WO1984000705A1

WO1984000705A1 - Composite package and solventless assembly thereof

Info

Publication number: WO1984000705A1
Application number: PCT/US1983/001085
Authority: WO
Inventors: Leonard Alan White
Original assignee: Baxter Travenol Lab
Priority date: 1982-08-09
Filing date: 1983-07-15
Publication date: 1984-03-01
Also published as: EP0115517A1

Abstract

Composite package (44), method and apparatus for assembling and using said package. There are commercially available receptacles for packaging an article within a semi-rigid container conforming closely to the shape and size of the article. These containers comprise a container member or bubble with a closure member or lid attached by means of a bonding agent. Typically, the bonding agent is applied by conventional means over substantially the entire surface of at least one side of the closure member. This results in inefficient use of the bonding agent and may prevent the usage of said package in sensitive areas such as packaging of medical related items. The present invention applies a bonding agent (32) to only the portion (24) of the closure (21) that will actually be sealed. This is accomplished by depositing finely divided, electrostatically chargeable bonding agent particles (32) onto the closure member (21), after which said member is juxtaposed with respect to the container member (25) such that the bonding particles (32) overlie the assembly lip (39), after which the bonding agent is heated to thereby adhere both members (21, 25) together.

Description

Composite Package and Solventless Assembly Thereof

This invention generally relates to a package including preassembly members adhered to each other by solventless bonding agent particles, and to an improved assembly method and apparatus therefor. More particularly, the invention provides bonding agent particles that are electrostatically deposited onto a preassembly member or onto a web of preassembly members. Thereafter, each preassembly member is positioned such that bonding agent particles are generally aligned along a lip that is on the face of a preassembly member, and complementary preassembly members are juxtaposed with respect to each other, after which electrostatically deposited bonding agent particles are heated along a seal pattern generally conforming to said lip in order to adhere the complementary preassembly members together.

Among the many packaging systems in wide use today are so-called blister packs for packaging an article within a semi-rigid container that can conform rather closely to the shape and size of the article being packaged. Typically, these types of packages are manufactured on machinery that forms the preassembly package members, fills the article being packaged therewithin, and seals the package members together. The container member or bubble preassembly member may be formed of a molded or thermoformed resin or polymer that can be generally transparent, while the closure member or lid portion may be made of paper or other cellulosic material, of the so-called synthetic paper, of thermoplastic films, or of other web stock. Typically, the container member for these types of packages has an opening through which the article being packaged is passed when the article is placed into the container member.

OMPI St The closure member for such packages has a relatively flat surface that interfaces with the container member such that, when the two are combined, the closure member overlies a lip of the container member opening, and the closure member is then sealed to the lip.

Often, the closure member and the container member are adhered to each other by means of an adhesive or glue bonding agent. In the usual commercial application, such bonding agents are applied to the closure member or the web of lid stock in conjunction with a suitable carrier, whereby the bonding agent is applied as a solution, an emulsion or a suspension. It is a common practice that such carrier-based bonding agents are applied by the manufacturer of the lid stock or by an intermediate converter, such application being by a roller, doctor knife, air blade, brush or the like to one side of the web stock. The packager purchases a supply of such lid stock having an adhesive coating throughout substantially the entire surface of at least one side of the lid stock. Although this practice results in an inefficient use of the bonding agent composition, it is in wide use because of the difficulty and expense that is involved in attempting to apply a carrier-based bonding agent to only that portion of the lid stock surface that will actually be sealed to the lip portion of the container member.

An additional negative aspect of this practice of coating the entire lid stock surface rather than only those portions that are needed to affix the lid to the container is encountered when the package that is formed, filled and sealed is subsequently subjected to bacteria-controlling conditions. For example, many medical implements, articles, devices or other products utilized in the medical industry must be packaged in a sterile or an aseptic environment so that they will be ready for immediate use when the doctor, nurse or medical technician removes the article or product from the package. Usually, this objective is achieved by placing the article (often previously sterilized) within the container member or bubble, sealing the lid stock over the opening through which the article was passed, and then subjecting the entire package to bacteria-controlling conditions usually in association with sealing the article- containing package within a gas barrier pouch.

