RU2533534C2 - Flexible package having reclosable clip - Google Patents

Abstract

FIELD: packaging industry.

SUBSTANCE: flexible package comprises opposed front and rear panels joined together to form a cavity, a reclosable clip comprising opposing cohesive layers formed using a solution of the solvent from a mixture of thermoplastic elastomer and a diluting polymer, located directly on each of the front and rear panels. The cohesive layers on the front and rear panels face directly each other, so that the flexible package can be closed when the opposite cohesive layers are in contact with each other. The bond strength of cohesive layers to the panels is greater than the cohesive strength of the bond between the opposed cohesive layers.

EFFECT: invention provides multiple opening of the front and rear panels by delamination without delamination of cohesive layers from panels.

15 cl, 14 dwg, 7 tbl

Description

The scope of the invention

The present invention mainly relates to the creation of re-closable clamps for flexible (soft) packaging and, in particular, to the creation of capable of interlocking repeatedly (repeatedly) lockable clamps for flexible packaging.

BACKGROUND OF THE INVENTION

Various types of closures or clamps are already being used to reseal previously opened flexible packaging. For example, mechanical reclosable clips, such as zippers, spring clips, closures, locks, etc., are commonly used. These mechanical closures can be bulky and can have complex configurations that require separate molding operations and the manufacture of a previous compound with a flexible film used to form a package. Since the closure itself can be cumbersome, it becomes difficult to operate with film rolls containing such structures, although mechanical closures can be used in forming, filling and sealing operations of the package, it is often necessary to carry out complex technological operations to apply , to connect and combine the characteristics of mechanical clamps for each design. Therefore, mechanical reclosable clamps often increase complexity and cost in the manufacture of flexible packaging.

Re-closing clamps on the basis of glue (adhesive) can serve as an alternative to mechanical clamps, however, clamps on the basis of glue have their drawbacks associated with the manufacture and formation of a resealable clamp. For example, pressure sensitive adhesives (PSAs) are already being used to form resealable clamps. However, conventional PSA resealable clamps have the disadvantage that these types of adhesives generally have high adhesive levels. Adhesiveness is the property of an adhesive material, which basically allows the material to form a bond with the surface of another material, after applying short-term or light pressure. Adhesion is often considered as quick adhesion, initial adhesion, or as a characteristic of rapid grip of material. PSA materials generally allow you to create a not-so-good re-closing clip, since the adhesive quickly adheres to most of the surfaces it comes in contact with. As a result, the PSA clip can adhere to machine components during package formation, to inappropriate areas. packaging film, and even to the product (or to its crumbs), which is contained in the package.

During the formation of flexible packaging using PSA (pressure sensitive adhesive), the adhesive can come into contact with machine components such as rollers (rollers), cutting inserts, bending (folding) devices, etc. Due to the high level of adhesiveness PSA, contact with these machine components can result in the transfer of PSA to these machine components. The transferred adhesive can then be re-transferred from these components of the machine to other undesirable areas of the packaging film, which can in some cases cause problems when tracking the web (tape) and other problems.

In existing packaging forming machines, the film is often wound into large rolls containing several hundred or several thousand yards of material, sometimes referred to as large rolls (elephants). In these coiled large rolls, high adhesive levels of PSAs can cause adjacent layers of the film to stick together, which is commonly referred to in the art as “blocking”. Locked large rolls are difficult and sometimes impossible to unwind, which typically leads to the inability to use them.

After forming in the package, resealable clips using PSA can also create problems for the consumer using the package. If the packaging is used to store crumbling or brittle (forming slices) of the product (brittle cheese, etc.), then the crumbs or slices of such a product can stick to the PSA, which reduces the effectiveness of the adhesive in the formation of sufficient sealing. With a significant clogging of the adhesive with the glue-based clamp product, it basically cannot form an adequate seal when the package is closed, since the adhesive sticks to the product crumbs, and not to the sides of the package.

Thermoplastic elastomers (TPEs), sometimes called thermoplastic rubber, are another type of adhesive that has been studied to create a reclosable clip. Some types of TPE copolymers (in particular some styrene block copolymers) show high cohesive characteristics, but have low tack levels, which allows them to be used effectively to create re-closable clips. However, such TPEs may have too high cohesive characteristics that make it difficult to use them to create a resealable clip in a flexible package, since TPE may peel off the film substrate rather than peel off the cohesive (adherent) interface. The disadvantage of TPEs is that these materials are thermoplastic and therefore their processing methods are mainly limited to heat treatment methods (i.e., a coating method by hot melt extrusion). When processing is performed using the heat of TPE in the form of a hot-melt solvent-free adhesive, this material is mainly applied continuously to the web by extrusion in the direction of movement of the machine, which does not allow using this method of applying the material in some types of existing packaging equipment in which the closure must be installed in the transverse direction of the web or in the transverse direction relative to the direction of movement of the machine. In addition, hot-melt adhesive without adhesive can generally not be applied intermittently in the form of a strip in the transverse direction of the web in an efficient or cost-effective manner.

The dissolution of TPEs in solvents so that the material can be printed in the transverse direction of the web is also associated with problems when packaging material is used to form food packaging. In some cases, organic solvents suitable for use with TPEs are not suitable for contact with food. The dissolution of TPEs in an aqueous solvent can be poor, and this creates additional problems associated with drying the coated material and removing the aqueous solvent. However, in some cases, even lower adhesive levels of TPE clamps can lead to technological problems in packaging equipment, such as transferring material to machine components and blocking material, as described above for PSA closures.

SUMMARY OF THE INVENTION

The present invention provides a gripable resealable clip and a flexible packaging that utilizes a gripable resealable clip. According to one embodiment, the flexible packaging may have front and rear flexible panels joined together to form a cavity between them to accommodate a product, such as a food product. Advantageously, a grip capable re-closable clip extends between the side edges of the front and back flexible panels at the opening of the package and is made with the possibility of repeated (multiple) opening and decompression.

In accordance with one aspect, a resilient clip capable of bonding (material for making it) can be supplied as a thermoplastic elastomer (TPE) diluted with a secondary polymer or allowing dilution with a polymer such as, for example, a copolymer of ethylene and vinyl acetate (EVA) having a melt flow rate of about 600 or higher, dissolved in an organic solvent (or a mixture of organic solvents). In some cases, TPE alone does not generally allow a suitable resealable clamp for flexible packaging to be formed, which can be easily and repeatedly opened and closed, since it has too high cohesive bond strength, which causes the clamp to it becomes impossible to open or it can peel off from the film forming the flexible packaging substrate, previously separated from the cohesive interface. However, by diluting TPE with effective but small amounts of a secondary or thinning polymer, such as an EVA copolymer, the desired cohesive tear strength suitable for use in flexible packages can be obtained.

In accordance with one approach, stable solutions of TPE and a secondary EVA copolymer have a fairly low viscosity (approximately from 50 to 1200 centipoise at a temperature of about 23 ° C) and a high solids content (approximately from 20 to 60%), so that they can print or roll. Suitable solvents are ethyl acetate, normal propyl acetate, isopropyl acetate, methyl ethyl ketone, methyl isobutyl ketone, ethyl alcohol, normal propyl alcohol, propylene glycol, normal propyl ether, butyl acetate, toluene, xylene, cyclohexane, cyclohexanol and mixtures thereof. The TPE solution can be applied in the form of a pattern onto a flexible film using a flexographic process or rotogravure printing, followed by drying to remove the solvent.

The adhesive coating polymer coating applied in the form of a drawing may have a corresponding configuration and may form opposable adhesion layers on the front and rear panels of the package. Capable of re-closing the clutch basically has an effective configuration, allowing it to be repeatedly opened and closed without significant delamination, plucking or moving material from the front and back panels forming the package. In accordance with one aspect, such a configuration can be obtained by using cohesive layers having enhanced cohesive bond strength, allowing for compaction when opposed cohesive layers mesh with each other but also having higher bond strength front and rear panels than the cohesive tear-off force (peeling force) required to open a resealable clip.

