Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D83/00—Containers or packages with special means for dispensing contents
  • B65D83/14—Containers for dispensing liquid or semi-liquid contents by internal gaseous pressure, i.e. aerosol containers comprising propellant
  • B65D83/38—Details of the container body
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/04—Homopolymers or copolymers of ethene
  • C08L23/08—Copolymers of ethene
  • C08L23/0807—Copolymers of ethene with unsaturated hydrocarbons only containing four or more carbon atoms
  • C08L23/0815—Copolymers of ethene with unsaturated hydrocarbons only containing four or more carbon atoms with aliphatic 1-olefins containing one carbon-to-carbon double bond
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/04—Homopolymers or copolymers of ethene
  • C08L23/06—Polyethene

Definitions

• Aerosol dispensing containers have found widespread use in the packaging of fluid materials including a variety of both liquid and powdered particulate products. Such containers are provided with a valve-controlled discharge orifice and operate by the action of a volatile propellant which is confined within the container together with the product to be dispensed. Because the propellant has an appreciable vapor pressure at room temperature, the product in the closed container is maintained under superatmospheric pressure.
• a typical aerosol unit comprises a hollow cylindrical container which is tightly closed at one end and is provided with an opening at its opposite end for receiving a dispensing valve assembly.
• a closure commonly referred to as a mounting cup, serves as the closure for the container and as a support for the valve assembly.
• the mounting cup comprises a pedestal portion for mounting the valve unit, a panel portion extending from the pedestal portion, a skirt portion depending from the periphery of the panel, and an annular channel portion extending outwardly from the skirt.
• the channel is positioned over the bead surrounding the container opening and the lower portion of the skirt adjacent to the channel is flared or clinched outwardly against the underside of the bead.
• the cup is provided with a gasket in the channel, or predominantly in the channel, of the cup.
• the method of invention of the '525 and '948 patents comprises passing a tubular sleeve of gasket material onto a compressible mandrel; initially positioning and aligning the skirt of the mounting cup and the contiguous end of the mandrel such that the sleeve of gasket material may pass onto the skirt, said mandrel having fixed and moveable portions with respect to each ' other and to their movement toward and away from the mounting cup; urging the moveable portion of the gasket material bearing mandrel toward the mounting cup such that the gasket material passes onto the skirt of the cup; causing the moveable portion of the mandrel to retract to its initial position, cutting the sleeve at a point between the mounting cup and the mandrel to leave a band of gasket material; and subsequently, advancing the mounting cup to a station whereat the band of the gasket material is urged further onto the skirt of the mounting cup, whereby, the band of gasket material does not extend beyond the skirt of the mounting cup.
• the dip tube of the container is usually slightly longer than the height of the container to insure that its end is positioned at the bottom of the container.
• the dip tube is slightly bent. This can provide an upward force which can displace the mounting cup from the container bead, interfering with proper clinching.
• protrusions are created around the skirt of the mounting cup which are below the container bead when the mounting cup is in position. Such protrusions 14a are also shown in Figure 1.
• the force provided by the bent dip tube is generally insufficient to overcome the retaining force provided by the protrusions.
• the protrusions are formed by a tool placed around, the pedestal of the mounting cup, which forces out particular sections of the skirt of the cup.
• aerosol containers are typically filled by the undercap filling method. First, the product to be dispensed is deposited into the container. Then a mounting cup, including the valve and dip tube, is placed on the container such that the bead of the container is within the channel of the mounting cup. The filling head of an undercap filling machine then encompasses the top of the container, creating an airtight seal. Air is then evacuated from the container. The suction created during evacuation raises the mounting cup off of the container bead.
• Propellant is then forced into the container opening beneath the mounting cup and the mounting cup is repositioned and clinched to the container bead.
• suction during evacuation or the force of the propellant during filling can displace the gasket from its position within the channel of the mounting cup, preventing a proper seal on clinching.
