Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1999-03-30
2001-10-30
Teskin, Fred (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S142000, C526S283000, C525S332100, C525S338000, C524S553000, C524S554000
Reexamination Certificate
active
06310160
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a norbornene polymer excellent in strength properties and processability and hard to undergo discoloration, and a production process thereof. The present invention also relates to a molding material comprising such a norbornene polymer.
BACKGROUND ART
Thermoplastic norbornene polymers obtained by subjecting a norbornene monomer to ring-opening polymerization or addition polymerization in the presence of a metathesis catalyst system and optionally hydrogenating a polymer formed after the polymerization are excellent in various properties such as transparency, insulating properties, low dielectric properties, heat resistance, moisture resistance and mechanical strength. Therefore, investigations are being made as to the applications of such norbornene polymers to various uses such as optical materials, medical materials and semiconductor materials. Among these uses, for example, medical bottles, syringes, vials, housings, casings, insulating materials, etc. are particularly required to improve their strength properties and resistance to discoloration.
As processes for producing norbornene polymers, there have heretofore been proposed, for example, the following various processes:
(1) In Japanese Patent Publication No. 4528/1989, there is proposed a process in which dicyclopentadiene is subjected to ring-opening polymerization using a metathesis catalyst system composed of WCl
6
/Bu
4
Sn (Group IVB)/Et
2
O. According to this process, however, the molecular weight distribution (Mw/Mn) of the resulting polymer becomes wide, and so its processability is lowered if its molecular weight is made high for the purpose of improving its strength properties.
(2) In Japanese Patent Publication No. 43412/1983, there is proposed a process in which dicyclopentadiene is subjected to ring-opening polymerization using a metathesis catalyst system composed of TiCl
6
/Et
3
Al/Et
3
N. According to this process, however, the molecular weight distribution of the resulting polymer cannot be sufficiently narrowed, and so it is difficult to balance the strength properties and processability of the polymer with each other at a high level. In addition, this process also involves a drawback that since the catalyst is used in a great amount, a great amount of a metallic catalyst residue is left in the polymer formed, and so the polymer undergoes discoloration.
(3) In Japanese Patent Application Laid-Open No. 197460/1989, there is proposed a process in which a norbornene monomer is subjected to ring-opening polymerization using a metathesis catalyst system composed of WCl
6
/i-Bu
3
Al/paraldehyde. According to this process, however, gelation tends to occur in the course of the reaction, and so it is difficult to produce a norbornene polymer having a high molecular weight and a sufficiently narrow molecular weight distribution.
(4) Japanese Patent Application Laid-Open Nos. 179575/1995, 188396/1995 and 206999/1995 each disclose a process for producing a norbornene polymer having a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of 1.36 or lower by a living metathesis polymerization method. However, this process involves a drawback that since a catalyst is used in a great amount due to living polymerization, a great amount of a metallic catalyst residue is left in the resulting norbornene polymer. In addition, the processability of such a polymer is insufficient.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide a norbornene polymer excellent in strength properties and processability and hard to undergo discoloration, and a production process thereof.
Another object of the present invention is to provide a molding material which comprises a norbornene polymer excellent in strength properties and processability and can retain high strength properties over a long period of time.
The present inventors have carried out an extensive investigation with a view toward overcoming the above problems involved in the prior art. As a result, it has been found that when the following catalyst system (I) or (II) is used as a metathesis catalyst system in a process for producing a norbornene polymer by polymerizing a norbornene monomer in the presence of the metathesis catalyst system, a norbornene polymer, which has a high molecular weight and a narrow molecular weight distribution and is extremely low in the content of a metallic catalyst residue (residual metal content), is obtained.
Catalyst System (I):
A catalyst system containing:
(1) at least one transition metal compound selected from the group consisting of W compounds, Mo compounds and Re compounds;
(2) an organoaluminum compound; and
(3) an alcohol,
wherein the sum total of the number of carbon atoms in the organic residue of the organoaluminum compound and the number of carbon atoms in the alcohol is at least 9.
Catalyst System (II):
A catalyst system containing:
(1) at least one transition metal compound selected from the group consisting of W compounds, Mo compounds and Re compounds;
(2) an organoaluminum compound;
(3) an alcohol; and
(4) another oxygen-containing organic compound than the alcohol.
Norbornene polymers obtained by using these catalyst systems feature that they are excellent in strength properties owing to their high molecular weights and in processability owing to their narrow molecular weight distributions, and hard to undergo discoloration owing to their low residual metal contents. When a stabilizer is contained in the norbornene polymers, their high strength properties are retained over a long period of time. The present invention has been led to completion on the basis of these findings.
According to the present invention, there is thus provided a norbornene polymer containing repeating units formed from a norbornene monomer in its main chain and having a weight average molecular weight (Mw) ranging from 10,000 to 1,000,000 and a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) ranging from 1.60 to 1.95.
According to the present invention, there is also provided a process for producing a norbornene polymer by polymerizing a norbornene monomer in the presence of a metathesis catalyst system, the process comprising using, as the metathesis catalyst system, a catalyst system containing (1) at least one transition metal compound selected from the group consisting of W compounds, Mo compounds and Re compounds, (2) an organoaluminum compound, and (3) an alcohol having at least 2 carbon atoms, wherein the sum total of the number of carbon atoms in the organic residue of the organoaluminum compound and the number of carbon atoms in the alcohol is at least 9.
According to the present invention, there is further provided a process for producing a norbornene polymer by polymerizing a norbornene monomer in the presence of a metathesis catalyst system, the process comprising using, as the metathesis catalyst system, a catalyst system containing (1) at least one transition metal compound selected from the group consisting of W compounds, Mo compounds and Re compounds, (2) an organoaluminum compound, (3) an alcohol, and (4) another oxygen-containing organic compound than the alcohol.
According to the present invention, there is still further provided a molding material comprising a norbornene polymer having a weight average molecular weight (Mw) ranging from 10,000 to 1,000,000 and a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) ranging from 1.60 to 1.95, and a stabilizer.
BEST MODE FOR CARRYING OUT THE INVENTION
Norbornene Polymer:
The norbornene polymers according to the present invention include norbornene polymers containing, as repeating units of its main chain, repeating units represented by a formula (1):
wherein R
1
to R
4
are independently a hydrogen atom, hydrocarbon group, halogen atom, hydroxyl group, ester group, alkoxy group, cyano group, amide group, imide group or silyl group, or a hydrocarbon group s
Dinsmore & Shohl LLP
Nippon Zeon Co. Ltd.
Teskin Fred
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