Kunihito Tanaka

Improvement in adhesive strength of fluorinated polymer films by atmospheric pressure glow plasma

Abstract We tried to treat poly (vinyl fluoride) (PVF), poly(tetrafluoroethylene- co -hexafluoropropylene) (FEP) and poly(tetrafluoroethylene- co -perfluoro [alkyl vinyl ether]) (PFA) films by atmospheric pressure glow plasma to increase their adhesive strength with an epoxy resin. Their adhesive strength could be improved; the maximum peel force values obtained from a 180° peel test were over 2.00, 0.90 and 0.62kgf 20 mm −1 , respectively. These values were near or higher than those of the control sample films treated by a surfactant: 1.06, 0.47 and 0.70kgf 20 mm −1 , respectively. In this study, we found that the O 2 /He plasma-treated films had the highest peel forces although their contact angles were highest and their amounts of incorporated oxygen or nitrogen atoms were least; He plasma treatment also showed better effects on the overall results.

Development of silica coating methods for powdered pigments with atmospheric pressure glow plasma

Abstract We examined silica coating methods on Fe 3 O 4 (black), FeOOH (yellow) and Lithol Rubine BCA (RED) powders by means of atmospheric pressure glow plasma CVD with tetraethoxysilane. These pigments were deteriorated easily by heating or oxidation. However, cooling the discharge tube and depositing protective films on the pigments before plasma oxidation could prevent the deterioration. We developed three ways to make protective films, which suited each pigments characteristics.

Development of powder antifoamer by atmospheric pressure glow plasma

Abstract Atmospheric pressure glow (APG) plasma treatment does not require a vacuum pump that is equipped with a low pressure plasma device. With treatment for organic powder, APG plasma can modify the surface roughness and wettability. In this study, we treated polystyrene films and powder by APG plasma, surveyed the changes of surface morphology, and examined the antifoaming effects of powders. A high exposure time (for this study, 20 min) in He+CF4 plasma, polystyrene powders were introduced onto approximately 55% of fluorine atoms. This powder gave a better result for antifoaming properties.

Deposition of Ethylene-Hexafluoropropene Gradient Plasma-Copolymer Using Dielectric Barrier Discharge Reactor at Atmospheric Pressure: Application to Release Coatings on Pressure-Sensitive Tape

Plasma-polymerized hexafluoropropene (PPHFP) film deposited using a dielectric barrier discharge reactor at atmospheric pressure had low enough adhesive strength, 22.2 Nm−1, for use as a release coating of pressure-sensitive adhesive tapes, but the bond strength between PPHFP film and a poly (ethylene terephthalate) (PET) substrate film was slightly weak: some part of the PPHFP deposits could be peeled from the PET substrate. Since the XPS results indicated that the bond strength between plasma-polymerized ethylene (PPE) film and PET substrate was strong enough, we tried to deposit PPE and plasma-polymerized ethylene - hexafluoropropene gradient plasma-copolymer between the PET substrate and the PPHFP film. This multi-layer film (MLF) had low enough adhesive strength, 36.6 Nm−1, for use as the release coating; this value was near that of a control sample, Teflon sheet, 21.6 Nm−1. Moreover, the bond strength between MLF and PET substrate became stronger than that between PPHFP and PET films.

Zirconia coating on amorphous magnetic powder by atmospheric pressure glow plasma

Abstract We examined a method for coating zirconia on flat amorphous Co 70.3 Fe 4.7 Si 10 B 15 powder (fa-Co) by atmospheric pressure glow plasma with Zr(OC 4 H 9 ) 4 . XPS analysis was performed to determine the existence of ZrO 2 on the surface of the treated powder. The fa-Co obtained strong resistance to oxidization by this zirconia coating method. Resistivity measurements revealed that fa-Co coated with ZrO 2 was insulating. We also improved the permeability as a function of frequency of composite cores made from fa-Co by this zirconia-coating method.

Ozone, ammonia and NOx destruction in corona discharge tubes coated with ozone catalyst

The NH 3 , O 3 and NO x reduction from NH 3 /air and NO x /air systems were studied in a corona discharge tube. In the negative corona discharge, the NH 3 was decomposed and NO x , NO, O 3 production was suppressed even in air. The NO x reduction reaction in corona discharge was explained by an enhancing of electron impact dissociation in a low field strength discharge.

Ashing of Organic Compounds with Spray-Type Plasma Reactor at Atmospheric Pressure

We examined the ashing treatment at atmospheric pressure by means of three spray-type reactors fed with O2/He or O2/Ar mixture gases. These differed in the size or the shape of their nozzles. Such reactors were able to ash an organic compound (OFPR-800; a photoresist) even at atmospheric pressure. The results showed that the following procedures are important for increasing the ashing rate: to make the gas speed after blowing out fast; to decrease the O2 content while increasing the gas speed; and to use a gas mixture which has a slow decay rate of the active species, such as the oxygen radicals. Especially, when we used O2/Ar mixture gas for the ashing treatment, the ashing rate became quite fast and was as fast as that of a general low pressure glow plasma.

Application of Spray-Type Atmospheric Pressure Glow Plasma Reactor: Ashing of Organic Compounds II

When plasma treatment is carried out in the after glow region of an electrical discharge, the decay rate and the density of the active species are very important factors for the treatment efficiency. They are known to depend on the linear gas flow rate (gas velocity) and on the residence time of the treatment gas in the discharge zone, respectively. In our previous study, we found that the spray-type atmospheric pressure glow plasma reactor with O2/He or O2/Ar mixture treatment gases had a satisfactory ashing rate of a solid organic compound (OFPR-800; a photoresist). However, the relationships between the gas velocity or the residence time and the ashing rate had not yet been examined. The present study showed clearly that the gas velocity influenced only the transit time, that is the time which the gas mixture took to progress from the slit nozzle to the sample surface, but it did not influence the generation of the active species. On the other hand, the generation rate of active species in the discharge zone was found to be strongly dependent on the residence time. The ashing rate was found to increase with increasing the residence time up to about 30 ms, beyond which it saturated. From optical emission spectroscopy measurements, the maximum ashing rate could be correlated with the emission intensities corresponding to He 3p3P-2s3S (388.8 nm) and O 3d5D-3p5P (926.5 nm) bands. These results are of practical interest.