DESC:FIELD
The present disclosure relates to high barrier thermoforming blister laminates.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicate otherwise.
The term “Aspect Ratio” of a geometric shape refers to a ratio of its sizes in different dimensions. For example, the aspect ratio of a rectangle is the ratio of its longer side to its shorter side (the ratio of length to height/ breadth).
The term “Masterbatch” refers to a solid additive for coloring of plastics (color masterbatch) or imparting other properties to plastics (additive masterbatch). Masterbatch is a concentrated mixture of additives encapsulated during a heat process into a carrier resin which is then cooled and cut into a granular shape.
The term “Thixotropic” refers to a property of a fluid by virtue of which the apparent viscosity of the fluid is temporarily reduced by previous deformation. This means that with thixotropic material, the viscosity depends on the time of stirring as compared with a pseudoplastic material which depends on the rate of shear.
The term “GSM” refers to “grams per square meter” To measure GSM, the weight of various types of paper/film is measured from a sample sheet cut to one square meter in size.
The term “ACLAR®” is a commercially available high barrier fluoropolymer films made from fluorinated-chlorinated polymer resins by Honeywell.
The term “Blister pack” refers to a formable web/multilayer laminate into which blisters or cavities are formed to pack the product, and a lid or a sealing layer, which is employed as a seal support/ cover the product. The product is placed within the blisters or cavities. It is a pre-formed plastic packaging used for small consumer goods, foods, and for pharmaceuticals.
The term “Substrate” or “Base” refers to a layer of a film made up of a polymer, covering/ protecting the blister pockets or cavities. The term “base” also refers to the plane surface of the laminate sheet from where the stretching takes place to form the cavity or a recess. The recess is thus formed within the laminate, and with a shoulder defining the base material in between the recesses; the recesses of the base are filled with the products; and the base, with the filled recesses, is then covered with a lid, wherein the lid is sealed or otherwise adhered to the shoulder of the base. The lid material provides the base or structural component upon which the final blister package is built. Lid material is made of a heat seal lacquer coated paper or a polymer or an aluminium laminate and a combination of all these materials that is often called peel off–push through foil.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
For packaging applications, polymeric films or laminates usually are monolayered or multilayered. Monolayer films have lower barrier properties as compared to multi-layered films. Polymers that are conventionally used for packaging are polyvinyl chloride, polyolefins, polyesters and the like. In addition, the polymers in the suspension forms are used to coat monolayered or multilayered film. However, the monolayer polymer films or the multilayer polymer films are unable to provide the requisite mechanical properties, and barrier protection to the packaged product.
Conventionally, co-polymerization of the monomers or laminating the existing polymeric films with other polymeric films have been done in order to get better barrier properties. For example, cyclic olefin copolymer (COC) laminates and ACLAR laminates are manufactured to provide improved barrier properties. The base of the blister pack is made up of at least one of ACLAR, (PCTFE poly Chlorotrifluoroethylene), and PVC (polyvinyl chloride). However, these materials are associated with lesser oxygen barrier properties and display a higher moisture vapor transmission rate (MVTR).
In addition, the exterior portion of the base/substrate is often made from PVC, polyamides, polyolefins, and polyesters. Typically, ACLAR is laminated with PVC to form PVC and ACLAR laminates, as ACLAR is well known to provide a high barrier against water vapour and the thickness of ACLAR varies as per the barrier requirement. However, the ACLAR is expensive, and therefore the use of ACLAR laminated PVC laminate is economically not a viable option.
Further, a more economical option to PVC-ACLAR laminate is to coat PVC film with water based Polyvinylidene chloride (PVdC). This PVdC coated PVC- laminate is sufficient to pack sensitive to moderately sensitive pharmaceutical products. Coating of PVdC on PVC film is well established technique and well known in the pharmaceutical packaging industry. However, the barrier properties of water based PVdC on PVC film is not suitable to achieve the desired barrier properties at a lower coating thickness.
There is, therefore, felt a need to provide high barrier thermoforming blister laminates that mitigates the drawbacks mentioned hereinabove or at least provide a useful alternative.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to ameliorate one or more problems of the background or to at least provide a useful alternative.
An object of the present disclosure is to provide a high barrier thermoforming blister laminates.
Another object of the present disclosure is to provide a high barrier thermoforming blister laminates which are economical.
Still another object of the present disclosure is to provide a high barrier thermoforming blister laminates at lower PVdC coating thickness.
Still another object of the present disclosure is to provide high barrier thermoforming blister laminates which can be produced with reduced consumption of materials.
Another object of the present disclosure is to provide a process for the preparation of high barrier thermoforming blister laminates.
Still another object of the present disclosure is to provide a simple process for the preparation of high barrier thermoforming blister laminates.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure relates to high barrier thermoforming blister laminates. The blister laminates comprise at least one substrate, defining an operative surface. The substrate comprises at least one first polymeric film defining an operative surface, and optionally, at least one second polymeric film, adhered to the operative surface of the first polymeric film by means of an adhesive, and at least one third polymeric film on the operative surface of the substrate.
DETAILED DESCRIPTION
The present disclosure relates to high barrier thermoforming blister laminates.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
For packaging application, monolayer polymeric films or multilayer laminates are usually used. Monolayer films have lower barrier properties as compared to the multi-layered films. Polymers that are conventionally used for packaging are polyvinyl chloride, polyolefins, polyesters and the like. In addition, the polymers in the suspension forms are used to coat monolayered or multilayered film. However, the monolayer polymer films or the multilayer polymer films are unable to provide requisite mechanical properties, and barrier protection to the packaged product.
Conventionally, co-polymerization of the monomers or laminating the existing polymeric films with other polymeric film have been done in order to get better barrier properties. For example, cyclic olefin copolymer (COC) laminates and ACLAR laminates are manufactured to provide improved barrier properties. The base of the blister pack is made up of at least one of ACLAR, (PCTFE poly Chloro Trifluoroethylene), and PVC (polyvinyl chloride). However, these materials are associated with lesser oxygen barrier properties and display a higher moisture vapor transmission rate (MVTR).
