethane dispersion. The contact adhesive can be coated with a composition comprising a dispersion or aqueous solution or a dispersion or solution of an organic solvent. Alternatively, the contact adhesive can be hot melt coated or coated with a 100% solids composition. For environmental and ease reasons, coating the adhesive with water (typically, distilled or ionized water) is preferred, although some adhesives are going to be understood.

"* * -'- A ~ - Desirable ones can only be coated with an organic solvent, such as heptane, toluene, isopropyl alcohol, methyl ethyl ketone, and the like. Additionally, for those adhesives available in the form of 100% solids in microspheres, granules, or blocks, conventional melt-coating techniques can be used to apply a coating of the contact adhesive on a substrate. Preferably, the rubber-free contact adhesive substantially natural latex is applied as a polymer dispersion in an organic solvent, water (also referred to herein as an aqueous contact adhesive or an aqueous dispersion (or water) of a contact adhesive) , or a mixture thereof. The viscosity and the percentage solids can be adjusted when desired and in accordance with the requirements of the coating process used in the manufacture of a cold seal package. Typically, the adhesive compositions include about 20% to about 40% solids. Optional additives for the contact adhesive composition may include ultraviolet light absorbers, antioxidants, viscosity modifiers, and other additives such as those known in the art for adhesive compositions. Anti-blocking agents, such as silica or glass bubbles, they can also be added to reduce blocking tendencies. Preferably, the natural latex rubber rubber free contact adhesives 14 and 16 (Figure 1) are coated on the anchor substrate 12 and the transfer substrate 18, respectively, each at a coating weight of approximately 25 g / m2. nasta approximately 0.15 g / m2. More preferably, each of the natural latex rubber-free contact adhesives is coated at a coating weight of about 4.0 g / m2 or less, and still more preferably at a coating weight of about 0.8 g / m2 or less . Advantageously, such coating weight is approximately ten times lower than a typical coating thickness of an adhesive containing natural latex rubber, which typically can be from about 4.2 g / m2 to about 8 g / m2. When storing non-assembled substrates, it is desirable to coat the surface of the substrate opposite the surface having the contact adhesive coated thereon with an anti-blocking material to prevent blocking of a roll or cylinder of the substrates. Suitable anti-blocking materials may be of identical or similar materials as those used in the release coating compositions, as described above. Other anti-blocking materials are well known in the art, such as those described in Pat. U.S. Nos. 3,938,659 (Wardwell), 4,804,573 (McCarthy et al.), 4,810,747 (Bornack, Jr., et al.), And 5,516,865 (Urquiola), and European Patent Publication No. 555830 (Bublitz et al.). Referring now to Figure 2, a cold seal gasket 10 partially assembled, is shown. The pressure is applied to the anchor substrate 12 coated with a contact adhesive 14 of the anchor coating and the transfer substrate 18 coated with a release coating 19 and the contact adhesive of the transfer coating 16, as shown by the arrows A, such that rubber-free contact adhesives substantially of natural latex 14 and 16 contact each other. Preferably, and advantageously, the pressure can be applied at room temperature, and even at temperatures within a range of about 15"C to about 50 ° C, which simplifies the sealing process because no tools are required Highly hot bonding bonds Once sealed, the rubber-free contact adhesives substantially of natural latex 14 and 16 form a substantially continuous adhesive portion between the anchoring substrate 12 and the transfer substrate 18. Although not wishing to be bound by any particular theory, it is believed that an interdiffusion occurs between the rubber-free contact adhesives substantially of natural latex 14 and 16 to form a joint. A bonding of the natural latex rubber-free contact adhesive between a contact adhesive and a coated transfer substrate for release in a cold seal package according to the invention is surprisingly strong, particularly in view of the coating of release 19. Advantageously, a cold seal package can be easily opened by peeling off the first and second substrates 12 and 18, respectively, as shown in Figure 3, to release an article 50 (e.g., a medical product) in the same. As shown by the arrows B, an opening force (or detachment force) is applied to each of the substrates 12 and 18. The second rubber-free contact adhesive substantially of natural latex 16 preferably adheres to the first adhesive of free contact of substantially natural latex rubber 14 on the first substrate 12. This leads to a substantially complete transfer of the second natural latex rubber free contact adhesive 16 from the transfer substrate 18 to the anchoring substrate 12 in the seal area. There may be other portions of the transfer contact adhesive that were not used in the formation of the cold seal that remains on the transfer substrate. The release coating 19 may also or may not be transferred with the contact adhesive 16. Typically and preferably, however, at least a portion of the release coating 19 is transferred with the contact adhesive 16 to the anchoring substrate 12. during the opening of the cold seal of the package 10, as shown in Figure 3. The transfer of the contact adhesive from the transfer coating 16 occurs during the opening of the cold seal package of the present invention because of the adhesion between the contact adhesive of the anchor coating 14 and the anchoring substrate 12 is greater than the adhesion between the contact adhesive of the