Glossary of Terms

A

Amber
A yellowish-brown color of glass or plastic containers used primarily to protect light-sensitive contents.


Autoclavable
A method used to sterilize containers with superheated steam under pressure.


B

Bail
The curved handle of a pail.


Bisphenol A (BPA)
A carbon-based synthetic compound used to make certain plastics and epoxy resins.


Blowmolding
A process for forming hollow containers in which the plastic is placed inside a mold and forced outward via air pressure to assume the shape of that mold cavity.


C

Capacity
The amount of space inside a container that holds a given amount of product.


Closed-head drum
A container that is supplied to the customer with the TOP and BOTTOM ends seamed to the body. (Also known as a tight-head drum.)


Closure
A metal or plastic cap which effects a primary seal when properly applied to the container.


Cork finish
The bottle opening (finish) that is sealed with a cork.


C-T closure
A continuous-thread design that begins near the bottom of the closure skirt and continues upward toward the liner. Closure size designation determines number of turns.


C-T finish
A continuous-thread finish that features an uninterrupted protruding helix on the neck of a container to aacommodate a screw-type closure.


D

Density
Weight per unit volume of a substance, expressed in grams per cubic centimer, pounds per cubic foot and so on.


Dispensing closure
A closure designed to be used to apply the contents of a container.


Dome
A closure that has a rounded surface.


Drop test
A test of strength accomplished by dropping an object in a specified manner for a specified number of times or until the article fails from impact.


Dropper cap
A bottle closure that features a dropper and rubber bulb, designed to dispense liquids in small drops.


E

Ears
Parts soldered, bumped or riveted to the side of a can or pail to which a bail (or handle) is inserted for easier carrying.


Extrusion
The shaping of a plastic material by forcing it through a specialty-shaped die.


F

"F" style can
A rectangular base can fitted with a screw cap.


Finish
The material surrounding the neck opening of any container; designed to accommodate a particular closure.


Fitment
A device used as a part of a closure assembly designed to accomplish a specific purpose, such as a powder shaker, sprinkler or dropper.


Fittings
Any parts (other than ends) necessary to complete the closure of a can, including plugs, screw necks, spouts, bungs, caps and more.


Flame treating
A method of bathing plastics in an open flame to promote oxidation of the surface, rendering it more receptive to inks, lacquers, paints, adhesives and more.


Flint
A glass color which is transparent and clear.


Flowed-in gasket
A gasket formed by a liquid material (vinyl or latex) poured (or flowed) directly into a gasket groove and cured in place, usually by baking; i.e. plastisol.


I

Injection blowmolding
A two-stage, plastic bottling process. First, a preform (or parison) is injection molded forming the bottle finish. Then, the preform is transferred to a blow mold where the bottle takes its ultimate shape.


K

K-Resin

By virtue of its sparkling clarity, high gloss, and impact resistance, K-Resin is ideally suited to a wide variety of packaging applications.


K-Resin, a styrene derivative, is a relatively expensive material which is processed and produced on polyethylene equipment. This material is similar to polystyrene in clarity and rigidity, but lacks significant barrier properties.


K-Resin is suitable for packaging aqueous and dry products but is specifically not compatible with fats and unsaturated oils or solvents. This material is frequently used for display packaging for items such as candy, beef jerky, etc.


L

Largeware
A term given to containers that are over one gallon in capacity.


Linerless closure
A closure that has been engineered to function in specific applications without the use of an additonal liner.


Lug pail cover
A type of cover usually used on open end 5 gallon steel pails. The pail cover is lined with a "cushiony" compound that seats on the top rim of the pail. The seal is "activated" by clinching the lugs (an integral part of the cover) to the pail rim.


M

Multilayer bottles
Containers composed of layers of specially selected plasxtics which are coextruded so that the unique characteristics of each material are retained. The objective is to improve the barrier qualities of the container, resulting in a longer shelf life.


N

Narrow mouth
The finish of a container that is small in proportion to the diameter of the body.


Natural color
Describes the translucent appearance of a plastic material which has not been colored.


Neck
The part of a container where the bottle cross-section slenderizes to form the finish.


O

Orifice
An opening in a dispensing closure or fitment from which the product is despensed.


Overcap
A cap (usually plastic) provided with some cans. It is used to cover the open end once the can has been opened. Sometimes, it is used to describe a cap which is used to cover the primary closure or other dispensing system, such as a fingertip sprayer or aerosol valve.


P

Phenolic
The generic name for phenolformaldehyde thermosetting plastic that's molded or cast.


Polyethylene, high-density (HDPE)
In the high-density grade, this thermoplastic material is more rigid and less permeable than the low-density grade. It also displays a higher tolerance to distortion temperatures.


HDPE is the most widely used resin for extrusion blown plastic bottles. This material is economical, impact resistant, and provides a good moisture barrier. HDPE is compatible with a wide range of products including acids and caustics but is not compatible with solvents. It is usually supplied in FDA approved food grade.


HDPE is naturally translucent and flexible. The addition of color will make HDPE opaque although not glossy. Adding extra weight to the bottle will yield a rigid container.


