Abrading – Abrading process – Utilizing fluent abradant
Reexamination Certificate
2001-04-27
2003-04-15
Hail, III, Joseph J. (Department: 3723)
Abrading
Abrading process
Utilizing fluent abradant
C428S063000, C428S163000, C428S173000
Reexamination Certificate
active
06547644
ABSTRACT:
DETAILED DESCRIPTION OF THE INVENTION
1. Field of the Invention
The present invention relates to a polishing pad for polishing the surface of a glass for a liquid crystal substrate, a glass substrate for a hard disk, a substrate such as a semiconductor wafer, an optical glass or a mirror, and use thereof.
2. Prior Art
In recent years, as a display, a semiconductor, and the like have come to have an ultra-fine and high-density structure, and it is accordingly required to polish the surface of,a substrate, etc., highly accurately for use therefor. In an optical glass, etc., further, the surface thereof is also required to have a high flatness for inhibiting a strain, and the like. Polishing methods have been developed in various ways, and it is current practice to carry out polishing with a slurry containing, as an abrasive, inorganic fine particles such as cerium oxide particles.
As a polishing pad for use in the above polishing, there is known a pad formed of a polyurethane resin, particularly, a polyurethane foam resin. However, the polyurethane resin involves problems that it has poor durability as a polishing pad since it is soft and that the entire convexo-concave surface of a work is polished since the pad is soft, so that not only a convex portion which needs polishing but also a concave portion is polished, and the convexo-concave shape is not easily removed.
Further, a pad formed of a nylon resin is used as well. However, an aqueous slurry containing fine particles is used together in many cases, and there is therefore caused a problem that the nylon resin absorbs water, so that the pad is deformed to cause streaks in the surface of a work.
Further, JP-A-9-11119 discloses the use of a resin having a Young's modulus of at least 1 GPa for a polishing pad. As a specific embodiment, this Publication describes a polishing pad made of a polycarbonate resin. A polycarbonate resin has a water absorption of approximately 0.3% by weight and easily absorbs water, so that nothing has been solved with regard to the above problem caused by the deformation of the pad when an aqueous slurry containing an abrasive is used.
Problems to be Solved by the Invention
It is an object of the present invention to provide a polishing pad having a proper hardness, having durability, having a low water absorption and having easy formability to various shapes.
Means to Solve the Problems
The present inventors have made diligent studies for overcoming the above problems and as a result have found that a resin formed of a ring-opened polymer from a metathesis-polymerizable cycloolefin satisfies properties required of a polishing pad, and the present invention has been accordingly arrived at.
That is, the present invention is as follows.
I. A polishing pad for polishing a surface of a work, which comprises
(A) said polishing pad being made of a resin formed of a ring-opened polymer from a cycloolefin by metathesis polymerization, and
(B) said resin having a heat distortion temperature of 90 to 135° C., a compression modulus of 980 to 2,940 MPa and a water absorption of 0.01 to 0.25% by weight.
II. A method of polishing the surface of a work with using, as an abrasive, a slurry containing fine particles, wherein the above pad is used as a polishing pad.
The present invention will be more specifically explained hereinafter.
The resin for forming the polishing pad of the present invention is a crosslinked polymer formed of a ring-opened polymer from a metathesis-polymerizable cycloolefin.
The above metathesis-polymerizable cycloolefin is selected from olefins having one or two metathesis-polymerizable cycloalkene groups per molecule, and it is preferably a compound having at least one norbornene skeleton per molecule. Specific examples thereof include dicyclopentadiene, tricyclopentadiene, cyclopentadiene-methyl cyclopentadiene co-dimeter, 5-ethylidenenorbornene, norbornene, norbornadiene, 5-cyclohexenylnorbornene, 1,4,5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 1,4-methano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-ethylidene-1,4,5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-ethylidene-1,4-methano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 1,4,5,8-dimethano-1,4,4a,5,8,8a-hexahydronaphthalene and ethylenebis(5-norbornene). Mixtures of these may-be also used. It is particularly preferred to use a cycloolefin mixture containing at least 50 mol %, preferably at least 70 mol %, of dicyclopentadiene based on the total of cycloolefins. It is the most preferred to-use a cycloolefin mixture containing at least 80 mol % of dicyclopentadiene based on the total of cycloolefins.
Further, a metathesis-polymerizable cycloolefin having a polar group containing different elements such as oxygen, nitrogen, etc., can be used as a comonomer as required. The above comonomer preferably has a norbornene structure unit, and the polar group preferably includes an ester group, an ether group, a cyano group, an N-substituted imide group and a halogen group. Specific examples of the above comonomer include 5-methoxycarbonylnorbornene, 5-(2-ethylhexyloxy)carbonyl-5-methylnorbornene, 5phenyloxymethylnorbornene, 5-cyanonorbornene, 6-cyano-1,4,5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, N-butyl Nadic acid imide and 5-chloronorbornene.
The resin used in the present invention is a crosslinked polymer obtained by metathesis polymerization of the above metathesis-polymerizable cycloolefin. The catalyst that is used for the metathesis polymerization can be selected from known catalysts. For example, a ruthenium-complex catalyst can be used as a metathesis polymerization catalyst. Further, there can be used a metathesis polymerization catalyst which is a combination of a catalyst component with an activator component as will be described later. It is substantially excellent to use, as a metathesis polymerization catalyst, a metathesis catalyst system which is a combination of a catalyst component and an activator component. The method for producing a crosslinked polymer of a cycloolefin in the presence of the above metathesis catalyst will be explained in detail below.
This method is a method in which a monomer solution is divided into two monomer solutions, the catalyst component for the metathesis polymerization catalyst system is incorporated into one monomer solution A (solution A), the activator component for the metathesis polymerization catalyst system is incorporated into the other monomer solution B (solution B) and these two solutions are mixed when polymerization and molding are carried out.
That is, the monomer solution A (solution A) contains the catalyst component for the metathesis polymerization catalyst system. The catalyst component can be selected from a halide or an ammonium salt of a metal such as tungsten, rhenium, tantalum, molybdenum, or the like. A tungsten compound is particularly preferred. The tungsten compound preferably includes tungsten hexahalide and tungsten oxyhalide, and more specifically, tungsten; hexachloride or tungsten oxychloride is preferred. Further, an organic ammonium tungstate may be used.
It is undesirable to directly add the above tungsten compound to a monomer, since it is already known that the above tungsten compound initiates cationic polymerization as soon as it is directly added. Preferably, therefore, the above tungsten compound is suspended in an inert solvent such as benzene, toluene or chlorobenzene in advance and a small amount of an alcohol compound and/or a phenolic compound are/is added to solubilize it before use.
For preventing the: above undesirable polymerization, it is preferred to add approximately 1 to 5 mol, per mole of the tungsten compound, of Lewis acid base or a chelating agent. This additive includes acetylacetone, acetoacetic alkyl ester, tetrahydrofuran and benzonitrile.
When a polar monomer is used, it can be among the above Lewis bases in some cases, and it sometimes has the above function without adding the above compound. In the above manner, the monomer solution A (solution A) containing the catalyst component comes to have subs
Yamada Takeyoshi
Yoshida Hidetsugu
Yoshikiyo Nobuo
Hail III Joseph J.
Ojini Anthony
Sherman & Shalloway
Teijin-Metton Kabushiki Kaisha
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