transfer coating 16 and the coated transfer substrate for the release 18. Also, preferably, the adhesion between the contact adhesive of the anchor coating 14 and the contact adhesive of the transfer coating 16 is greater that the adhesion between the contact adhesive of the transfer coating 16 and the coated transfer substrate for the release 18. More preferably, the peel strength between the two contact adhesives 14 and 16 (i.e., the peel strength of the cold seal) is greater than about 600 grams / 2.5 cm while the peel strength between the contact 16 and the coated transfer substrate for section 18 is approximately 600 grams / 2.5 cm or less. More preferably, the peel strength between the contact adhesive 16 and the coated transfer substrate for release 18 is from about 4 grams / 2.5 cm to about 600 grams / 2.5 cm, and even more preferably, about 100 grams / 2.5 cm to approximately 140 grams / 2.5 cm. The level of adhesion between the contact adhesive of the transfer coating 16 and the coated transfer substrate for the release 18 can be a reflection of the adhesion level at the interfaces between the adhesive and the release coating, between the release coating and the release coating. the substrate, or both. Accordingly, the level of adhesion between the contact adhesive and the coated transfer substrate for release does not specifically refer to any of these interfaces. Because of the relative peel strengths (ie, the difference in adhesion) as described above, a cold seal gasket according to the invention can be opened by peeling off the first substrate 12 and the second substrate 18, preferably, without breaking the integrity of each of the substrates. That is, a cold-seal gasket according to the invention does not typically require the transverse tear (i.e., in the direction that is substantially normal to or substantially perpendicular to) the bonded substrates. Accordingly, a cold seal gasket of the present invention can typically be opened without irrigating the contents of the packages with contaminants. In addition, a cold-seal gasket according to the invention can be opened in a clean manner typically such that there are no "cords" (i.e., there are no segments of the adhesive that remain adhered to both substrates and that extend over the gap between them). Referring now to Figures 4A and 4B, other preferred embodiments of a cold seal gasket of the present invention are shown, wherein a cold seal gasket can be formed from a single substrate. In one embodiment shown in Figure 4A, a cold seal gasket 20 is formed from a single substrate 22 in the form of a sheet material in which portions of an internal surface of the substrate they are adhered together to form a seal of the fin type. Alternatively, in a embodiment shown in Figure 4B, the portions of an inner surface and an outer surface of the single substrate 22 'are adhered together to form a seal of the type of superposition. The single substrate (22 and 22 'shown in Figures 4A and 4B, respectively) can be formed from any of the materials described above. A portion (34 and 34 'in Figures 4A and 4B, respectively) is coated with a release coating (23 and 23' in Figures 4A and 4B, respectively) analogous to the transfer substrate 18, also as described with reference to Figures 1 and 2. Another portion (32 and 32 'in Figures 4A and 4B, respectively), which is preferably modified to improve the adhesion of the contact adhesive, is analogous to the anchoring substrate 12, as described in FIG. reference to Figures 1 and 2. A first rubber-free contact adhesive substantially of natural latex 24 (24 'in Figure 4B) and a second rubber-free contact adhesive substantially of natural latex 26 (26' in Figure 4B) ) are provided on the portions 32 and 34 (32 'and 34' in Figure 4B), respectively. Therefore, as described above, the Relative peel strengths are provided between the inner surface portions 32 (anchor portion) and 34 (transfer portion) shown in Figure 4A and, similarly, between the inner portion 32 'and the outer portion 34' shown in Figure 4B , such that during the opening of the package, the contact adhesives 26 and 26 'are transferred to the anchoring portions 32 and 32'. In the illustrative embodiments described herein, it is to be understood that cold sealing between the substrates can be formed using a rubber-free contact adhesive substantially of natural latex. That is, the same natural latex rubber-free contact adhesive can be applied to both a portion of the transfer substrate and a portion of the anchoring substrate. Accordingly, a cold seal can be formed from a single rubber-free contact adhesive substantially natural latex. Alternatively, two different contact adhesives can be used. Because an anchoring substrate and a transfer substrate (each described as above) are employed, the adhesion of the cold seal of the rubber-free contact adhesive substantially of natural latex to the anchoring substrate is greater than the adhesion of the adhesive. Cold-sealed rubber-free contact adhesive substantially natural latex and coated transfer substrate for release. Preferably, the release resistance of the rubber-free contact adhesive substantially natural latex to the anchoring substrate is greater than about 600 grams / 2.5 cm while the peel strength between the rubber-free contact adhesive substantially of natural latex and the Coated transfer substrate for release is approximately 600 grams / 2.5 cm or smaller. More preferably, the peel strength between the natural latex rubber-free contact adhesive and the coated transfer substrate for the release is from about 4 grams / 2.5 cm to about 600 grams / 2.5 cm, and most preferably, from approximately 100 grams / 2.5 cm to approximately 140 grams / 2.5 cm. In any embodiment of the present invention, the relative peel strengths are significant