Such bacteria-controlling procedures typically include treatment either with a gas which must pass through a breathable lid stock or with radiation that passes through the sealed package in order to treat the interior of the sealed composite package. When a gas treatment is used, the porosity or breathability needed for accomplishing this procecure is impaired when the carrier-based bonding agent is coated on substantially the entire surface of the lid stock. This decreased porosity requires a longer and harsher bacteria-controlling or sterilization procedure than that required for passage through the same lid stock that is not so coated, thereby increasing treatment costs and developing additional stresses on the package seals during treatment. When radiation sterilization is carried out, the coating on the lid member of the carrier-based bonding agent will be subjected to radiation which will alter the coating and possibly thwart the bacteria- controlling objective. These disadvantages and difficulties are overcome by the present invention which eliminates the need to coat the entire surface of the lid stock with a bonding agent that is laid down by a solvent or an emulsion system, such being accomplished through the utilization of electrostatic deposition techniques that avoid the use of liquid carriers and that permit an inexpensive and accurate means for depositing a bonding agent in a seal pattern which, when desired, can be of virtually any configuration that is suitable to provide a precise seal pattern by which container preassembly members are bound together by such bonding agent particles. The package according to this

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^ R^XO invention is one by which the preassembly members, preferably including a lid or closure member and a container member or bubble, are sealed together by means of solventless bonding agent finely divided particles that are electrostatically deposited, usually onto the closure or lid member, and said bonding agent particles adhere the preassembly members together along a seal pattern that conforms to the shape of a lip of one of said preassembly members. The apparatus electrostatically deposits bonding agent particles onto a web of preassembly members, the apparatus further including a sealing station having an assembly for activating the electrostatically deposited bonding agent particles to form a seal pattern that generally conforms to the shape and size of a lip of a preassembly member.

Accordingly, a general object of the present invention is to provide an improved package.

Another object of this invention is to provide an improved method and apparatus for adhering together components of dissimilar material for packaging applications. Another object of the present invention is to provide an improved method, apparatus and product utilizing electrostatic deposition techniques to form a precise sealing pattern. Another object of this invention is to provide an improved product and an improved apparatus and method for making same which does not substantially alter the physical properties of the components being sealed together, except at the sealing locations. Another object of this invention is to provide an improved method and product which avoids the use of solvents for adhering one member to another during a form/ fill/seal operation.

Another object of the present invention is to utilize electrostatic techniques for adhering a lid to a container bubble member.

^^NATlO Another object of the present invention is an improved package closing method that includes applying label copy or other indicia to one or both sides of the lid stock as part of the operation by which the bonding agent is applied to the lid stock.

These and other objects of the present invention will become apparent from the following detailed description and drawings, wherein:

Figure 1 is a schematic view illustrating the method of this invention and an apparatus for carrying out the method;

Figure 2 is a plan view along the line 2-2 of Figure 1 illustrating a closure member web having a plurality of seal patterns thereon; Figure 3 is a detailed sectional view of the sealing means and procedure included in Figure 1;

Figure 4 is a plan view of a sealed package according to this invention; and

Figure 5 is an end view of the package illustrated in Figure 4.

By the present invention, illustrated generally in Figure 1, a preassembly member or continuous web of pre¬ assembly members 21 as illustrated are brought into contact with an endless surface 22 having an electrostatic charge pattern thereon. Typically with the assistance of a charged transfer'platten 23, the electrostatic charge pattern on the endless surface 22 is transferred to each preassembly member 21 in order to form seal patterns of bonding agent particles, which may take any desired form, such as the seal patterns 24 illustrated in Figure 2. Thereafter, each preassembly member 21 having the seal pattern is combined with another preassembly member, typically a container member 25, and the two preassembly members are adhered to each other by applying energy to the bonding agent particles.

With more particular reference to Figure 1, the apparatus illustrated therein includes two basic units. one being an electrostatic deposition unit 26, and the other being a package assembly and sealing unit 27, which can be a form/fill/seal device. The electrostatic deposition unit 26 supplies preassembly members 21, which typically are closure members 21a, to the packaging assembly and sealing unit 27, and both of the units 26 and 27 can be of substantially conventional construction. Major structural and functional details of a typical electrostatic deposition unit 26 include the endless surface 22 which has a photoconductive material on its outside aurf ce, a lens system 28 in association with a light system 29 for developing an electrostatic charge pattern on the endless surface 22, which pattern is of a configuration determined by the original pattern 31 that passes through the lens system 28, wherein the light energy supplied by the light system 29 selectively alters the electrostatic charge characteristics of the endless surface 22. A powder transfer station 32 deposits finely divided, heat-activatable bonding agent particles onto the endless surface 22 at the location of the selectively altered electrostatic charge pattern in order to form a substantially identically shaped pattern of particles on the endless surface 22. This pattern of particles is then transferred to each preassembly member 21, typically with the assistance of the charged transfer platten 23. Residual particles remaining after this transfer to closure member 21 are removed by a suitable removal means 33, such as a vacuum system, after which that portion of the endless surface 22 is ready for repetition of this cycle including selective charging, powder deposition, and transfer.

