Method and apparatus for sealing a plastics material to a metal substrate
AssigneeMetal Box Limited
InventorMartin F. Ball
Life of this patent
Estimating the term…
Abstract
A method and apparatus associated with plastics material applied by injection moulding to a metal substrate by surrounding at least a portion of the substrate with a mould and injecting flowable plastics material into the mould, characterized in that the method and/or the apparatus utilizes locally induced heat in the portion of the metal substrate surrounded by the mould to bond and sealingly adhere the plastics material to the metal substrate in total surface-to-surface contact.
Claims25
A method of forming a closure member in a metal container comprising the steps of providing a metal container end having opposite surfaces and an aperture therethrough of a predetermined size and peripheral outline, providing a mould formed of two dies each having a cavity of a predetermined size and peripheral outline larger than the predetermined size and peripheral outline of the aperture and at least one of the dies having a die portion transparent to electromagnetic energy, clamping the metal container end between the dies with the aperture in general alignment with the die cavities and proximate the die portion thereby exposing to each cavity and the die portion a peripheral edge portion of the metal container end contiguous the aperture, injecting flowable plastics material into the cavities and the aperture therebetween, generating electromagnetic energy exteriorly of the cavity so as to transmit the same through the die portion, and thereby effect localized induction heating of only the aperture peripheral edge portion during the injection step to sealingly adhere the plastics material to the opposite surface at the peripheral edge portion thereby forming a closure member in the container end.
A method of forming a closure member in a metal container end comprising the steps of providing a metal container end having opposite inner and outer surfaces, a central panel, a curl outboard of the central panel, the curl opening in a direction toward and being defined in part by the inner surface, the aperture being of a predetermined size and peripheral outline and being defined by a peripheral edge portion within the central panel, the method comprising the steps of applying coatings to the outer and inner surfaces of the metal container end to which plastics material will respectively generally no adhere and will generally adhere, providing a mould formed of two dies each having a cavity of a predetermined size and peripheral outline larger than the predetermined size and peripheral outline of the container and aperture, clamping the metal container end between the dies with the aperture in general alignment with the die cavities thereby exposing to each cavity the peripheral edge portion of the metal container and contiguous the aperture, injecting flowable plastics material into the cavities and the aperture therebetween, and induction heating at least the aperture peripheral edge portion during the injection step to sealingly adhere the plastics material to the inner surface at the peripheral edge portion thereby forming a closure member in the container end whose surface adjacent the outer surfaces is generally not adhered thereto.
A method of injection moulding a plastics material onto a metal substrate comprising the steps of providing first and second dies between which a metal substrate is adapted to be disposed when the dies are closed, at least one of the dies including a cavity of a predetermined peripheral outline exposed to an opening in a direction toward a predetermined surface portion of the metal substrate which is to be coated with plastics material, positioning the metal substrate between the first and second dies when the latter are opened, closing the first and second dies, injecting plastics material into the cavity in conformity therewith and against the predetermined surface portion of the substrate, generating electromagnetic energy exteriorly of the cavity approximate a portion of the die, and transmitting the generated electromagnetic energy through the die portion to thereby effect localized induction heating of the surface portion during the injecting of the plastics material into the cavity while otherwise restricting the transmission of the same generated electromagnetic energy into the cavity through remaining die portions.
Apparatus for injection moulding a plastics material onto a metal substrate comprising first and second dies between which a metal substrate is adapted to be disposed when said dies are closed, at least one of said dies including means for defining a cavity of a predetermined peripheral outline exposed to and opening in a direction toward a predetermined surface portion of the metal substrate which is to be coated with plastics material, means for injecting plastics material into said cavity in conformity therewith and against said predetermined surface portion, at least one of said dies being defined in part by a die portion transparent to electromagnetic energy, and means for generating electromagnetic energy exteriorly of said cavity approximate said die portion and transmit the same through said die portion to thereby effect localized induction heating of the predetermined surface portion during the injecting of the plastics material into said cavity.
Apparatus for forming a closure member in a metal container end having opposite surfaces and an aperture therethrough of a predetermined size and peripheral outline bounded by a peripheral edge portion comprising a mould formed of two dies each having a cavity of a predetermined size and peripheral outline larger than the predetermined size and peripheral outline of an associated metal container aperture, at least one of said two dies having a die portion transparent to electromagnetic energy, means for clamping the metal container end between the dies with the aperture in general alignment with the die cavities and proximate the die portion thereby exposing to each cavity and the die portion the peripheral edge portion of the metal container end, means for injecting flowable plastics material into the cavities and the aperture therebetween in overlapping relationship to the opposite surfaces of the peripheral edge portion, and an induction coil means for generating electromagnetic energy exteriorly of the cavity so as to transmit the same through said die portion inducing heat only at the aperture peripheral edge portion during the injection step and while the dies are closed to sealingly adhere the plastics material to the opposite surfaces at the peripheral edge portion.
Dependencies are inferred from the claim text.