EXTRUSION
COATING

Extrusion coating is the coating of a molten web of synthetic resin onto a substrate material. It is a versatile coating technique used for the economic application of various plastics, notably polyethylene, onto paperboard, corrugated fiberboard, paper, aluminium foils, cellulose, Non-wovens, or plastic films.

Extrusion lamination brings two films together using a layer of molten resin extruded through computer-controlled extruder dies with advanced gauge controls (nuclear gauge monitoring and automatic profile control). The two films and the molten resin form a multilayer flexible packaging lamination.

In the extrusion coating process an extruder forces melted thermoplastic resin through a horizontal slot-die onto a moving web of substrate. The resulting product is a permanently coated web structure.

Extrusion coating operations use high melt temperatures to lower the melt viscosity. This improves coating thickness uniformity and adhesion. On-line gauging is used in some operations to measure the film thickness.

Benefits of extrusion lamination

Cost-effectively adding rigidity or thickness.

Enhancing barrier properties (depending on the resin , mostly LDPE is used)

Greater puncture resistance.

Why Bajaj ?

Not only we offer our products as a stand alone version but we strive hard and ensure to offer a complete solution to Extrusion coating / Lamination customers with consistent product quality, sustainable cost-effectiveness in sync with market dynamics and best in class service through our Customer relationship persisting for more than 3 decades.
Our products are manufactured with state of the art technology and full fledged RnD lab with Quality control & Assurance to ensure offering our customers best in class , consistent quality for this application.

Our mission is to ensure our customers get convinced on our batch to batch consistency as they admire us for aesthetics in the final product , high purity, temperature stability, weather fastness, Zero moisture & contamination , long term endurance and so on.

Unique features

Specialized fillers made with finest particle size of CaCO3 have been designed solely for this extrusion coating / lamination application on PP fabric / HDPE raffia with LDPE coating so as to make our customers delightful & chosen us as their favorite source for many years.
Free from agglomeration, our fillers facilitates whiteness, transparency, gloss , smooth surface and of course enhances productivity also.
It has good strengthening ability, sustenance against water , liquid or moisture and it helps to shorten the production cycle specifically cooling time significantly to economize the process yielding more profit to the manufacturers.
We also manufacture speciality grade of White masterbatch exclusively for Extrusion coating application with the right combination of TiO2 , carrier resin , additives and state-of-the art technology manufacturing equipments supported with full fledged RnD & QA .
Besides adding opacity & whiteness , our White Masterbatches also facilitates UV stability , Anti static , Anti fibrillating, heat resistance upto 270c while extrusion coating process is done with high speed machines.
Our Products ensure to give adequate properties required for extrusion coating / lamination such as uniform particle size distribution, smooth surface , facilitating adhesion / bonding to prevent de-lamination, improving sealing properties, barrier properties, dart impact strength , puncture resistance and so on.

Trouble shooting guide

PROBLEMPOSSIBLE CAUSESSOLUTIONS
Poor AdhesionLess Polymer melt wetting on to the substrate.Increase temperature upto 300c for LLDPE & 260c for PP. Check the heater elements.
Less chemical bondingIncrease air gap between die and nip roll for better bonding or reduce line speed.
Increase LDPE blend percentage with PP for PP fabric coating or LLDPE blend % for HDPE raffia fabric coating .
Polymer melt cooled due to low chill roll temperature.Reduce chill roll temperature.
Void in polymer melt.Pre-heat to avoid volatile content in the polymer material.
Pin holesSubstrate roughness.Make fabric substrate with better smoothness.
Low coating weights.Ensure uniform coating thickness.
SurgingBridging in hopper & screwCheck on proper screw design,L/D ratio
Edge TearIrregular flow of melt through die.Set proper temperature & condition of the die ends.
Excess draw downReduce line speed
Draw ResonanceNon-uniform thickness in machine directionDecrease the die gap or increase the coating thickness.
Polymer degradationSet proper temperature profile
Rough wavy appearanceImproper material mixingSelect similar rheology blend
Poor purgingFlush it thoroughly
Polymer degradationSet proper temperature profile
Breaks Molten curtainDraw down too low or too highSet proper line speed
Neck - InIrregular flow across dieReduce line speed
Reduce melt temperature
Select high MFI or low density material.

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