when the contents are sterile and the aseptic delivery of the contents is not only desired but required. For example, a cold seal gasket can be opened simply by holding an outer edge of each of the substrates (as is shown in Figure 3) and removing the substrates by detachment. In another example, a cold seal gasket can be opened in a simple manner by holding a free edge of the substrate and releasing the seal, as shown by arrows D and D ', in Figures 4A and 4B, respectively. Additionally, the opening of a cold seal gasket typically does not require tearing of the packaging substrates in the transverse direction. The contents (e.g., article 50 shown in Figure 3), such as a medical bandage, bandage, or the like, can be emptied from a cold-sealed package into a sterile field. Also, because the natural latex rubber-free contact adhesive preferably adhere to a substrate, it is less likely that the contents will be accidentally fixed to the package, which could lead to contamination of the contents. Once a cold seal gasket is opened, the two substrates can not be easily resealed during the application of a pressure. A nonrefurable seal formed between the two substrates is particularly important in the areas of packaged medical products and foodstuffs, where evidence of misuse (such as pre-opening) is desired. If a sealing package has been previously opened, the end user will be provided with both visual and tactile indications. Visually, a cold seal gasket typically looks wrinkled or curled in areas where previous seals have been opened. In addition, even if they could be resealed, a cold seal gasket would typically exhibit a very small or nonexistent force for reopening. Additionally, the non-recoverable cold seal and the differential peel strength characteristics of the anchoring substrate and the transfer substrate are not affected by the presence of impressions or graphics. The graphic or printing indicia can be applied to either the anchoring substrate, the transfer substrate, or both prior to the application of the rubber-free contact adhesive substantially natural latex. In a preferred embodiment of the anchoring substrate, the substrate material can be first treated with a crown arc and the graphic indications can be applied to the surface treated with the crown arc. The contact adhesive of the anchor coating can then be applied directly on the graphic display. In another preferred embodiment, the graphic indications can be applied on the surface of the anchor substrate opposite the surface to which the contact adhesive of the anchor coating is applied. In a preferred embodiment of the transfer substrate, the substrate material can be first treated with a corona arc and the graphic indications can be applied to the surface treated with the corona arc. Graphic indications (for example, text and corporate identifications) can be printed using conventionally used processes in the graphic arts industry. Such processes include flexographic or direct gravure printing, for example. Printing inks are commercially available from a variety of sources such as Sun Chemical (Tokyo, Japan) or Superior Printing Ink Co., Inc. (New York, NY). Cold sealing gaskets can be made by a variety of conventional coating technologies. For example, the release coating and the adhesive coating layers can be coated onto any substrate by conventional coating techniques, such as a flood coating, a coating by means of a template, a coating by a pneumatic knife, a coating by inverse roller, a flexographic or gravure coating, etc., with the coating by means of a template that is preferred. Alternatively, any of the substrates and coatings can be made by extrusion, including coextrusion techniques. For coatings as thin as those of the present invention, gravure coating techniques can produce coatings with air entrainment and grooving problems. The groove is explained in Modern Coatinq and Drying Technology, E. Cohen and E. Gutoff, VCH Publishers Inc., NY, NY, 1992, pages 79-81. It is well known that air entrainment is largely caused by cavitation, which occurs on the outlet side of the gravure cylinder and the backup or support roller. By selecting the width and rigidity of the scraper blade, the angle of the scraper blade with the horizontal, and applying enough pressure to cause the leading edge of the scraper blade to rise from the surface of the photogravure cylinder, air entrainment may be controlled enough to produce acceptable coatings. The characteristics of the scraper blade can be determined empirically as described in Modern Coating and Dryinq Technology, page 105. The grooving can also be reduced by the choice of the cell geometry of the photo-engraving cylinder. In general, it is believed that a cell density relatively low (e.g., about 70 cells / 25 mm) and a relatively high cell angle (e.g., about 60 °) can produce flatter coatings (i.e. coatings without flanges or channels). In the preferred embodiments, after the application of a rubber-free contact adhesive substantially of natural latex to a surface of a substrate from a solution or a dispersion, it is preferable that the rubber-free contact adhesive substantially natural latex be dried (typically, in a conventional drying oven) to prevent the penetration of the solvent from the adhesive into the substrate. If a release coating is applied to a surface of the substrate from either a solution or a dispersion, it is also preferable that the release composition be dried to prevent penetration of the solvent from the release coating composition into the substrate. More preferably, the release coating composition is dried prior to the application of the rubber-free contact adhesive substantially natural latex. Typically, the coating compositions are applied in such a way as to provide smooth, flat coatings.

