Tamper evident closures and packages with color changing means and separable portions of the closures and method of forming the same

A resealable tamper evident twist cap for closing, opening and reclosing a container having an externally threaded neck finish, wherein the cap is adapted to change color to indicate the condition of the container, comprising:

• a skirt of plastic with an internally threaded upper portion for twisting onto and from the externally threaded neck finish to close, open and reclose the container;
• at least one internal recess in said plastic skirt below said threaded portion which forms a thin section and which preferentially stretches upon the application of tensile stress thereto to effect a color change in said skirt,
• a separable portion on and about said skirt below said internal recess for coacting with the container to tensile stress and effect a color change in said thin section, and
• an interconnecting portion between and connecting said skirt and separable portion for imparting the color changing tensile stress to said thin section and for separating said separable portion from said skirt at a relatively low cap removal torque when the cap is initially twisted off the container, to thereby indicate the condition of the container.

A tamper evident twist cap for closing, opening and reclosing a container and for indicating the condition of the container, comprising:

• a top and a depending annular skirt of plastic including
• an upper portion having at least one internal recess therein which forms a thin section and which stretches upon the application of tensile stress thereto to effect a color change in said skirt,
• a lower separable portion below said internal recess for engaging the container to preferentially stretch and effect a color change in said thin section, and
• an interconnecting web portion connecting and forming a line of fracture between said upper and lower portions having a tear initiator circumferentially spaced from said thin section for initiating and propagating tearing in said web portion at a relatively low cap removal torque wherein, upon initial twist off of the cap, the engagement between said separable portion and the container tensile stresses said thin sections to effect the color change and tear said web portion to separate said lower separable portion from said upper skirt, and thereby indicate the condition of the container.

A heat treated tamper evident plastic twist cap for closing, opening and reclosing a container having an externally threaded neck finish with a ring therebelow, wherein cap is adapted to indicate the condition of the container, comprising:

• a top and a depending annular skirt of plastic including
• an upper portion having an internally threaded portion for twisting onto and from the externally threaded neck finish, at least one internal recess therein below said threads which forms a thin section and which preferentially stretches and stress whitens upon the application of tensile stress thereto to effect a color change in said skirt, and a thicker section contiguous to said thinner section which remains substantially unstretched and does not stress whiten when tensile stress is applied to said thinner section,
• a lower separable rim below said internal recess having an internal projection for engaging the ring on the neck finish for preferentially stretching and effecting a color change in said thin section, and
• an internal groove in said skirt between said rim and skirt forming a thin interconnecting tear line where, upon initial twist off removal of the cap, the engagement between said projection and the rim tensile stresses said thin section to effect the color change therein and separate said rim from said skirt along said tear line and at a relatively low cap removal torque, to thereby indicate the condition of the container.

A heat treated tamper evident plastic cap for closing, opening and reclosing a bottle, and for indicating the condition of the bottle, comprising:

• a top and a depending annular skirt of plastic including
• an upper portion having internal recesses therebelow which form opposing thin sections and which preferentially stretch upon the application of tensile stress thereto to effect a color change in said skirt,
• a lower tearaway ring below said internal recesses for engaging the bottle for preferentially stretching and effecting a color change in said thin sections, and
• a thin interconnecting portion between said skirt portion and lower rim a having web directly beneath said thinner sections connecting said skirt to said rim and tear initiators in said web and between said thin sections wherein, upon initial twist off removal of the cap, the engagement between said ring and the container tensile stresses said web portions and said thin sections to effect a color change in said thin sections and at relatively low cap removal torques propagate tears in said web portions beginning at said tear initiators to separate said rim from said skirt, to thereby indicate the condition of the container, and wherein the removal torque is relatively low because the tensile stress is minimal at said tear initiators and lessens in said interconnecting web portions as the tears propagate therein, and because heat treatment reduces elongation to break and thereby enhances tearability.