In accordance with another aspect, the engaging re-closable clip can also be configured to enhance the adhesion of the clip to the desired surfaces and at the same time minimize and, predominantly, prevent the clip from adhering to the unwanted surfaces. In accordance with one approach, a traction-capable, resealable clamp may have a relatively low adhesiveness to substantially minimize adhesion to unwanted surfaces and, at the same time, also has an increased cohesive bond strength allowing a resealable seal to be formed, while still having a relatively high durability of communication with front and rear panels. In one specific form, the adhesiveable resealable clip comprises a solvent-based thermoplastic elastomer (TPE) such as a styrene block copolymer diluted with a secondary polymer that has low tack and good cohesive bond strength, but relatively higher bond strength with the front and rear panels than its cohesive bond strength. To this end, the adhesiveable resealable clip may comprise a mixture of a styrene block copolymer and a secondary polymer, such as a copolymer of ethylene and vinyl acetate. According to one approach, the clamp making solution contains a major (predominant) amount of TPE and a minor amount of EVA.

In an alternative form, the adhesiveable resealable clip may include a solvent-based and polymer based adhesive layer TPE that has an open adhesive surface in combination with one or more non-adhesive spacer layers adjacent to the adhesive layer. In this form, the outer surface of the non-adhesive spacer layer may be configured such that it protrudes outwardly toward the adhesive surface of the adhesive layer so that it is recessed (recessed) with respect to the outer surface of the non-adhesive spacer layer. This configuration of the interlockable resealable clamp allows a gap to substantially be formed between the adhesion surface and the outer surface of the non-adhesive spacer layer, which effectively allows the clamp to form bonds with the desired surfaces (for example, when the clamp is closed during compression) and also minimizes and, advantageously , to exclude bonds with undesirable surfaces (for example, when spacer layers make contact with the adhesive layer difficult, as described further in more detail).

For example, a non-adhesive spacer layer basically functions so that it limits the contact of the adhesive layer with adjacent surfaces (such as equipment parts or adjacent packaging panels) by maintaining a gap between the adhesive surface and the adjacent surface since the adjacent surface is first comes into contact with the outer surface of the spacer layer, and then with a surface capable of adhesion. In order to close the clamp or to engage in an otherwise capable adhesion layer, the adjacent surface should overlap the gap formed by deepening the adhesive layer. Since the backing film and the clamping materials are typically flexible, the package can be closed by folding the package film to close the gap and form a bond with the external adherent surface of the matched closure on the opposite panel of the package. Such engagement may occur when the user presses the film with a finger or compresses the surfaces together.

Brief Description of the Drawings

Figure 1 shows a perspective view of an exemplary package having an engaging re-closable clip which is shown in an open position.

FIG. 2 shows a perspective view of an exemplary package shown in FIG. 1, which is shown in the closed position.

FIG. 3 is a cross-sectional view of an exemplary engageable reclosable clamp.

4 is a cross-sectional view of another example of an engaging re-closable clip that is shown in an open position.

FIG. 5 is a cross-sectional view of the engaging re-closable clip shown in FIG. 4, which is shown in the closed position.

FIG. 6 is a cross-sectional view of another example of an engaging re-closable clip shown in a partially open or unsealed position.

FIG. 7 is a cross-sectional view of the engaging re-closable clip of FIG. 6, which is shown in a closed or sealed position.

FIG. 8 is a cross-sectional view of another example of an engaging re-closable clamp.

Fig. 9 schematically shows an exemplary method of forming a flexible package having an engaging re-closable clip thereon.

FIG. 10 is a cross-sectional view of an exemplary arrangement of a flexible package, where you can see a clutchable resealable clip relative to an adjacent, exemplary machine component.

11 shows a partially cross-sectional view of an exemplary roll of a film substrate, where you can see the engaging re-closable clip relative to adjacent layers of the film substrate in a wound film roll.

12 shows an exemplary method of applying an engaging re-closable clamp to a film substrate.

13 shows an exemplary method of forming a flexible package in which an engaging re-closable clip is used.

14 is a cross-sectional view of another engaging re-closable clip.

DETAILED DESCRIPTION OF THE INVENTION

According to the present invention, there is provided a package 10 having an interlockable resealable clip 12, which is generally shown in FIGS. 1-8. Figure 1 mainly shows an open package 10, and Figure 2 mainly shows a sealed or closed package 10. In accordance with one exemplary shape, the package 10 is formed from a flexible sheet material or from a film 14 (which is sometimes referred to here as a substrate ( basis) or a film substrate), forming respectively the front and rear flexible panels 16 and 18. In this exemplary form, the package 10 may also include a blind fold 20 along its lower edge 22 and transverse or side seals 24 along its side edges 26, so that packing 10 o a cavity 28 is formed between the front panel 16 and the rear panel 18 to accommodate a product, such as a food product or other material. It should be borne in mind that the shown packaging form 10 is only an example of one type of packaging that is suitable for use with a clutchable resealable clamp 12, and other shapes, configurations, materials and types of containers / packages can also be used in conjunction with the clutch with a resealable clamp 12. The package 10 may further have other folds, seals, inserts and / or valves, which are mainly necessary for a specific application. Optionally, the package 10 may also have seals 11, above or below the resealable clip 12, as is mainly described in patent application 11/267, 174, which is incorporated herein by reference in its entirety.

In one aspect, the interlockable resealable clip 12 and the package 10 are basically designed or structured to minimize the adhesion of the clip 12 to undesirable surfaces, but still function effectively as a resealable clip. Thus, the clip 12 can be opened and closed many times to seal the contents in the cavity 28 during use by the user, but not peel off from the film substrate forming the front and rear panels 16 and 16. For this, it is capable of re-adhesion the closable clip 12 mainly contains adhesive with relatively low levels of tack to minimize adhesion to unwanted surfaces, which however has a selected tensile strength when connected or opened, sufficient to mashing or re-closing the package 10, as well as allowing disconnection to open and / or re-open the package. At the same time, the clip 12 has a strong bond with the film substrate. In accordance with one approach, the clamp (clamp material) may comprise a mixture of styrene block copolymers and a copolymer of ethylene and vinyl acetate.

It should generally be borne in mind that bonding material is typically more easily bonded to similar materials than to other materials (i.e., has a self-bonding characteristic). Suitable adhesion materials used here generally have relatively low adhesiveness upon contact with undesirable surfaces, good bond strength with desired surfaces (so that there is no peeling from the flexible front and rear panels), and relatively good bond strength with adhesion or self-adhesion to hold flexible packaging (or pocket) closed, but still with the possibility of opening or peeling by hand. It should be borne in mind that the selected adhesion materials used here may, in some cases, have the properties of pressure sensitive adhesives (properties of pressure sensitive adhesives), in the sense that the bond can be formed more quickly when pressure is applied than when using heat, solvent, or other means. The adhesion materials selected also allow bond breaking or peeling from such similar materials, so that the adhesion layers can be repeatedly separated by peeling without significant damage to the adhesion material and / or any substrate underlying it. When the adhesive material is separated by peeling, it should be borne in mind that the selected adhesive materials have sufficient internal integrity and mainly peel off at the interface of the cohesive joint, mainly purely, without significant plucking and fibrous material and without peeling from the substrate , and / or without other significant defects in the material (formation of droplets, granules, etc.).

As described in more detail below, the adherent material contains mixtures of a major amount of a thermoplastic elastomer (TPE) diluted with minor amounts of a secondary or thinning polymer, such as having a relatively low molecular weight (i.e. a melt flow index of about 600 or more), an ethylene copolymer and vinyl acetate (EVA). Diluting TPE with an EVA copolymer or diluting TPE with another material having a melt flow rate of about 600 or more allows an effective reclosable clamp to be formed that can still form an adequate bond with the flexible film forming the front and back panels. Other diluents may be used, provided that they dissolve in the desired solvent and mix with TPE to form a stable dispersion or solution that allows for roller coating or printing.