In a method of preparing a cold seal packaging, a release coating composition is applied to the first major surface of a transfer substrate and dried to form a release coating on the first major surface of the transfer substrate. A first rubber-free contact adhesive substantially natural latex is then applied to the release coating and dried. A second rubber-free contact adhesive substantially of natural latex is applied to a first surface of an anchoring substrate and dried. Preferably, a configuration or template of the second rubber-free contact adhesive substantially of natural latex is applied to a first surface of an anchoring substrate. More preferably, the second rubber-free contact adhesive substantially natural latex is applied to a peripheral portion of the first surface of the anchoring substrate. A sealed, cold seal gasket is formed by applying pressure to the coated transfer substrate and the coated anchoring substrate, wherein the first rubber-free contact adhesive substantially natural latex and the second rubber-free contact adhesive substantially natural latex they make contact with each other at a temperature no greater than about 50 ° C. A bond of the cold seal adhesive can be formed by applying sufficient pressure for a sufficient period of time while the two layers of the contact adhesive are in contact with each other to achieve the desired cold seal. The period of time required to achieve a cold seal (that is, the bond between the two layers of the contact adhesive) is about 1 second or less. The cold seal pressure (ie, the application of pressure at a temperature of about 50 ° C or less) typically ranges from about 1.3 x 10 5 Pascals to about 6.9 x 10 5 Pascals, preferably about 5.5 x 10 5 Pascals .

