Plastic and nonmetallic article shaping or treating: processes – Reactive gas or vapor treatment of work – Work is organic material
Reexamination Certificate
1997-06-12
2001-03-06
Silbaugh, Jan H. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Reactive gas or vapor treatment of work
Work is organic material
C264S127000, C427S222000, C427S570000, C427S575000, C204S165000, C204S177000, C422S186050
Reexamination Certificate
active
06197234
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the invention
The present invention concerns a method of increasing the anti-wettability of a body—i.e. of making it more hydrophobic vis a vis a fluid.
The invention is also directed to the bodies obtained after treatment by the method of the invention.
These bodies can be porous bodies treated directly by a plasma process or bodies obtained by sintering balls treated by a plasma process.
2. Description of the prior art
It is desirable to increase the wettability of a porous body vis a vis a fluid in many applications.
One of these applications concerns the writing tips of markers. French patent application n° 96 01 700 of Feb. 12, 1996 describes a method of increasing the wettability of a porous body such as the writing tip of a marker vis a vis the ink. This method consists in subjecting the porous body to a post-discharge nitrogen plasma.
In contrast, the present invention is directed to increasing the anti-wettability of a porous body, i.e. to reducing its ability to absorb a fluid.
European patents 0 516 538 and 0 681 924 describe a marker having a body enclosing an ink reservoir and a tip having one end in contact with the ink and surrounded by a porous polymer material sleeve.
The Applicant has found that the marker works better if the anti-wettability of the aforementioned porous sleeve vis a vis the ink is increased.
The invention is specifically directed to achieving this particular objective, without limiting its application to the above example.
SUMMARY OF THE INVENTION
In the method of the invention of increasing the anti-wettability of a body relative to a fluid the body is subjected in a treatment enclosure to a post-discharge nitrogen plasma into which a fluorinated vapor is fed on the input side or on the output side of the discharge cavity.
Surprisingly, it has been found that subjecting a body to a plasma generated in the post-discharge area in a gas containing a fluorinated gaseous compound increases the anti-wettability of said body, which is the opposite of what is obtained in a pure nitrogen plasma.
The post-discharge area is an area remote from the discharge area proper. In this post-discharge area, the active atomic or molecular species are neutral (non-ionized).
The bodies treated can be porous polymer material bodies or a polymer powder in the form of balls.
The fluorinated gas can be a carbon polyfluoride or a nitrogen fluoride (NF
3
)
The pressure of the gas in the treatment enclosure is preferably between 1 hectopascal and 200 hectopascals.
In the case of the powder, it is preferable for the latter to be in suspension in the treatment enclosure, for example in a fluidized bed or in a rotating reactor.
After treatment of the powder in the treatment enclosure, the powder is agglomerated by sintering to produce a body having the required shape.
The invention also consists in a sintered body consisting entirely or partly of balls treated by the method of the invention.
The invention also consists in a sintered body consisting partly of balls treated and sintered by the method of the invention and partly by balls treated and sintered by the method described in French patent application n° 96 01 700, i.e. treated with a nitrogen plasma.
A process of this kind is used to adjust the anti-wettability of the body.
Other features and advantages of the invention will emerge further from the following description, which is given by way of non-limiting example with reference to the accompanying drawings.
REFERENCES:
patent: 4264750 (1981-04-01), Anand et al.
patent: 4508781 (1985-04-01), Yagi et al.
patent: 5147678 (1992-09-01), Foerch et al.
patent: 5360455 (1994-11-01), Hannemann et al.
patent: 5376413 (1994-12-01), Callebert et al.
patent: 5447756 (1995-09-01), Kamen
patent: 5693273 (1997-12-01), Wolbrom
patent: 4141805 (1993-06-01), None
patent: 0254424 (1988-01-01), None
patent: 0343038 (1989-11-01), None
Andre Ricard et al., EP 305 241 A1 (abstract only), Mar. 1, 1989.
Bedhome Vincent
Chavatte Philippe
Dessaux Odile
Duez Jose
Goudmand Pierre
Banner & Witcoff , Ltd.
Conte SA
Jones Kenneth M.
Silbaugh Jan H.
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