• the gasket can be completely displaced by the propellant filling the container, forcing the gasket into the container. This is referred to as a "blown" gasket.
• LDPE low density polyethylene
• HDPE high density polyethylene
• a multi ⁇ layer gasket comprising a middle layer of a stiffer plastic material and inner and outer layers of softer plastic material adjacent both sides of the middle layer.
• the middle layer is preferably HDPE while the inner and outer layers are preferably LLDPE.
• the seal between the mounting cup and the aerosol container remains of great concern to both the valve assembly plants and the filling plants since it must be capable of being air tight for a period of years.
• the seal between the mounting cup and the aerosol container must be low in cost to enable aerosol products to be competitive with non-aerosol products in the consumer market.
• a plastic polymer having a flexural modulus, 1% secant, of at least about 70,000 psi as measured by ASTM method D 790 and a hardness no greater than about 60 Shore D as measured by ASTM method D 2240.
• a flexural modulus of at least about 90,000 psi and a hardness between about 53-56 is preferred.
• the gasket be a sleeve type gasket and the polymer be a thermoplastic.
• a gasket for sealing a channel of a mounting cup to a bead of a container comprises a mixture of a stiffer plastic material and a softer plastic material which mixture meets the flexural modulus and hardness limits described above.
• the gasket is preferably a sleeve type gasket and the plastic materials are thermoplastics.
• the gasket material comprises a mixture of high density polyethylene (“HDPE”) and linear low density polyethylene (“LLDPE”) .
• the * preferred HDPE is about 43% by weight of the gasket and the 5 preferred LLDPE is about 57% by weight of the gasket.
• a layer of thermal adhesive on the surface of the gasket material to be in contact with the mounting cup.
• a 10 gasketed mounting cup comprising a panel, a skirt integral with and depending from the periphery of the panel, the skirt being outwardly flared to form an annular channel for receiving a container bead that defines a container opening; and a gasket disposed partially within the channel of the 15 mounting cup and partially along the skirt of the mounting cup, wherein the gasket material is as described above.
• the gasket's 20 position on the mounting cup meet certain critical requirements.
• Figure 1 is a cross-sectional view of a gasketed mounting cup in accordance with the present invention.
• Figure la is a cross-sectional view of the channel of the gasketed mounting cup of Figure 1, clinched to a container bead;
• Figure 2 is a cross-sectional view of a portion of a gasket prior to its being advanced into the channel of a mounting cup; and Figure 3 is a cross-sectional view of a portion of the punch preferred for use in manufacturing the gasketed mounting cup of the present invention.
• Figure l shows a gasketed aerosol valve mounting cup of the present invention generally designated as 10 resting on a container bead 12 of an aerosol container (not shown) .
• Figure la shows the channel portion 20 of the gasketed mounting cup 10 clinched to the container bead 12.
• the mounting cup has a pedestal portion 14 which depends from the interior edge of a panel portion 16.
• a skirt 18 depends from the exterior edge of the panel portion 16 opposite the pedestal portion 14 and is concentric thereto. The top portion of the skirt 18 curves into an annular channel portion 20 which terminates in an edge portion 22.
• the channel portion 20, edge portion 22 and skirt 18 form an annular concave receptor for receiving the bead 12 of the aerosol container, as shown.
• the gasket 24 of the invention is positioned partially within the channel 20 of the mounting cup 10.
• the gasket 24 has a first portion 24a in contact with part of the channel portion 15 of the mounting cup 10.
• the gasket 24 also has a second portion 24b in contact with the skirt 14 of the mounting cup 10.
• dimples 26 which retain the gasket 24 and mounting cup 10 on the container bead prior to undercap filling. Such dimples are described in more detail in U.S.S.N. 07/814,370, filed on the same day as the present application and assigned to the same assignee. U.S. Serial No. 07/814,370 is incorporated by reference herein.
• the mounting cup 10 is preferably a standard mounting cup for use in a standard one inch opening of an aerosol container.