Examples The following examples are offered to assist in the understanding of the present invention and are not to be construed as limiting the scope thereof. Unless indicated by > otherwise, all parts and percentages are by weight.

Example 1 This example describes the construction and opening characteristics of a package prepared with contact adhesives for cold sealing based on polyurethane on the paper and film substrates, with the paper substrate having additionally a release coating layer. A transfer substrate made of 16 kg medical grade paper (Wausau Mills, Rhinelander, Wl) was coated with a release coating composition containing a dispersion of 15% solids aqueous polyamide, MICROMID 321RC (Union Camp Corp.). ) using a bar coater with blades at a setting of the 10 micron hole. The release coating composition was dried immediately at about 120 ° C for several seconds to remove the water. A transfer coating contact adhesive containing a 35% solids aqueous polyurethane dispersion, WD4007 (HB Fuller Co., St. Paul, MN), is overcoated to approximately 50 microns in a rectangular pattern or configuration with a brush of paint, and immediately_ it is dried at approximately 120 ° C for several seconds to prevent the penetration of water into the paper.

An anchoring substrate made of a high density polyethylene (HDPE) film 50 microns thick, treated with a crown arch (Huntsman Performance Films, S. Deerfield, MA, treated with a crown arch on a surface in air at approximately 44-48 dynes / cm surface tension) was coated on the treated surface with the crown arc with a contact adhesive of the anchor coating containing an aqueous polyurethane dispersion at 35% solids, WD4008-M ( HB Fuller Co.) using a knife bar coater with an orifice setting of 12 microns. The contact adhesive of the anchor coating was dried at 80 ° C for five minutes to give a coating thickness of approximately 6.3 microns. In sealed packaging it was formed by passing the two coated substrates through the pressure rollers at a setting of 17.8 Newtons / cm with the overlapping coatings to activate a cohesive bond between the two contact adhesives. The package could easily be opened without tearing or destroying the substrates by holding the edge of each substrate and removing them by detachment causing the transfer-shaped adhesive with rectangular shape to remain attached to, and transferred to, the anchor substrate coated with the adhesive . The open package it could not be resealed by pressing the two substrates back together.

Example 2 The force required to detach a coating of the contact adhesive from a coated substrate for release (detachment strength T) was measured for several cold sealed packages in this example. The release coating layers listed in Table 1 were coated with a coiled bar of # 4 wire on transfer substrates made of an HDPE film., treated with a crown arch (Hunstman Performance Films, corona treated on an air surface at approximately 44-48 dynes / cm surface tension) and dried. The release coating layers were coated on the treated surface with the corona arc of the HDPE film. A dispersion of aqueous polyurethane at 35% solids, WD4007 (HB Fuller Co.), was coated by means of a bar on the surface treated with the corona arc of the HDPE film at a coating weight of approximately 8.4 g / m2 and dry. An anchoring substrate made of HDPE film (Huntsman Performance Films, treated with a corona arc on an air surface at approximately 44-48 dynes / cm surface tension) was coated with a bar with a 35% solids aqueous polyurethane dispersion, WD4008-M (HB Fuller Co.), to a coating weight of approximately 4.2 g / m2 and dried. The sealed packages (Masters 2A, 2B, and 2C) were formed by passing a coated transfer substrate paired with the coated anchor substrate through the pressure rollers as described in Example 1. The Tear-Off forces T were then measured. using the method ASTM D1876 (1996) at an adjustment of the separation speed of 30.5 cm / minute. The results are given in Table 1.