In addition, the exterior portion of the base/substrate is often made from PVC, polyamides, polyolefins, and polyesters. Typically, ACLAR is laminated with PVC to form PVC and ACLAR laminates and the thickness of ACLAR varies as per the barrier requirement. However, the ACLAR is expensive, and therefore the use of ACLAR laminated PVC laminate is economically not a viable option.
The present disclosure relates to high barrier thermoforming blister laminates.
In an aspect, the present disclosure provides high barrier thermoforming blister laminates.
The blister laminates comprise:
a. at least one substrate, defining an operative surface, wherein the substrate comprises;
i. at least one first polymeric film defining an operative surface;
ii. optionally, at least one second polymeric film, adhered to the operative surface of the first polymeric film by means of an adhesive;
and
b. at least third polymer film disposed on the operative surface of the substrate.
In accordance with an embodiment of the present disclosure, the first polymeric film comprises at least one first polymer.
In accordance with an embodiment of the present disclosure, the first polymer is optionally modified.
In accordance with an embodiment of the present disclosure, the second polymeric film comprises at least one second polymer.
In accordance with an embodiment of the present disclosure, the second polymer is optionally modified.
In accordance with an embodiment of the present disclosure, the third polymeric film comprises at least one third polymer.
In accordance with an embodiment of the present disclosure, the third polymer is optionally modified.
In accordance with an embodiment of the present disclosure, the first polymer is at least one thermoplastic polymer.
In accordance with an embodiment of the present disclosure, the thermoplastic polymer is at least one selected from the group consisting of halogenated polymer, polyolefin, polyester, thermoformable polyamide, polyacrylate, polymethyl methacrylate and polyurethane. In an exemplary embodiment, the thermoplastic polymer is polyvinyl chloride (PVC).
In accordance with an embodiment of the present disclosure, the halogenated polymer is selected from the group consisting of polyvinyl chloride (PVC), polyvinylidene fluoride (PVdF), poly chloro trifluoro ethylene (PCTFE), and poly tetrafluoro ethylene (PTFE)).
In accordance with an embodiment of the present disclosure, the polyolefin is selected from the group consisting of polyethylene polymer and polypropylene polymer.
In accordance with an embodiment in the present disclosure, polyethylene polymer is at least one selected from the group consisting of high density polyethylene (HDPE), medium density polyethylene, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), cross-linked polyethylene, chlorinated polyethylene and ultra-high molecular weight polyethylene (UHMWPE).
In accordance with an embodiment in the present disclosure, the polypropylene polymer is at least one selected from the group consisting of propylene homopolymer, polypropylene co-polymer, polypropylene random copolymers, polypropylene impact copolymers and polypropylene block copolymers.
In accordance with an embodiment of the present disclosure, the polyamide polymer is selected from the group consisting of a blend of semicrystalline polyamide and amorphous copolyamide.
In accordance with an embodiment of the present disclosure, the semicrystalline polyamide is selected from the group consisting of Nylon 6, Nylon6,6, Nylon 6,9, Nylon 6,12, Nylon 12,12 and copolymer.
In accordance with an embodiment of the present disclosure, the polyacrylate is selected from the group consisting of polymethyl acrylate, polyethyl acrylate, polymethyl methacrylate, copolymer of ethylene and vinyl acetate, and copolymer of ethylene and methacrylic acid.
In accordance with an embodiment of the present disclosure, a thickness of the first polymeric film is in the range of 100 µ to 500 µ. In accordance with another embodiment, the thickness of the first polymeric film is in the range of 200 µ to 350 µ.
In accordance with an embodiment of the present disclosure, the solid content of the material in first polymer is in the range of 0.5 mass% to 30 mass% with respect to the total mass of the first polymer. The solid content of barrier material in the first polymer refers to the amount of material such as oil dispersion present in the first polymer. The solid content of the material affects the mechanical properties and the barrier properties of the resultant polymer composite if the solid content is less than 0.5 mass% and more than 30 mass%. The material acts as a barrier additive for the laminate.
In accordance with an embodiment of the present disclosure, the second polymer is at least one selected from the group consisting of polypropylene (PP), polyethylene (PE), and polyamide (PA). In an exemplary embodiment, the second polymer is polypropylene (PP). In another exemplary embodiment, the second polymer is polyethylene (PE). In yet another exemplary embodiment, the second polymer is polyamide (PA).
In accordance with an embodiment of the present disclosure, the solid content of the material in second polymer is in the range of 0.5 mass% to 60 mass% with respect to the total mass of the second polymer. The solid content in the second polymer refers to the amount of material such as oil dispersion present in the second polymer. The solid content of the material affects the mechanical properties and the barrier properties of the resultant second modified polymer if the solid content is less than 0.5 mass% and more than 60 mass%. The material acts as a barrier additive for the laminate.
In accordance with an embodiment of the present disclosure, the adhesive is selected from the group consisting of pure acrylic adhesive, polyester based adhesive, polyurethane based adhesive, polyolefin based adhesive and ester acrylic adhesive.
In accordance with an embodiment of the present disclosure, a thickness of the second polymeric film is in the range of 10 µ to 60 µ.
In accordance with an embodiment of the present disclosure, the third polymer is polyvinylidene chloride (PVdC).
In accordance with an embodiment of the present disclosure, a thickness of the third polymeric film is in the range of 12 µ (20 GSM) to 110 µ (180 GSM).
In accordance with another embodiment of the present disclosure, a thickness of the third polymeric film is in the range of 24 µ (40 GSM) to 72 µ (90 GSM).