• the radius "r" of the bead 12 of the container is 0.06 inches.
• Optimum ranges for certain critical dimensions for the gasket's 24 position on the mounting cup 10 have been ascertained and are one aspect of the invention.
• the length "L-l" of the gasket as measured from the center of the channel 20 of the mounting cup to the end of the second portion 24b. is preferably at least 0.150 inches and is most preferably about 0.175 inches. L-l is shown in Figure 1.
• the gasket material 24 should be positioned far enough into the channel 20 of the mounting cup such that the diameter "d" of the gasket flare, as measured at the end of the first portion 24a of the gasket 24 through the center of the mounting cup 10, as shown in Figure 1, is preferably greater than about 1.100 inches. It is more preferably greater than about 1.180 inches. It is most preferably about 1.200 inches. Such a flare diameter places the end of the first portion 24a of the gasket 20 at approximately the 10 o'clock position within the annular convex receptor. Such placement of the gasket shows improved resistance to dislodgement from the channel 20 of the mounting cup 10.
• the length "L- 2" of the gasket material after being cut from the sleeve is the length "L- 2" of the gasket material after being cut from the sleeve
• the gasket 20 is preferably between about 0.013-0.016 inches thick. It is most preferably 0.014 inches thick.
• these dimensions can improve the performance of any gasket material on a standard mounting cup.
• the optimum dimensions and positioning of the gasket can improve sealing in non-sleeve type gaskets, applied by processes other than the preferred process described herein.
• the gasket material 24 of the invention is a plastic polymer having a flexural modulus, 1% secant, of at least about 70,.000 psi as measured by ASTM method D 790, and a hardness no greater than about 60 Shore D as measured by ASTM method D 2240.
• a material has a stiffness sufficient to maintain the gasket in position partially within the channel 20 of a mounting cup and is sufficiently soft to provide an adequate seal between the channel 20 of the mounting cup 10 and a container bead 12 when clinched.
• the flexural modulus is at least about 90,000 psi and the hardness is 56 or less, as measured above.
• the plastic is preferably a thermoplastic polymer.
• Sleeve gaskets are preferably positioned in accordance with the process described in the '525 and '948 patents, and U.S. Serial No. 07/814,370.
• Thermoplastics are preferred for use with sleeve gaskets because they soften when heated, easing placement within the channel of the mounting cup, and harden on cooling, retaining their shape conforming to the channel of the cup.
• Suitable thermoplastic materials include polyethylenes, polypropylenes, other polyolefinic compounds such as -12-
• ethylvinylacetate (EVA) copolymers, ethyl vinyl alcohol copolymers, polypropylene and ethylene copolymers, and polyethylene modified by elastomers such as rubber.
• EVA ethylvinylacetate
• polypropylene and ethylene copolymers polypropylene and ethylene copolymers
• polyethylene modified by elastomers such as rubber.
• polyurethanes, polyesters, ionomers, polycarbonates and some polyamides such as nylon 11 can be used.
• the particular plastic chosen needs to be chemically resistant to the product and propellant in the aerosol container and could, therefore, vary depending on the application.
• the plastic also needs to have sufficient resistance to environmental stress to withstand the pressure and compression forces endured by aerosol gaskets. Environmental stress crack resistance as measured by D 1693 of at least about 400 hours is preferred.
• the plastic needs to be resistant to cold flow as well.
• DEHD 1796 (“DEHD”) , a polyethylene available from Union Carbide, will provide satisfactory performance.
• DEHD is a commodity material used by Union Carbide to form other plastics, such as DHDA 2463, also available from Union Carbide.
• Typical property data for DEHD follows:
• the gasket can also comprise a mixture of a first plastic material providing sufficient stiffness to maintain the gasket in position partially within the channel 20 of the mounting cup 10 and a softer plastic material providing sufficient softness to provide a reliable seal between the channel 20 of the mounting cup 10 and the container bead 12 when clinched such that the mixture has a flexural modulus, 1% secant, of at least about 70,000 psi, as measured by ASTM method D 790, and preferably at least about 90,000 psi.