For all samples, the package could be opened by detachment quickly without tearing or destroying the substrates. The adhesive coating for the transfer was transferred cleanly to the anchoring substrate. The refixation of the substrate films was not possible due to the use of finger pressure.

Example 3 A transfer substrate made of an HDPE film, treated with a crown arc, of 50 microns (Hunstsman Performance Films, treated with a corona arc on a surface in air at approximately 44-48 dynes / cm of surface tension) is coated with a coating composition for the release of a dispersion of 10% solids aqueous polyamide, MICROMID 321RC (Union Camp Corp.), using a coiled bar of # 4 wire and dried immediately with a stream of hot air from a heating gun. The release coating composition was coated on the treated surface with the corona arc of the HDPE film. A contact adhesive of the transfer coating of an aqueous polyurethane dispersion at 35% solids, WD4008-M (H.B. Fuller), was overcoated on the release layer using a rolled bar with # and wire immediately dried with a heating gun. An anchoring substrate made of an HDPE film, treated with a crown arc, of 50 microns (Hunstman Packaging Corp., treated with a crown arc on a surface in air at approximately 44-48 dynes / cm of surface tension) it was coated with a stick with an anchor coating contact adhesive of a 35% solids aqueous polyurethane dispersion, WD4007 (HB Fuller), to a thickness of about 18 microns. The dispersion was immediately dried with a heating gun, to give a coating weight of approximately 3.2 g / m2 on the surface treated with the corona arc of the HDPE film. A sealed package was formed as described in Example 1. The package could be easily peeled without tearing or destroying either the transfer substrate or the anchoring substrate. The contact adhesive layer for the transfer was transferred cleanly to the layer of the anchor contact adhesive. The detachment force T of the contact adhesive for the transfer with respect to the coated transfer substrate for the release was measured as described in Example 2 and found to be of 150 g / 25 mm. The refixation of the substrate films was not possible due to the use of finger pressure.

Example 4 This example describes the construction of a two-part package consisting of two substrates coated in such a way that a sealed enclosure is created by bridging the two films together and applying a normal finger tip pressure. A first substrate, a transfer substrate having a release coating and a contact adhesive for transfer thereon, was constructed from a HDPE film, treated with a crown arc, of 62.5 microns thick (Hunstman Performance Films, S. Deerfield, MA, grade 990, treated with a crown arch on an air surface at approximately 44-48 dynes / cm surface tension). An aqueous polyamide dispersion, MICROMID 321-RC (Union Ca p Corp.), was diluted to 10% solids with distilled water and coated on the treated side with the corona arc of the film using a coating rod wound with # 4 wire. The dispersion was immediately dried in a standard laboratory oven at 66 ° C (150 ° C) for 15 minutes to form a coating for release.

An aqueous polyurethane dispersion, WD-4008-M (H.B. Fuller Co.), was diluted to 20% solids with distilled water and coated on the polyamide MICROMID layer using a coating rod wound with # 4 wire. The dispersion was immediately dried in a standard laboratory oven at 66 ° C (150 ° C) for 15 minutes. A second substrate, an anchoring substrate having a contact adhesive coating for anchoring thereon, was constructed from an HDPE film, treated with a clear, 50-millimeter thick corona arc (Hunstman Performance Films). ., S. Deerfield, MA, grade 990, treated with a crown arch on an air surface at approximately 44-48 dynes / cm surface tension). An aqueous polyurethane dispersion at 35% solids, WD-4007 (H.B. Fuller Co.), was coated on the corona treated side of the clear HDPE film using a coating rod wound with # 4 wire. The dispersion was immediately dried in a standard laboratory oven at 66 ° C (150 ° F) for 15 minutes. These two substrates were then laminated together with the adhesive surfaces together to form a package as described in Example 1. The package was opened by detachment easily without tear or destroy either the transfer substrate or the anchoring substrate. The adhesive coating on the transfer substrate was transferred cleanly to the anchoring substrate.

