Tight Bonding between Two Sheets of Biaxially Oriented Polyester Induced by Exposure to Oxygen-Implicated Plasma

Abstract

Biaxially oriented polyethylene terephthalate (PET) films were exposed to oxygen-implicated plasma. They were pressed at 100℃ with their exposed surfaces faced, then bonded tightly without using glue. X-ray photoelectron spectroscopy showed increase in C=O group at the exposed surface, and gas chemical modification method showed increases in-OH and-COOH groups. They might indicate that a mechanism of the two-sheets bonding is related to hydrogen bond or condensation reactions concerning these functional groups.

Ultralong Lifetime of Active Surface of Oxygenated PET Films by Plasma-irradiation and Bonding Elements

“…FTIR-ATR spectrum around 1716 cm -1 for the nonirradiated sample (100μm) is shown in Figure 5. This peak arises from C=O bond included in the original PET material [3]. After the irradiation the absorption is increased around 1711 cm -1 (see an inset).…”

“…Sample size is 100 mm x 200 mm, and thickness is 1 μm and 100 μm. The film samples were attached on a grounded drum electrode in a vacuum chamber [3]. The chamber was evacuated down to 10 Pa, then O 2 gas was introduced with 20 cc/min to 40 Pa.…”

“…We developed a technique of plasma-irradiation-induced direct bonding of plastic films without using any glues [3]. Normally the plasma irradiation effects on the plastic surfaces have very short lifetime, say several days [4].…”

Water adsorption and desorption on plasma-activated PET film surface, indication of hydrogen bonding

“…However, we have to collect the organic solvents in used lamination processes, because they cause environmental problems. 12) We demonstrated the direct bonding between PET and PET, [13][14][15][16] and PET and other plastic films 4) by a plasma irradiation technique and low thermal press 5,[13][14][15][16] without using any glues. The bonding force is stronger than the film cohesion force, as demonstrated in Fig.…”

“…The bonded films have peel strengths larger than 10 N/cm in the 180°peel test, beyond which they show cohesion failure. 5,13) We propose that the mechanism of bonding involves dehydrated condensation reactions between the plasma-created active OH and COOH groups 17,18) at the interface of two irradiated films under the low temperature press. [13][14][15][16] It was found that this plasma irradiation effect on bonding capability can be maintained for more than six years when the irradiated films are kept in the normal atmosphere.…”