Attaching Cellophane/Cellulose film to polystyrene

[muddybrown]

Hello everyone,

I'm completely new to Polymer Engineering, but I have a problem on hand and trying to figure out a solution.

I need to attach cellophane film to a substrate. The substrate at this point is polystyrene, but could be anything, as long as injection molding can be done (and it is fairly small part). Cellophane cannot be changed (it is a specific type, not a simple cellophane tape). Options I'm considering are: 1) Heat seal; 2) adhesive.

What would be the most cost effective way to achieve this? I tried heat seal using a soldering iron and polystyrene, but did not work well. So far super-glue is working fine, but I'd rather use industrial glue or heat seal to cut down cost in the long run. If you know a good method of heat sealing (only from the top, substrate piece is thick(~1mm) compared to film), please let me know.

Thanks

 

[Compositepro]

A hot melt glue or solvent based glue should work fine. It really depends on what your manufacturing process is like.

 

[muddybrown]

ADD>>

I forgot to mention something. If you have good suggestion for substrate material (polymer) that's fairly cheap and easily injection molded, AND works well in attaching cellophane either heat seal or adhesive, please let me know.

I tried "gluing" cellophane film and polystyrene using Chloroform, which worked in the beginning, but once dried, adhesiveness was so low that film fell off by touching.

thanks!

 

[muddybrown]

Hey thanks Compositepro!

I'm exploring basics right now for prototyping the process. Once up and running, I'm expecting manual labor first; someone brushing on the glue and stick the film.

Contact area is about 1mm in width, and have multiple pillars (substrate).

thanks again

 

[IRstuff]

Why not use the same type of adhesive that you find on Scotch tape? You didn't specify the degree of adhesiveness.

There are, or were, dispensers for double-sided adhesive, i.e., Scotch tape without the tape, on a roller dispenser.

Also, you could look to the junk mail suppliers. They have some sort of gel-ish adhesive that they use to glue your credit cards to its mailing form. and for other similar uses.

TTFN

FAQ731-376

 

[muddybrown]

Is there any possibility of having heat sealing done from one side? This way, it's less messy cut down on material costs. again, I have freedom of picking substrate material (plastic).

 

[patprimmer]

Is your Cellophane truly cellophane or just a clear plastic film.

If it is really cellulose based, you can still buy cellulose ester moulding compounds. gluing like to like is easier.

From memory, Cellophane was cellulose acetate or cellulose nitrate. Cellulose acetate should solvent weld OK to either.

Regards
Pat
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[muddybrown]

I am using Standard Regenerated Cellulose Dialysis Membrane. So maybe it's not a cellophane? Either way, I must attach the film onto substrate, which is a small, thin (~1mm wide) pillars. I cannot coat the entire surface of membrane with adhesive; only along the pillars.

Thanks for all the inputs!

 

[patprimmer]

You can make a solvent adhesive from cellulose acetate and acetone. This will very nicely bond cellulose acetate film to a cellulose acetate moulding.

To much solvent and it will eat holes in the film and to little and it will not bond. You may need to experiment a little to get the correct mix.

Regards
Pat
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[btrueblood]

Um, from what I can gather on a quick google search, a "reconstituted cellulose" membrane is essentially cotton lint pressed felt paper.

 

[Compositepro]

Cellophane (and Rayon) is essentially pure cellulose. Wood fiber are dissolved in caustic and carbon disulphide which break down the molecule to smaller segments. It is then reconstituted in film of fiber form. Cellophane in water will swell and become like jello but will not dissolve. It is used as a semipermeable membrane. It is also used as a shrink wrap to provide compaction pressure while curing rubber and composite parts because it will not melt at high temperatures and it shrinks quite a bit as it dries. And it does not stick well to other plastics.

Muddybrown, If you need really good adhesion you may have to surface treat the cellophane. Corona or flame treating can be done and is probably available from the film manufacturer.

 

[muddybrown]

Thanks again Compositepro!

My adhesion requirement does not concern strength too much. I just need the film to be stay put while in use, but the use is completely stationary and should not require strong bonding. If I cannot "easily" peel the film off substrate using my fingers, then it should be ok.

This being said, is there any simple (relatively) adhesion solution? I will look into corona or flame treating, but trying to cut the cost down as well. I saw 3M Plastic Bonding Adhesive 2665, which might work, but I probably don't need anything that strong. So far, super glue have been working fine, minus the cost factor.

 

[IRstuff]

How clean does this process need to be? There's a 3M spray adhesive:

http://www.staples.com/3M-Spray-Mount-Adhesive/product_130831?cmArea=SEARCH

which is basically rubber cement in a spray can.

TTFN

FAQ731-376

 

[dgowans]

muddybrown,

The same process used for in-mold decorating might work for you. You're already injection molding parts, so that's not an issue. You should be able to incorporate your film in existing tooling, if the geometry supports it.

Where I believe this may fall apart, based on your information, is that it sounds like you need to have intermittent contact between the film and the substrate. In any case, food for thought...

 

[muddybrown]

thanks everyone for some great inputs!

dgowans, in-mold decoration is a great idea. I'll think more about that. Does it matter if I use cellulose "decorative film" and other plastic to be injected? OR would it be most ideal if the injected plastic is similar kind, such as cellulose acetate?

IRstuff, I'll also look into spray adhesive as you recommended. Thanks!

Patprimmer, your idea is also promising and would like to look into it more. Do you think cellulose acetate - acetone solvent adhesive would work well in bonding reconstituted cellulose and cellulose acetate? Because I cannot change the "film" material and it will be reconstituted cellulose acetate. Thanks a bunch!

 

[muddybrown]

I meant to say regenerated cellulose (probably means the same thing as reconstituted cellulose).

 

[dgowans]

muddybrown,

I don't believe that you have to use "like" materials in the IMD process, but I believe the two materials do need to be able to bond to each other. Best bet is to speak to your molder and film supplier.

 

[patprimmer]

I may have misled you. Composite pro is correct. Cellophane is viscose rayon film, not cellulose acetate. It will not disolve in acetone.

Regards
Pat
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[Demon3]

In IMD, in order to get adhesion, the two materials must be of similar polarity (you can check this in books). Adhesion of polymers occurs when the chains of each polymer intertwine. If the two polymers are miscible (and you give them enough time) they will give great adhesion. If they are immiscible then very poor adhesion. The polarity match does not have to be exact to get decent adhesion.

So low polarity includes PE, PP, COC

Medium polarity includes PVC, PMMA, PET, PBT

High polarity PA6 and PA6,6

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry

 

[muddybrown]

Thanks!