DESC:FIELD
The present disclosure relates to pharmaceutical packaging. In particular, the present disclosure relates to a compact blister pack.
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 “cold forming process” in the context of the present disclosure refers to stamping, for shaping solid material at or near room temperature in to a desired shape and size, which is achieved by application of force on a multilayer laminate in perpendicular direction to its parting line.
The term “blisters cups” in the context of the present disclosure refers to a pack of several types of pre-formed plastic packaging used for small consumer goods, foods, and for pharmaceuticals, in which a blister cup is a cavity or pocket made from a formable web, usually a thermoformed plastic or an aluminum foil.
The term “oriented polyamide” in the context of the present disclosure refers to alignment or position along the axis relative to the direction of stretching of a polyamide polymeric film in a specified direction.
The term “draft” in the context of the present disclosure refers to an amount of taper provided for molded or cast parts perpendicular to the parting line.
The term “draft angle” in the context of the present disclosure refers to a draft provided to an article or sheet which is measured in degrees.
The term “doctoring technique” in the context of the present disclosure refers to a system of principles taught and/or advocated for manufacturing a product/ commodity.
The term “parting line” in the context of the present disclosure means a plane in which the two halves of a mold set meet in which all features should be oriented perpendicular to the parting line to facilitate removal from the mold.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Blister packages are employed for packaging numerous products including, but not limited to, consumer goods, foods, and pharmaceutical products. These blister packages protect the sealed product from external factors like humidity, light, contamination and any other factors which may affect the quality of the sealed packed product.
The blister pack comprises a formable web/multilayer laminate into which blisters or cavities are formed, and a lidding, which is employed as a seal, the product being placed within the blisters or cavities. The process for forming the blisters or blister cups or cavities is termed as a cold forming process. Typically, a blister (also known as a “blister cup”) is a cavity structure formed on a multilayer laminate by the action of force acting on the multilayer laminate. A die is used for forming the blister cups or cavities on the multilayer laminate.
Typically, the multilayer laminate can comprise a first polymer layer, a metal layer, and a structural strengthening layer which can be a second polymer layer. The polymer in the first polymer layer can be polyvinyl chloride (PVC), the metal employed can be aluminum and the structural strengthening layer can comprise a polymer such as a polyamide polymer component (the second polymer). The product placed within the blister is in contact with the inner layer of the multilayer laminate which is generally the PVC layer.
Typically, the metal used is in the form of a sheet/foil which is stacked between the first polymer and the structural strengthening layer (which can be a second polymer). This metal layer provides structural stability, protection from the environmental factors and other factors. Further, the structural strengthening layer (as the name implies) provides the required mechanical properties. The first polymer layer along with the structural strengthening layer/second polymer (which can be a polyamide polymer) prevents the ingress of moisture into the package.
In the multilayer laminate comprising PVC as the inner layer (that is in contact with the product such as pharmaceutical tablets), the intermediate layer which can be an aluminum foil, and the structural strengthening layer (polyamide polymer) as the outer layer, it is observed that the draft angle (referred to as angle ?) that can be achieved is in the range of 30? to 75?. The blister cups having a larger angle ? needs to be spaced apart in the blister pack and hence results in a blister pack with larger size and/or volume. This is not desired.
There is, therefore, felt a need to provide a blister pack having compact size and/or volume.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
It is an object of the present disclosure to ameliorate one or more problems of prior art or to at least provide a useful alternative.
An object of the present disclosure is to provide a compact blister pack.
Another object of the present disclosure is to provide a compact blister pack with reduced area.
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
In accordance with an aspect of the present disclosure, a compact blister pack is disclosed.
The compact blister pack comprises blister shaped cups made of a multilayer laminate having: an inner layer comprising a first polymer; an intermediate layer comprising a metal foil; and an outer layer comprising a second polymer; and a base.
