CONFINED FLAME CONFINED FLAME … FLAME CONFINED FLAME TREATMENT: THE PROCESS TREATMENT: THE PROCESS...

2006 AIMCAL Fall Technical Conference Peppermill Resort, Reno, NV - October 22 - 25, 20061

CONFINED FLAME CONFINED FLAME TREATMENT: THE PROCESS TREATMENT: THE PROCESS

AND ITS APPLICATIONSAND ITS APPLICATIONS

Stefano MancinelliesseCI SRL Process Engineer

esse CIflame treaters®

Via Flaminia Ternana no.386

05035 – Narni (TR) - ITALY

www.essecinet.com


SUMMARYSUMMARY

1.Brief introduction to flexible packaging

2.Web surface treatment techniques

3.Confined flame treatment characteristics

5.Confined flame treatment applications


1.1.11 FLEXIBLE PACKAGINGFLEXIBLE PACKAGING“Flexible packaging is a packaging having an

internal pressure in dynamic balance with total external pressure”

Flexible packaging advantages vs. inflexible one:

l Lower weight;

l Infrangible;

l Cheaper transportation;

l Lower storage overall dimensions;

l Lower production energy cost;

l More effective product promotion;

l Processed by FFS machines.


1.1.22 FLEXIBLE PACKAGINGFLEXIBLE PACKAGING

Process of Extrusion:

q Flat films;q Blown films.

Films finishing:q Stretching;

q Thermal stabilization;

q Surfaces modifications;

q Metallization and coating.


1.1.33 FLEXIBLE PACKAGINGFLEXIBLE PACKAGING

Typical production process of a metallized BOPP film

Surface

TreatmentMetallization

Printing

and

Laminating

EXTRUSION MDO, TDO


2.2.11 WEB SURFACE WEB SURFACE TREATMENT TECHNIQUESTREATMENT TECHNIQUES

In order to increase the attitude of polymerous films to be printed, coated, lacquered, metallized, several techniques can be used. The most common are the followings:

q PRIMING q CORONA TREATMENT;q COLD PLASMA TREATMENT;q HOT PLASMA (FLAME) TREATMENT.


2.2.22 WEB SURFACE WEB SURFACE TREATMENT TECHNIQUESTREATMENT TECHNIQUESq C-H link breaking vs. C-C link breaking;q OH > O > H >> HO2

RH+OH Þ R°+H2O; Initiating stepRH+H Þ R°+H2

R°+OH Þ ROH;

R°+HO2 Þ ROOH; Propagating stepR°+O2 Þ ROO;R°+H2O2 Þ ROO+OHR°+O Þ RO

R°+H Þ RH; Terminating step



b-scission reaction:

-C-C-C- Þ -C=O + C

ô

O

O Þ alkoxy radicals RO° Þ LMWOM.



qO/C RATIOq IMWOM vs. LMWOM

INCREASED SURFACE ENERGY

ü Chain Scission behaviourü “Aging” behaviourü Metallizing barrier effect & Improved surface

properties


2.2.55 WEB SURFACE TREATMENT WEB SURFACE TREATMENT

TECHNIQUESTECHNIQUES

Pin-holes formation

Ozone production

Difficulties in hoods position optimization

Not selective

Not uniform

Not repeatable

Poor treatment at higher speeds

Backside treatment

Film treated surface aspect at high trt

Heat distributed to the surrounding room

Room conditions influence on flame yield

Std. FLAME TREATMENT

CORONA TREATMENT COLD PLASMA TREATMENT

High Depth of treatment

Production of LMWOM

Cannot be used on common BOPP film widths

Poor treatment levels



Lambda value vs. Room Temperature

at different relative humidity values.Natural Gas combustion (d=0.59).

Stoichiometric at 20°C; H% = 0

0,4

0,5

0,6

0,7

0,8

0,9

1

1,1

0 20 40 60 80 100

Room Temperature [°C]

Lam

bd

a v

alu

e

RH 0%

RH 25%

RH 50%

RH 75%

RH 100%



Thickness meter device measurements vs. lab ones

y = 6E-06x2 - 0,0042x + 18,776

R2 = 0,8407

0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750

TD coordinate [cm]

Thickness

[ m]

]

Lab values Thickness meter values


3.13.1 CONFINED FLAME TREATMENT CONFINED FLAME TREATMENT

CHARACTERISTICSCHARACTERISTICS


3.3.22 CONFINED FLAME CONFINED FLAME

TREATMENT CHARACTERISTICSTREATMENT CHARACTERISTICS




Bottom Burner version




Top Burner version




Confined flame treatment advantages:

q Higher surface quality at higher treatment levels;

q Improved after treatment web surface properties;

q No radiating heat to the surrounding room;

q Access easiness to the burner body;

q Possibility to control the combustion room conditions;

q Possibility to add inert gases to the combustion area.




