Intro to Packaging Chapter 11 and 12(Thermoforming) and 13(Closures)

List 10 considerations critical to the design or selection of an effective closure tem

Product compatibility, container compatibility, ease of handling, contain and protect functions, hermetic seal, recloseability, user friendliness, economics, convenience safety, demographic considerations, decorative appeal, product viscosity.

What body has jurisdiction over industry finish and closure standards?

The International Society of Beverage Technologists (ISBT)

On a bottle finish, what are the I, T, E, H, and S dimensions? What are the corresponding dimensions on a closure?

I=diameter at smallest opening inside finish;

T=thread diameter measured across the threads

E=thread root diameter

H= top of finish to top of bead or to intersection with bottle shoulder on beadless designs

s= the vertical distance from the top of the finish to the start of the thread. Corresponding dimensions are S, H, T, and E.

4. Which thread style is preferred for plastic closures?

M, or modified buttress thread

How are closures designated?

By diameter and thread design

What is the advantage of a metal lug closure over a metal threaded closure

fewer degrees of rotation, faster and more positive application.

What are the disadvantages of a fip-spout type of dispensing closure?

leave a small amount of product at the dispenser tip

What are the advantages press-on/twist-off closures?

creates a vacuum seal.

Why are liners necessary in metal closures? What is the p urpose of the backing material in a lined closure?

To achieve a hermetic set, create the actual barrier and seal.

Explain how an induction inner seal works. What container or closure body materials would interfere with the creation of a seal?

Introduction heat-sealing heads have sealing coils powered by generators running at 50 to 500 kilohertz; they produce energy that couples with the aluminum foil that is part of the inner seal. The foils temperature rises and transfers heat to the heat-seal coating, which then bonds with the container's land area.

b). Rigid glass containers and metal closures do not change or deform under normal stress

For what applications might you specify a closure made from a thermoset plastic?

A compression molding, vacuum metabolizing, close dimensional tolerances, high use temperature, solvent resistance, viscoelastic deformation problems

What material are the majority of plastic closures made from? By what processes are they made?

polypropylene, either injection or compression molded.

What might we specify polyethylene as a closure material? Where might we specify to polystyrene?

You might specify polyethylene for closures that require elongation or some deformation (snap-on tube lids). Polyethylene also might be specified when better cold resistance is needed. Polystyrene might be specified for closures that require press-fit bases that snap over an interference ridge on a container or that require a hard, bases that snap over an interference ridge on a container or that require a hard, glossy surface or complex designs; also, when a fast capping process is desired

What features and designs are available in plastic closures that cannot be made easily in metal?

Flip top, push-pull, plug orifice dispenser

Define application torque, removal torque, removal torque and stripping torque.

Application torque- measure of the tightness to which the capping machine turns the closure. Removal torque- force necessary to loosen and remove the closure.

Stripping torque- torque level that will cause the closure or bottle finish to distort to the point where the closure threads will override the matching closure or finish threads, resulting in component damage, loose caps or no seal.

Explain what might happen if a bottle's S dimension is too short or too long.

too short-closure could wind down past the bottle thread

too long- not all of the closure threads may completely engage the finish threads.

Explain what will happen if the bottle's H dimension is too small

the cap will bottom out in the bottle neck bead

Why should the common term "tamper proof" not bee used?

Because no practical package can thwart a determined tamperer.

List 8 packaging systems that are considered to be tamper evident?

Film wrappers, blister or strip packs, bubble packs, shrink seals and bands, foil, paper or plastic pushes, bottle inner seals, tape seals, breakwater closures, sealed collapsible tubes, sealed cartons, aerosol containers.

What is the design principle of a good child-resistant closure?

depend on the limited manual dexterity of a child

What is the relationship between tamper-evident closures and child resistant closures?

Both are worldwide, value- added closures providing tamper evidence, dispensing capabilities and child resistance.

What causes loss of torque in a plastic closure application?

viscoelastic flow

Where would a double tight lid be used?

On a paint can

Loss of torque would be higher when a polypropylene closure is applied to a polyethylene bottle than if a polypropylene closure is applied to a polypropylene bottle. Explain why.

Polypropylene is less subject to viscoelastic deformation than polyethylene.

List 3 conditions or situations that contribute to loss of torque

Application torque, closure and container materials, geometries, tolerances and time.

What advantages are associate with multiple lead closures?

Ease of application, secure seal, small rotations of closure.

What are combinations of vacuum, pressure and mechanical assists used in thermoforming?

Plug assist vacuum forming-heated plastic sheet is forced into a cavity mold by a plug above the mold and then vacuum is pulled to conform the plastic fro the mold cavity. Billow forming uses air to push the film upward and then a plug pushes the stretched film into the cavity, and a vacuum pulls the intruded material to conform to the cavity.

Parts made by injection molding have tighter tolerance ranges than parts made by extrusion blow molding or thermoforming. Why?

Injection molds can make complex design. Extrusion blow molding makes bottles.

Molded open tubs can be made either by injection molding or by thermoforming. What are the implications of choosing one method over the other? What feature can be incorporated easily into a thermoformed tub that would be difficult with injection molding? How can you tell which process was used to make the tub?

The main difference is tooling cost. Thermoforming can run multilayer sheets. You can tell which method created the tub because a)an injection mold has a small, obvious gate point and mold parting lines and b) thermoforming has no obvious parting lines

In thermoforming, cavity molds are preferred over plug molds. Why?

Plug molds have poor material distribution and limited draw. Cavity molds have better material distribution with the use of plug assist.

Name the commodity packaging plastic that

b.is used mostly for thermoforming

j. is used for thermoformed film when packaging luncheon meat

B. PVC, J. PA