Industrial cleaning sponge

Cleaning and liquid contact with solids – Processes – Using sequentially applied treating agents

Reexamination Certificate

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Details

C134S002000, C134S022100, C134S022110, C134S022130, C134S022170, C134S026000, C134S094100, C134S095100, C134S100100, C134S103200

Reexamination Certificate

active

06235125

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an industrial sponge used for cleaning surfaces. More specifically, the invention is a synthetic industrial sponge made of polyvinyl acetal, and a method for extracting residue from the sponge to yield a sponge that leaves less particulate matter and has a longer life than conventional sponges, and a method of cleaning semiconductor material using the sponges.
2. Description of the Related Art
The use of synthetic sponges, made of polyvinyl acetal for example, is well known. For example, U.S. Pat. No. 4,566,911 discloses a scrubbing device using a polyvinyl acetal elastic material. Conventional sponges have been shaped in various forms, such as rollers and pads. These sponges are used to clean critical materials such as thin film disks, semiconductor wafers, data storage media, and other materials requiring removal of particles in the 0.1 micron range, i.e. “ultimate cleaning”. Conventional synthetic sponges have a polymer structure with “dead end pockets” formed therein that trap residue and trace amounts of metals. As the sponge wears, these metals can come out of the sponge in the form of particulate matter. Such particulate matter can damage the surfaces that are to be cleaned. Further, this type of sponge has tiny fibrils in the pores thereof that are a result of spaces between the pore forming chemical additive during a cross-linking reaction. “Cross-linking” is the formation of ester bonding between chains of the two adjacent hydroxyl groups that occur with the reaction of polyvinyl alcohol and aldehyde. This reaction hardens and strengthens the resulting material.
U.S. Pat. No 4,098,728, the disclosure of which is incorporated herein by reference, discloses a polyvinyl acetal sponge and a method for making the same. In this method, pore spaces in the sponge are formed by gas bubbles; not pore forming chemical additives such as starch/sulfate combinations. Because the sponge disclosed in this patent does not have any starch residue, or the like, it has been particularly useful in medical applications in which starch residues can cause a foreign body reaction when in contact with mucosal tissue.
Also, conventional sponges have been used to form cleaning rollers or the like having projections formed on a surface thereof. However, the conventional projections have walls that extend perpendicular to an outer surface of the sponge body. Such a configuration creates stress concentration areas. Accordingly, the projections break off of the roller surface after continued use. Therefore, conventional sponges having projections have a short useful life.
Finally, extraction processes, also known as purification processes, are used to remove particulate matter and residue from the sponge before the sponge is used for cleaning. However, conventional extraction processes have not adequately removed residue to the extent necessary for reliably cleaning semiconductor wafers or similar materials.
SUMMARY OF THE INVENTION
It is an object of the invention to overcome the limitations of the prior art polyvinyl acetal sponges.
It is a further object of the invention to minimize particulate residue in a polyvinyl acetal sponge.
It is still a further object of the invention to extend the life of polyvinyl acetal sponges.
The invention achieves these objectives by forming a polyvinyl acetal sponge with a process in which the pores are formed by gas to provide an open pore structure having no fibrils. Additionally, the sponge is purified by alternating exposure of the partially cross-linked sponge to solutions of high pH and low pH. The sponge is sterilized by electron beam radiation to destroy micro organisms that can cause contamination of the final product. Residue in the sponge is reduced to 2 ppm or less, preferably 1 ppm or less for many elements, zinc and calcium in particular.
The resulting sponge material is formed into an industrial sponge having a cylindrical body and a plurality of projections extending from the body. The projections are tapered truncated cones having a cross-sectional radius that decreases with distance from the body. The projections of the invention provide increased contact pressure without reducing the life of the industrial sponge to unacceptable levels. The sponge material can be used for cleaning semiconductor wafers or other materials by rolling the sponge across a surface of the material in a known manner.


