Learn Flexible Packaging!
In Flexible Packaging we come across various type of Pouches every name.
We may come across Pouch based on Application as well
Tie Layers help adhere polar (EVOH, PA etc.) resins to non-polar (PE etc.) resins in single-step co-extrusion process.
Ethylene-vinyl alcohol co-polymer or EVOH is a flexible, crystal clear, and glossy thermoplastic co-polymer with excellent flex-crack resistance, and very high resistance to hydrocarbons, oils and organic solvents.
It also has some of the best barrier properties to gases such as oxygen, nitrogen, and carbon dioxide making it especially suited for packaging of food, drugs, cosmetics, and other perishable or delicate products to extend shelf life.
When compared to other common films, EVOH is considered to have superior barrier properties.
However, when exposed to moisture, EVOH loses its good gas barrier properties. For this reason, EVOH is often used in a multi-layer co-extruded film structure with materials such as HDPE, PP and PET, all of which have superior moisture barrier properties.
A polymer is considered polar if the it’s charge can be measured as positive or negative.
If a polymer has no charge, we say it is non-polar.
Some examples of polar plastics are PA, PC, PMMA, and ABS.
The most common non-polar plastics are PP, PE, SEBS, PS and PTFE.
When two or more Polymers are molted simultaneously to form a single sheet of film, that film is known as “Co-Extruded Multi-Layer Film” and process is known as Co-Extrusion.
In Flexible Packaging, no single Layer of Film can give all required properties. In order to achieve all selected Polymers were melted in such a way that form a film with Unique Properties of all Films.
Co-extrusion is the process where two or more polymers are extruded together to make a composite film.
Type of Co-Extruded Plants
The selection of layers depends upon end properties required as well as items to be packed.
Trim Waste in kg = weight of roll x trim size in mm / roll size
Weight of Roll = 325 kg
Rolls Size = 875 mm
Trim Size = 15 mm
Trim Waste in kg = 325 x 15 / 875 = 5.57 kg
Trim Waste % = trim size / roll size %
Trim Waste % = 15 / 875% = 1.71%
Convert Roll OD to kg
Formula = pi x h x (R² – r²) x film density / 1000000
pi = 3.14
h = film / web / roll width
R² = square of Roll OD Radius (R = OD/2)
r² = square of Roll ID Radius (r = ID/2)
film density = BoPP 0.91, Pet 1.4, Foil 2.7
1st Layer – 12µ Pet Density 1.4
2nd Layer – 50µ LDPE/Poly (Natural) Density 0.93
How much 2nd Layer required for 250 kg Pet ?
2nd Layer gsm x printed Quantity ÷ 1st Layer gsm
(50 * 0.93 * 250) ÷ (12 * 1.4) = 691.96 kg
1st Layer Pet 12µ – 250 kg
2nd Layer Poly 50µ – 691.96
Final Laminated Material required 1000 kg
Job Structure 12µ Pet + 50µ LDPE
Pet Density 1.4
Poly Density 0.93
12µ Pet gsm = 12 x 1.4 = 16.8
50µ Poly gsm = 50 x 0.93 = 46.5
Composite gsm = Pet Film gsm + Poly gsm = 16.8 + 46.5 = 63.3
Pet required for 1000 kg Laminate = Pet Film gsm x Total Output ÷ Composite gsm
= 16.8 * 1000 ÷ 63.3 = 265.40 (kg)
LDPE required for 1000 kg Laminate = LD Film gsm x Total Output ÷ Composite gsm
= 46.5 * 1000 ÷ 63.3 = 734.60
Total Laminate (Pet + LDPE) = 265.40 + 734.60
Convert Roll kg to Meter to Meter Square Flexible Packaging using Excel Sheet.
In any Flexible Packaging job, we have to convert Running Meter or Linear Meter to Square Meter (m²). In this video you can learn and use Excel Sheet to Convert Linear Meter of Film (BoPP, Pet, LDPE etc.) to Square Meter. First we convert roll kg to meter using subjected Roll Width or Coil Size.