The blisters are defined by a first side wall having a first edge and a second edge, the first side wall extending in an operative upward direction from the base and slanted at an angle ? with respect to a normal to the base; a flat wall extending from the second edge of the first side wall; a second side wall extending from a second edge of the flat wall in an operative downward direction abutting the base and slanted at an angle ? with respect to a normal to the base; a third side wall extending from a first lateral edge of the flat wall in an operative downward direction abutting the base and slanted at an angle ? with respect to a normal to the base; and a fourth side wall extending from a second lateral edge of the flat wall in an operative downward direction abutting the base and slanted at an angle ? with respect to a normal to the base.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The blister pack of the present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates the draft angle of the blister cups formed in a multilayer laminate of a conventional blister pack;
Figure 2 illustrates the draft angle of the blister cups formed in a multilayer laminate of a blister pack in accordance with one embodiment of the present disclosure; and
Figure 3 illustrates the top view of the blister cup in accordance with one embodiment of the present disclosure.
DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
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.
The present disclosure envisages a blister pack that overcomes the drawbacks of the conventional blister pack.
Figure 1 illustrates angle ? 104 of blister cups 102 (cross sectional view) formed in a multilayer laminate of a conventional blister pack 100.
Figure 2 illustrates angle ? 204 of the blister cups 202 (cross sectional view) formed in a multilayer laminate of a blister pack 200 in accordance with one embodiment of the present disclosure.
The inventors of the present disclosure have surprisingly found that if the multilayer laminate has good stretchability, it is possible to form blister cups having angle ? in the range of 15? to 25? as compared to the conventional multilayer laminates where angle ? could be in the range of 30? to 75? and could not be reduced below this range.
It is evident from the figures 1 and 2 that the size of the blister pack prepared by using the multilayer laminate of the present disclosure is small as compared to the size of the blister strip prepared by the multilayer laminate of the present disclosure, wherein the angle ? of the blister cups in the is less as compared to that in the blister cups of the conventional blister pack. In other words, a relatively more number of blister cups can be formed in the multilayer laminate using the presently disclosed multilayer laminate as compared to that in case of the conventional blister pack. This result in reduction in the blister pack size and also the amount of multilayer laminate needed.
In accordance with an aspect of the present disclosure, a compact blister pack is disclosed.
The compact blister pack, of the present disclosure, comprises blister shaped cups made of a multilayer laminate having: an inner layer comprising a first polymer; an intermediate layer comprising a metal foil; and an outer layer comprising a second polymer; and a base.
Figure 3 illustrates a blister cup 300 defined by a first side wall 302 having a first edge and a second edge, the first side wall 302 extending in an operative upward direction from the base 310 and slanted at an angle ? with respect to a normal to the base 310. Further the blister cup 300 has a flat wall extending from a second edge of the first side wall 302, a second side wall 304 extending from a second edge of said flat wall in an operative downward direction abutting the base 310 and slanted at an angle ? with respect to a normal to the base 310, a third side wall 306 extending from a first lateral edge of said flat wall in an operative downward direction abutting the base 310 and slanted at an angle ? with respect to a normal to the base and a fourth side wall 308 extending from a second lateral edge of the flat wall in an operative downward direction abutting the base 310 and slanted at an angle ? with respect to a normal to the base 310.
In accordance with the present disclosure, the first polymer is at least one of a polyethylene polymer and polypropylene polymer. The intermediate layer comprises a foil of aluminum and the second polymer is an oriented polyamide polymer. It is found that use of the first polymer which is at least one of a polyethylene polymer and polypropylene polymer leads to improvement in the stretchability of the multilayer laminate and the multilayer laminate does not break or rupture during the cold forming process even when angle ? is of less than 30? are attempted, typically in the range of 15? to 25?.
In accordance with the present disclosure, the inner layer can be made of a first polymer that provides enhanced stretchability. In accordance with one exemplary embodiment of the present disclosure, the first polymer can be a polyethylene polymer, wherein the polyethylene polymer can be at least one selected from the group consisting of high density polyethylene (HDPE), medium density polyethylene, low density polyethylene, linear polyethylene, cross-linked polyethylene, chlorinated polyethylene and ultra-high molecular weight polyethylene (UHMWPE). In another exemplary embodiment of the present disclosure, the first polymer can be a polypropylene polymer. The inner layer with enhanced stretchability permits cold forming of the blisters in the multilayer laminate without rupturing. Typically, the thickness of the inner layer can be in the range of 40 micron to 80 micron.
In accordance with the present disclosure, HDPE is mixed with linear block copolymer based on styrene and butadiene with bound styrene of 29.5% mass to obtain modified HDPE.
