ABS to PUR bond failure

[easy123]

We are having ABS to PUR bond failures on our impact door assemblies. ABS cover sheets are roll coated with PUR and assembled to "core" and held in a press in a controlled environment per PUR supplier recomendations for temp, humidity. ABS sheets completely delaminate from PUR at random, 2 of 40 sheets today, leaving the cured PUR fully bonded to the core materials, Polyester scrim, wood and PVC

 

[patprimmer]

Is there a mould release or any greasy substance on the ABS.

Regards
Pat
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[Demon3]

ABS is a complex material. It may contain a lot of surfactant that will migrate to the surface and ruin your adhesion by forming a weak boundary layer. Whether or not it depends on how it was made (by a solution process without surfactant or an emulsion process which means surfactant). The process used depends on the manufacturer. For example Dow uses solution and BASF uses emulsion.

As Pat mentioned, oils may be present. Silicone oil and other oils are added to some ABS and they would ruin adhesion.

Assuming you have cleaned the surface so that the first two problems above do not apply then the exact type of ABS will have an effect. ABS can contain different amounts of acrylonitrile in the SAN copolymer, that affects polarity and thus adhesion. So try different grades and ask your suppliers.

Try corona treating the cleaned sheets to increase surface polarity and bonding.

Chris DeArmitt

"Knowledge has no value except that which can be gained from its application toward some worthwhile end."
Think and Grow Rich - Napoleon Hill

 

[unclesyd]

You may want to contact Reltek about a chemical primer to use on the ABS after a good cleaning.

You also might look at an abraded surface to improve the bond.

The use of Corona treatment to promote bonding as mentioned in the previous post is available as Corona treated ABS sheets.

Flame etched sheet should also be available.

You also may want to contact Spartech about their line of alloy plastic, as in your case a preformed sheet of PUR/ABS to eliminate one possible bonding line failure.

http://www.reltekllc.com/index.html

http://www.spartech.com/alloys.html

 

[easy123]

There is no mold release or grease that is noticable.
supplier response is due as to the manufacturing process and BOM component %'s and additives.
Etching is NG.
We have an independent lab anaylzing the material.
We arew studying Corona treatment.
Same random issue with textured surface.
We are having a brainstorming session with PUR adhesive supplier, ABS supplier, Environmental controls equipment supplier to confirm all process parameters are satisfied. Materials information (PUR and ABS) to be discussed in detail.
Thank You!