Depending upon certain particulars of the system according to this invention, such as whether the charged transfer platten 23 adequately adheres the particles to the preassembly member 21, and whether the preassembly member 21 having the seal patterns thereon must be stored

^ftNATl for any length of time and possibly rolled onto itself, there may be provided a heat source 34 for more thoroughly fusing the seal pattern to the preassembly member 21 before the preassembly member 21 is transferred to the package assembly and sealing unit 27.

The package assembly and sealing unit 27 illustrated in Figure 1 is of the type by which the preassembly container members 25 are thermoformed from a web 35 of moldable polymer, the molding thereof being accomplished at a molding station 36. Articles 37 being packaged in accordance with this invention are, when desired, inserted into each container member 25 at a location between the molding station 36 and a closure station 38 at which each preassembly member 21, typically a closure member 21a, is positioned in overlying relationship with respect to another preassembly member such as a container member 25. This overlying relationship is, with the assistance of certain timing and positioning means (not shown) , preferably accomplished such that each seal pattern of bonding agent particles is in alignment with a sealing lip 39 of the container member 25, which lip 39 is on that face of the container member 25 that includes an access opening or mouth 40. Next, the preassembly member 21a and a container member 25, and preferably while in web form as illustrated, move to a sealing station 41, which is shown in greater detail in Figure 3.

Sealing station 41 includes heat application means 42, such as a heated sealing bar or plate as illustrated which preferably includes elongated bosses 43 having a configuration generally complementary to that of the sealing lip 39 of the container member 25 to thereby concentrate the sealing energy at those areas to be sealed. By this procedure, the electrostatically deposited bonding agent particles along the seal pattern 24 are raised to a sealing temperature therefor that is at or above its softening point and below the softening point of the materials out of which the closure member 21a and the

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OMPI container member 25 are made. Typical sealing temperatures are usually not substantially lower than about 95°C and possibly as high as about 330°C if the seal time is rapid (on the order of a fraction of a second) and/or if the bonding agent is exceptionally responsive to heat activation.

At this point, the closure member 21a and the container member 25 are combined into a closed package 44 having the articles 37 sealed therewithin. (Figures 4 and 5) . When the closure members 21a and container members 25 are, as is preferred, processed through the package assembly and sealing unit 27 in web form, the webs are divided into a plurality of individual closed packages 44 by suitable severing means (not shown) . Should it be desired to form a partially sealed package into which an article may be filled at a later date, such can be accomplished by sealing less than the full extent of the seal pattern 24, in order to leave an opening large enough to insert an article 37 thereinto when desired.

When the closed packages 44 are to be treated for bacterial control, the closed packages 44 are transported to a suitable bacterial control station 45, whereat a suitable treatment source, such as gas or radiation, surrounds and enters the closed package 44, including passage through the sealed closure member 21a thereof, to thereby treat inner and outer surfaces of the closed package 44, as well as the surface of the article 37 therewithin. Maintenance of the bacterial-controlling treatment for extended periods of time can be enhanced by thereafter sealing the closed package 44 within an overpouch or other barrier means (not shown) .

As an optional feature of the present invention, the preassembly member 21 may also be imprinted with labeling information or the like on either side or on both sides thereof. Such can be at least partially accomplished by including the desired labeling information as part of the original pattern 31, which will provide simultaneously imprinted information on the preassembly member 21. Another unit similar to the electrostatic deposition unit 26 may be provided to accomplish additional imprinting, including labeling information, lot numbers and date codes, on the preassembly member 21 and/or for imprinting in multiple colors. Such optional additional electrostatic deposition unit may be utilized either before or after the preassembly member 21 passes through the electrostatic deposition unit 26.

The preassembly member 21 can be the closure member 21a, a web thereof, the web 35 of moldable polymer, or combinations thereof. Electrostatically applying the seal pattern of this invention to the web 35 expands the types of materials out of which the container member 25 can be made when compared to conventional methods which utilize carrier-based bonding agents. The ability of a particular container member 25 to be bonded to a particular closure member 21a can be sometimes limited for a variety of reasons, such as wide discrepancies in melt temperatures, that make it extremely difficult to bond such materials together. These reasons are eliminated to a significant extent by the electrostatic application aspects of this invention. Concerning the electrostatic deposition unit, the electrostatic charging and discharging thereof can be arranged such that the pattern is made on the endless surface 22 by a system that either charges or discharges the endless surface 22 by application of actinic energy from the light system 29. The electrostatic charge pattern on the endless surface 22 can be formed by first electro¬ statically charging the endless surface 22 and then selectively discharging same to form the electrostatic charge pattern. Alternatively, the endless surface can be selectively electrostatically charged to form the electrostatic charge pattern. Whatever the means by which the electrostatic charge pattern is formed, bonding agent particles provided at the powder transfer station 22 are electrostatically treated so that they adhere to the electrostatic charge pattern. By this electrostatic procedure, the activatable bonding agent particles and the electrostatic charge pattern on the endless surface