In accordance with the present disclosure, a combination of LLDPE and LDPE is modified by using linear triblock copolymer based on styrene and ethylene/ butylene with polystyrene content of 13%.
In accordance with the present disclosure, the intermediate layer can be made of a metal foil that is ductile. Typically, the metal foil used is aluminum foil, as it offers a near complete barrier for moisture and oxygen. Further, as aluminum foil is fully opaque to light, the multilayer laminate provides good shielding against light. Typically, the thickness of the intermediate layer can be in the range of 20 micron to 60 micron.
In accordance with the present disclosure, the outer layer provides structural strength to the cold formed multilayer laminate and blister pack made therefrom. In accordance with the present disclosure, the outer layer is made of a second polymer, which can be an oriented polyamide polymer (OPA). The oriented polyamide polymer is biaxially oriented. The biaxial orientation of polyamide provides the structural strengthening property to the multilayer laminate. The biaxially oriented polyamide provides high durability high strength, abrasion resistance, and resilience. The oriented polyamide films provide good balance between mechanical strength and barrier properties against oxygen, smell and oils. Typically, the thickness of the outer layer can be in the range of 10 micron to 60 micron. In one embodiment, the outer layer is 25 micron thick.
In the conventional laminates, the structure comprises Nylon/adhesive/Aluminum/adhesive/PVC, wherein it is observed that there is tendency of delamination after forming. During forming excess stresses is generated at the bottom and the nylon layer leaves aluminum foil. To overcome this conventionally primer is applied on the metal foil prior to adhesive application so delamination is minimized. The reason for delamination is hygroscopic nature of nylon, wherein moisture penetrates in the nylon layer and reacts with the adhesive which in turn weakens the bond between aluminum and nylon.
In accordance with the present invention, the above-mentioned problem is tackled by providing the outer layer, wherein the outer surface is metallized. Metallization of the outer layer prevents moisture ingress through nylon and hence prevents delamination of the laminate post cavity/blister formation.
In an embodiment, the outer layer comprising the second polymer is metallized on an operative outer surface thereof. The metallization of the operative outer surface of the outer layer prevents delamination occurring between the outer layer and the metal foil. In one embodiment, the metal used for metallization is aluminum. Any other metal can also be used and is within the scope of the present invention. Metallization can be done by vacuum metallization or sputtering.
It is observed that the multilayer laminate of the present disclosure, described herein above, is characterized by having high stretchability as compared to the multilayer laminate with the first polymer being PVC.
In accordance with another aspect of the present disclosure, a process for preparing a blister pack using the multilayer laminate of the present disclosure is provided.
The multilayer laminate can be fabricated by known process. Typically, the process involves stacking the inner layer, the intermediate layer and the outer layer and then passing them through a press roller. Typically, the process for fabricating the multilayer laminate of the present disclosure can be one of dry lamination and wet lamination process.
In dry lamination process, the substrate, which may be polyethylene polymer and/or polypropylene polymer and/or aluminum foil and/or oriented polyamide, is brought in contact with gravure roller through a un-winder and then the gravure roller picks up the adhesive/lacquer from a tray and deposits it on the substrate. The various layers are stacked over the lacquered substrate. The doctoring technique is applied prior to deposition of the lacquer in order to ensure uniform deposition of the lacquer. The lacquered substrate stacked with other layers travels through a controlled heating tunnel with a predetermined passage length (which can be in the range of 5 meters to 10 meters) where it is dried. In accordance with an exemplary embodiment, the pressure that is applied on to the lacquered substrate stacked with other layers can be in the range of 5 kg to 8 kg. The temperature of the nip roller can be in the range of 65?C to 75?C and the oven temperature can be in the range of 140?C to 180?C.
Typically, an adhesive can be used between the layers to achieve adhesion there between. The adhesive that can be used includes, but is not limited to, acrylic based adhesive. Typically, the acrylic adhesive can be at least one selected from pure acrylic adhesive, and ester acrylic adhesive. Other adhesives are also envisaged to be within the scope of the present disclosure.