In accordance with another aspect, the package 10 and clip 12 are also designed in such a way that the bond strength or the tensile strength of the adhesiveable resealable clamp 12 relative to the film substrate 14, 16, 18 of the package is generally greater than the tensile strength when opened between themselves capable of adhesion by the layers of the clamp 12 (layers 32 and 34). Thus, the resealable clip 12 basically remains adhered to the film substrate 14 and does not mainly peel off, form threads or peel off the substrate 14, 16, 18 when the consumer opens the package 10 by opening the clip 12 by peeling. It can be assumed that the mixture of TPE and diluent, together with the construction of the film substrate, are effective to create the desired bond strength and tensile strength.

Let us now turn to the consideration of figure 3, which shows one form of a resealable clamp 12, which contains the opposite capable of adhesion layers 30 and 32, one of these layers is located on the front panel 16, and the other layer is located on the rear panel 18. Layers The clamps 30 and 32 are generally aligned with each other, so that the outer surfaces 34 and 36 of the respective clamp layers 30 and 32 facing each other are opposed to each other and can contact each other in a closed or sealed position when capable of leniyu layers are engaged with each other.

Advantageously, each of the opposable adhesion layers 30 and 32 is applied in the form of a solution that contains a thermoplastic elastomer (TPE) diluted with a copolymer of ethylene and vinyl acetate (EVA) in an organic solvent or mixture of organic solvents. As described in more detail below, the use of a solvent-based solution is preferable, since it allows roll coating of dissolved TPE into intermediate and transverse stripes using roll printing or coating, in the form of adhesive layers 30 and 32 applied to the film substrate 14 in such a way that this simplifies the formation of the package 10 on traditional machines for forming, filling and sealing (FFS) packages. As also described in more detail below, such intermediate and transverse stripes obtained by web printing or coating cannot generally be obtained using more conventional hot melt extrusion coating processes.

According to one form, the clamp contains a majority of the thermoplastic elastomer, which may be a styrene block copolymer containing TPEs such as Kraton ® D SIS styrene-isoprene-based block copolymer, Kraton ® D SBS styrene-butadiene-based block copolymer, Kraton ® G SEBS block copolymer with hydrogenated middle block styrene-ethylene / butylene-styrene, or Kraton ® SEPS block copolymer with hydrogenated middle block styrene-ethylene / propylene-styrene, or mixtures thereof. In some cases, additional additives may be required, such as plasticizers, fillers, antioxidants, or other polymers, which may be necessary when creating the TPE composition in order to customize the characteristics of the coating and its processing.

In accordance with one approach, the clamp may also contain a small amount of a copolymer of ethylene and vinyl acetate (EVA), which is used to dilute TPE. As already mentioned above, without the use of EVA, the clamp basically cannot work as a reclosable clamp, since the self-coupling of the TPE itself is approximately more than 700 grams per square inch and, in some cases, even approximately more than 1500 grams per square inch, which is undesirable for the formation of a resealable clamp on flexible substrates, because it tends to delaminate before complete separation due to peeling at the cohesive surface ate. According to one approach, EVA is an irregular copolymer that basically has a melt flow rate of about 600 or more, and contains about 19% vinyl acetate and about 81% ethylene. An EVA with a lower vinyl acetate content and / or a melt flow rate of approximately less than 500 does not form a stable solution in toluene.

In accordance with one approach, a suitable clamp manufacturing mixture comprises about 7 to 9 parts TPE and about 0.5 to 2 parts EVA, and preferably about 8 parts TPE and about 1 part EVA. However, an EVA diluent may comprise from about 5 to 50% solution. One form of solution, which contains approximately 20 to 60% solids (as polymer), in a compatible solvent such as methyl ethyl ketone, cyclohexane or toluene, has a viscosity of 50 to 1200 centipoise at a temperature of about 23 ° C., is an effective composition moreover, this solution can be applied by printing or roller coating (roll coated) on a flexible substrate. When this solution is applied to the film substrate 14 and dried to remove the solvent, then the dry TPE layer 30 or 32 has a coating thickness of approximately 0.0001 to 0.0030 inches. After drying, the TPE layer may have a residual solvent of about 50 ppm (parts per million) or less. However, the coating may have a different thickness and weight, depending on the specific application. Depending on the desired product-specific characteristics, the desired TPEs or TPE-based compounds may be purchased from firms such as GLS Corporation (a Division of PolyOne) (McHenry, Illinois), Dow Chemical (Midland, Michigan), or Kraton Polymers (Houston , Texas). Similar products can be obtained from other manufacturers.

As mentioned here above, the adhesiveable resealable clamp basically has a cohesive bond strength that allows the adhesiveable layers 30 and 32 to join together to close or seal the package 10. For example, a consumer may press two opposed layers against each other that close or seal the package, as shown by arrows 33 in figure 3. According to one approach, the bond between the adherent layers 30 and 32 is basically sufficient to seal the layers 30 and 32 by bonding them together and, in some cases, sufficient to form a tight seal. Here, an airtight seal is generally understood to mean an airtight seal. In accordance with one example, the selected TPE forms cohesive layers 30 and 32, which may have a cohesive bond or peel strength of approximately 100 to 700 grams per inch, and in some cases, approximately 100 to 400 grams per inch, with measured in accordance with ASTM Test 3395 for peeling D. However, the resealable clamp may have other peel strengths, depending on the specific application or the specific test used to measure. Cohesive peel strengths that exceed a specified level are generally too high for use in resealable flexible packages.

Adhesive materials also advantageously have a relatively low stickiness, which minimizes and, advantageously, eliminates (limits) the adherence of the clamp 12 to undesirable materials and surfaces, such as food particles, forming equipment surfaces, rollers (rollers), etc. In accordance with one approach, the selected TPE may have a stickiness level upon contact with unwanted surfaces that does not exceed approximately 5 psi (psi) at preload e is about 4.5 pounds, and generally does not exceed approximately 15 psi with a preload of about 10 pounds when the ASTM D 2979 adherence test is performed. However, it should be borne in mind that tack levels can also vary, depending on the specific TPE and its application and on the test used to measure.

Even with such relatively low tack levels when in contact with unwanted surfaces, the adhesive layers 30 and 32 still form a relatively strong bond with the film substrate forming the front and back panels 16 and 18, so that the adhesive layers 30 and 32 are mainly They do not peel off when the package 10 is opened. According to one approach, the bond strength (adhesion) of the adhesive layers 30 and 32 to the film substrate at its interface 38 generally exceeds the peel strength of the most cohesive material. For example, the peel strength of the selected adhesive material from the film substrate forming the front and back panels is generally approximately more than 700 grams per inch, advantageously approximately more than 1000 grams per inch, and more preferably approximately more than 1200 grams per inch. However, it should be borne in mind that the tensile strength can also vary, depending on the film substrate 14, TPE and other factors.

It can be assumed that the increased bond strength of the materials capable of adhesion to the film substrate can be achieved due to the increased interfacial, mechanical or chemical bonding of the material capable of adhesion to a specific substrate, due to the increased surface energy of the substrate obtained by the primer layer, surface treatment, and / or combinations thereof. For example, various types of surface treatment (substrate surface) can be used to increase surface energy (such as corona treatment, plasma treatment, flame treatment, etc.), or chemical coatings such as soil coatings (primers) or adhesion promoters. By way of non-limiting examples, it can be pointed out that these primers can be based on acrylates, polyesters, vinyls and alcohols. One example of such a primer coating is described in US Pat. 4,493,872 A is a copolymer that contains isophthalic acid and at least one aliphatic dicarboxylic acid, at least one sulfonomer and alkylene glycol. In the case of corona treatment, the ideal surface energy after treatment should be approximately more than 40 dyne.