In accordance with an embodiment of the present disclosure, an aqueous suspension of the third polymer is made. Typically, this aqueous suspension serves as a coating on the substrate which contributes towards better packaging material. The aqueous suspension of polyvinylidene chloride (PVdC) (third polymer) serves as a barrier coating material which offers barrier against moisture, and other gases with comparatively better thermoforming ability and mechanical properties.
In accordance with an embodiment of the present disclosure, the solid content of polyvinylidene chloride (PVdC) in the aqueous suspension is in the range of 58% to 61% with respect to the total mass of the aqueous suspension. In an exemplary embodiment, the solid content of the polyvinylidene chloride (PVdC) in the suspension is 58% with respect to the total mass of the suspension.
When the solid is in the range of 58% to 61%, the coating of 40 gsm provides a water vapour barrier of 0.68 g/m2/day. If the solid content is lower than 58% then the coating of 40 gsm will not provide the requisite barrier, it will show lower barrier property.
In accordance with an embodiment of the present disclosure, the third polymer is modified with at least one material selected from water absorbing material, water repelling material and nanomaterial.
In accordance with an embodiment of the present disclosure, a water absorbing material or repelling material is added into the polyvinylidene chloride (PVdC) suspension to achieve better barrier properties at a comparatively lower coating thickness of PVdC material.
In accordance with an embodiment of the present disclosure, the water absorbing material is at least one selected from the group consisting of alumino-silicate clay, dry sodium sulphate, anhydrous calcium chloride, magnesium chloride, sodium chloride, molecular sieves, porous carbon microparticles, cellulose, polyvinyl alcohol, starch, silica, alumina and biopolymers.
In an exemplary embodiment, the biopolymer is MA Pectin.
In accordance with an embodiment of the present disclosure, the water repelling material is at least one selected from the group consisting of polysiloxane, polyisobutene, polyisoprene, and microcellulose (natural fiber).
In accordance with an embodiment of the present disclosure, a particle size of the microcellulose (natural fiber) is in the range of 40 µ to 50 µ.
In accordance with an embodiment of the present disclosure, the first polymer, the second polymer and the third polymer are independently modified with at least one material selected from at least one nanomaterial and/ or porous carbon microparticles.
In accordance with an embodiment of the present disclosure, the first polymer, the second polymer and the third polymer are independently modified with at least one nanomaterial.
In accordance with an embodiment of the present disclosure, the nanomaterial is at least one selected from the group consisting of metal, metal oxide, and clay.
In accordance with an embodiment of the present disclosure, the metal is at least one selected from the group consisting of copper, silver, gold, and zinc.
In accordance with an embodiment of the present disclosure, the metal oxide is at least one selected from the group consisting of alumina, silica, copper oxide, zinc oxide, cerium oxide, and iron oxide.
In accordance with an embodiment of the present disclosure, the clay is at least one selected from the group consisting of bentonite, smectite, montomorilonite, and hectrorite.
The clays are mostly aluminosilicate materials with platelet like structure. These materials have good ion exchange properties and when exfoliated these materials, display thixotropic and suspension properties. Further, these materials are biocompatible and less hazardous. Furthermore, when the inorganic ions exchanged with organic ions, these clays turned in to organoclay and thus can easily be used with organic and polymeric systems.
In accordance with the present disclosure, the clay is uniformly exfoliated in the first polymer to obtain a modified first polymer (clay-polymer nanocomposite). Exfoliation is achieved by blending organoclay with the first polymer and by exfoliating through polymerization.
In accordance with the present disclosure, the first polymeric film comprises thermoplastic polymer and nanomaterial masterbatch.
Nanomaterial masterbatch in the present disclosure is prepared by blending nanoparticles in the range of 5 mass% to 30 mass% into the first polymer.
In accordance with an embodiment of the present disclosure, the amount of the nanomaterial in the modified second polymer is in the range of 0.5 to 60 mass % with respect to the total amount of the modified second polymer. In another embodiment, the amount of the nanomaterial in the modified second polymer is in the range of 0.5 to 25 mass % with respect to the total amount of the modified second polymer. In still another embodiment, the amount of the nanomaterial in the modified second polymer is in the range of 0.5 to 15 mass % with respect to the total amount of the modified second polymer. In yet another embodiment, the amount of the nanomaterial in the modified second polymer is in the range of 0.5 to 10 mass % with respect to the total amount of the modified second polymer.
In an exemplary embodiment, the amount of the nanomaterial is 13.33 mass%. In another exemplary embodiment, the amount of the nanomaterial is 6.25 mass%. In yet another exemplary embodiment, the amount of the nanomaterial in the modified polymer is 0.8 mass%.
In accordance with the present disclosure, the clay/ metal oxide nanoparticles are blended with the first polymer in the range of 0.5 mass% to 30 mass% to form polymer-organoclay/metal oxide modified first polymer. Masterbatch of organoclay/ metal oxide nanoparticle is blended with masterbatch polymer in the range of 60 mass% to 80 mass% and then pelletized. These masterbatch pellets then are blended into polymer matrix and a film is formed either by calendaring or by extrusion process.
In accordance with an embodiment of the present disclosure, the solid content of the nanomaterial is in the range of 0.1 mass% to 10 mass% in the suspension with respect to the total mass of the suspension. The solid content in the suspension refers to the amount of material such as oil dispersion present in the suspension. Higher weight percentage of the additive affects stability of the polymer suspension therefore, weight percentage of the additive is optimized to obtain better barrier property with stability of the suspension.
In accordance with an embodiment of the present disclosure, the nanomaterial is in the form of nanoparticles, nanoplatelets, nanotubes, and nanofibers.
In accordance with an embodiment of the present disclosure, an aspect ratio of the nanoplatelet is in the range of 5 to 100.
In accordance with an embodiment of the present disclosure, a particle size of the nanomaterial is in the range of 20 nm to 100 nm. In an embodiment, the particle size of the nanomaterial is in the range of 20 nm to 80 nm. In another embodiment, the particle size of the nanomaterial is in the range of 20 nm to 40 nm.
