PLA film is an advanced type of packaging for application to the containers of soft drink

Soft drink

A soft drink is a non-alcoholic beverage that typically contains water , a sweetener, and a flavoring agent...

s and dairy product

Dairy product

Dairy products are generally defined as foods produced from cow's or domestic buffalo's milk. They are usually high-energy-yielding food products. A production plant for such processing is called a dairy or a dairy factory. Raw milk for processing comes mainly from cows, and, to a lesser extent,...

s. It can be a film overwrap and is heat-shrinkable

Shrink wrap

Shrink wrap, also shrinkwrap or shrink film, is a material made up of polymer plastic film. When heat is applied it shrinks tightly over whatever it is covering. Heat can be applied with a hand held heat gun or the product and film can pass through a heat tunnel on a conveyor.-Composition:The...

. These sleeves are usually made of petroleum

Petroleum

Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...

-based plastic films such as Polyethylene terephthalate

Polyethylene terephthalate

Polyethylene terephthalate , commonly abbreviated PET, PETE, or the obsolete PETP or PET-P, is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination...

 (PET), Oriented polystyrene (OPS) and Polyvinyl chloride

Polyvinyl chloride

Polyvinyl chloride, commonly abbreviated PVC, is a thermoplastic polymer. It is a vinyl polymer constructed of repeating vinyl groups having one hydrogen replaced by chloride. Polyvinyl chloride is the third most widely produced plastic, after polyethylene and polypropylene. PVC is widely used in...

 (PVC). PLA shrink film is a recently-developed eco-friendly alternative made of corn starch. Unlike petroleum-based films, PLA film is naturally biodegradable
, so the material may be of interest to some for environmental reasons.

Process

Like most polymer materials, PLA can be processed to films using casting

Casting

In metalworking, casting involves pouring liquid metal into a mold, which contains a hollow cavity of the desired shape, and then allowing it to cool and solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process...

, extrusion

Extrusion

Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed or drawn through a die of the desired cross-section...

 and extrusion blow molding

Blow molding

Blow molding is a manufacturing process by which hollow plastic parts are formed. In general, there are three main types of blow molding: extrusion blow molding, injection blow molding, and stretch blow molding. The blow molding process begins with melting down the plastic and forming it into a...

, as well as calendering

Calendering

Calendering is a finishing process used on cloth where fabric is folded in half and passed under rollers at high temperatures and pressures. Calendering is used on fabrics such as moire to produce its watered effect and also on cambric and some types of sateens.In preparation for calendering, the...

. It can then be printed as desired. A study conducted by the California Polytechnic State University

California Polytechnic State University

California Polytechnic State University, or Cal Poly, is a public university located in San Luis Obispo, California, United States. The university is one of two polytechnic campuses in the 23-member California State University system....

 found that the printability of PLA films was comparable to that of standard petroleum based films. PLA films can also be used for packaging in shrink tunnel

Shrink tunnel

A Shrink tunnel or Heat tunnel is a heated tunnel mounted over or around a conveyor system. Items such as packaging, have shrink film loosely applied; with heat, the film shrinks to fit snugly around the wrapped object.-Uses:* Shrink labels...

s.

Characteristics

Customers can see and check the sleeves on the container when they buy soft drinks or dairy products. The shrink sleeves are stuck without glue on the containers and mould to intricate shapes. This is possible because the material of the sleeve is heat-shrinkable, as if the containers wear a stocking.

Recycling

Efforts on recycling
in-factory scrap are beginning. There is concern about the post-consumer ability of PLA to be sorted from other plastics and the possible detrimental effects of mixing PLA with other plastics. SPI Resin identification code

Resin identification code

The SPI resin identification coding system is a set of symbols placed on plastics to identify the polymer type. It was developed by the Society of the Plastics Industry in 1988, and is used internationally....

7 is applicable. Any corn and/or sugar based film is not able to be mixed with any petroleum based plastics, therefore the recycling of materials is watched closely to ensure contamination of PLA based plastics does not take place.