Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B1/00—Layered products having a non-planar shape
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/20—Layered products comprising a layer of metal comprising aluminium or copper
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B27/10—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of paper or cardboard
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
  • B32B27/20—Layered products comprising a layer of synthetic resin characterised by the use of special additives using fillers, pigments, thixotroping agents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
  • B32B27/306—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising vinyl acetate or vinyl alcohol (co)polymers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2435/00—Closures, end caps, stoppers
  • B32B2435/02—Closures, end caps, stoppers for containers
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
  • Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]

Definitions

• the present invention relates to a lidstock material suitable for making lids to be sealed over plastic containers such as pharmaceutical blisters.
• Background of the Invention [0002] Many products are placed in containers covered by a lidstock material and such products can range from yogurt to disposable contact lenses. Such lidstocks must be sealable to a very wide class of materials, peelable and resistant to both hot and cold temperatures.
• Many pharmaceuticals and disposable contact lenses are packaged in blister packages consisting of 2 pieces: a base and a lid.
• the base is an injection molded plastic shaped to include a bowl-shaped or rectangular recess for receiving the contents.
• each blister pack generally contains a contact lens and enough solution to prevent drying and to maintain the contact lens ready for use.
• the lid covering the base is heat sealed over the recess containing the contents of the blister package.
• the lid must be easily peelable from the base in order to provide easy access without spilling the contents.
• the lid must be seal compatible with a wide variety of materials.
• Martinez U.S. 4,691,820 suggests a polypropylene base and cover of polypropylene film/aluminum foil laminate.
• Yamada in U.S. 5,061,532 suggests a thermoplastic rim and a lid made of the same material as the rim.
• Stevenson in U.S. 5,626,929 suggests a lidstock material containing a mixture of butene-1 and ethyl ene copolymer, an ethyl ene homopolymer or copolymer, an inorganic filler and optionally a propylene homopolymer or copolymer laminated to a metal or polymer substrate.
• the prior art lidstock materials generally suffer from one or more serious disadvantages making them less than entirely suitable for their intended purpose, including compatibility with an extensive class of substrate or blister package sealing lids, for example compatibility with polystyrene (“PS”), polypropylene (“PP”), polyethylene (“PE”) and with all three of polyvinyl chloride (“PVC”), polyethylene terephthalate (“PET”), and polyvinylidene chloride (“PVDC”).
• PS polystyrene
• PP polypropylene
• PE polyethylene
• PVDC polyvinylidene chloride
• polyester resins appear to be further described in U.S. Patent Specification Nos. 5,292,783; 5,446,079; and 6,342,304B1 (all Buchanan et al.) for possible use as fibers, molded objects and films.
• Mueller in U.S. Patent Specification No. 6,503, 549B1, teaches polyethylene terephthalate (PET) tray typed packages with lidding films directly sealable to the tray where the films include glycol-modified polyethylene terephthalate sealant layers.
• a principal objective of the present invention is to provide a lidstock material for lids having excellent burst strength, good cohesive peel properties, acceptable heat resistance and excellent compatibility with all of PVC, PET and PVDC, as well as with PS, PP and PE. [0009] Additional objectives and advantages of the present invention will become apparent from the following detailed description of some preferred embodiments.
• a peelable and heat sealable material suitable bonding to a wide variety of substrates comprising a solid substrate joined to a film comprising aliphatic-aromatic copolyester, parti culate inorganic filler, butene-1 polymer, and ethylene- vinyl acetate copolymer.
• the invention also consists essentially of and consists of such components.
• the copolyester can include a biodegradable component.
• the particle size of the filler is very important and ranges from 0.5 micrometer (micron) to 10.0 micrometer.
• the film contains from about 25 wt. % to about 50 wt.
• the substrate can be, for example, metal foil, plastic or paper but the preferred substrate is aluminum foil.
• the preferred range is from about 10 wt. % to about 30 wt. % of butene-1 polymer and about 10 wt. % to about 30 wt. % ethylene- vinyl acetate copolymer.
• composition/substrate provides excellent bonding sealing and cohesive peeling to all of PVC, PET and PVDC as well as more easily bondable packaging such as PS, PP and PE.
• Plastic and metal substrates are easily bonded to films of this material. These materials are particularly useful as a "peelable” “heat sealable” “lidstock material” for containers.
• the term “lidstock material” refers to a metal, polymer, or paper substrate laminated with a heat seal layer or film. Lidstock material of the present invention is made into container lids by cutting the material into desired shapes such as circles or rectangles.
• the term “heat sealable” refers to the ability to form a bond between a plastic container and its lid when heat and pressure are applied locally for a sufficient time. The bond is gas-tight and preferably has sufficient burst strength to resist separation of the lid from the container body, even when the sealed container is retorted at an elevated temperature.
• the term “peelable” refers to the ability of a sealed lid to separate and to release from sealed engagement with a container body while both the lid and the body substantially retain their integrity. Such separation and release are achieved by manually applying a separating force to an outer edge portion of the lid.
• the lidstock material of the invention preferably a substrate laminated with a film comprising a polymer mixture of this invention.
• the substrate can be an aluminum foil having a thickness of about 0.25 mil to 3.0 mils (0.00025 inch to 0.003 inch (6.35 to 76.2 micrometers)).
