Leadership through Innovation PSPD ITC LIMITED Paperboards and Specialty Papers Division...

Leadership through InnovationPSPD

ITC LIMITEDPaperboards and Specialty Papers Division

UNDERSTANDING THE ISSUE OF PEEL OFF WHILE PROCESSING PACKAGING GRADE BOARD AT PRINTER.

Bhadrachalam

Workshop on “Technological advancements in Manufacturing Packaging Grades of Paper”


Myself• Y. Chandra Sekhar– Chemical Engineer– Learning Paper Making since 1995


M/s.ITC Limited is an integrated Paper and Paper Board Mill situated in Bhadrachalam, Dt.Khammam, Andhra Pradesh producing approx.1,50,000 MT of fine paper per annum (PM II, III & VI) of various grammages and applications.

The mill was established in 1979 with recycled Board manufacturing with an annual capacity of 40,000 MT and grown to produce 5,50,000 MT as on date. The Mill has upgraded itself to expand and manufacture specialty Paper Boards and Fine Papers.

About Us• 1979 Commercial production with

recycled boards• 1986 Coated boards – offline• 1989 PM2&3 commissioned. Started

producing paper• 1992 Unit Bollaram – cast coated papers

& boards• 1997 PM4 from Valmet – LPB and

Cigarette boards• 2002 ECF fibre line – first in India, ahead

of legislation.• 2002 Merged with ITC along with

Tribeni Tissues Division.• 2004 Unit Kovai – Recycled boards• 2004 PM5 from Voith in Oct’04 –

recycled & virgin boards.• 2008 Ozone Bleaching Line – first in

India, ahead of legislation• 2008 PM6 - Paper Machine for Copier

and Writing, Printing Paper• 2009 Green Boiler• 2012 PM 7 – recycled and virgin boards.


Introduction• This project investigates the properties of the paperboard with regard to

peel-off. Experiments to study the effect of sheeting speed on paperboard and defect simulation experiment in bulk packaging have been discussed. It also explores the methods to improve the scuff resistance of paperboard and relevant tests which can be used to quantify the peel-off. Lastly, it describes the equipment which can be used to upgrade the packaging methodology and stresses the need for workforce awareness and training.


What is Peel-off• Peel-off is the tendency of the top or bottom layer of the paperboard to roll into a cylindrical

mass or quill (as shown in Figure 3) on the surface of the paperboard. When the paperboard with peel-off is passed on to the off-set printing press, it damages the blanket and subsequent paperboards which are fed for printing. This defect is found to occur in paperboards which are sheeted according to the customer requirements and is not seen in rolls.


Approach• Discussion of problem with technical and quality personnel • Literature survey • Data collection • Analysis of properties • Analysis of finishing operations

– Study of sheeting operations – Study of packaging operations

• Identifying suitable tests • Identifying methods to improve board properties • Finding measures and methods to upgrade and improve packaging

operations


Literature

• Measure of the Internal Bond Strength of paper/board – Koubaa and Koran (1995)

• A Method For Determination Of Delamination Toughness In Different Positions In The Thickness Direction Of Paperboard – Lundh and Fellers(2004)

• Australian paper mills

• Iggesund Reference Manual


Brain storming

• Peel-off occurs in paperboards of higher GSM. • The most likely reason is handling of paperboards after sheeting. • The complaints are almost equal in bundle and bulk packaging. • Product Parameters which may be related to peel-off are,

– a) Plybond – b) Caliper – c) Substance (GSM) – d) Moisture – e) Roughness


Packaging Type Vs Type of Peel-Off

• The contingency table given below summarises the peel-off type and packaging type. The analysis follows after the table.

• Back Layer Top Layer All • Bulk 13 15 28 • Bundle 22 23 45 • All 35 38 73

– Pearson Chi-Square = 0.042, DF = 1, P-Value = 0.838 – Likelihood Ratio Chi-Square = 0.042, DF = 1, P-Value = 0.838 – Result: P-value of 0.838 indicates that there is no relationship between the type of

packing and the type of peel-off. – A P-value of 0.838 indicates that there is no relationship between the packaging type

and the type of peel-off.


Analysis of Paperboard Properties • Analysis of board properties (complaint versus non complaint lots)

– Caliper– Moisture– Ply bond– Roughness

• Tools used– Box Plot– Capability Analysis– Hypothesis Testing– T test for equality of means


Box Plot analysis

• Overall variability is same across Non-Complaint and Complaint lot


Capability

• Capability index of complaint and non-complaints are same.


Test of Hypothesis & two sample T test


Study of Finishing Operations • Effect of Sheeting Speed on Board Properties

– Sheeter speed versus plybond– Sheeter speed verusu ZDTS

• Bulk Packaging Defect Simulation – Hypothesis test for good and bad ply bond, ZDTS, PPS & Bendsten TS & BS. – Two sample t test for good and bad ply bond, ZDTS, PPS & Bendsten TS & BS.


Hypothesis Testing Test for Equality of Variances


Two Sample T-Tests


Summery • The finishing experiments show that the sheeting operation

may have some effect on the strength properties of paperboard and during bulk packaging occurrences of peel-off in paperboard have been observed. In fact, in all three simulated experiments conducted in the bulk packaging the occurrence of peel-off has been observed.


Conclusions• None of the paperboard properties studied is able to consistently

discriminate between the paperboards with regard to peel-off. • With increase in sheeting speed there is a slight drop in the Plybond and

ZDTS values of paperboards along the edges, particularly during ramp-up. • Experiment of bulk packaging defect simulation showed that restacking of

sheets is the costliest operation in packaging in terms of the occurrence of peel-off. Whenever there is restacking there is a possibility of peel-off.


Recommendations • Use of pile turner for bulk packaging. • Use of Scuff Resistance (Peeling) Test of paperboard to quantify peel-off. • Use of aqueous emulsion of polyethylene with water-soluble polyethylene

oxide and similar methods should be tested for their effect in scuff resistance of paperboard.

• Recording of Bulk Packaging Defect Simulation Experiment should be prepared to incorporate in training of work force as well as to sensitize customer about the handling conditions that may create peel-off in paperboard.


Precautions

• Avoid sliding bundles of paper on top of each other. Sliding of heavy pile of paperboard over another pile increases the chances of peel-off.

• During stacking lift the paperboard and place it on top of the previous stack instead of sliding it across the top face.

• During all steps of handling avoid damaging the edges of the sheet. • Whenever the sheeter is shutdown all the sheets cut in the end should be

checked. • Table covers of workbenches should be regularly replaced.


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Leadership through Innovation PSPD ITC LIMITED Paperboards and Specialty Papers Division...

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