22 are of opposite polarity or one of them is substantially uncharged while the other holds a high voltage charge.

The bonding agent particles are finely divided particles that are typically dielectric in nature and that exhibit bonding properties when activated, such as by heating, to a state at which the activated bonding agent particles adhere the preassembly members together. The particular bonding agent chosen should have a softening temperature equal to or less than the softening point of the closure member 21a or of the container member 25, whichever has the lower softening point. Typically, these bonding agents are thermoplastic polymers or resins, although certain thermosetting materials also can be utilized, these bonding agents typically possessing dielectric properties to the extent that they are not totally conductive and can hold a charge. The specific bonding agent particles can be chosen so as to be tailored for the particular closure member and container member being adhered together. They include bonding agent particles that cannot be applied by carrier systems or that can be applied only by carrier systems that are not water-based but include substantial quantities of organic solvents. When the closed package is to be of the peel pouch variety, the bonding agent particles are selected so as to provide a releasable seal between the material of the closure member and the material of the container member. Representative heat-activatable powders include copolymers of polyethylene and ethylene vinyl acetate, of polyethylene and methyl methacrylate, of polyethylene and ethylene acetate, as well as other olefins that are modified to enhance their hot tack properties. Container members 25 and the web of moldable polymer 35 are of a material that has thermoplastic properties, including substantially.any thermoformable material. Representative materials include polystyrene, polyethylene and polyvinyl chloride. Closure members 21a, when the porosity thereof is not significant, may be made of these same types of thermoplastic materials; in addition, the closure members 21a may be made of other less-rigid polymers, including flexible polyolefin copolymers and acrylonitriles. If it is desired to provide a porous closure member 21a, then cellulosic materials and synthetic breathable materials such as so-called synthetic paper may be used.

This invention can be embodied in various forms, and therefore is to be construed and limited only by the scope of the appended claims.

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Claims

1. A solventless method for assembling preassembly members of composite packages, comprising: electrostatically depositing finely divided, electrostatically chargeable bonding agent particles in an electrostatic charge pattern on an endless surface, said bonding agent particles being activatable to a state at which the activated bonding agent particles adhere composite package preassembly members together; contacting said endless surface with one preassembly member of a composite package in order to transfer said electrostatic charge pattern to the one preassembly member for electrostatically depositing bonding agent particles in said electrostatic charge pattern on the one preassembly member; said step of depositing the bonding agent particles on the one preassembly member including sizing the electrostatic charge pattern so as to accommodate a preassembly member lip, said lip defining a seal pattern on the face of the preassembly member; juxtaposing the one preassembly member relative to another preassembly member, after which juxtaposing step the bonding agent particles of said one preassembly member overlie ^"said seal pattern; and activating the electrostatically deposited particles of said one preassembly member to thereby adhere one of said preassembly members to said lip along said seal pattern in order to form a composite package.

2. The assembly method of claim 1, wherein said step of sizing the charge pattern shapes and sizes the charge pattern to overlie said lip without appreciably over¬ lying an access opening on said preassembly member face having said lip.

3. The assembly method of claim 1, wherein said bonding particles of the preassembly member are heated prior to said juxtaposing step in order to heat-set the particles onto the preassembly member.

4. The assembly method of claim 1, wherein said electro¬ static charge pattern on the endless surface is formed by electrostatically charging the endless surface and then selectively discharging same to form said electro- static charge pattern.

5. The assembly method of claim 1, wherein said electro¬ static charge pattern on the endless surface is formed by electrostatically charging the endless surface to form said electrostatic charge pattern.

6. The assembly method of claim 1, wherein said activatable bonding agent particles are electrostatically charged prior to said electrostatic depositing step.

7. The assembly method of claim 1, wherein said activatable bonding agent particles are deposited onto said endless surface having the electrostatic charge pattern thereon prior to said transfer of the electrostatic charge pattern to the preassembly member.