Typically, in accordance with the present disclosure, the blister cups or cavities can be formed by the known cold forming process, wherein a die is used to stamp the multilayer laminate of the present disclosure to obtain a multilayer laminate with one or more blister cups formed thereon. The product can be placed in the blister cups and the open end of the blister cups can be typically sealed with the base.
In accordance with the present disclosure, high density polymer ethylene (HDPE) modified polymer is obtained by blown film process. A polymer melt of high density polymer ethylene (HDPE) and the additives is extruded through an annular slit die, usually vertical to form a thin wall tube. Air is introduced through a hole in the centre of the die to blow up the tube like balloon. A high speed air ring mounted on top of the die blows onto the hot film to cool down. Further, the tube of film continues an upward movement along with continuous cooling until the film passes through nip rolls where the tube is flattened to create “lay-flat” tube of film.
Typically, the expansion ratio between the die and blown tube of the film is in the range of 1.5 to 4 times the diameter of the die.
The multilayer laminate of the present disclosure can be used to make blister packs that can be employed for packing food products and pharmaceutical products.
The multilayer laminate of the present disclosure provides barrier against moisture, light and gas, which enhances the overall the shelf life of the product that is packaged.
The reduction in angle ? is possible because of the enhanced stretchability of the modified high density polyethylene molecules in conjunction with aluminum. This results in reduction of the blister pack volume by 10 to 25% as compared to the conventional multilayer laminate. Further, the reduction in volume leads to reduction in the amount of multilayer laminate required for fabricating the blister pack.
The foregoing description of the embodiments has been provided for purposes of illustration and 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.
Example 1:
A three layer laminate was prepared having a first layer of 25 micron nylon, a second layer of 45 micron aluminum and a third layer 40 micron regular HDPE.
Example 2:
A three layered laminate was prepared as per example 1 except a modified HDPE and metallized nylon were used.
Example 3:
A three layered laminate was prepared as per example 1 except a regular combination of LDPE and LLDPE along with metallized nylon or nylon/adhesive/primer/aluminum/adhesive/LLDPE+LDPE was used.
Example 4:
A three layered laminate was prepared as per example 3 except a modified combination of LDPE and LLDPE along with metallized nylon or nylon/adhesive/primer/aluminum/adhesive/modified combination of LDPE and LLDPE.
Example 5:
A conventional three layered laminate was prepared having a first layer of 25 micron of nylon, a second layer of 45 micron of aluminum and a third layer of 60 micron of polyvinyl chloride.
The mechanical properties of the film obtained in examples 1-3, 4 and 5 can be seen in table 1 and table 2 respectively.
Table 1.
Properties Unit Example 1 Example 2 Example 3
Nylon/Aluminum/HDPE
(25/45/40) micron Metallized Nylon/Aluminum/ Modified HDPE
(25/45/40) micron Nylon/adhesive/primer/aluminum/adhesive/LLDPE+LDPE
(25/5/1/45/3/50) micron
Tensile strength
Longitudinal Kg/cm2 578.52 637.71 540.25
Transverse 539.85 623.59 525.23

Elongation
Longitudinal % 16.41 15.81 17.45
Transverse 12.53 15.45 15.16
Table 2.
Properties Unit Example 4 Example 5
Metallized nylon or nylon/adhesive/primer/aluminum/adhesive/modified combination of LDPE and LLDPE
(25/5/1/45/3/50) micron Nylon/Aluminum/PVC
(25/45/60) micron
Tensile strength
Longitudinal Kg/cm2 657.1 528
Transverse 530.78 615

Elongation
Longitudinal % 23.87 31.52
Transverse 17.28 38.74

It can be observed from table 1 and table 2 that the compact blister pack formed in example 2 and example 4 shows much better tensile strength than the conventional blister pack as obtained in example 5.
Example 6:
The comparison of compact blister pack obtained as per the examples 2 and 4 of the present application with the conventional blister pack in terms of the area can be seen in table 3 below.
Table 3
Pack Length Width Dosages/pack Area (mm2)
Conventional blister pack “0” size capsule 140 83 10 1162
Compact blister pack “0” size capsule 71 105 10 745.50
It can be observed from table 3, that a compact blister pack of the present invention shows area reduction of 35.84%.