In accordance with an embodiment of the present disclosure, the first polymer, the second polymer and the third polymer are modified with porous carbon microparticles.
In accordance with an embodiment of the present disclosure, a particle size of the porous carbon microparticles is in the range of 10 µ to 70 µ. In another embodiment, the particle size of carbon microparticles is in the range of 20 µ to 50 µ. In yet another embodiment, the particle size of carbon microparticles is in the range of 20 µ to 40 µ.
The blister laminates of the present disclosure are characterized by having a weight gain of less than 0.04 g/day.
In accordance with the present disclosure, the modified third polymer based suspension displayed improved barrier properties. This improvement is achieved through the introduction of porous carbon microparticles in the third polymer suspension. In an exemplary embodiment, the PVdC suspension is available in base coat (Solvay A-736) and Top coat (Solvay D-193).
The carbon microparticles are introduced in the water based PVdC base coat dispersion and found that these particles are uniformly dispersed in the base coat without change in pH. Coating of these carbon microparticles based suspensions applied on thermoformable film/ laminate, a uniform coating formed by air knife process or rotogravure process and the coated film showed comparatively better barrier properties at lower coating thickness than conventional PVdC coated thermoformable film/ laminate.
In accordance with an embodiment of the present disclosure, the solid content of the porous carbon nanomaterial is in the range of 0.1 mass% to 10 mass% in the suspension with respect to the total mass of the suspension.
In accordance with the present disclosure, PVdC coated thermoformable films and laminates are well known in the packaging industry and well suited for packaging of pharmaceutical products having sensitivities from mild to high. Barrier property of PVdC coating increases, as coating thickness increases, thus 90 GSM PVdC coated thermoformable film/ laminate showed higher barrier properties than 40 GSM PVdC coated thermoformable film/laminate.
In accordance with the present disclosure, due to the crystallinity and polymer chain packing of Polyvinylidene chloride (PVdC), the barrier properties such as low permeability to a wide variety of gases and moisture are obtained. The degree of crystallinity in the case of PVdC can reach up to 80%. Further, during the film forming, the polymer chains pack themselves in close proximity, thus increasing packing density and leaving less free volume. These two characteristics such as a high degree of crystallinity and high packing density of the PVdC provide high barrier properties toward gases and moisture. These characteristics find their roots in the symmetric nature of vinylidene chloride units that would facilitate good packing of polymer chains with very low free volume in the amorphous phase.
Conventionally available PVdC suspension contains anti-oxidants, surfactants, and the like with minimum solid content maintained in the range of 58 mass% to 61%. Aqueous PVdC composition is acidic and very sensitive in nature. The incorporation of additional material to PVdC suspension leads to either the breaking of suspension and precipitation or an increase in pH. The pH of the suspension be maintained below 3. Thus, while mixing of the additional material, pH and stability of the suspension has to be considered to improve the properties of PVdC.
In accordance with the present disclosure, the porous carbon microparticles are utilized as fillers in the PVdC suspension. The excellent adsorption properties of the porous carbon microparticles find their roots in very high surface area and interactive sites and porosity. These materials found applications in wide areas such as healthcare, water and gas purification and colour/ odour removing agents and the like. These particles are non-hazardous and environment friendly. The addition of porous carbon microparticles in the PVdC suspension is carried out in a very simple mechanical mixing process. This process does not require any addition of surfactants or stabilizing agents to achieve uniform suspension. The advantage of the use of these microparticles is that they do not alter the pH of the PVdC suspension drastically and do not affect the stability of the suspension.
In accordance with the present disclosure, the carbon microparticles are added directly to PVdC suspension under mechanical stirring to obtain a uniform suspension. The addition of microparticles can also be carried out by preparing an aqueous suspension of microparticles, and the aqueous suspension of microparticles can then be mixed with PVdC suspension under mechanical stirring at a room temperature. This microparticle-based PVdC suspension then applied on the polymer substrate to form a uniform transparent coating on polymer substrate which acts as barrier layer to moisture and gases. This microparticle based PVdC suspension is found to be flexible enough so that it can easily be used for thermoforming as well as cold forming laminates.
In accordance with the present disclosure, the polymer substrate that is used for coating is at least one selected from the group consisting of PVC film (having a thickness in the range of 100 µ to 500 µ), PVC and PE laminates, PVC and PP laminates, PVC and polyamide (PA) film. The substrate is in the form of single layer or multi-layer. The carbon microparticle based PVdC suspension is used to coat the polymeric films and laminates that can be used as packaging films and laminates for pharmaceutical and food products.
In accordance with an embodiment of the present disclosure, the high barrier multilayer laminate for thermoforming blisters comprises:
a. at least one substrate, defining an operative surface, wherein the substrate comprises;
i. at least one PVC film comprising PVC optionally modified with at least one nanomaterial, defining an operative surface;
ii. optionally, at least one polypropylene film comprising polypropylene optionally modified with at least one nanomaterial, adhered to the operative surface of the first polymeric film by means of an adhesive;
and
b. at least one PVdC film comprising PVdC optionally modified with at least one nanomaterial, disposed on the operative surface of the substrate.
In accordance with an embodiment of the present disclosure, the high barrier multilayer laminate for thermoforming blisters comprises:
a. at least one PVC film, defining an operative surface; and
b. at least one PVdC film comprising PVdC optionally modified with at least one nanomaterial, disposed on the operative surface of the PVC film.
In accordance with an embodiment of the present disclosure, the high barrier multilayer laminate for thermoforming blisters comprises:
a. at least one PVC film, defining an operative surface; and
b. at least one PVdC film comprising PVdC modified with cellulose (natural fiber), disposed on the operative surface of the PVC film.
