Stretch Film

[krunalacharya]

I am using Metallocene in the core layer of a co-extruded (stretch film) cast film. The other two layers include a linear low density polyethene on one side and a low density polythene (anti cling layer) on the other. This give me a good film with good impact properties. The melt curtain is around 45mm. However, the film has less load holding capacity at low stretch percentage. I want to enhance the existing properties and increase the load holding capacity of my films.
Can any one give me some suggestions?
Krunal

 

[patprimmer]

What is the relative thickness of each layer.

What is the stress strain relationship of each polymer.

Can you substitute the LDPE for MDPE. This might work if that layer is the thickest.



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[Demon3]

Yes, I can suggest that you try Styroflex. Adding about 5% of Styroflex (a type of SBS) to PE gives fantastic stretch films, much better than you can get using PE. The stretch property, recovery and puncture resistance all improve hugely. Due to that you can even downguage and save money while having a better film. Search Google to find links to Styroflex or if you get stuck I can tell you where to find out more.

 

[ZiggyK]

Besides the final physical properties, you might want to investigate melt strength and a laboratory that performs blending of polymers on a brabender.
The previous responce included a co-polymer of polystyrene and that would help a great deal, but you must look at compatibility and processibility.

 

[Demon3]

I already know from real results that blends of Styroflex and PE give excellent stretch films allowing downguaging. The two polymers are compatible.

 

[krunalacharya]

Thank you Mates.

This posts are valuable for me.
However, Demon, I would like to ask you in particular:
1. What will be the cling, will it have any effect in the cling of the film?
2. What will be the effect on pinning? Will it cause loss of trims?
3. What should be the temperature range, if I am using a machine which will produce 50T/Day film?
4. What will be the thicknesses I would be able to get the best properties? Can I use it for 20 micron film, 17micron film, 23 micron film, what level?

Your answers will be very valuable to me. Thanks. Keep Posting.

Krunal

 

[Demon3]

Hello krunalacharya,

I know that the Styroflex works really well as an additive for PE in cling film and is commercial I believe because it allows great properties and downgauging to save costs. I have seen the results myself and it's quite spectacular. I do not know the answers to any of those last questions though, sorry. I suggest you go to

http://www.styroflex.com

and get a contact to get more detailed help.