Further, the strip pack (comprising the blister pack) of the present disclosure is compared with the commercially available strip packs in table 4 below:
Table 4
Brand L w dosages/pack Area (mm²) % saving
Zyntac 150 171 129 30 735.30
Compact Blister 108 75 30 270.00 63
Omez 10 122 138 15 1,122.40
Compact Blister 86 82 15 470.13 58
Augmentin Duo 100 176 10 1760.00
Compact Blister 104 61 10 634.40 64
• L – length of the strip
• w – width of the strip
• Area – area of the strip
• Compact blister made in accordance with the present disclosure
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a compact blister pack fabricated, wherein the blister pack has reduced volume and the amount of multilayer laminate required for making the blister pack is less.
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 disclosure to achieve one or more of the desired objects or results. While certain embodiments of the disclosure have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. Variations or modifications to the formulation of this disclosure, 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 disclosure.
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 disclosure 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. A compact blister pack comprising
a. blister shaped cups made of a multilayer laminate having:
? an inner layer comprising a first polymer;
? an intermediate layer comprising a metal foil;
? an outer layer comprising a second polymer; and
b. a base.
2. The compact blister pack as claimed in claim 1, wherein said blister shaped cup being defined by
a first side wall having a first edge and a second edge, said first side wall extending in an operative upward direction from said base and slanted at an angle ? with respect to a normal to said base;
a flat wall extending from said second edge of said first side wall;
a second side wall extending from a second edge of said flat wall in an operative downward direction abutting said base and slanted at an angle ? with respect to a normal to said base;
a third side wall extending from a first lateral edge of said flat wall in an operative downward direction abutting said base and slanted at an angle ? with respect to a normal to said base; and
a fourth side wall extending from a second lateral edge of said flat wall in an operative downward direction abutting said base and slanted at an angle ? with respect to a normal to said base.
3. The compact blister pack as claimed in claim 2, wherein said angle ? is in the range of 15° to 25°.
4. The compact blister pack as claimed in claim 1, wherein said first polymer is at least one of polyethylene polymer and polypropylene polymer.
5. The compact blister pack as claimed in claim 4, wherein said polyethylene is selected form high density polyethylene (HDPE), low density polyethylene (LDPE) and liner low density polyethylene (LLDPE) or combination thereof.
6. The compact blister pack as claimed in claim 5, wherein said high density polyethylene (HDPE) is modified by adding linear block copolymer based on styrene and butadiene with bound styrene of 29.5% mass.
7. The compact blister pack as claimed in claim 5, wherein said liner low density polyethylene (LLDPE) and linear density polyethylene (LDPE) is modified by using linear triblock copolymer based on styrene and ethylene or butylene with polystyrene content of 13%.
8. The compact blister pack as claimed in claim 1, wherein said metal foil is aluminum foil.
9. The compact blister pack as claimed in claim 1, wherein said second polymer is an oriented polyamide polymer.
10. The compact blister pack as claimed in claim 1, wherein said outer layer is metallized on an operative outer surface thereof.
11. The compact blister pack as claimed in claim 10, wherein said metal used for metallization is aluminum.
12. The compact blister pack as claimed in claim 1, wherein said layers are adhered to each other using an adhesive.
13. The compact blister pack as claimed in claim 12, wherein said adhesive is acrylic based adhesive.
14. The compact blister pack as claimed in claim 12, wherein said acrylic based adhesive is selected from the group consisting of pure acrylic adhesive, and ester acrylic adhesive.
15. A compact blister pack comprising
a. blister shaped cups made of a multilayer laminate having:
? an inner layer comprising a first polymer; wherein said first polymer is at least one of polyethylene polymer and polypropylene polymer and wherein said polyethylene is selected high density polyethylene (HDPE) modified by adding linear block copolymer based on styrene and butadiene with bound styrene of 29.5% mass or linear low density polyethylene (LLDPE) and linear density polyethylene (LDPE) modified by adding linear triblock copolymer based on styrene and ethylene or butylene with polystyrene content of 13%;
? an intermediate layer comprising a metal foil wherein said metal foil is aluminum foil;
? an outer layer comprising a second polymer, said second polymer is an oriented polyamide polymer, wherein said outer layer is metallized on an operative outer surface thereof; and
b. a base.