In addition, it is further contemplated that an increase in interfacial, mechanical, or chemical bonding of adhesion materials 30 and 32 to substrate 14 can be achieved through specific structures of the materials of substrate 14, which increase the surface binding energy. In accordance with one approach, the substrate 14 may be a single layer or multilayer film, the deepest layer of the film of the substrate 14 forming the front and back panels 16 and 18, can be formed mainly from a copolymer of ethylene and vinyl acetate (EVA), and more preferably, from EVA having a low concentration of additives, such as glidants or anti-blocking additives (which are usually added to the packaging film in order to obtain a coefficient of friction that allows the film to be processed on molding machines, filling and sealing packages). Typically, such additives may contain a certain amount of fatty acid amides, and it has been found that such compounds can adversely affect the bond strength of adhesion materials to the film.

Thus, in accordance with one approach, the film substrate 14 may have approximately less than 700 ppm of fatty acid amides in the volume of the entire deepest layer or, in some cases, in the volume of the entire substrate 14. Without wishing to be bound by any theory, all it can be assumed that fatty acid amides, which are low molecular weight components, can migrate to the film surface and adversely affect the bond strength between the film surface and materials capable of adhesion. Despite the fact that corona treatment or flame treatment can initially burn any fatty acid amides on the film surface, which allows to obtain a good initial TPE bond strength, over time, additional fatty acid amides can migrate to the film surface, which leads to a decrease in bond strength in over a long period of storage. Based on the foregoing, we came to the conclusion that it is desirable to reduce the content of fatty acid amides in the film (in the volume of the entire deepest layer or in the volume of the entire film substrate) to levels below 700 ppm, which allows both a good initial bond strength and good long-term bond strength, because over time only such small amounts of these impurities will migrate to the film surface. Alternatively, such a composition of the film substrate material can be used in combination with other surface treatments (corona treatment, plasma treatment, flame treatment, etc.) or other coatings that are necessary for a specific application.

In accordance with yet another aspect, it is contemplated that an increase in interfacial, mechanical, or chemical bonding of adhesive layers to a flexible film substrate can also be achieved by incorporating fillers (such as inorganic materials, minerals, oxides, and the like) by in at least one surface layer of the substrate in order to enhance the bond of the TPE clamp 12 to the substrate 14. Micro or nano-sized fillers of clay, calcium carbonate, montmorillonite, dolom are examples of suitable fillers one microcrystalline silica, talc, mica, oxides (silicon oxide, aluminum oxide, etc.), other additives and / or combinations thereof. Not wishing to be bound by any theory, one can still assume that such additives can increase the bond strength between the coating and the substrate in at least two ways. First of all, at the microscopic level, these fillers create a rough surface, which increases the active contact area between the substrate and the coating, due to which more sites are created for chemical and / or mechanical bonding. Secondly, the filler itself, if present on the surface, can increase surface energy, which helps to create a stronger bond between the coating and the substrate. In accordance with one approach, it is believed that approximately 0.5 to 10 wt.% Of filler (mainly montmorillonite) in the film have a positive effect on the bond strength.

According to one approach, suitable flexible films forming the front and back panels 16 and 18 can be polyethylene based films with a thickness of about 2 to 5 mils, and in some cases, about 3 mils. Turning now to the consideration of FIG. 14, it is shown that, in accordance with one approach, the flexible film 16 or 18, forming the front or rear panels, respectively, is a multilayer film obtained by blown extrusion containing a structural base of one or several layers (two layers shown) of high density polyethylene 702 (HDPE) and an outer or receiving EVA hot seal adhesive layer 704 filled with filler 706. According to one approach, the outer layer may contain linear EVA blends low density polyethylene and filler. For example, an extruded EVA layer may contain approximately 60 to 80% EVA, approximately 5 to 20% polyethylene, and approximately 3 to 10% filler. According to this approach, a grip clamp 12 is applied to the outer layer 704 of the EVA hot seal, which forms the inner surface of the flexible package 10. In this approach, the multilayer film may contain many layers, with approximately two-thirds of the film being high polyethylene Density and approximately one third of the film is an EVA-filled organoclay.

As shown in FIG. 14, the filler 706, which is mainly exaggerated for explanation, is uniformly dispersed throughout the volume of the outer EVA layer 704, with at least some of the filler 708, for example, having at least a portion that is open or protrudes slightly from the outer surface 710 of the EVA layer 704. Alternatively, the filler may not be open on the surface 708, but may create a rougher outer surface. Not wishing to be bound by any theory, it can still be assumed that the filler 708 at the surface, combined with corona treatment, can enhance the bond of the clamp to the film substrate, which can create an effective bond with the film that exceeds the cohesive tensile strength between the two bonding layers 32 and 34. Generally, when the cohesive peeling force (peeling force) is less than approximately 600 to 700 grams per inch, peeling does not occur during repeated peeling / repetitive cycles seals.

Using the adhesion clamps and film substrates described herein, a re-closable adhesive-based clip can be repeatedly opened and closed without peeling off the flexible base, which can be provided stably over time and can provide mostly reproducible results, even if such a clip Was clogged or contaminated with a product such as food crumbs. Even if the adhesion clamp is clogged with food crumbs or contaminated with edible oils, however, the claimed adhesion clamp does not have an unacceptable drop in cohesive properties.

According to one approach, the claimed adhesion capable clamps can maintain cohesive or autocohesive peel strength when contaminated with food, food chips, oils, and the like, amounting to approximately 100 to 650 grams per inch, and provide residual adhesion or residual cohesion after clogging or contamination, representing approximately 25 to 100% of the cohesion levels before contamination. Residual adhesion or residual cohesion is defined as the percentage of peel strength due to clogging or contamination of the clamp to the peel strength of a clean or uncontaminated clamp. As further described in the examples below, the claimed adhesion clips have residual cohesion of approximately 25% and approximately 100% when contaminated with fine Triscuit biscuit chips and wheat crumbs, respectively. A comparable pressure-sensitive adhesive has corresponding residual values of approximately 1.2% and approximately 8%, when contaminated with fine Triscuit biscuit crumbs and wheat crumbs, respectively, at similar levels.

Returning to FIGS. 4 and 5, an alternative re-closable clip 112 is shown in which the adhesive layers 30 and 32 are combined with an adjacent non-adhesive or buffer spacer layer 140. The adjacent spacer layer 140 is located so that it protrudes substantially outward beyond the outer surfaces 34 and 36 of the adhesive layers 30 and 32, so that the adhesive layers 30 and 32 are generally recessed relative to the outer surface 142 of the spacer layer 140.

The non-adhesive spacer layer 140 may be formed from a material from which a non-adhesive or non-adhesive portion of the package 10 is formed, for example, from a material that does not form a bond with other materials. According to one approach, the non-adhesive spacer layer 140 may be formed from a material such as a polyolefin, polyamide or other non-adhesive material. For example, the spacer layer 140 may comprise polyester, polyethylene, polypropylene, polybutylene, a copolymer of ethylene and vinyl acetate, nylon, polyethylene terephthalate, polyvinyl chloride, polyvinylidene chloride, a copolymer of ethylene and vinyl alcohol, polyvinyl alcohol, polystyrene, and mixtures thereof. In one embodiment, the spacer layer 140 comprises a polyolefin. Polyolefins are particularly suitable for use as materials for a spacer layer, because they are generally not adhesive after drying and generally easily allow the creation of aqueous dispersions or solvent dispersions that can be easily applied as a picture using flexographic processes or rotational intaglio printing. Advantageously, the non-adhesive spacer layer 140 is formed from an aqueous dispersion or dispersion of a solvent of non-adhesive material dissolved or dispersed in the solvent. The dispersion is then intermittently (periodically) applied in the form of a coating or printed next to the adhesive layers 32. Generally speaking, the thickness of the dried coating layers can be from about 0.1 mil to 2 mil.

As shown in FIG. 4, the non-adhesive spacer layer 140 advantageously comprises a pair of non-adhesive spacer layers 144 and 146 located adjacent to the sides 148 or 150 of the adhesive layers 30 and 32, respectively. In the specific embodiment shown in FIGS. 4 and 5 , you can see the spacer layers 144 and 146, which are located on the adhesive layer 32 and offset to the distal ends of the layers 30 and 32, which are mainly adjacent to the edges of the sides 148 and 150.