In accordance with an embodiment of the present disclosure, the high barrier multilayer laminate for thermoforming blisters comprises
a. at least one PVC film comprising PVC optionally modified with at least one nanomaterial, defining an operative surface; and
b. at least one PVdC film disposed on the operative surface of the PVC film.
In accordance with an embodiment of the present disclosure, the high barrier multilayer laminate for thermoforming blisters comprises:
a. at least one substrate, defining an operative surface, the substrate comprising;
i. at least one PVC film, defining an operative surface; and
ii. at least one polypropylene (PP) film, adhered to the operative surface of PVC film by means of an adhesive;
and
b. at least one PVdC film comprising PVdC optionally modified with at least one nanomaterial, disposed on the operative surface of the substrate.
In accordance with an embodiment of the present disclosure, the high barrier multilayer laminate for thermoforming blisters comprises:
a. at least one substrate, defining an operative surface, the substrate comprising;
i. at least one PVC film, defining an operative surface;
ii. at least one polypropylene (PP) film comprising polypropylene (PP) modified with at least one nanomaterial, adhered to the operative surface of PVC film by means of an adhesive;
and
b. at least one PVdC film disposed on the operative surface of the substrate.
In accordance with an embodiment of the present disclosure, the high barrier multilayer laminate for thermoforming blisters comprises:
a. at least one substrate, defining an operative surface, the substrate comprising;
i. at least one PVC film, defining an operative surface;
ii. at least one polypropylene (PP) film comprising polypropylene (PP) modified with at least one nanomaterial, adhered to the operative surface of PVC film by means of an adhesive;
and
b. at least one PVdC film comprising PVdC optionally modified with porous carbon microparticles, disposed on the operative surface of the substrate.
Barrier properties of the modified PVC films; PVdC suspension modified with nanomaterial and coated on PVC laminates; regular PVC and PVC coated with regular PVdC films are studied as per method for determining Water vapour transmission rate (WVTR) given under USP 671. Typically, the films are formed in to blisters and then filled with pre- dried coloured silica beads. This silica filled blisters are then sealed with aluminium foil based lidding foil and exposed to 40°C and 75% RH in a Humidity chamber or stability study chamber. A study of weight gain for the exposed blister is carried out for at least 35 days.
In another aspect, the present disclosure relates to a process for the preparation of a high barrier thermoforming blister laminate. In the process, a predetermined amount of a first polymer is obtained. Optionally, the first polymer is modified by using a predetermined amount of a material to obtain a modified first polymer. Thereafter, a film of the first polymer is made to obtain a first polymeric film.
In the next step, a second polymeric film, is obtained and adhered to the first polymeric film using at least one adhesive to obtain a substrate. Thereafter, a predetermined amount of a third polymer suspension is obtained. The third polymer is optionally modified by adding a predetermined amount of a material to the third polymer to obtain a modified suspension. Thereafter, the suspension is coated on the substrate to form a coating of a predetermined thickness, followed by drying the coating at a predetermined temperature to obtain a high barrier thermoforming blister laminate.
The foregoing description of the embodiments has been provided for purposes of illustration and is not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
EXPERIMENTAL DETAILS
Example 1: Nanomaterial modified PVC (first polymer) (having a thickness of 250 µ) nanocomposite laminates/films, in accordance with the present disclosure
Virgin polyvinyl chloride (PVC) (first polymer) pellets were taken into silos/hoppers. 30 mass% of aluminium oxide nanoparticles having a size of 20 nm were obtained. The Virgin PVC pellets and aluminium oxide nanoparticles were mixed through the silos/hoppers to obtain a mixture of PVC and aluminium oxide nanoparticles. The PVC- aluminium oxide nanoparticles mixture was charged into the extrusion screws to obtain nanoparticles modified PVC molten mass. The temperature in the extrusion screws was maintained at 240 °C. The nanoparticles modified PVC molten mass was pumped into T die to obtain nanoparticles modified PVC film having a thickness of 250 µ by calendaring process. The temperature of the T die was also maintained at 240 °C. The nanoparticles modified PVC film was used for blister preparation. Blisters (5 each) were formed at 130 °C by using a flatbed thermoforming machine. Barrier performance was studied according to USP 671 procedure. Also, normal PVC blisters were formed by a conventional method. The formed blisters were then packed with previously dried coloured silica desiccant beads and sealed at 170°C with aluminum lidding foil having water base HSL (heat sealing layer). Silica beads packed blisters were then exposed to 40°C and 75% relative humidity in stability chamber and weight gain were recorded. After 35 days, rate of weight gain was recorded.
The weight gain of the resulting nanomaterial modified PVC (first polymer) film is mentioned in Table 1:
Table 1: Weight gain of the normal PVC and nanomaterial modified PVC films after 35 days:

Composite/film Values (weight gain in g/day) at 35th day WVTR (g/m2/day)
normal 250 µ PVC Blister 0.0314 4.42
250 µ of nanomaterial modified PVC films 0.0213 3.57
From Table 1, it is evident that the weight gain of the blister formed by the nanomaterial modified PVC laminate was lesser as compared to the normal PVC film.
Example 2: 40 GSM of PVdC (third polymer) coating on nanoparticle modified PVC (first polymer) film (having a thickness of 250 µ), in accordance with the present disclosure:
PVC (first polymer) film of 250 µ modified with Aluminum oxide nanoparticles (nanomaterial modified PVC film) was coated with 40 GSM of unmodified PVdC (third polymer) suspension and the same procedure was followed as mentioned in example 1 for weight gain studies. The rate of weight gain found is mentioned in Table 2 below.
Table 2: The comparison of weight gain of the PVdC coated (40 GSM) nanomaterial modified PVC film (first polymer) and PVdC coated (40 GSM) PVC (first polymer) film of thickness 250 µ after 35 days.