FLAME SPEED Mallard-LeChatelier Theory

SL ~ (b ´ RR)1/2

b=Thermal Diffusivity=l/rcp



TREATMENT APPLICATIONSTREATMENT APPLICATIONS




Upstream hood - Exhaust gases temperatures at different speed and

mixture flow values

40

60

80

100

120

140

160

180

40 50 60 70 80 90 100 110 120

Mixture flow [Nmc/h]

Exhaust

s te

mpera

ture

[°C]

speed 100 m/min

speed 300 m/min

speed 500 m/min




Downstream hood - Exhaust gases temperatures at different speed and

mixture flow values

50

100

150

200

250

40 50 60 70 80 90 100 110 120

Mixture flow [Nmc/h]

Exhaust temperature

[°C]

speed 100 m/min

speed 300 m/min

speed 500 m/min




Energy to the exhausts

Energy to the treater roll

40 - 45%

Energy to the web (1%)

15 - 20%

COMBUSTION ENERGY

STANDARD FLAME TREATMENT DISTRIBUTION ENERGY MAP

40 - 45%

Energy to the burner

STANDARD FLAME

TREATMENT PROCESS




Energy to the exhausts

Energy to the treater roll

35 - 40%

Energy to the web (1%)

10 - 15%

COMBUSTION ENERGY

CONFINED FLAME TREATMENT DISTRIBUTION ENERGY MAP

50 - 55%

Energy to the burner

CONFINED FLAME

TREATMENT PROCESS




•• • •Anti -blocking particles

Layer “C” – Heat Seal

Layer “A” – Al deposition receptive

Layer “B” –PP Structural

Al layer (deposition under vacuum)

•

A) Metallized Coex films




Mixture flow per web

meter [Ncm/(h m)]

Air Gap [mm]

Line Speed [m/min]

Treatment Roll

Temperature [°C]

STANDARD FLAME

TREATMENT

CONFINED FLAME

TREATMENT

70,5

5,0

45

3,8

1.020

30

277

Mixture lambda value 1.020

27

335

Treatment level

[dynes/cm] 46/48 60

STANDARD VS. CONFINED FLAME TREATMENT PARAMETERS




108

235

176

82

320

229

0

50

100

150

200

250

300

350

1

Metallized film properties: Confined vs. Standard flame treatment

OTR [cc/day, dry 22.8°C]

Transversal Rexam [g/cm]

Longitudinal Rexam[g/cm]

OTR [cc/mq day, dry 22.8°C]

Transversal Rexam [g/cm]

Longitudinal Rexam [g/cm]

STANDARD FLAME

TREATMENT

CONFINED FLAME

TREATMENT




0,68

0,44

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

1

Metallized Film WVTR: Confined vs.Standard Flame Treatment

WVTR [g/mq day; 37.8°C, 100%RH]

WVTR [g/mq day; 37.8°C, 100%RH]

Standard

Flame

Treatment

Confined

Flame

Treatment




Metallized BOPP film aging curves

30

35

40

45

50

55

60

65

70

0 5 10 15 20 25 30 35 40 45

Days after treatment

Tre

atm

ent

leve

l [d

ynes/

cm]

Confined Flame Treatment

Standard Flame Treatment



TREATMENT APPLICATIONSTREATMENT APPLICATIONSB) White Opaque films / Synthetic Paper

Mixture flow per web

meter [Ncm/(h m)]

Air Gap [mm]

Line Speed [m/min]

Treatment Roll

Temperature [°C]

STANDARD FLAME

TREATMENT

CONFINED FLAME

TREATMENT

62,5

4,0

40

3,5

1.020

18

260

Mixture lambda value 1.020

20

250

Treatment level

[dynes/cm] 40/42 46/48

STANDARD VS. CONFINED FLAME TREATMENT PARAMETERS




106

129 132

182

0

20

40

60

80

100

120

140

160

180

200

Sealing Strength [g/cm]

1

Confined vs. Standard Flame treatment on white opaque films:

sealing strength

SIT 105°C

SIT 115°C

SIT 105°C

SIT 115°C

Standard Flame

Treatment

Confined Flame

Treatment




Confined vs. Standard Flame Treatment: aging curves

30

32

34

36

38

40

42

44

46

48

50

0 10 20 30 40 50 60

Days after treatment

Tre

atm

ent

leve

l [d

ynes/

cm]






121°C

+3°C

122°C

+4°C

124°C

+6°C

114°C

0°C

116°C

+2°C

112°C

0°C

SIT-Delta T[°C]

NNNNNNFilm aspect

(stripes)

424448484852Dynes/cm

181820252525Roll Temp.[°C]

300300300280280300Speed [m/min]

810820820795795812T Jono [°C]

3.53.53.83.53.53.2Gap [mm]

333342323227Mixt. [m3/h*m]

654321

C) Sealable Coex films




189,4

261,5

0,0

50,0

100,0

150,0

200,0

250,0

300,0

1

Confined vs. Standard Flame Treatment: sealing strength



SIT: 122°C;

46 dynes/cm

SIT: 116°C;

50 dynes/cm

Sealing Strength [g/inch]




CONFINED FLAME TREATMENT PROCESS ADVANTAGES

q Higher treatment levels with improved web surface properties;

q Improved final properties on metallized, white opaque and sealable treated films;

q No corrugation/deformations on white opaque films;

q Simple system to run;q Costs-saving technology;q Room friendly technology .

CONFINED FLAME CONFINED FLAME … FLAME CONFINED FLAME TREATMENT: THE PROCESS TREATMENT: THE PROCESS...

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