• the mixture has a hardness no greater than about 60 Shore D, as measured by ASTM method D 2240, and is preferably 56 or less. Generally, the stiffer material will have higher density than the softer material.
• the polymers forming the mixture are preferably thermoplastics.
• the mixture should have sufficient resistance to environmental stress to withstand the pressure and compression forces endured by aerosol container gaskets. As above, environmental stress crack resistance of at least about 400 is preferred.
• the plastic must be resistant to cold flow, as well.
• Suitable stiffer materials include HDPE, other stiff polyethylenes such as LLDPE of suitable molecular weight, polyamides, polycarbonates, polypropylenes, polyesters, acrylonitrilebutadienstyrenes (“ABS”) , or acetyls.
• the flexural modulus of the stiffer materials is greater than
• Suitable softer materials include some polyethylenes and other polyolefins, ethylene-ethyl acrylate copolymer, polyesters, polyurethanes and most other thermoplastic elastomers.
• the hardness of the softer materials is less than 60 as measured as described above, and is preferably below 56. -15-
• the plastics chosen must be compatible in order to form a homogenous mixture.
• the materials chosen also need to be chemically resistant to the product and propellant and could therefore vary depending on the application. Suitable mixtures include HDPE and LLDPE or LDPE, or polyethylene and polypropylene.
• the relative quantity of the softer and stiffer plastic materials combined to form the mixture having the characteristics described above depends on their softness and stiffness. For example, if the soft material and stiff material are each close to the desired hardness and flexural modulus values, mixtures of between about 60% of one to 40% of the other may be utilized to yield mixtures having the characteristics of hardness and flexural modulus described above. If either or both of the hardness and flexural modulus values of either material are far from the desired values, larger quantities of one material may be required to yield the desired values in the mixture. For example, mixtures of between about 60%-70% of one to about 40%-30% of the other, about 70%-80% of one to about 30%-20% of the other or even greater than 80% of one and less than 20% of the other, may be utilized.
• the preferred stiffer material is HDPE having a flexural modulus of at least about 140,000 psi. A higher flexural modulus is even more preferred.
• the preferred HDPE is
• the LLDPE has a hardness no greater -16-
• the preferred LLDPE is DNDA-7340 Natural 7 (“DNDA-7340”) , available from Union Carbide.
• HDPE 38%-48% HDPE are preferred.
• a soft material such as LLDPE
• LLDPE low density polyethylene
• Fiberglass fiber, glass beads, talc, or calcium carbonate are suitable additives.
• Coupling agents may be required to bond the inorganic filters to the organic base material, as is known in the art.
• an adhesive is preferably used to further secure the gasket of the invention to the mounting cup.
• the gasket is of the sleeve type, applied in accordance with the process of the '525 and '948 patents, it is further preferred to use a thermal adhesive.
• the thermal adhesive prevents the gasket from prematurely bonding to the mounting cup, preventing its advancement into its final position partially within the channel 20 of the mounting cup
• the adhesive is a mixture of about 64.67%
• DNDA-7340 LLDPE and about 43% by weight of AltavenTM HDPE 6200B were added to a ID Banbury Mixer with a capacity of 30 pounds and mixed for about 2.5 minutes.
• a mixer is available from Farrel Machinery, for example.
• the mixing started at room temperature and reached 380- 400 ⁇ F by the end of the mixing period.
• the mixture was then conveyed to a Farrel 41 inch extruder, preheated to about 400-420°F.
• the mixture was discharged from the extruder at a rate of about 600 pounds per hour to a cooling trough and a Cumberland Strand Pelletizer, available from Cumberland, Inc.
• the pelletized mixture was later converted into a sleeve gasket by extrusion, as is known in the art.