8. The assembly method of claim 1, wherein said one preassembly member is a closure member and said another preassembly member is a container member, and wherein said juxtaposing step includes positioning the bonding agent particles of the closure member into substantial alignment with said lip of the container member.

9. The assembly method of claim 1, wherein said one preassembly member is a container member and said another preassembly member is a closure member.

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10. The assembly method of claim 1, further including providing a plurality of said one preassembly members as a continuous web of preassembly members, and providing a plurality of said another preassembly members as a continuous web.

11. The assembly method of claim 1, further including treating the composite package for bacterial control.

12. The assembly method of claim 1, further including electrostatically imprinting indicia onto said one preassembly member.

13. The assembly method of claim 1, further including electrostatically imprinting indicia onto said one preassembly member simultaneously with said step of electrostatically depositing bonding agent particles on the one preassembly member.

14. The assembly method of claim 1, further including selecting said bonding agent particles to have a softening temperature lower than that of either of said preassembly members.

15. An improved composite package made according to the solventless method of claim 1.

16. In a package having preassembly members that are adhered to each other by means of a bonding agent, at least one of the preassembly members including a face having a lip, and said bonding agent being activatable after it is applied to a preassembly member in order to adhere the preassembly members together, wherein the improvement comprises: said bonding agent is solventless, said bonding agent includes electro¬ statically chargeable, finely divided particles that are activatable to a state at which the activated bonding agent particles adhere composite package preassembly members together, said finely divided bonding agent particles are electrostatically deposited to one of the preassembly members, and said finely divided particles adhere the preassembly members together along a seal pattern that conforms substantially to the shape of the lip of said preassembly member.

17. The improved package of claim 16, wherein said preassembly member having said lip on a face thereof further includes an access opening on said face.

18. The improved package of claim 16, wherein said preassembly member having said lip on a face thereof further includes an access opening of said face, and wherein said seal pattern of electrostatically deposited bonding agent particles overlies said lip without appreciably overlying said access opening.

19. The improved package of claim 16, wherein said bonding agent has a softening temperature lower than that of both said preassembly members.

20. The improved package of claim 16, wherein one of said preassembly members is a container member made of a thermoformable polymer.

21. The improved package of claim 16, wherein one of said preassembly members is a closure member made of a material selected from the group consisting of cellulosic materials, synthetic porous materials, thermoformable polymers, flexible polymers, and semi-rigid polymers.

22. The improved package of claim 16, wherein the composite package is treated for bacterial control.

23. The improved package of claim 16, wherein said pre¬ assembly members are initially integrally joined to each other.

24. In an apparatus for forming, filling and sealing composite packages, the apparatus including a station for providing webs of feedstock to form preassembly members of composite packages, one of said preassembly members including a face having a lip; a closure station at which one of said webs of preassembly members is positioned in overlying relationship with another of said webs of preassembly members; and a sealing station for adhering respective preassembly members together by means of a bonding agent, the improvement comprising: said apparatus further including electrostatic deposition means for electrostatically depositing electrostatically chargeable finely divided, bonding agent particles onto one of said webs, said bonding agent particles being activatable to adhere the pre- assembly members together, and said sealing station includes means for activating deposited bonding agent particles to form a seal pattern that generally conforms to the shape and size of the preassembly member lip.

25. The improved apparatus of claim 24, wherein said electro¬ static deposition means electrostatically deposits the seal pattern on said preassembly member web, and wherein said closure station aligns said seal pattern with said lip of the preassembly member.

26. The improved apparatus of claim 24, wherein said apparatus includes an article filling station for inserting articles between the preassembly member^'s, said article filling station being upstream of said sealing station.

27. The improved apparatus of claim 24, wherein said station for providing webs of feedstock includes means for providing an access opening on said preassembly member face having said lip, and wherein electrostatic deposition means deposits the bonding agent particles in a seal pattern that is sized and shaped to overlie said lip without appreciably overlying said access opening.

28. The improved apparatus of claim 24, wherein said apparatus includes a bacterial controlling station downstream of said sealing station.

29. The improved apparatus of claim 24, wherein said electrostatic deposition means electrostatically imprints indicia simultaneously with said electrostatic deposition of the bonding agent particles that adhere the preassembly members together.

30. The improved apparatus of claim 24, wherein said station for providing webs of feedstock includes means for thermofor ing at least one of said webs into a plurality of container members having an access opening on said preassembly member face having said lip.

31. The improved apparatus of claim 24, wherein said bonding agent particles are dielectric.

32. The improved apparatus of claim 24, wherein one of said preassembly members is a shaped container member, and another of said preassembly members is a substantially flat closure member.