Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2001-03-06
2003-05-06
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S348000, C526S158000, C526S142000, C526S128000, C526S134000, C526S123100, C526S125300, C502S103000, C502S111000, C502S126000, C502S127000, C502S132000, C502S133000
Reexamination Certificate
active
06559249
ABSTRACT:
BACKGROUND OF THE INVENTION AND PRIOR ART
The present invention relates to a catalyst for preparing an ultra high molecular weight polyethylene (UHMWPE) and also a method for preparing a UHMWPE with the use of that catalyst, and particularly relates to a solid complex titanium catalyst supported by a carrier containing magnesium for production of UHMWPE along with a preparation method by the use of that catalyst, of a UHMWPE with a large bulk density and narrow particle distribution with few untowardly large or small particles.
UHMWPE, a sort of polyethylene resin, having a molecular weight of at least 10 g/mol or more, and, according to ASTM 4020, is defined as “linear polyethylene having a relative viscosity of 2.30 or more when measured in 100 ml of 0.05% decahydronaphthalene solution at 135° C.” Because UHMWPE has a larger molecular weight than the polyethylene for ordinary use, it has excellent characteristics in strength, wear resistance, self-lubricating ability, chemical resistance, and electrical properties. Owing to these excellent properties, UHMWPE can be considered a special raw material having high quality obtained from a common raw material.
UHMWPE prepared by the process of polymerization is so large in molecular weight it can not be prepared in pellets, as is the case for ordinary polyethylene, but in powder for commercial use. In powder form, the size and distribution of the polymer powders should be considered important. Thus the particle size distribution of the polymer, and the existence or absence of minute particles are the decisive factors for the quality of the catalyst used.
A magnesium-containing catalyst, based on titanium, for the preparation of UHMWPE and its manufacturing process have been reported. A method making use of a magnesium solution intended to obtain a catalyst for polymerization of olefin having high bulk density has also been learned. U.S. Pat. No. 4,962,167 has disclosed the process of preparing a catalyst obtained by reacting what has been produced by reaction of a magnesium halide compound and a titanium alkoxide compound on one hand with what has been obtained by reaction of an aluminum halide and a silicon alkoxide compound on the other. The catalyst thus prepared provides a polymer of relatively high bulk density, but has to be improved, not to say the problems in the catalytic activity.
U.S. Pat. No. 5,587,440 disclosed a preparation method for a polymer with a narrow particle size distribution and a high bulk density by reducing a titanium(IV) halide to an organic aluminum compound and subjecting it to a post-treatment process, but this product has a demerit of relatively low catalytic activity.
As has been examined above, a preparation method for a catalyst with high polymerization activity to produce an UHMWPE having a high bulk density as well as narrow particle size distribution so that the polymer may have a reduced amount of untowardly big or minute particles, through a simple process though, is demanded to be developed.
To meet such a need, the present invention hereby intends to provide a method for preparation of a catalyst, which is excellent in its catalytic activity and can help produce a UHMWP having a high bulk density and, a narrow particle size distribution with few untowardly large or small particles; the method can be performed through a simple process by using raw materials of low cost. In addition, the detailed steps or processes for production of the catalyst, provided by the present invention, have never been known in any prior art.
OBJECT OF INVENTION
An objective of the present invention is to provide a highly active catalyst for the production of UHMWPE, leading to production of a polymer of high bulk density and such a narrow particle distribution as to evade too large or too small particles.
Another objective is to provide a UHMWPE by a simple yet practical production method and process. Still other objectives and advantages of the present invention will be seen more clearly by referring to the following descriptions and the claims of the present invention.
DETAILED DESCRIPTION OF INVENTION
The catalyst of the present invention for UHMWPE production is characterized by comprising the following, simple yet effective steps: (i) forming a magnesium compound solution by contact-reacting a mixture of a halogenated magnesium compound and an aluminum or a boron compound with alcohol; (ii) reacting the formed magnesium compound solution with an ester compound having at least one hydroxy group and a silicon compound having an alkoxy group; and (iii) producing a solid titanium catalyst by adding a mixture of a titanium compound and a silicon compound thereto.
The kind of halogenated magnesium compounds which can be used in production of the catalyst in the present invention includes: dihalogenated magnesiums such as magnesium chloride, magnesium iodide, magnesium fluoride, or magnesium bromide; alkylmagnesium halides such as methylmagnesium halide, ethylmagnesium halide, propylmagnesium halide, butylmagnesium halide, isobutylmagnesium halide, hexylmagnesium halide, or amylmagnesium halide; alkoxymagnesium halides such as methoxymagnesium halide, ethoxymagnesium halide, isopropoxymagnesium halide, butoxymagnesium halide, or octoxymagnesium halide; and aryloxymagnesium halides such as phenoxymagnesium halide or methylphenoxymagnesium halide. Of the above-named compounds, a mixture of two or more can also be used, and these magnesium compounds can also be effective when they are used in the form of a complex with other metals.
The above-listed magnesium compounds can be represented by simple chemical formulae, but some magnesium compounds can not be represented by simple formula, depending on their manufacturing process. In such cases they generally can be regarded as mixtures of these listed magnesium compounds. For instance, the following compounds can also be used in the present invention: as the compounds obtained by reacting a magnesium compound with a polysiloxane compound, a halogen-containing silane compound, ester, or alcohol; the compounds obtained by reacting a magnesium metal with alcohol, phenol, or ether in the presence of halosilane, phosphor pentachloride, or thionyl chloride. The preferable magnesium compounds are magnesium halides, specifically, magnesium chloride, alkylmagnesium chloride, preferably including alkyl group having the number of 1~10 carbon atoms, alkoxymagnesium chlorides, preferably including alkoxy group having the number of 1~10 carbons; aryloxy magnesium chlorides, preferably including aryloxy group having the number of 6~20 carbons. The magnesium solution used in the present invention can be produced by using the aforesaid magnesium compounds in an alcohol in the presence or absence of a hydrocarbon solvent. The kinds of hydrocarbon solvent which can be used here include, for instance: aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decan or kerosene; alicyclic hydrocarbons such as cyclobenzene, methylcyclobenzene, cyclohexane, or methylcyclohexane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene, or cymene; and such halogenated hydrocarbons such as dichloropropane, dichloroethylene, trichloroethylene, carbon tetrachloride, or chlorobenzene.
As for the aluminum compound to be used together with the magnesium compound in the present invention is preferably one or more compounds chosen from the group consisting of: aluminum halides including aluminum fluoride, aluminum bromide, aluminum chloride or aluminum iodide; compounds having a general formula of AlR
1
n
(OR
2
)
3−n
, (wherein, R
1
is hydrocarbon having 1~20 carbons or a halogen element, R
2
represents hydrocarbon having 1~20 carbons, and “n” means a natural number from 0 to 3) and; mixtures thereof. The compound represented by the general formula AlR
1
n
(OR
2
)
3−n
includes, for example aluminum triethoxide, aluminum triisopropoxide, aluminum tributoxide, or aluminum tri-2-ethylhexanoate, etc. can be used.
As for the boron compound to be used together with
Chang Ho-Sik
Lee Weon
Yang Chun-Byoung
Choi Ling-Siu
Meyertons Eric B.
Meyertons Hood Kivlin Kowert & Goetzel P.C.
Samsung General Chemicals Co. Ltd.
Wu David W.
LandOfFree
Catalyst for producing an ultrahigh molecular weight... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Catalyst for producing an ultrahigh molecular weight..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Catalyst for producing an ultrahigh molecular weight... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3009930