Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Utility Patent
1999-06-25
2001-01-02
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...
C526S346000, C526S348000, C585S010000, C585S012000
Utility Patent
active
06169154
ABSTRACT:
DESCRIPTION
1. Technical Field
The present invention relates to a novel branched ethylenic macromonomer, its polymer, and a branched ethylenic polymer obtainable by hydrogenating the macromonomer. More specifically, the present invention relates to a branched ethylenic macromonomer which can function as a comonomer to provide a copolymer having excellent molding and working properties and which can be hydrogenated to provide a hydrogenated product as a wax useful in various uses, a copolymer having the excellent molding and working properties obtainable by using this macromonomer as a comonomer, and a branched ethylenic polymer (a wax) having a low-molecular weight obtainable by hydrogenating the macromonomer.
2. Background Art
Heretofore, with regard to a polyethylene or an ethylene-&agr;-olefin copolymer, its primary structure has been controlled by adjusting molecular weight, a molecular weight distribution or copolymerization properties (random properties, a blocking tendency and a branching degree distribution), or by adding a third component such as a diene to the polymer so as to introduce branches thereto.
On the other hand, for ethylenic polymers, various molding methods are usable, and typical known examples of the molding methods include injection molding, extrusion, blow molding, inflation, compression molding and vacuum forming. In such molding methods, the impartment of high-speed molding properties and the reduction of molding energy have been investigated for a long period of time in order to improve working properties and to thus lower a working cost, and so it is an important theme that optimum physical properties suitable for each use is imparted and the molding can be carried out with the optimum working properties.
In recent years, it has been elucidated that a uniform metallocene catalyst is excellent in the copolymerization properties between olefins, can obtain a polymer is having a narrow molecular weight distribution, and has a much higher catalytic activity as compared with a conventional vanadium catalyst. Therefore, it has been expected that the metallocene catalyst will be developed in various technical fields by the utilization of such characteristics. However, a polyolefin obtained by the use of the metallocene catalyst is poor in molding and working properties, and for this reason, the application of the metallocene catalyst to the blow molding and the inflation is unavoidably limited.
In order to solve such a problem, various olefinic polymers have been disclosed into which the long-chain branches are introduced. For example, there have been disclosed (1) an olefin copolymer having the long-chain branches obtained by the use of an &agr;,&ohgr;-diene or a cyclic endomethylenic diene (Japanese Patent Application Laid-open No. 34981/1972), (2) a process for preparing a copolymer containing a higher non-conjugated diene content in a high-molecular weight segment than in a low-molecular weight segment which comprises carrying out polymerization in two steps to copolymerize the non-conjugated diene with an olefin (Japanese Patent Application Laid-open No. 56412/1984), (3) an ethylene-&agr;-olefin-1,5-hexadiene copolymer obtained by the use of a metallocene/aluminoxane catalyst (Japanese Patent Application PCT-through Laid-open No. 501555/1989), (4) a process for introducing the long-chain branches by copolymerizing an &agr;,&ohgr;-diene and ethylene in the presence of a catalyst comprising a zero-valent or a divalent nickel compound and a specific aminobis(imino) compound (Japanese Patent Application Laid-open No. 261809/1990), and (5) a polyethylene containing both of the short-chain branches and the long-chain branches which can be obtained by polymerizing ethylene alone by the use of the same catalytic component as in the above-mentioned (4) (Japanese Patent Application Laid-open No. 277610/1991).
However, in the copolymer of the above-mentioned (1), a crosslinking reaction takes place simultaneously with the formation of the long-chain branches by the diene component, and at the time of the formation of a film, a gel is generated. In addition, melt properties inversely deteriorate, and a control range is extremely narrow. Moreover, there is a problem that copolymerization reactivity is low, so that low-molecular weight polymers are produced, which leads to the deterioration of physical properties inconveniently. In the preparation process of the copolymer described in the aforesaid (2), the long-chain branches are introduced into the high-molecular weight component, so that the molecular weight noticeably increases due to crosslinking, and thus insolubilization, nonfusion or gelation might inconveniently occur. Furthermore, the control range is narrow, and the copolymerization reactivity is also low, and hence, there is a problem that owing to the production of the low-molecular weight polymers, the physical properties deteriorate inconveniently. In the copolymer of the above-mentioned (3), a molecular weight distribution is narrow, and for this reason, the copolymer is unsuitable for extrusion, blow molding and film formation. In addition, since branch points are formed by the progress of the cyclizing reaction of 1,5-hexadiene, an effective monomer concentration is inconveniently low. In the process for introducing the long-chain branches described in the above-mentioned (4), there is a problem that a range for controlling the generation of a gel and the physical properties is limited. In addition, the polyethylene of the above-mentioned (5) is a polymer which contains neither ethyl branches nor butyl branches and therefore the control of the physical properties, for example, the control of density is accomplished by methyl branches, so that the physical properties of the polyethylene tend to deteriorate.
Furthermore, there has been disclosed a method for preparing an ethylenic polymer to which working properties are imparted by the utilization of copolymerization, for example, a method which comprises forming a polymer ([&eegr;]=10-20 dl/g) by preliminary polymerization, and then preparing an ethylene-&agr;-olefin copolymer by main polymerization (Japanese Patent Application Laid-open No. 55410/1992). This method has an effect that melt tension can be increased by changing the melt properties of the obtained copolymer, but it has a drawback that a film gel tends to occur.
In addition, there have been disclosed ethylenic polymers obtained in the presence of a metallocene catalyst and methods for preparing the same, for example, (1) a method for preparing an ethylenic polymer in the presence of a constrained geometrical catalyst and an ethylenic copolymer obtained by this method (Japanese Patent Application Laid-open No. 163088/1991 and WO93/08221), (2) a method for preparing a polyolefin in the presence of a metallocene catalyst containing a porous inorganic oxide (an aluminum compound) as a carrier (Japanese Patent Application Laid-open No. 100808/1992), and (3) an ethylene-&agr;-olefin copolymer which can be derived from ethylene and the &agr;-olefin in the presence of a specific hafnium catalyst and which has a narrow molecular weight distribution and improved melt flow properties (Japanese Patent Application Laid-open No. 276807/1990).
However, in the technique of the above-mentioned (1), the obtained ethylenic copolymer has a narrow molecular weight distribution and a narrow branching degree distribution, and both of these disadvantages cannot separately be controlled. Furthermore, there is a description that in this ethylenic copolymer, long-chain branches are present and so the ethylenic copolymer is excellent in working properties, i.e., melt flow properties, but these properties are still poor. In addition, there is no concrete description regarding other important working properties, above all, molding stabilities (a swell ratio, melt tension and the like).
According to the preparation method of the above-mentioned (2), the obtained copolymer of ethylene and the &agr;-olefin has a large die swell ratio, but in view
Machida Shuji
Mitani Masahiro
Watanabe Masami
Yabunouchi Nobuhiro
Idemitsu Kosan Co. Ltd.
Lu-Rutt Caixia
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Wu David W.
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