Composite/film Values (weight gain g/day) at 35th day WVTR (g/m2/day)
250 µ of PVC and 40 GSM PVdC 0.0164 0.68
250 µ of nanoparticle modified PVC film and 40 GSM PVdC 0.0091 0.5655
From Table 2, it is evident that the weight gain of the blister formed by nanoparticle modified PVC film coated with 40 GSM of normal PVdC suspension was lesser as compared to 40 GSM of PVdC coated on normal 250 µ of PVC film.
Example 3: 40 GSM 1.5% organoclay in PVdC (third polymer) coated on PVC (first polymer) film (having a thickness of 250 µ), in accordance with the present disclosure
1.5 mass% of organoclay powder was dispersed uniformly in PVdC (third polymer) suspension (A- 736, Solvay, 58% solid) under mechanical stirring at 1400 rpm. The mixing of organoclay powder was carried out for 30 minutes. After uniformly mixing, the uniform suspension was obtained without any appreciable change in pH, specific gravity and total solid content of the PVdC suspension. The organoclay based suspension was then coated on 250 µ of PVC (first polymer) by using a conventional commercial coating machine. The coating thickness thus achieved during coating was found to be 40 GSM. The organoclay based PVdC coated PVC films were then subjected to barrier testing under standard USP 671 protocol wherein 5 blisters were formed on a flatbed thermoforming machine at 130°C, filled with pre-dried silica beads and sealed with aluminum based lidding foil. These silica bead-packed blisters were then exposed to 40°C and 75% RH in a humidity chamber. Samples were taken out periodically and kept to attain a room temperature. Weight gain for blisters was recorded. Weight gain exercise was carried out till 35 days as per the USP 671 protocol.
Table 3: The comparison of weight gain of PVC (first polymer) film of 250 µ coated with organoclay modified 40 GSM PVdC (third polymer) coating and normal PVC (250 µ) coated with normal PVdC (40 GSM):
Composite/film Values (weight gain g/day) at 35th day WVTR (g/m2/day)
250 µ of PVC and 40 GSM PVdC 0.0164 0.68
250 µ of PVC and 40 GSM modified PVdC with 1.5% organoclay 0.0137 0.5789
From Table 3, it is evident that the weight gain of the blister formed by 250 µ of PVC and 40 GSM modified PVdC with 1.5% organoclay laminate was lesser as compared to 250 µ of PVC coated with 40 GSM PVdC laminate.
Example 4: PVC (first polymer) film (having a thickness of 250 µ) and polypropylene (PP) (second polymer) (having a thickness of 25 µ) and 40 GSM of nanoparticle modified PVdC (third polymer), in accordance with the present disclosure:
2.5 mass% of organoclay was suspended in PVdC (third polymer) base coat (A-736 Solvay, 58% solid) under mechanical stirring for 30 minutes and coated with a thickness of 40 GSM on250µ PVC- 25µ PP laminate. The same experimental procedure was followed for the weight gain study as mentioned in example 1.
Table 4: The comparison of weight gain of PVC (first polymer) (having a thickness of 250µ) and PP (second polymer) (having a thickness of 25µ) and 40 GSM of nanoparticle modified PVdC (third polymer) and PVdC (40 GSM) coated PVC 250µ.
Composite/film Values (weight gain g/day) at 35th day WVTR (g/m2/day)
250 µ of PVC and 40 GSM of PVdC 0.0164 0.68
250 µ of PVC, 25 µ of PP, 40 GSM of nanoparticle modified PVdC 0.0095 0.5035
From Table 4, it is evident that the weight gain of the blister formed by250µ PVC, 25 µ of PP, 40 GSM of nanoparticle modified PVdC laminate was lesser as compared to 250 µ of PVC coated with 40 GSM PVdC laminate.
Example- 5 Organoclay modified natural polymer (microcellulose) blended with aqueous suspension of PVdC (third polymer) and then coated on PVC (first polymer) film (having a thickness of 40 GSM), in accordance with the present disclosure
Aqueous suspension of organoclay modified microcellulose was blended with PVdC suspension in the weight ratio of 2.5: 97.5 under mechanical stirring to obtain a uniform suspension. The uniform suspension showed no change in pH of PVdC suspension which is usually below 3. This suspension was then coated on PVC film of 250 µ thickness with 40 GSM thickness. The weight gain studies were carried out according to USP 671 method as stated in example 1 and values were compared with regular PVC coated with 40 GSM PVdC laminate.
Table 5: The comparison of weight gain of coating of PVdC modified by organoclay- cellulose suspension (40 GSM) on 250µ PVC film and PVC 250µ/ 40 GSM PVdC and 250µ PVC/ 90 GSM PVdC:
Composite/film Values (weight gain g/day) at 35th day WVTR (g/m2/day)
250 µ of PVC and 40 GSM of PVdC 0.0164 0.68
250 µ of PVC and 90 GSM of PVdC 0.0086 0.35
250 µ of PVC and microcellulose blended with organoclay modified PVdC (40 GSM) 0.0104 0.5556
From Table 5, it is evident that the weight gain of the blister formed by 250µ PVC/ Organoclay-cellulose suspension modified PVdC (40 GSM) is between 250 µ of PVC coated with 90 GSM PVdC and 250 µ of PVC coated with 90 GSM PVdC.
The example 5 utilizes sustainable natural fibers so as to endure in a relatively ongoing way across various domains of life. Also, the cost of microcellulose is very low as compared to other polymers.
