Originally Posted by Man Of Lint
r from excessive or abusive wearing, exposure to water (rain) or the heat from a dry cleaners press.
Unless the bond was extremely weak to begin with, wearing will not soften it. Neither will water dissolve the resin. Pressing
will not do it, but many dry cleaners do not press- they steam on a dummy and that's what kills it.
Prior to sewing, the resin on the interlining is melted at a high temperature while the cloth and interlining are being fed through a machine with rollers exerting a lot of pressure so a bond is formed between the two. If the bond is heated while under pressure (during pressing) there is little or no risk of delamination. If, however, the garment is subjected to heat and humidity (steam) without pressure to keep the bond, then you have a risk of bubbling. In a factory, if we need to separate the interlining from the cloth for whatever reason, we just give it a shot of steam and it peels of pretty easily. That's why you should never steam a fused suit.
If you see what you think may be bubbling on a suit, it could be from other things as well. There is excess cloth worked into various areas which, when pressed properly, stay flat. When exposed to humidity, they can pucker (another reason not to steam a suit).