Advantageously, the non-adhesive spacer layer 140 forms a gap 152 between the outer surface 142 of the spacer layer 140 and the adherent surface 34 or 36 of the cohesive material. In accordance with one approach, the gap is approximately 2.5 to 50 microns. Referring to FIGS. 10 and 11, it is shown that the gap 152 or otherwise formed deepening of the adhesion surfaces 34 or 36 allows the clamp 112 to limit the contact of the adhesion layer 30 or 32 with undesirable surfaces. As shown in FIG. 10, the spacer layers 140 and the gaps 152 tend to maintain the gap between the adhesion layer 32 and the part of the exemplary machine, which is shown as the roller 154 of the exemplary machine (however, as a non-limiting example, it can be any the number of machine components, such as rollers (rollers), beams, knives, guides and casting pipes). The deepening of the adhesive layer 30 or 32 due to the spacer layers 140 reduces and mainly eliminates the tendency for the cohesive material to come into contact with the machine part and transfer or remove the adhesive to this component, because the adhesive layer 30 or 32 is generally offset from these unwanted surfaces due to the spacer layer 140 in contact with the adjacent surface (i.e., the roller 154 of the machine) prior to contacting the adhesive layer 30 or 32 in contact with it and due to the deepening of the adhesive layer from it. As is mainly shown in FIG. 11, the spacer layer 140 and the gap 152 also tend to reduce and mainly eliminate the tendency for the clip 112 to adhere to other film layers 14 when the film substrate 14 is wound onto a roll or into a large roll. The formed gap 152 can keep the adhesion layer 32 biased from adjacent wound film layers 14, which basically reduces and mainly eliminates the tendency to block the wound roll, because again, the adhesion layer 32 is offset from the back side of the adjacent film layer 14 because the spacer layer 140 is engaged with the adjacent film layer 14 of the previously adhesive layer 30 or 32.

Referring again to FIG. 5, it is shown that for closing the package 10, the user presses the front and rear panels 16 and 18 between the spacer layers 140 to bend the panels 16 with fingers (or due to the closing operation of the machine during packaging filling operations) and 18 inward through the gap 152, in order to forcefully engage the opposable adhesion layers 30 and 32 and form a cohesive bond between them, to seal the packaging 10. To open the packaging 10, the user exfoliates e pack legs 156 located above the adhesion clamp 112 in opposite directions 157 to peel the adhesion layer 30 from the adhesion layer 32. According to one approach, the adhesion layers 30 and 32 are capable of closing and re-opening many times, and, in some cases, the adhesive layers 30 and 32 mainly have sufficient structural integrity and bond integrity, allowing you to close and open the packaging approximately 5 to 10 times. However, it should be borne in mind that specific cohesive layers and corresponding packaging can be closed and reopened any number of times, depending on the specific configuration, coating weight and other parameters of the cohesive layers and the film substrate.

We now turn to a consideration of FIGS. 6, 7 and 8, which show alternative construction options for a resealable clip. Figures 6 and 7 show a resealable clip 212 in which the spacer layers 240 are adjacent to the adhesion layers 30 and 32 and are located on the film substrates 16 and 18. In Fig. 8, the spacer layers 240 are adjacent to the adhesion layers layers 30 and 32, but offset from them, since the spacer layers 240 do not have to come into contact or engage with the cohesive layers 30 or 32, and, in some cases, manufacturing inconsistencies can lead to a gap between the layers 240 and layers 30 and 32.

In these alternative embodiments, the same weight of the wet coating forming both the adhesion layer 30 or 32 and the spacer layer 240 can be applied to the film substrate 14, however, a gap 152 and a deepening of the adhesion surfaces 34 and 36 can be formed in by changing the percentage of solids in the solvent solution to form adhesive layers relative to the percentage of solids in the solvent solution or in the aqueous solution to form a spacer layer Used for wet coating. For example, a solution for the formation of a cohesive material (material capable of adhesion layers) may have a lower percentage of solids than a solution for the formation of a spacer layer, so that, after drying and mainly removal of the solvent, the adhesive layers 30 and 32 will have a smaller dry coating weight or less thickness. According to one approach, a cohesive material solution may contain approximately 25 to 45% solids, and a solvent solution to form a spacer layer may contain approximately 45 to 65% polyolefin solids, so that the adhesive layer forms a coating thickness that significantly thinner than the thickness of the spacer layer. For example, the adhesion layer may have a thickness of approximately 10 to 20 μm, and the spacer layer may have a thickness of approximately 20 to 40 μm.

Turning now to FIG. 9, an outline is shown schematically of an exemplary method of forming a resealable clip 12, 112, or 212 that utilizes a discontinuous step motion process. For example, the film substrate 14 can be fed from a roll 402 by unwinding it in the direction of travel of the machine 404. The first coating station 406 periodically applies a first cohesive dispersion strip 408 in the transverse direction relative to the movement of the tape. The first coating station 406 may include a flexography applicator, gravure applicator, or other suitable applicator for periodically applying a solvent dispersion in the transverse direction relative to the moving tape. The film tape 14 is then moved a step or wound a first distance 410 in the direction of movement of the machine, after which the first coating station 406 applies a second cohesion dispersion strip 412 in the transverse direction of the tape. The tape is then moved a step or wound onto a second distance 414, which may be shorter than the first distance 410, after which the first coating station 406 applies a third transverse strip 416 in the transverse direction of the tape. This application pattern is then repeated with alternating short and long steps, while continuously unwinding the tape 14 from the roll 402. Alternatively, the tape can be moved at the same steps between the operations of applying transverse stripes.

The tape, which has coatings 408, 412 and 416 applied thereto, is then dried or cured using a drying oven or other drying device 420 to remove solvent and form dry, adhesive bonds. A package 10 can then be formed from the film strip 14 by cutting 422, folding 424, forming 426 side seals and filling 428 with product 430 (such as a food product, such as crushed cheese).

If spacer layers 140 are used, then a second coating station 432 may be used. If used, then the second coating station 432 will wet the dispersion of the spacer layer next to the dispersion of the cohesive material, similarly, sequentially or simultaneously with the application of the adhesive layer, using a flexography applicator, gravure applicator or other suitable applicator to periodically apply a dispersion of solvent across the moving belt. Advantageously, the spacer layers are also applied substantially parallel to the adhesion layer.

Turning now to FIG. 12, another example of a suitable method 500 is shown that can be used to form a substrate having a resealable clip 12, 112 and / or 212 on it. In this example, a solvent is used to form the coating, and the process of printing, rotogravure printing or flexography for applying adhesive layers and / or spacer layers (if used) onto a film substrate. It should be borne in mind that, if necessary, for specific applications, other coating processes can be used. In the described alternative approach, a film substrate having a closure thereon is wound into a roll, which is later used to form a flexible package on a machine to form, fill and seal the package.

In this exemplary method 500, the film substrate 14 is obtained from a roll or a large roll 502 of base film, which may be a single layer or multilayer film having EVA as the material of the inner layer 504 on which the adhesives are applied. The film is wound from a roll and sent to a first coating station 506 where an adhesive layer of a clamp can be applied. According to one approach, the first coating station 506 may include an applicator 508 for applying a cohesive polymer solvent solution, such as an extrusion head, a solution tank, or other means for supplying a solution. For example, a TPE-containing solvent solution can be applied to a first or plate cylinder 510, which transfers the solution to a second or offset cylinder 512 having an image or imprint 514 on it with a configuration, size and shape of an adhesive band applied to the film 14. Second cylinder 512 then transfers the solvent solution of the cohesive material to the moving film substrate 14 to form a first strip of TPE containing material 516 on the tape.

The tape 14 is then sent to a drying oven 520 to dry, cure or remove any residual solvent in the applied bonding layer. After drying this bonding layer sufficiently, a tape coated with a dry bonding layer can be wound into the intermediate roll 522 for storage or transferred to the next forming station to carry out the process of forming, filling and sealing the package, as is mainly shown in FIG. 13.