Example 6: Films/laminates of PVC (first polymer) (having a thickness of 250µ) and PVdC (third polymer) (90 GSM); PVC (first polymer) (having a thickness of 250 µ), nanomaterial modified PP (second polymer) (having a thickness of 25 µ) and porous carbon microparticles modified PVdC (third polymer) (40 GSM); and PVC (first polymer) (having a thickness of 250 µ), nanomaterial modified PP (second polymer) (having a thickness of 25 µ) and porous carbon microparticle modified PVdC (third polymer) (60 GSM), in accordance with the present disclosure
0.4 mass % of porous carbon microparticles were dispersed thoroughly in 2 litres of water to obtain a slurry and then this so obtained slurry was mixed with PVdC (third polymer) suspension and stirred vigorously with a mechanical stirrer to obtain a uniform suspension. The uniform suspension of porous carbon microparticles in PVdC (third polymer) was obtained. The suspension was then coated on 250 µ of PVC (first polymer) and 25 µ of nanomaterial modified PP (second polymer) film laminate. The same experimental procedure was followed for the weight gain study as mentioned in example 1. The rate of weight gain at 35th day, of these composite/film was compared with 250µ PVC (first polymer) and 90 GSM of PVdC (third polymer) laminate is mentioned in Table 6.
Table 6: The weight gain of the resulting PVC (having a thickness of 250µ) and PVdC (90 GSM); PVC (having a thickness of 250 µ), nanomaterial modified PP (having a thickness of 25 µ) and porous carbon microparticle modified PVdC (40 GSM); and PVC (having a thickness of 250 µ), nanomaterial modified PP (having a thickness of 25 µ) and porous carbon microparticle modified PVdC (60 GSM), at 35th day:
Composite/film Values (weight gain g/day) at 35th day WVTR (g/m2/day)
250 µ of PVC and 90 GSM of PVdC 0.0086 0.35
250 µ of PVC, 25 µ of nanomaterial modified PP and 40 GSM of porous carbon microparticle modified PVdC 0.007 0.4061
250 µ of PVC, 25 µ of nanomaterial modified PP and 60 GSM of porous carbon microparticle modified PVdC 0.0058 0.37
From Table 6, it is evident that the weight gain of the blister formed by 250 µ of PVC, 25 µ of nanomaterial modified PP and 60 GSM of porous carbon microparticle modified PVdC was lesser as compared to 250 µ of PVC, nanoparticles modified 25 µ of nanomaterial modified PP and 40 GSM of porous carbon microparticle modified PVdC and 250 µ of PVC and 90 GSM of PVdC.
Example 7: Comparison of rate of weight gain for PVdC modified with biopolymer of thickness 40 GSM, 60 GSM and 90 GSM coated on normal 250 micron PVC GC film with conventional 250 micron PVC/ 40 GSM PVdC, 250 micron PVC/ 60 GSM PVdC and 250microns PVC/ 90 GSM PVdC films.
3g of biopolymer (MA Pectin) water suspension (1%) was added to commercially available aqueous PVdC suspension from Solvay (A 736) and stirred under a mechanical stirrer for 15 min. to obtain uniform suspension of biopolymer-PVdC. This suspension was coated with coating thicknesses such as 40 GSM, 60 GSM and 90 GSM on a separate PVC films having a thickness of 250 µ. The specific gravity of PVdC suspension was maintained at 1.30 with solid content 60%. Barrier properties of the coated films were tested using the procedure according to USP 671 wherein films were thermoformed into blisters (5 each) on flatbed machine at 130° C and then coloured silica beads were packed and sealed at 170° C with aluminum lidding foil. Blisters were exposed to environmental conditions at 40 °C and 75% relative humidity in the humidity chamber or stability chamber after 35th day.
Table 7: Comparison of rate of weight gain for PVdC modified with biopolymer of thickness 40 GSM, 60 GSM and 90 GSM coated on normal 250 micron PVC GC film with conventional 250 micron PVC/ 40 GSM PVdC, 250 micron PVC/ 60 GSM PVdC and 250microns PVC/ 90 GSM PVdC films.
Sr. No. Complex Rate of weight gain at 35 days (g) WVTR (g/m2/day)
1 Conventional 250 micron PVC/ 40 GSM PVdC 0.0164 0.68
2 Conventional 250 micron PVC/ 60 GSM PVdC 0.0114 0.55
3 Conventional 250 micron PVC/ 90 GSM PVdC 0.0086 0.35
4 250 micron PVC/ 40 GSM Biopolymer modified PVdC 0.0074 0.43
5 250 micron PVC/ 60 GSM Biopolymer modified PVdC 0.0104 0.40
6 250 micron PVC/ 90 GSM Biopolymer modified PVdC 0.0099 0.33
It is evident from the table 7 that the WVTR of biopolymer-modified PVdC coated on 250 microns PVC GC showed lower WVTR than conventional counterparts.
Comparative Example 1: Aqueous PVdC suspension coated with 40 GSM, 60 GSM, and 90 GSM on PVC films (having a thickness of 250 µ)
Commercially available aqueous PVdC suspension from Solvay (A 736) was coated with various coating thickness such as 40 GSM, 60 GSM and 90 GSM on a separate PVC film having a thickness of 250 µ. The specific gravity of PVdC suspension was maintained at 1.30 with solid content 60%. The coating was carried out on a commercial coating machine having dry air oven attached to it. Barrier properties of the coated films were tested using the procedure according to USP 671 wherein films were thermoformed in to blisters (5 each) on flat bed machine at 130° C and then coloured silica beads were packed and sealed at 170° C with aluminum lidding foil. Blisters were exposed to environmental conditions at 40 °C and 75% relative humidity in the humidity chamber or stability chamber after 35th day.
Table 8: The weight gains of the resulting composite of aqueous PVdC suspension coated with 40 GSM, 60 GSM, and 90 GSM on PVC films (250 µ) after 35 days:
Composite/film Values (weight gain in g/day) at 35th day WVTR (g/m2/day)
250 µ PVC/ 40 GSM PVdC 0.0164 0.68
250 µ PVC/ 60 GSM PVdC 0.0114 0.55
250 µ PVC/ 90 GSM PVdC 0.0086 0.35

From Table 7, it is evident that, at higher GSM value, the coated PVdC film showed lower weight gain as compared to the lower GSM of PVdC. The higher GSM will provide better barrier against moisture, so weight gain was lower.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of high barrier thermoforming blister laminates that:
• has a high barrier property at a lower PVdC coating thickness;
• has a high barrier against moisture, gases, and light; and
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising, will be understood to imply the inclusion of a stated element, integer or step,” or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention.
