Claims
- 1. An improved method of forming a fracturable seal of the type wherein a thermoplastic cup-shaped closure is sealed to a thermoplastic planar surface, said cup-shaped closure being formed with a radially outwardly extending sealing portion, said method comprising the steps of assembling the closure on the planar surface with said portion seated on said surface; heating a sealing die above the melting temperature of the thermoplastic material of the closure and surface; bringing said sealing die toward and against said portion; and pressing said sealing die into said portion and said surface to depress said surface at least 0.005 inch from its original height by the sealing action of the die and to displace said portion material into a bead outwardly and form a fracturable seal normal to the plane of said surface, whereby said seal will be fractured in a plane substantially parallel to said surface thereafter due to tension stress when the closure is removed from the planar surface.
- 2. An improved method as set forth in claim 1, wherein said sealing die is heated in the range of 1.degree. F. to 100.degree. F. above the melting point of said thermoplastic.
- 3. An improved method as set forth in claim 1, wherein said closure includes a chamfer and said method includes the step of centering said sealing die on said chamfer.
Parent Case Info
This is a division of application Ser. No. 777,753, filed Mar. 14, 1977, now U.S. Pat. No. 4,127,208.
US Referenced Citations (3)
Divisions (1)
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Number |
Date |
Country |
Parent |
777753 |
Mar 1977 |
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