If the bonding layer contains possible buffer or spacer layers 140 or 240, then the method 500 may also include the use of a second station 530 for applying the solution. The second post 530 for applying the solution may be similar to the first post 506, but is configured to apply and place the spacer layer 140 next to the adhesion layer, as mentioned above. To this end, the second application post 530 may be configured to apply a spacer layer 140 or 240 on the upper surface of the adhesive layer or adjacent to it, as mentioned above.

In accordance with one approach, the second application station 530 may also comprise a solution applicator 532 (solvent solution or aqueous solution), a first or plate cylinder 534, a second or offset cylinder 536 having an image or print on it 538 with the configuration, size and shape of the desired the spacer layer or layers 140 and / or 240. The second cylinder 536 then transfers the strip or strips of the solution of the spacer layer to the tape in the correct orientation and in the correct location relative to the adhesive layer. The tape, which contains both cohesive and spacer layers, is then fed into the drying oven 520 to remove residual solvents and then wound into an intermediate large roll 522. Alternatively, the second application station 530 may be located downstream of the furnace 520, so that spacer layers are applied next to the dry adhesive layer. In this case, the tape with the spacer layers applied is then fed to a second drying oven similar to oven 520.

Turning now to FIG. 13, an exemplary packaging machine 600 is shown for forming, filling, and sealing a package using an intermediate roll 522 obtained by method 500 (which can be pre-cut to obtain a suitable size previously used in machine 600), moreover, this machine 600 allows the formation of a sealed package 602. In this example, use a vertical packer or continuous packaging process to wrap the film 14 around the filler pipe 604. The first node 606 is hot its seals form the first hot seal 607 in the direction of movement of the machine. The second transverse hot seal assembly 608 with an integrated cutting device then forms the second and third transverse hot seals 609 and 611, so that these hot seals will be located respectively on each side of the engaging re-closable closure 613. As shown 13, the seal 609 is below the cohesive closure 613, however, it should be borne in mind that the seal 609 may also be above or above and below the closure 613. Finally, a cutting device integrated in the transverse assembly of the hot seal cuts the film between the engaging re-closable closure 613 and the lower seal 611 of the adjacent bag, thereby separating the bag that has just been filled and sealed from the next bag which is in filling process. It should be borne in mind that the exemplary processes shown in FIGS. 9, 12 and 13 are just one example of suitable methods for forming and filling a flexible package having a re-closable clip capable of adhesion on it, so that other forming methods can also be used with the need for appropriate specific application.

The advantages and design options of the described clip are further explained in the following examples. However, it should be borne in mind that the specific modes, processing schemes, materials and their quantities that are indicated in these examples, as well as other conditions and details, should not be construed as limiting the claimed method. In the examples, all percentages are given in weight percent, unless expressly agreed otherwise.

Examples

Example 1

An adhesion-capable reclosable clamp was prepared and compared with a standard clamp based on pressure sensitive adhesives (PSA-Control, PSA test clamp) obtained from the serial packaging of Nabisco Chips Ahoy Snack'n Seal (Fasson, Avery Dennison Corporation).

Adhesive clamp was prepared using approximately 8 parts styrene block copolymer (TPE, LC347-042B, GLS Corporation) and 1 part by weight of a copolymer of ethylene and vinyl acetate (EVA 1980a, AT Plastics, Edmonton, Alberta, Canada), which were dissolved in toluene . EVA contains approximately 19% vinyl acetate and has a melt flow rate of about 600. The mixed and diluted solution contains about 22% solids and has a Brookfield viscosity of about 155 centipoise at a temperature of about 21 ° C. This solution was applied to a 2.7 mils multilayer substrate. the use of two displaced bars for testing for impact with a notch having micrometric regulation. The coated substrate was dried by double passing through an oven at a temperature of about 150 ° F (total drying time of approximately 2.5 to 3 minutes) to form a dry coating of about 3 mils thick to form a bonding clip.

As the substrate film (Pliant Corporation), a multilayer coextruded film was used, having two layers of high density polyethylene and one outer layer, which is an organic clay filler and an ethylene vinyl acetate (EVA) copolymer hot seal layer. The outer EVA hot seal layer of the coextruded film contains about 80% EVA, about 10% polyethylene, and about 6% filler from organoclay. The surface of the EVA layer was also corona treated to 40 dyne. The grip clamp was fixed to the EVA hot seal layer. When using this film, the adhesion clips of this example do not peel off the film substrate, so that the bond with the film and the EVA hot seal layer will be greater than the cohesive peel strengths, the test results of which are given below.

Both the adhesion clamp and the PSA control clamp were tested for T-peeling without contamination and contamination with Triscuit biscuit crumbs (Kraft Foods), small wheat crumbs (Kraft Foods) and coffee beans. Tables 1-3 below show the results of a T-peeling test (grams per inch at a crosshead speed of about 12 inches per minute), without contamination and contamination with crumbs. Table 3 shows the residual adhesion after contamination, which is the ratio of peeling after contamination to peeling without contamination.

All adherent samples and control samples were contaminated, completely covering their sticky surface with food crumbs, after which each sample was understood and shaken lightly to remove excess crumbs that did not adhere to the strip. In the case of Triscuit biscuit crumbs and small wheat crumbs, these crumbs are equivalent to those found at the bottom of serial grocery boxes. In the case of a sample of coffee beans, whole coffee beans were placed in the sample and then removed. It is believed that the coffee bean oil contaminates the sample.

Table 1:
PSA test clamp and claimed clutch capable of contamination with food chips Factor Baby Triscuit Small wheat chips Coffee beans PSA control clamp g / inch The claimed clamp, g / inch PSA control clamp g / inch The claimed clamp, g / inch PSA control clamp g / inch The claimed clamp, g / inch Pollution 0 281 7 755 151 572 Pollution 5 24 16 604 138 621 Pollution four 137 four 504 186 615 Pollution 3 82 69 733 186 471 Average g / inch 3 131 24 649 208 639 Table 2:
PSA test clamp and declared clutch capable of being contaminated with food chips Factor Baby Triscuit Small wheat chips Coffee beans PSA control clamp g / inch The claimed clamp, g / inch PSA control clamp g / inch The claimed clamp, g / inch PSA control clamp g / inch The claimed clamp, g / inch Pollution 196 165 259 476 271 652 Pollution 253 414 248 376 183 642 Pollution 259 563 330 638 271 820 Pollution 261 595 - 697 276 715 Average g / inch 242 524 279 547 250 707 Table 3:
Residual grip after contamination with food chips Factor Baby Triscuit Small wheat chips Coffee beans % residual adhesion PSA control clamp g / inch The claimed clamp, g / inch PSA control clamp g / inch The claimed clamp, g / inch PSA control clamp g / inch The claimed clamp, g / inch

1.2 25 8.6 118.7 83 90.3

As shown above, the grip-capable clamp is much more resistant to food chips contamination than the PSA control clamp. The adhesion clamp has a% residual adhesion (that is, the ratio of peeling when soiled to peeling without soiling × 100) of at least about 25%, and in some cases at least about 100%. As a result, the grip-capable clamp has no significant loss of peel strength and works just as well when contaminated by food cats, as well as without contamination. In contrast, the PSA clamp has a significant loss of peel strength when contaminated with food cats.

To carry out the above T-peeling tests, a shear / peeling test tester (model SP-102B-3M90, Instrumentors, Inc., Strongsville, Ohio) was used. In the T-peeling test mode, the machine was turned on at a speed of about 12 inches per minute. Adhesive samples were cut into strips with a width of about 1 inch and a length of about 10 inches, with two strips glued together by joining together their adhesive coated sides. The glued samples were rolled 2 times forward and backward (4 passes in total) using a silicone-coated rubberized roller weighing 4.5 lbs (Chemsultants International Network, HR100, 4.5 lb manual roller). The peeling test involves obtaining average readings at intervals of about 5 seconds, using about 5-8 readings for each strip.