• Aluminum foil provides an excellent barrier against penetration of gases and moisture. Aluminum foil also protects the package contents from ultraviolet light and has an aesthetically pleasing appearance.
• a particularly preferred aluminum foil substrate has a thickness of about 2 mils (0.002 inch-50.8 micrometers).
• the substrate is preferably coated with a print primer.
• the print primer facilitates application of printed labeling on the substrate.
• a particularly preferred print primer has a coating weight of about 0.4 to 0.9 pound per 3000 square feet (0.6-1.4 g./sq meter).
• the peelable and heat sealable film has a total weight of about 17 lb per 3000 square feet (27 g/sq meter).
• the filler enhances peelablity of the coating by assisting the seal failure upon peeling from adhesive failure at the container-coating layer interface to cohesive failure in the coating layer itself.
• the filler preferably is selected from at least one of talc, silica or alumina and comprises at least about 15 wt. % of the coating, preferably about 15 wt. % to 30 wt. %, more preferably about 20 wt. % to 30 wt. %.
• the filler is preferably a powder having an average particle size of about 0.5-10 micrometers (microns). Talc having an average particle size of about 12 0.5 to 10 micrometers is particularly preferred.
• the talc or other filler is preferably provided with a surface coating comprising about 0.5 wt.
• a carboxylic acid surface coating is particularly preferred.
• the surface coating contributes to talc dispersion and adhesion within the polymer.
• the carboxylic acid in the surface coating may be a mono or dicarboxylic acid or a mixture of such acids.
• Some preferred acids include stearic acid and isostearic acid, which is a liquid mixture of mostly C 18 saturated fatty acids having the general formula C ⁇ 7 H 35 COOH. Other saturated C ⁇ o-C 2 n carboxylic acids or mixtures thereof may also be useful.
• a particularly preferred butene-1 polymer is sold by Basell Polyolefins under the Tradename "PB 1710 M' and has a density of 0.908; a melt flow rate of 1.0 min by ASTM D 1238; and a melting point of 241° F (116° C).
• Figure 1 is a top plan view of one embodiment of a container, here a blister pack, which might be made with the present invention
• Figure 2 is a side elevational view of the blister pack of Figure 1 with the lid partially peeled back
• Figure 3 is an enlarged fragmentary, cross-sectional view of the lid of the blister pack shown in Figure 2
• Figure 4 is a perspective view of a food container which might be made with the present invention.
• FIGS 1 and 2 there is shown one type of many varieties of containers that are useful with the lidstock material of this invention; a blister pack 10 made in accordance with the present invention, with a lid 12 partially peeled back to reveal its contents. While the present invention will be described with a blister pack this is in no way to be taken as limiting.
• the pack 10 comprises an injection molded plastic container body 14 heat sealed to the lid 12.
• the body 14 defines a bowl-shaped recess 16 having a diameter of about 2 cm. and a depth of about 0.5 cm.
• a flange 18 extending around the recess 16 includes a tapered curled lip 20 spaced apart from the recess 16.
• the recess 16 here houses a contact lens 22 and a saline solution 24.
• the recess 16 is circumscribed by a seal area 26 which is part of the flange 18.
• the lid 12 is preferably attached to the body 14 by heat sealing in the seal area 26. Other suitable means for attaching the lid 12 to the body 14 include induction sealing and sonic welding.
• the total interior volume defined by the recess 16 and the lid 12 is preferably less than 1 milliliter.
• the body 14 is preferably made from a plastic material which can be shaped by injection molding or thermoforming.
• the plastic material for the body is preferably polypropylene but may also be other plastic materials having similar properties, such as polyethylene, polyethylene- polypropylene mixtures, polyethylene-polypropylene copoiymers, polybutylene, polyesters (e.g. PET), polycarbonates, and other thermoplastics. Plastics having low vapor transmission rates are most preferred. Plastics such as PVC, PET and PVDC are also bondable with the lidstock material of this invention. [0025] Referring now to Figure 3, the lid 12 is made from lidstock material comprising substrate 30, preferably aluminum foil, having a polyurethane adhesive layer 31 joining a film 32 to the substrate 30. An exterior side of the substrate 30 displays graphic matter (not shown) printed over a print primer 33.
• the substrate 30 has a thickness of about 2 mils. (0.002 inch-50.8 micrometers).
• the print primer 33 has a weight of about 0.4 to 0.9 pounds per 3000 square feet.
• the film 32 has a thickness of about 25 micrometers (1 mil.), corresponding to a weight of about 17 pounds per 3000 square feet.
• the lid 12 includes only a single layer of the film 32.
• Figure 4 shows another type container that might use the lidstock material of this invention.
• the container 40 has a cavity 42 within the body for containing food such as prepared cake, frosting, pudding, yogurt, cream cheese, or apple sauce, juice, coffee and the like with a lip/flange 44 extending radially outward from the body 46 and a lid 12 made from lidstock material having the same configuration as Figure 3.
• the preferred blister pack 10 shown in Figures 1 to 3 has a lid 12 heat sealed to an injection molded polypropylene body 14.
• the film 32 on the lid 12 may have the compositions as follows:
• the copolyester is a mixture of aliphatic-aromatic copolyester and a biodegradable component selected from the group consisting of cellulose, cellulose monoacetate, starch and mixtures thereof making up from 0.5 wt. % to 10 wt. %, based on the weight of the copolyester.
• the preferred range of copolyester is from about 20 wt. % to 40 wt. %.
• the inorganic filler is selected from the group consisting of talc, silica, alumina, alumina trihydrate, and mixtures thereof.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Laminated Bodies (AREA)
• Packages (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Adhesives Or Adhesive Processes (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (3)

Families Citing this family (12)

Family Cites Families (16)

• 2004
  • 2004-06-10 US US10/866,541 patent/US20050276940A1/en not_active Abandoned
• 2005
  • 2005-06-09 WO PCT/US2005/020376 patent/WO2005123515A2/en not_active Ceased
  • 2005-06-09 EP EP05760433A patent/EP1753663A2/de not_active Withdrawn

Non-Patent Citations (1)

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