• the sleeve gasket should be visually inspected to ensure that the gasket thickness is uniform. Thinned areas of the sleeve can interfere with the integrity of the seal, causing displacement of the gasket prior to clinching, or leaks.
• To form the preferred thermal adhesive about 64.67% by weight of ATX 325, about 35.67% by weight of DNDA-7340 LLDPE and 0.55% by weight of H. Kohnsta m PB 3962 blue colorant were added to the Banbury mixer and mixed for 2 minutes, up to 300-320°F.
• the mixture was then conveyed to an extruder and extruded at a rate of about 600 pounds per hour at between 300-320"F. It was then pelletized as above.
• the thermal adhesive and sleeve gasket were coextruded into a tool where the layers were merged, as is known in the art.
• the gasket material was approximately 0.014 inches thick while the layer of thermal adhesive, which is located on the inside surface of the sleeve gasket material, was approximately 0.00075 inches thick.
• The.sleeve gasket should be visually inspected to ensure that the thermal adhesive has been applied evenly.
• the gasket of the invention is preferably positioned on the mounting cup as generally described in the '525 and '948 patents.
• a single station gasket mounting cup assembly machine is utilized instead of the six station assembly machine shown in Figure 3 of the '948 patent. It has been found that the sleeve gasket material may be positioned on a single mounting cup faster and more accurately than if sleeve gasket material is concurrently positioned on six mounting cups. In addition, higher temperatures are currently used than those disclosed in these patents.
• a one piece punch 30 is preferred for advancing the gasket 24 into the channel 20 of the mounting cup.
• the punch preferably includes an extension 30a for engaging the end of the first portion 24a of the gasket 24 as it is being advanced into the channel 20 of the mounting cup 10 as shown in Figure 3.
• the extension 30a ensures that the gasket is advanced to its preferred position within the channel 20 of the cup, yielding the preferred gasket flare d, as shown in Figure 1.
• a shoulder 34 is provided to engage the top of the second portion 24b of the gasket 24 and to advance the gasket to its final position.
• the punch further includes a series of lugs 32 formed by pins 32a pressfit into the punch 30. These lugs form the dimples 26 shown in Figure 1 and described further in U.S. Serial No. 07/814,370. Further details concerning the process and preferred punch utilized in manufacturing the gasketed mounting cup of the present invention are described in U.S.S.N. 07/814,370.
• 12 gaskets are considered a representative test sample.
• the maximum pressure where none of the 12 test gaskets 5 failed (“PI") and the minimum pressure that caused all 12 to fail (“P2") were determined.
• a failure is a blown gasket.
• a higher PI indicates better resistance to blown gasket failure while a small difference between PI and P2 indicates consistent product performance.

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• Chemical & Material Sciences (AREA)
• Dispersion Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Containers And Packaging Bodies Having A Special Means To Remove Contents (AREA)
• Closures For Containers (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Citations (4)

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• 1992
  • 1992-12-07 ZA ZA929464A patent/ZA929464B/xx unknown
  • 1992-12-09 GB GB9225688A patent/GB2262742A/en not_active Withdrawn
  • 1992-12-14 MX MX9207246A patent/MX9207246A/es not_active Application Discontinuation
  • 1992-12-22 PT PT101150A patent/PT101150A/pt not_active Application Discontinuation
  • 1992-12-23 CA CA002130352A patent/CA2130352A1/en not_active Abandoned
  • 1992-12-23 AU AU34201/93A patent/AU3420193A/en not_active Abandoned
  • 1992-12-23 WO PCT/US1992/011184 patent/WO1993012901A1/en not_active Application Discontinuation
  • 1992-12-23 EP EP93902734A patent/EP0618848A4/en not_active Withdrawn
  • 1992-12-24 CN CN 92115376 patent/CN1078423A/zh active Pending
  • 1992-12-24 TW TW081110355A patent/TW245666B/zh active

Patent Citations (4)

Non-Patent Citations (1)

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