Color change time is money

Open House 2012 Color change time is money Dieter Rothe

Agenda Our problem down time and waste Master batch and flow channels Possible solutions Summary Page 2

Color change takes forever Why? The converter blames it to the head manufacturer Head manufacturer says it s the screw Machine manufacturer advices to check the parameters Others ask Is it the master batch? Meanwhile the problem goes on Page 3

Subject colored line in the product We have started to look into this! If a color change takes 4to 6 or 8 hours At a throughput of 200kg/h Color change once a week Per year 200hours and 10tons of resin wasted Page 4

Agenda Our problem down time and waste Master batch and flow channels Possible solutions Summary Page 5

Master batch Contains color pigments Carrier mostly LLDPE and LDPE Can be organic or inorganic Additives Or even both Have dispersin g aid, oil, wax Page 6

Good things to know about master batch Temperature stability can be e.g. 180 C 300 C! But this is only up to 5 min (EN12877) LLDPE as a carrier has a low melting point LDPE carrier is higher in melting point Both carriers are higher in MFI than HDPE So we have a different viscosity Batchers like to see an early melting for a good dispersion, but Contamination on the screw Page 7

Melt flow channel basics Always a laminar flow Turbulent flow would clean better Velocity in the center is high L Metal wall v 0 Velocity at the wall is almost ZERO High risk of deposits Color pigments will increase the risk Smaller Ø would increase the velocity v index : max Ø But also increase the pressure drop p 1 p 2 Page 8

Complete extrusion system Page 9

It all starts with the screw layout Color deposit in the melt channel Melt channel too large? Residence time too long Page 10

Key points of a screw Screw for the correct throughput min/max. Proper screw design Screw tip and mixing Page 11

Head and extruder adaptors Change from turbulent to laminar flow Change from ring channel into pipe Dimensions here are very important Too large, gives a high risk for deposits Too small, creates to much back pressure Ø Screw tip Solid melt Page 12

Head and extruder adaptors Change from turbulent to laminar flow Change from ring channel into pipe Dimensions here are very important Too large, gives a high risk for deposits Too small, creates to much back pressure Composition of the master batch? Ø Makes a big difference Screw tip Solid melt Page 13

Melt flow divider for a multi parisonhead Same requirements as the adaptors p in Streamlined and balanced design Adjust pressure drop and channels p 1 to p 6 should be equal e.g. 80 bar split 120kg/h 2x60kg/h Consider shear rate/velocity Deposit as in the adaptor will continue 6x20kg/h P1 P2 P3 P4 P5 P6 But different, due to flow channel split Page 14

Melt flow divider for a multi parisonhead Same requirements for the adaptors Pin Streamlined and balanced design Adjust pressure drop and channels split p 1 to p 6 should be equal e.g. 80 bar Consider shear rate/velocity Deposit as in the adaptor will continue Cooled down HDPE melt out of this manifold But different, due to flow channel split Reason why outer parisons take longer Page 15

Pinola head design Heart curved shape Top or side fed system For mono and multilayer Equal flow due to double heart curve Double Single Overlapping Page 16

Pinola head design Heart curved shape Top or side fed system For mono and multilayer Equal flow due to double heart curve Overlapping principle of Kautex No weak spots as at spider legs 3D Overlapping heart curved system of Kautex Maschinenbau Page 17

Pinola head design Heart curved shape Top or side fed system For mono and multilayer Equal flow due to double heart curve Overlapping principle of Kautex No weak spots as at spider legs But longer color change why? Join line of the melt flow is visibly 2D Overlapping heart curved system of Kautex Maschinenbau Page 18

The heart curve and the join line All heart curves have the same phenomenon Color deposits from the adaptors/flow channels stay accumulated visibly at the join line Joining point at the parison and at the bottle Page 19

The heart curve and the join line All heart curves have the same phenomenon Color deposits from the adaptors/flow channels stay accumulated visibly at the join line Joining point at the parison and at the bottle Very sensitive are effect pigments like pearl Misaligned / optical refraction Source: Merck Page 20

Torpedo head Spider leg design: 2 and more legs Just one channel or two (inner/outer) Legs can leave weak spots at a low MFI For mono layer only Best in color change, central flow e.g. 30 min 4 x 4 spider legs Color deposit is still the same But is not so much visible (360 ) 2 spider legs Page 21

Agenda Our problem down time and waste Master batch and flow channels Possible solutions Summary Page 22

What can we do? Simply don t use any colors Page 23

What can we do? Simply don t use any colors... Optimize the master batch Pigment formulation Heat stability Suitable carrier Page 24

What can we do? Simply don t use any colors... Optimize the master batch Direct compounding Page 25

What can we do? Simply don t use any colors... Optimize the master batch Direct compounding Liquid colors Page 26

What can we do? Simply don t use any colors... Optimize the master batch Direct compounding Liquid colors Polymer processing aid s PPA s Source: Dynamar TM Regular polymer flow A dynamic coating of PTFE based additive reduces friction and change the velocity Page 27

What can we do? Simply don t use any colors... Optimize the master batch Direct compounding Liquid colors Polymer processing aid s PPA s Arc -Gas phase PVD coating e.g. TiCN PVD Physical Vapour deposition Page 28

What can we do? Simply don t use any colors Optimize the master batch Two groups purging compound Direct compounding Liquid colors Polymer processing aid s PPA s PVD coating Mechanical purging compound Contains abrasive particles Cleaning agents Chemical purging compound Contains foaming agent and reacts inside the melt Page 29

What can we do? Simply don t use any colors... Optimize the master batch Very effective Direct compounding Liquid colors Polymer processing aid s PPA s PVD coating Cleaning agents Manual cleaning Risk of damage Takes time and manpower Page 30

Agenda Our problem down time and waste Master batch and flow channels Possible solutions Summary Page 31

Summary Pigment and master batch formulation is important Keep adaptors short Select your optimum support for a faster color change Screw and flow channels need to match the throughput Choose the best suitable head design for your application Improving color change stays an important subject, and we are continuously working on this. Page 32

Thank you very much for for your your attention! attention. Any questions?