Example 5 This example describes the construction of a two-piece package as in Example 4 with the coating for modified release with a contact adhesive. A first substrate, a transfer substrate having a release coating and a contact adhesive coating for transfer thereon, was constructed from a white HDPE film, 62.5 microns thick (Hunstman Performance Films., S. Deerfield, MA, grade 990, treated with a crown arch on an air surface at approximately 4 -48 dynes / cm surface tension). An aqueous mixture of a polyamide dispersion, MICROMID 321-rc (Union Camp Corp.), and a polyurethane dispersion, WD-4007 (HB Fuller Co.), was coated on the treated side with the corona arc of the film using a coating rod wound with # 4 wire. Mixing of polyamide MICROMID 321-RC and polyurethane WD-4007 consisted of 10 parts of MICROMID 321-RC, 1.2 parts of WD-4007, and 23 parts' of distilled water. The mixture was immediately dried in a standard laboratory oven at 66 ° C (150 ° F) for 15 minutes to form a release coating. An aqueous polyurethane dispersion, WD-4008-M (HB Fuller Co.), is diluted to 20% solids with distilled water and coated onto the coating of the MICROMID / WD-4007 mixture using a rolled coating rod with # 4 wire. The dispersion was immediately dried in a standard laboratory oven at 66 ° C (150 ° F) for 15 minutes. This substrate was laminated to the anchoring substrate of Example 4 with the adhesive surfaces together to form a package as described in Example 1. The package could be opened by peeling easily without tearing or destroying either the transfer substrate or the substrate. anchorage. The adhesive coating on the transfer substrate was transferred cleanly to the anchoring substrate.

Example 6 This example describes the construction of an anchor substrate printed by gravure. An HDPE film, treated with a corona, clear, 50 micron of coarse (Hunstman Performance Films, S. Deerfield, MA, grade 990, treated with a crown arch on an air surface at approximately 44-48 dynes / cm surface tension) was coated with a 35% aqueous polyurethane dispersion of solids, WD-4007 (HB Fuller Co.) in a frame-style configuration. The frame-style coating configuration was made using a direct gravure coating station, forward, conventional, such as that illustrated in H. Weiss, Rotogravure and Flexographic Printing Presses, page 165, Converting Technology Corp. (Milwaukee, Wl), 1985. The gravure cylinder was engraved or stamped in a frame style with The following geometry of the cell: 70 cells / 25 mm, cut with a style angle of 120 ° and a cell angle of 60 °, and cut to 90% of the total depth. There are no connection channels between the cells. The engraver or stamper was made by Ohio Electronic Engraving, Dayton, Ohio. After the engraving or stamping of the cylinder, it was veneered with 4 microns of chromium and polished transversely to a RZ (normalized radius of roughness in the Z direction) of 0.5 microns. The gravure station was equipped with a doctor blade (250 microns per 37.5 mm). As shown in Figure 5, scraper blade 60 was placed to make contact with the cylinder photogravure 62 in approximately the 1:00 position and at an angle of 12 ° from the horizontal. Sufficient pressure was applied to bend the doctor blade until the leading edge of the blade was lifted from the surface of the gravure cylinder in no more than 76 microns to allow the gravure cylinder to be cleaned by scouring the blade side instead of the front edge of the blade. If this distance increased beyond 76 microns, a channel of the fluid began to form on the surface of the gravure cylinder. When this happened, the pressure applied to the scraper blade was then reduced until the fluid channel on the gravure cylinder disappeared. In this way, entrainment of the air bubbles within the coating can be controlled. The dispersion was immediately dried in a conventional direct ignition airflow oven at about 80 ° C to produce an average coating weight in the coated areas of 4.2 g / m2. The dry coating was substantially free of bubbles and showed minimal channel formation (i.e., ripples) after lamination to a transfer substrate coated by flood. All patents, patent documents, and publications cited here are incorporated for reference as if each were individually incorporated for reference. Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the spirit and scope of this invention, and it should be understood that this invention is not limited to the illustrative embodiments described herein.