HDPE is supplied flame-treated on a stock basis and lends itself readily to silk screen decoration. While HDPE provides good protection at below freezing temperatures, it cannot be used with products filled at over 160 F or products requiring a hermatic seal.


Polyethylene, low-density (LDPE)
Squeezability is good, especailly in the low-density grade of this thermoplastic material. It also displays better resistance to impact than the high-density grade.


LDPE is similar to HDPE in composition. It is less rigid and generally less chemically resistant than HDPE, but is more translucent. LDPE is used primarily for squeeze applications. LDPE is significantly more expensive than HDPE, but will yield a glossy bottle when produced in colors.


Polyethylene, medium-density (MDPE)
MDPE combines the characteristics of low and high density polyethylene. Bottles are less translucent than LDPE but more flexible than HDPE. Like LDPE, MDPE is glossy when produced in colors.


Polyethylene terephthalate (PET)
A resin with outstanding clarity and good resistance to impact, along with good barrier properties to resist grease and oil, cold and sunlight.


Polyethylene Terephthalate is an excellent material for use in orientation blow molding (stretch blow molding). It is commonly used for carbonated beverage bottles. Oriented PET provides very good alcohol and essential oil barrier properties, generally good chemical resistance (although acetones and ketones will attack PET) and a high degree of impact resistance and tensile strength. The orienting process also serves to improve gas and moisture barrier properties.


This material does not provide resistance to high temperature application (max. temp. 160 F). However, heat-set PET creates a container which will accept a 195 F hot fill and exhibit the clarity of other PET containers. This process provides an alternative to glass for products such as juice.


Polyethylene terephthalate glycol (PETG)
A resin with good barrier properties and outstanding clarity, with a slightly higher tolerance to distortion temperatures, as compared to PET.


PETG: Glycol modified Polyethylene Terephthalate is a durable material with excellent gloss, clarity and sparkle desired for clear bottles. PETG can be processed via conventional extrusion blow molding methods, generally on machines designed to process PVC.


Applications include shampoos, soaps, and detergents. PETG exhibits a good impact strength and gas barrier. The chemical resistance of PETG is fair and compatibility testing is recommended, especially with products that contain alcohol.


Polypropylene (PP)
A tough, lightweight, rigid plastic made by the polymerization of high-purity propylene gas in the presence of an organometallic catalyst at relatively low pressures and temperatures.


Polypropylene is a naturally translucent material which provides contact clarity and an excellent moisture barrier.


PP is easily processed via injection molding (jars and closures), and injection, extrusion, or stretch blow-molding (bottles). One major advantage of polypropylene is its stability at hight temperatures, up to 200 F. Polypropylene is autoclavable and offers the potential for steam sterilization. The compatibility of PP with high filling temperatures is responsible for its use with hot fill products such as pancake syrup.


PP has excellent chemical resistance, but provides poor impact resistance in cold temperatures. Oriented PP offeres improved impact resistance and clarity at low temperatures. Produced in color, PP exhibits a glossy finish.


Polystyrene (PS)
Thermoplastic compound used to make plastic containers, closures and more.


Polyvinyl chloride (PVC)
A thermoplastic material composed of polymers of vinyl chloride; a colorless solid with outstanding resistance to water, alcohols, concentrated acids and alkalis.


PVC is naturally clear, has extremely good resistance to oils, and has very low oxygen transmission. It provides an excellent barrier to most gasses and its drop impact resistance is also very good. This material is also very chemically resistant, but it is vulnerable to solvents. PVC is a semi-rigid material which, when produced on extrusion blow-molding equipment, can accommodate handled designs.


PVC is available in different grades depending on its application. These grades include general purpose grade, food grade, and fragrance-guard perume grade. The occurrence of the blue tint in clear PVC can be modified by controlling the toner levels in each of these grades. PVC is also available in a rigid injection blow molding grade.


General Purpose PVC exhibits poor resistance to high temperatures and will distort at 160 F, making it incompatible with hot filled products. New PVC grades are able to withstand temperatures up to 190 F and can be hot filled. Since it provides a good oxygen barrier, PVC is an excellent choice for salad oil, mineral oil, and vinegar. It is also commonly used for shampoos and cosmetic products.


Polyvinylidene chloride (PVDC)
Improves barrier properties to increase shelf life or to protect product. Used as a barrier material in a coating form, a layer in lamination or as part of a coextruded structure for a rigid container.


S

Shelf life (or storage life)
The time period a product can be stored under specified temperature conditions and still remain usable.


Styrene-Acrylonitril (SAN)
A styrene derivative that offers the clarity and rigidity of polystyrene in an engineering grade plastic. SAN has superior barrier properties, as well as improved chemical resistance when compared to polystyrene.


T

Tamper-evident
Any device which shows visible signs that the container has been opened.


Thread
The profile of a container finish which will accommodate specific closures.


U

Unlined
A closure with no special sealing features and no liner.


Urea
The generic name for urea-formaldehyde-the themosetting compound that's used to mold light-colored closures.


W

Wide mouth
Containers with a large finish opening or those that have a large finish size in proportion to their capacity.


Window stripe
A see-through vertical stripe on a molded bottle; used primarily to monitor the level of the contents.