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Basics

What is Poly?

Density 0.93

Low density polyethylene or LDPE is the largest volume commodity thermoplastic and cheapest packaging film which is used for a wide variety of applications.

It is easy to process, and can be blended with other polymers and/or additives, like EVA, HDPE, LLDPE, fillers, pigments to alter its basic properties.

PE film is soft, very flexible, clear and glossy and has good tear resistance and good moisture barier but only fair gas barrier properties. Some major disadvantages and limitations of LDPE are poor weathering resistance, difficult to bond and poor temperature capability.

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Basics

What are Polymers ?

A polymer is a molecule, made from joining together many small molecules called monomers. The word “polymer” can be broken down into “poly” (meaning “many” in Greek) and “mer” (meaning “unit”).

In Flexible Packaging, mostly we use these Polymers

  • PE / LDPE / Poly
  • Pet / Polyester
  • HDPE
  • PVC
  • PP
  • PS

Natural Polymer – Wool, cotton and silk are natural polymer-based materials.

Categories
Basics

What is density ?

Density, of a substance is its mass per unit volume. The symbol most often used for density is ρ.

For eg. Density of common used films are below

BoPP 0.905

Pet 1.4

Foil 2.7

LD 0.93

CPP 0.91

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Basics

What is gsm ?

gsm stands for grams per square meter.

gsm = micron x density

For eg. Pet gsm = 12 x 1.4 = 16.8

Where

12 – Thickness of Pet film in Micron

1.4 – Density of Pet film

Categories
Basics

What is Micron ?

Micron is the unit of Thickness of Film.

For eg. 30 Micron BoPP Film.

1 Micron = 1 millionth of meter.

1,000,000 Micron = 1 Meter.

Micron Symbol is μ.

On Computer you can add Micron Symbol by holding Alt Key.

Alt + 0181 = µ