It is noted that in relation to this date the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, property is claimed as contained in the following

Claims (15)

1. A method for manufacturing a cold seal gasket, characterized in that it comprises the steps of: applying a first rubber-free contact adhesive substantially of natural latex to a fixing or anchoring surface to form a contact adhesive coating for fixing or anchoring; applying a releasable coating composition to a transfer surface to form a coated transfer surface for release; applying a second rubber-free contact adhesive substantially natural latex to the coated transfer surface for release, to form a contact adhesive coating for transfer; and contacting the contact adhesive coating for fixing or anchoring with the adhesive coating for the transfer contact, each of which is at a temperature of about 50 ° C or less, to form a cold seal substantially not reactable between the anchoring surface and the coated transfer surface for release, wherein, during removal by detachment from the anchoring and transfer surfaces, substantially the entire coating of the contact adhesive for fixing or anchoring and the coating of the contact adhesive for transfer, which formed the cold seal, remain on the fixing or anchoring surface.

2. The method according to claim 1, characterized in that the first rubber-free contact adhesive substantially of natural latex and the second rubber-free contact adhesive substantially of natural latex comprise the same contact adhesive.

3. The method according to claim 1, characterized in that the first rubber-free contact adhesive substantially of natural latex and the second rubber-free contact adhesive substantially of natural latex comprise different contact adhesives.

4. The method according to claim 1, characterized in that the first and second rubber-free contact adhesives substantially natural latex rubber have a free time or unsealed for at least about 24 hours at a temperature of about 50 ° C or less.

5. The method according to claim 1, characterized in that the anchoring surface and the transfer surface are on two separate substrates.

6. The method according to claim 1, characterized in that the anchoring surface and the transfer surface are on two different portions of a laminated material or adjacent sheets.

7. The method according to claim 1, characterized in that in addition the step of contacting the adhesive coatings to form a cold seal substantially not reafianzable produces an enclosure within the packaging.

8. The method according to claim 7, characterized in that it further comprises the steps of placing a medical product in the enclosure before sealing the package and sterilizing the medical product after sealing the package.

9. A cold seal gasket, characterized in that it is produced by the method according to claim 1.

10. A cold seal gasket, characterized in that it comprises: an anchoring substrate having a first main surface and a second main surface; a transfer substrate having a first main surface and a second main surface, wherein the first main surface of the transfer substrate has a coating for release thereon, to form a coated surface for release; and a rubber-free contact adhesive substantially natural latex placed between the first main surface of the anchoring substrate and the release coating of the coated surface for the release of the transfer substrate that forms a cold seal substantially not reactance between the substrate of anchoring and the transfer substrate; wherein the adhesion between the contact adhesive and the first main surface of the anchoring substrate is greater than the adhesion between the contact adhesive and the coated transfer substrate for the release.

11. A cold seal gasket according to claim 10, characterized in that substantially all of the contact adhesive free of substantially natural latex rubber remains on the first major surface of the anchoring substrate during the opening of a cold seal gasket by removing by detachment the anchoring substrate and the transfer substrate.

12. A cold seal gasket according to claim 10, characterized in that the Release Force T between the coated transfer substrate for the release and the rubber-free contact adhesive substantially of natural latex is approximately 600 g / 2.5 cm or less.

13. A cold seal gasket according to claim 10, characterized in that the anchoring substrate and the transfer substrate each have a contact adhesive free of rubber substantially natural latex coated thereon.

14. A cold sealing gasket according to claim 10, characterized in that the anchoring and transfer substrates and the sealing in cold form an enclosure inside the packaging, and the packaging also includes a medical product inside the enclosure.

15. A cold seal gasket according to claim 10, characterized in that the coating for the release comprises a release material mixed with a rubber-free contact adhesive substantially natural latex.