Example 2

The adhesion clamp of Example 1, made of a TPE / EVA mixture, which contains approximately 8 parts of TPE and 1 part of EVA, was tested for changes in T-tensile strength over time. The results are shown below in table 4.

Table 4:
Results of T-peeling over time Time 0 hours 24 hours | 96 hours 1 Week

T-peeling, grams per inch 211 231 205 294 282 327 319 316 270 337 327 362 215 307 306 290 200 335 288 249 250 335 319 290 250 333 343 290 130 326 331 317 Average 240 316 305 301

Example 3

The adhesion clamp of Example 1, made from a TPE / EVA mixture, was tested for a reduction in peel strength during multiple peeling / re-compaction cycles in quick succession using the procedures described in Example 1. All samples were tested sequentially without long Excerpts between tests, with the exception of re-compaction and rolling of samples. The exposure time between tests was about 2 minutes or less. The results are shown below in table 5. As shown in table 5, the cohesive tensile strength was about 80% of the highest level of initial tensile strength after many attempts to re-compaction.

Table 5:
Results after multiple peeling / re-compaction cycles Iteration First Second Third Fourth T-peeling, grams per inch 177 136 120 119 255 247 237 231 283 309 316 249 280 317 339 283 297 330 362 266 323 378 367 293 310 365 340 303 275 382 350 310 Average 275 308 304 257

Comparative Example 1

The film substrate of example 1 was coated similarly to that described in example 1, but only using TPE (LC 347-042B) in toluene, without using a diluent. In this case, the initial tensile strength was about 339 grams per inch (average), but the tensile strength after 24 hours was unacceptably high and was about 1,500 grams per inch (average). The results are shown below in table 6.

Table 6:
Peel strength with undiluted TPE Time Initial 24 hours T-peeling, grams per inch 344 366 362 279 1510 343 1544 308 1592 357 1528 353 1625 Average 339 1560

Reference Example 2

An attempt was also made to use other diluents, but this did not result in acceptable products. First of all, polyvinyl butyral (PVB) (Wacker Chemical) was used in a mixture with TPE in toluene, similar to that described in Example 1, with ratios of about 1: 1, about 3: 1 and about 7: 1 (TPE / PVB). Then, cohesive peel strength tests were carried out, also similar to those described in Example 1. None of the samples showed acceptable results, since cohesive peeling was too high or too low. At a 1: 1 ratio, the sample had a low initial peeling of about 23 grams per inch, but peeling after 24 hours increased to 293 grams per inch, but then, after 96 hours, it again fell to a value of approximately less than 100 grams per inch. At a 3: 1 ratio, cohesive self-adhesion initially amounted to about 294 grams per inch and after 24 hours increased to a value greater than 1,100 grams per inch. Finally, at a 7: 1 ratio, cohesive adhesion was initially about 394 grams per inch and after 24 hours increased to more than 1,700 grams per inch. The results are shown below in tables 7, 8 and 9. These samples are unacceptable, since they have too low or unacceptably high peeling.

Table 7:
Initial peeling values (TPE and PVB mixtures) T-peeling, grams per inch TPE / PVB Ratio 1/1 3/1 7/1 25 306 361 23 318 385 16 328 373 21 295 357 31 268 434 24 277 409 297 395 262 438 Average: 23 294 394 Table 8:
Flaking values after 24 hours (TPE and PVB mixtures) T-peeling, grams per inch TPE / PVB Ratio 1/1 3/1 7/1 269 1227 1696 342 1272 1867 319 1103 1794 237 1083 1703 309 1091 1745 328 657 1777 269 678 1090 272 569 749 Average: 293 1155 1764 Table 9:
Flaking values after 96 hours (mixture of TPE and PVB) T-peeling, grams per inch TPE / PVB Ratio 1/1 3/1 7/1 68 557 Does not exfoliate 90 498 Does not exfoliate 61 443 Does not exfoliate 74 481 Does not exfoliate 86 426 Does not exfoliate 81 377 Does not exfoliate 64 357 Does not exfoliate 79 419 Does not exfoliate Average: 75 445 Does not exfoliate

Reference Example 3

Various ethylene vinyl acetate copolymers (EVA) were also evaluated for use as a diluent. An EVA diluent was studied which contains about 18% vinyl acetate and has a melt flow rate of about 150 (EVA 1850A, AT Plastics), and it turned out that it does not dissolve in toluene and does not form a stable solution with TPE. Another EVA diluent, which contains about 18% vinyl acetate and has a melt flow rate of about 500 (EVA 1880A, AT Plastics), was also investigated, and it also turned out that it does not dissolve in toluene and does not form a stable solution with TPE.

It should be borne in mind that despite the fact that the preferred embodiment of the invention has been described, given to clarify the essence of the proposed packaging, it is clear that specialists in this field can make changes and additions regarding parts, materials and packaging layout and the method of its formation, which correspond to the principles and scope of the claimed invention and do not go beyond the scope of the claims.

Claims (46)