REFERENCES:
patent: 1002842 (1911-09-01), Harriss
patent: 1002913 (1911-09-01), Harriss
patent: 1094361 (1914-04-01), Blevney
patent: 1775186 (1930-09-01), Bartling
patent: 2053604 (1936-09-01), Dullinger
patent: 2485428 (1949-10-01), Bleier et al.
patent: 2525965 (1950-10-01), Smith
patent: 2609347 (1952-09-01), Wilson
patent: 2932859 (1960-04-01), Rockoff
patent: 3190843 (1965-06-01), Hofelmann et al.
patent: 3318856 (1967-05-01), Deyrup
patent: 3481888 (1969-12-01), Sinclair
patent: 3591543 (1971-07-01), Stafford
patent: 3663470 (1972-05-01), Nishimura et al.
patent: 3673125 (1972-06-01), Takahashi et al.
patent: 3737398 (1973-06-01), Yamaguchi
patent: 3858329 (1975-01-01), Koide et al.
patent: 3915671 (1975-10-01), Kagawa
patent: 3988245 (1976-10-01), Wang
patent: 4083906 (1978-04-01), Schindler et al.
patent: 4098728 (1978-07-01), Rosenblatt
patent: 4111666 (1978-09-01), Kalbow
patent: 4197371 (1980-04-01), Holst et al.
patent: 4279752 (1981-07-01), Sueoka et al.
patent: 4430447 (1984-02-01), Pospich et al.
patent: 4552138 (1985-11-01), Hofeditz et al.
patent: 4566911 (1986-01-01), Tomita et al.
patent: 4692473 (1987-09-01), Wright et al.
patent: 4750915 (1988-06-01), Tomita et al.
patent: 4767793 (1988-08-01), Schisler et al.
patent: 4806339 (1989-02-01), Hayashi
patent: 4841680 (1989-06-01), Hoffstein et al.
patent: 4902511 (1990-02-01), Kronman
patent: 4925453 (1990-05-01), Kannankeril
patent: 4969226 (1990-11-01), Seville
patent: 5009652 (1991-04-01), Morgan et al.
patent: 5059659 (1991-10-01), Gregor et al.
patent: 5071648 (1991-12-01), Rosenblatt
patent: 5144711 (1992-09-01), Gill, Jr.
patent: 5155138 (1992-10-01), Lundqvist
patent: 5164088 (1992-11-01), Hanel et al.
patent: 5169904 (1992-12-01), Ziemelis et al.
patent: 5217663 (1993-06-01), Seville
patent: 5284468 (1994-02-01), Nelson
patent: 5288763 (1994-02-01), Li et al.
patent: 5311634 (1994-05-01), Andros
patent: 5326629 (1994-07-01), Vaughn et al.
patent: 5370656 (1994-12-01), Shevel
patent: 5387206 (1995-02-01), Valentine et al.
patent: 5414914 (1995-05-01), Suzuki et al.
patent: 5447505 (1995-09-01), Valentine et al.
patent: 5453078 (1995-09-01), Valentine et al.
patent: 5460655 (1995-10-01), Pisacane et al.
patent: 5466231 (1995-11-01), Cercone et al.
patent: 5469864 (1995-11-01), Rosenblatt
patent: 5502082 (1996-03-01), Unger et al.
patent: 5504124 (1996-04-01), Cassidy et al.
patent: 5524642 (1996-06-01), Rosenblatt
patent: 5526546 (1996-06-01), Kamen
patent: 5554658 (1996-09-01), Rosenblatt
patent: 5554659 (1996-09-01), Rosenblatt
patent: 5556391 (1996-09-01), Cercone et al.
patent: 5639311 (1997-06-01), Holley et al.
patent: 5744150 (1998-04-01), Cercone
patent: 5745945 (1998-05-01), Manfredi et al.
patent: 5979459 (1999-11-01), Cercone et al.
patent: 6004402 (1999-12-01), Cercone et al.
patent: 6027573 (2000-02-01), Cercone et al.
patent: 6080092 (2000-06-01), Cercone et al.
patent: 6103018 (2000-08-01), Cercone et al.
patent: 6120616 (2000-09-01), Bahten
patent: 62-42886 (1987-09-01), None
patent: 2-234774 (1990-09-01), None
patent: 2-234775 (1990-09-01), None
patent: 3-29100 (1991-04-01), None
patent: 4-72304 (1992-06-01), None
patent: WO 91/10688 (1991-07-01), None
patent: WO 94/25189 (1994-11-01), None
patent: WO 95/24174 (1995-09-01), None

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