The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.
,CLAIMS:WE CLAIM:
1. High barrier thermoforming blister laminates comprising:
a. at least one substrate, defining an operative surface, wherein said substrate comprises;
i. at least one first polymeric film, defining an operative surface;
ii. optionally, at least one second polymeric film, adhered to said operative surface of said first polymeric film by means of an adhesive;
and
b. at least one third polymeric film disposed on said operative surface of said substrate.
2. The blister laminates as claimed in claim 1, wherein
• said first polymeric film comprises at least one first polymer, wherein said first polymer is optionally modified.
• second polymeric film comprises at least one second polymer, wherein said second polymer is optionally modified; and
• said third polymeric film comprises at least one third polymer, wherein said third polymer is optionally modified.
3. The blister laminates as claimed in claim 2, wherein said first polymer is a thermoplastic polymer.
4. The blister laminates as claimed in claim 3, wherein said thermoplastic polymer is at least one selected from the group consisting of halogenated polymer, polyolefin, polyamide, polyacrylate, and polyurethane.
5. The blister laminates as claimed in claim 4, wherein
• said halogenated polymer is selected from group of polyvinyl chloride (PVC), polyvinylidene fluoride (PVdF), poly chloro trifluoro ethylene (PCTFE), poly tetrafluoro ethylene (PTFE);
• said polyolefin is selected from polyethylene polymer and polypropylene polymer, wherein said polyethylene polymer is selected from the group consisting of high density polyethylene (HDPE), medium density polyethylene, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), cross-linked polyethylene, chlorinated polyethylene and ultra-high molecular weight polyethylene (UHMWPE); and said polypropylene polymer selected from group consisting of propylene homopolymer, polypropylene co-polymer, polypropylene random copolymers, polypropylene impact copolymers and polypropylene block copolymers;
• said polyamide polymer is a blend of a semicrystalline polyamide and an amorphous copolyamide, wherein said semicrystalline polyamide is selected from the group consisting of polyamide selected from Nylon 6, Nylon 6,6, Nylon 6,9, Nylon 6,12, Nylon 12,12 and copolymer; and
• said polyacrylate is selected from the group consisting of polymethyl acrylate, polyethyl acrylate, polymethyl methacrylate, copolymer of ethylene and vinyl acetate, and copolymer of ethylene and methacrylic acid.
6. The blister laminates as claimed in claim 1, wherein a thickness of said first polymeric film is in the range of 100 µ to 500 µ.
7. The blister laminates as claimed in claim 6, wherein a thickness of said first polymeric film is in the range of 200 µ to 350 µ.
8. The blister laminates as claimed in claim 2, wherein said second polymer is at least one selected from the group consisting of polypropylene (PP), polyethylene (PE), and polyamide (PA).
9. The blister laminates as claimed in claim 1, wherein said adhesive is selected from the group consisting of pure acrylic adhesive, ester acrylic adhesive, polyurethane adhesives, polyolefin based adhesives and polyester adhesives.
10. The blister laminates as claimed in claim 1, wherein a thickness of said second polymeric film is in the range of 10 µ to 60 µ.
11. The blister laminates as claimed in claim 2, wherein said third polymer is polyvinylidene chloride (PVdC).
12. The blister laminates as claimed in claim 1, wherein a thickness of said third polymeric film is in the range of 12 µ (20 GSM) to 110 µ (180 GSM).
13. The blister laminates as claimed in claim 2, wherein
• said first polymer is modified with at least one material selected from a nanomaterial and porous carbon microparticles, wherein an amount of said material is in range of 0.5 mass% to 30 mass % with respect to the total amount of said first polymer;
• said second polymer is modified with at least one material selected from a nanomaterial and porous carbon microparticles, wherein an amount of said material is in range of 0.5 mass% to 60 mass % with respect to the total amount of said second polymer; and
• said third polymer is modified with at least one material selected from a nanomaterial, water absorbing material and water repelling material, wherein an amount of said material is in range of 0.1 mass% to 10 mass % with respect to the total amount of said third polymer.
14. The blister laminates as claimed in claim 13, wherein said nanomaterial is at least one selected from the group consisting of metal, metal oxide, and clay.
15. The blister laminates as claimed in claim 14, wherein said metal is at least one selected from the group consisting of copper, silver, gold, and zinc.
16. The blister laminates as claimed in claim 14, wherein said metal oxide is at least one selected from the group consisting of alumina, silica, copper oxide, zinc oxide, cerium oxide, and iron oxide.
17. The blister laminates as claimed in claim 14, wherein said clay is at least one selected from the group consisting of bentonite, smectite, montomorilonite, hectrorite and organoclay.
18. The blister laminates as claimed in claim 13, wherein
• said water absorbing material is at least one selected from the group consisting of alumino-silicate clay, dry sodium sulphate, anhydrous calcium chloride, magnesium chloride, sodium chloride, molecular sieves, porous carbon microparticles, cellulose, polyvinyl alcohol, starch, silica, alumina and biopolymers; and
• said water repelling material is at least one selected from the group consisting of polysiloxane, polyisobutene, polyisoprene, and microcellulose.
19. The blister laminates as claimed in claim 13, wherein a particle size of said nanomaterials is in the range of 20 nm to 100 nm.
20. The blister laminates as claimed in claim 13, wherein a particle size of said porous carbon microparticles is in the range of 10 µ to 70 µ.
21. The blister laminates as claimed in claim 1 are characterized by having a weight gain of less than 0.04 g/day.

Dated this 28th day of April, 2023

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
of R.K.DEWAN & CO.
Authorized Agent of Applicant

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT MUMBAI