Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2001-01-10
2003-03-11
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...
C526S126000, C526S154000, C526S155000, C526S160000, C526S943000, C502S063000, C502S072000, C502S073000, C502S074000, C502S080000, C502S081000, C502S083000, C502S084000, C502S087000, C502S118000, C502S240000, C423S326000, C423S327100, C423S328100
Reexamination Certificate
active
06531552
ABSTRACT:
The present invention relates to an olefin polymerization catalyst. Particularly, the present invention relates to an olefin polymerization catalyst using a specific co-catalyst having an acidity and an acid strength controlled.
It is well known to produce an olefin polymer by polymerizing an olefin in the presence of a catalyst using a clay or a clay mineral as an olefin polymerization catalyst component (JP-A-5-295022 and JP-A-5-301917). Also, an olefin polymerization catalyst containing an acid-treated or salt-treated ion-exchange layered compound as a component is well known (JP-A-7-228621, JP-A-7-309906, JP-A-7-309907, JP-A-7-228621, JP-A-8-127613 and JP-A-10-168109). Further, an olefin polymerization catalyst containing an ion-exchange layered compound treated in the presence of an acid and a salt as a component is well known (JP-A-10-168110). However, these methods have a problem that a catalytic activity is insufficient.
The present invention provides a highly active olefin polymerization catalyst by controlling properties of a co-catalyst physically and chemically, particularly an ion-exchange layered compound.
The present inventors have noted that a certain kind of clay mineral has a function as a solid acid, and have intensively studied, and the present invention has been accomplished as a result of this study. It is necessary to use a transition metal compound belonging to Group 3 to Group 12 of the Periodic Table for polymerizing an olefin, and a certain acid is used as a means for activating such a metal compound. The present invention provides a highly active catalyst by using an ion-exchange layered silicate having a specific acid strength and acidity as a co-catalyst.
That is, the present invention provides an olefin polymerization catalyst comprising the following components (A) and (B), and an olefin polymerization catalyst component comprising the following component (A).
Component (A): an ion-exchange layered silicate having an acid site of at most −8.2 pKa, the amount of the acid site is equivalent to at least 0.05 mmol/g of 2,6-dimethylpyridine consumed for neutralization;
Component (B): a compound of a transition metal belonging to Group 3 to Group 12 of the Periodic Table.
Also, the present invention provides an olefin polymerization catalyst comprising the above components (A) and (B), and component (C) of an organic aluminum compound.
Also, the present invention provides an olefin polymerization catalyst, wherein the above component (A) is a chemically treated smectite group silicate.
Also, the present invention provides an olefin polymerization catalyst, wherein the above component (A) is an acid-treated smectite group silicate.
EXPLANATION OF COMPONENT (A)
(1) Acid Site and its Amount
The present invention employs an ion-exchange layered silicate having an acid site of at most −8.2 pKa, the amount of the acid site is equivalent to at least 0.05 mmol/g of 2,6-dimethylpyridine consumed for neutralization. The term “acid” used herein is one category classifying a material, and is defined as a material of Bronsted acid or Lewis acid. Also, the term “acid site” is defined as a constituting unit of a material exhibiting a property as an acid, and its amount is analyzed by the following titration method and is expressed as a mol amount per unit weight. An acidity of at most −8.2 pKa is usually called as “strong acidity”. It has been discovered by the present invention that a polymerization activity is remarkably improved by using an ion-exchange layered silicate having a specific strong acidity site in an amount of at least a specific amount as catalyst component (A).
In determination of an acid site by titration method, 2,6-dimethylpyridine is used as a titration reagent and anthraquinone is used as an indicator. A test sample, anthraquinone and toluene are placed in a flask, and 2,6-dimethylpyridine is added dropwisely thereto until yellow color, which is an acidic color, of the indicator disappears. An amount of 2,6-dimethylpyridine added is determined to be an amount of a strong acid site of at most −8.2 of pKa of the test sample.
The state “disappearance of yellow color” means such a point that after starting a color change by adding a titration reagent, the color does not change any more by further adding the titration reagent, and it is not necessary that the color completely disappears. Also, when a sample originally has a color, it is not always a yellow color but is a color generated by adding an indicator.
When the color does not change to yellow even by adding anthraquinone as an indicator, an amount of a strong acid site of at most −8.2 pKa is considered to be 0 (nil). In order to avoid influence by oxygen and moisture, it is necessary to carry out the above titration test in an atmosphere of a purified inert gas such as nitrogen or argon. Also, when an addition speed of a titration reagent is extremely fast or slow, an accurate measurement becomes difficult. In such a case, it is necessary to add 2,6-dimethylpyridine dropwisely at a slow speed, for example, in an amount of 0.5 to 5 &mgr;mol, preferably about 1 &mgr;mol per g for 1 minute. The measurement is carried out at a temperature of 10° C.
The above method is based on the same principle as a method disclosed in J. Phys. Chem. vol. 59, p.827, 1955 by O. Johnson. If it is impossible to measure by the above titration method, other methods such as reverse titration method may be used.
An amount of a preferable acid site is equivalent to an amount of 2,6-dimethylpyridine consumed for neutralization, e.g. preferably at least 0.07 mmol, more preferably at least 0.10 mmol, most preferably at least 0.12 mmol per gram of ion-exchange layered silicate. Usually, the amount of a preferable acid site is preferably as large as possible, and its upper limit is not restricted, but practically at most 2 mmol (expressed by an amount of 2,6-dimethylpyridine), preferably at most 1 mmol.
The ion-exchange layered silicate as component (A) used in the present invention preferably has the following performance (I) or/and (II).
(I) Performance that in desorption isotherm by nitrogen adsorption-desorption method, a ratio of a remaining adsorption amount (b) at a relative pressure P/Po=0.85 to an adsorption amount (a) at a relative pressure P/Po=1 satisfies the formula, (b)/(a)≧0.8;
(II) Performance that in adsorption isotherm and desorption isotherm by nitrogen adsorption-desorption method, a difference between a remaining adsorption amount (b) at a relative pressure P/Po=0.85 and an adsorption amount (c) in adsorption isotherm at a relative pressure P/Po=0.85 satisfies the formula, (b)−(c)>25 (cc/g).
Measurement of adsorption and desorption isotherm by nitrogen adsorption-desorption method is explained hereinafter.
A potential energy of reciprocal action of adsorption is considered to be almost constant when a temperature is constant and a solid and a gas are determined. Accordingly, an amount of a gas adsorbed on a solid is a function to a pressure only, and a curve illustrating a relation between the two is generally called as “adsorption isotherm”. In the present invention, measurement is carried out at a temperature of 77 K and a pressure is a relative pressure P/Po (Po represents atmospheric pressure), and a curve obtained when increasing the relative pressure is “adsorption isotherm” and a curve obtained when decreasing the relative pressure is “desorption isotherm”.
The adsorption isotherm changes its curve shape depending on a kind of a solid, and the desorption isotherm does not correspond to the adsorption isotherm in a zone of a relative pressure P/Po of at least 0.3, and is non-reversible, and the desorption isotherm is positioned above the adsorption isotherm in a relative pressure range. This is called as an adsorption history phenomenon or an adsorption hysteresis. There is no theory to explain all of this phenomenon, but Kramer and McBain explain a theory of “ink bottle type” pore model wherein an entrance is narrower than th
Nakano Hiroshi
Takahashi Tadashi
Tayano Takao
Uchino Hideshi
Japan Polychem Corporation
Rabago R.
Wu David W.
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