1. A flexible packaging having a resealable clip comprising:
opposite front and rear panels connected together to form a cavity;
a reclosable clip containing opposable adhesion layers formed using a solvent solution of a mixture of thermoplastic elastomer and a thinning polymer located on each of the front and rear panels, with the adhesive layers on the front and rear panels facing each other, so that the flexible packaging may be closed when opposed adhesion layers are in contact with each other; moreover
the bond strength of the adhesive layers to the panels is greater than the cohesive bond strength between the opposite adhesive layers, so that the front and rear panels can be repeatedly opened by peeling without significant peeling of the adhesive layers from the front and rear panels. 2. The flexible packaging of claim 1, wherein the adhesive layers comprise a major amount of a thermoplastic elastomer containing a styrene block copolymer or a mixture of styrene block copolymers diluted with a small amount of a diluting polymer containing an ethylene vinyl acetate copolymer to form cohesive bond strength. 3. The flexible packaging of claim 2, wherein the adhesive layers comprise from about 7 to 9 parts of a thermoplastic elastomer and from about 0.5 to 2 parts of a copolymer of ethylene and vinyl acetate. 4. The flexible packaging according to claim 2, in which the styrene block copolymer is selected from the group consisting of SIS block copolymer based on styrene and isoprene, SBS block copolymer based on styrene and butadiene, SEBS block copolymer with a hydrogenated middle block styrene-ethylene / butylene-styrene, or SEPS block copolymer with a hydrogenated middle block styrene-ethylene / propylene-styrene, or mixtures thereof. 5. The flexible packaging according to claim 1, in which the cohesive bond strength is approximately 100 to 700 grams per inch (40 to 280 g / cm), with a residual cohesive bond strength after contamination, comprising approximately 25 to 100% cohesive strength communication before pollution. 6. The flexible packaging according to claim 5, in which the adhesive layer has an adhesive level not exceeding approximately 5 psi with a preload of about 4.5 lbs (2 kg), and not exceeding approximately 15 psi with a preload of about 10 pounds (4, 5 kg). 7. The flexible packaging of claim 6, wherein the adhesive layer has a peel strength of approximately more than 700 grams per inch (280 g / cm). 8. The flexible packaging according to claim 1, in which the material of the front and rear panels is selected from the group consisting of a copolymer of ethylene and vinyl acetate, polyethylene, polypropylene, polybutylene, nylon, polyethylene terephthalate, polyvinyl chloride, polyvinylidene chloride, a copolymer of ethylene and vinyl alcohol, polyvinyl alcohol polystyrene, or combinations thereof. 9. The flexible packaging of claim 8, wherein the front and rear panels comprise a copolymer of ethylene and vinyl acetate, at least in their inner surfaces. 10. The flexible packaging according to claim 1, wherein at least the inner surfaces of the front and rear panels contain approximately less than 10% of the filler. 11. The flexible packaging of claim 10, wherein the filler is selected from the group consisting of micro- or nanoscale inorganic materials. 12. The flexible packaging of claim 11, wherein the filler comprises clay, calcium carbonate, montmorillonite, dolomite, talc, mica, and mixtures thereof. 13. The flexible packaging of claim 1, wherein the front and rear panels contain approximately less than 700 parts per million fatty acid amide or other additives that can migrate to the surface of the panel and reduce bond strength with adhesive layers. 14. The flexible packaging of claim 1, wherein the solvent is an organic solvent selected from the group consisting of ethyl acetate, normal propyl acetate, isopropyl acetate, methyl ethyl ketone, ethyl alcohol, normal propyl alcohol, propylene glycol, normal propyl ether, butyl acetate, toluene, cyclohexane, cyclohexanol and mixtures thereof. 15. The flexible packaging of claim 1, wherein the resealable clip has about less than 50 ppm of residual organic solvent. 16. A resealable clip suitable for flexible packaging, comprising:
a pair of opposable adhesion layers, each of which is applied to a flexible film and has an open adhesion surface; and a pair of opposing non-adhesive spacer layers having an outer surface and adjacent to the corresponding one of the adhesion layers, each non-adhesive spacer layers protruding outwardly to the adhesion surface of the corresponding one of the adhesion layers, so that the adhesion surface of each of the adhesion layers is deepened relative to the outer surface of each of the adjacent non-adhesive spacer layers. 17. The resealable clip of claim 16, wherein each of the pair of adjacent non-adhesive spacer layers is located adjacent to a side of a corresponding one of the adhesive layers. 18. The reclosable clip of claim 17, wherein each of the pair of adjacent non-adhesive spacer layers is located on a bonding surface of a corresponding one of the bonding layers. 19. The resealable clip of claim 17, wherein each of the pair of adjacent non-adhesive spacer layers is located on a flexible film. 20. The resealable clip of claim 16, wherein the adjacent non-adhesive spacer layer comprises polyamide, polyester, polyethylene, polypropylene, polybutylene, ethylene vinyl acetate copolymer, polyethylene terephthalate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polystyrene, and combinations thereof. 21. The resealable clip of claim 16, wherein each of the pair of adhesive layers comprises a thermoplastic elastomer and a thinning polymer. 22. The resealable clip of claim 21, wherein the thermoplastic elastomer is a compound containing a styrene block copolymer or a mixture of styrene block copolymers, and the fluidizing polymer is a copolymer of ethylene and vinyl acetate. 23. The resealable clip of claim 22, wherein said compound further comprises a plasticizer, a filler, antioxidants, or mixtures thereof. 24. The reclosable clip of claim 22, wherein the styrene block copolymer is selected from the group consisting of styrene-butadiene-based SIS block copolymers, styrene-butadiene-based SBS block copolymers, SEBS block copolymers with a hydrogenated middle block styrene-ethylene / butylene-styrene , SEPS hydrogenated middle block styrene-ethylene / propylene-styrene block copolymers, and mixtures thereof. 25. The resealable clip of claim 16, wherein each of the adhesion surfaces has a cohesive bond strength of about 100 grams per inch to 700 grams per inch (40 to 280 g / cm). 26. The resealable clip of claim 25, wherein each of the adhesion surfaces has an adhesive level not exceeding approximately 5 psi with a preload of about 4.5 lbs (2 kg) and not exceeding approximately 15 psi with a preload of about 10 pounds (4.5 kg). 27. The resealable clip according to clause 16, in which between the outer surface of each of the adjacent non-adhesive spacer layers and the adhesive surface of the corresponding one of the adhesive layers is formed a gap of approximately 2.5 to 50 microns. 28. A flexible container having a resealable clip comprising:
opposite front and rear panels; and
a reclosable clip on each of the front and rear panels, each reclosable clip comprising an adhesive layer located on the panel and having an external surface offset by a first distance from the panel, a non-adhesive layer adjacent to the adhesive layer and having an external a surface offset by a second distance from the panel greater than the indicated first distance from the panel, so that the adhesion layer is mainly buried relative to the outer surface a layer, wherein each of the outer surfaces of the adhesion layers has at least one portion, wherein said portions cohesively engage with each other to form a closed package, the adhesion layers on each of the front and rear panels being opposite to each other and non-adhesive layers on each of the front and back panels are opposite to each other. 29. The flexible container according to claim 28, wherein said first offset distance from the panel of the outer surface of the adhesive layer is approximately 2.5 to 50 microns. 30. The flexible container of claim 28, wherein said second displacement distance from the panel of the outer surface of the non-adhesive layer layer is approximately 2.5 to 100 microns. 31. The flexible container of claim 28, wherein the non-adhesive layer is located on the outer surface of the adhesive layer. 32. The flexible container of claim 28, wherein the non-adhesive layer is located on the panel. 33. The flexible container according to p, in which the thickness of the adhesive layer is approximately 2.5 to 50 microns, and the thickness of the non-adhesive layer is approximately 5 to 100 microns. 34. The flexible container of claim 28, wherein the non-adhesive layer comprises polyolefin, polyamide, polyester, polyethylene, polypropylene, polybutylene, ethylene vinyl acetate copolymer, polyethylene terephthalate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polystyrene, and combinations thereof. 35. The flexible container of claim 28, wherein the adhesive layer comprises a thermoplastic elastomer or a mixture of thermoplastic elastomers selected from the group consisting of a styrene block copolymer or a mixture of styrene block copolymers. 36. The flexible container of claim 28, wherein the cohesive layer has a cohesive bond strength of about 100 grams per inch to 700 grams per inch (40 to 280 g / cm). 37. The flexible container of claim 36, wherein the adhesive layer has an adhesive level not exceeding approximately 5 psi with a preload of about 4.5 lbs (2 kg) and not exceeding approximately 15 psi with a preload of about 10 pounds (4.5 kg ) 38. A method of forming a flexible packaging having a resealable clip, which includes the following operations:
longitudinal movement of the flexible film;
periodically applying to the flexible film the first and second strips of a solution containing a thermoplastic elastomer, perpendicular to the direction of movement of the film, the first and second strips offset from each other by a first gap along the direction of movement of the film;
periodically applying to the flexible film a third strip of a solution containing a thermoplastic elastomer parallel to one of the first and second stripes, the third strip being offset from the first or second strip to a second gap smaller than the first gap;
applying a strip of polyolefin solution next to each of the alternating stripes of the thermoplastic elastomer, so that the outer surface of the strip of dried thermoplastic elastomer is buried from the outer surface of the strip of dried polyolefin; and
drying strips of thermoplastic elastomer and strips of polyolefin. 39. The method according to § 38, which further provides for the formation of a flexible film of flexible packaging, so that one of the alternating strips of thermoplastic elastomer will face the other of the alternating strips of thermoplastic elastomer to form a resealable clip. 40. The method according to § 38, in which the percentage of solids in the solution containing the thermoplastic elastomer is less than the percentage of solids in the polyolefin solution, so that the dried strip of thermoplastic elastomer will have a smaller thickness than the adjacent dried strip of polyolefin. 41. The method according to p, in which the solution containing a thermoplastic elastomer has a percentage of solids in the range of approximately from 25 to 45%. 42. The method according to paragraph 41, in which the polyolefin solution has a solids content in the range of approximately from 45 to 65%. 43. The method according to § 38, in which the dried strip of polyolefin is applied to the outer surface of the dried strip of thermoplastic elastomer. 44. The method according to § 38, in which the dried strip of polyolefin is applied to a flexible film. 45. A method of forming a flexible packaging having a resealable clip, which includes the following operations:
longitudinal movement of the flexible film;
periodically applying to the flexible film the first and second strips of a solution containing a thermoplastic elastomer, perpendicular to the direction of movement of the film, the first and second strips offset from each other by a first gap along the direction of movement of the film;
periodically applying to a flexible film a third strip of a solution containing a thermoplastic elastomer parallel to one of the first and second stripes; and
drying strips of thermoplastic elastomer to form a reclosable clip. 46. The method according to item 45, in which a solution containing a thermoplastic elastomer, contains approximately from 25 to 45% solids in a solution of styrene block copolymer and a secondary polymer in an organic solvent.

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