JP3107633B2 - Method for producing polyolefin particles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing tack-free polyolefin particles.

[0002]

2. Description of the Related Art
Polyolefins having rubber elasticity are used for various applications similar to rubber. However, the polyolefin having rubber elasticity has a large amount of an amorphous polymer portion, so the polymer itself has tackiness, and is rarely obtained in the form of particles by polymerization, and is obtained in the form of particles. Even so, it is difficult to obtain smooth particles with good fluidity because the particles adhere to each other due to the stickiness of the particles.

When the fluidity of the polyolefin particles is insufficient, problems such as shelf fishing in the hopper may occur, and the polyolefin particles may be clogged in the piping by pneumatic transportation, making it difficult to handle. There was a problem.

[0004]

Means for Solving the Problems The present inventors have made intensive studies for the purpose of solving the above-mentioned problems, and as a result,
It has been found that polyolefin particles having good particle properties can be obtained by polymerizing an olefin in a specific solvent, and the present invention has been completed.

That is, according to the present invention, an olefin is polymerized in a liquid medium of a polymerization monomer having 3 to 5 carbon atoms itself (hereinafter, simply referred to as a medium) in which a hydrocarbon solvent having 6 or more carbon atoms is 0.1 volume% or less. A method for producing polyolefin particles, comprising:

The polyolefin particles used in the present invention may be either homopolymers or copolymers of α-olefins. In particular, the effect of the present invention is remarkable in the case of polyolefin particles having a p-xylene soluble content of 30% by weight or more at room temperature. Polyolefin particles having a p-xylene soluble content of 30% by weight or more at room temperature contain a large amount of an amorphous polymer portion, so that the particles easily adhere to each other. The cause is considered to be that the amorphous polymer portion is easily dissolved in a hydrocarbon solvent having 6 or more carbon atoms, and the dissolved material bleeds on the particle surface. Specific examples of the polyolefin particles suitably used in the present invention include, for example, an ethylene-propylene random copolymer, an ethylene-propylene block copolymer, an ethylene-butene random copolymer, and an ethylene-butene block copolymer. Α- such as propylene-butene random copolymer, propylene-butene block copolymer, ethylene-propylene-butene random copolymer, ethylene-propylene-butene block copolymer, ethylene-propylene-diene random copolymer, etc. Copolymers of two or more olefins can be given.

In the present invention, the hydrocarbon solvent having 6 or more carbon atoms (hereinafter may be simply referred to as a hydrocarbon solvent) is
Usually, it is used as a diluent for a catalyst component composed of a titanium compound, an organic aluminum component, an electron donor component and the like in the production of polyolefin. For example, since the catalyst component is generally in the form of a solid powder, when industrially supplied to a polymerization tank, the catalyst component should be converted into a slurry with a hydrocarbon solvent having 6 or more carbon atoms to improve the performance stability of the catalyst and the piping. And an advantageous method for achieving a stable supply operation. In addition, it is often preferable to dilute the organic aluminum component, the electron donor component, and the like in the supply operation in which the concentration is controlled.

As the hydrocarbon solvent having 6 or more carbon atoms used for diluting each of these components, those which are liquid and have a low boiling point in the temperature range of use are generally used in terms of drying and quality of the resulting polymer. For this reason, hexane, heptane, cyclohexane, octane, decane and the like are used, and among them, hexane and heptane having a low boiling point are usually used.

However, when the amount of the above-mentioned hydrocarbon solvent having 6 or more carbon atoms is present in the polymerization medium in a certain amount or more, a phenomenon has been found in which the properties of the produced polyolefin particles, particularly the fluidity, are adversely affected. Was.

[0010] The medium containing the above hydrocarbon solvent includes:
It is a polymerized monomer having 3 to 5 carbon atoms, such as propylene, butene, and pentene.

The amount of the hydrocarbon solvent having 6 or more carbon atoms contained in the medium must be 0.1% by volume or less. If the amount of the hydrocarbon solvent exceeds the above range, polyolefin particles cannot be obtained with good fluidity and fluidity. In particular, in order to obtain polyolefin particles having good fluidity, the amount of the hydrocarbon solvent is 0.07% by volume.
Hereinafter, it is further preferred that the resin is not substantially used.

A specific method for adjusting the amount of the hydrocarbon solvent having 6 or more carbon atoms contained in the medium to the above range is as follows, for example:
The amount of a hydrocarbon solvent having 6 or more carbon atoms is reduced as a catalyst used for storing or dispersing a catalyst made of a titanium compound, a cocatalyst made of organoaluminum, or an electron donating compound, And the method of using the polymerization monomer itself.

For the polymerization of olefins in a medium having a content of the hydrocarbon solvent having 6 or more carbon atoms of 0.1% by volume or less, a known method can be employed without any limitation. For example,
Examples include a method of randomly copolymerizing different types of olefins, a method of sequentially block copolymerizing different types of olefins, and the like.

The polyolefin particles can be separated by a known method, for example, by flashing the slurry containing the polyolefin particles obtained by the polymerization.

[0015]

The polyolefin particles obtained by the method of the present invention have a smooth feel and good fluidity.
Therefore, in the handling of the above polyolefin particles, for example, there is no problem such as shelf fishing in the hopper, and even if a transportation method such as pneumatic transportation is adopted, the polyolefin particles are not clogged in the piping, Further, when the above-mentioned polyolefin particles are mixed with another resin, a filler or the like, the mixing with other components can be performed uniformly.

[0016]

【Example】

 Examples (1) Bulk specific gravity Performed according to JIS K6721.

(2) Dropping seconds The outlet having a diameter of 10 mm is provided at the center of the lower part, and the height is 175 m.
m, the inner diameter of the upper cylindrical part is 68 mm, and the height of the cylindrical part is 60
100 ml of the particles were placed in a metal funnel having a shape of mm, and the polyolefin particles were discharged while applying a vibration of 2 mm width in the lateral direction, and the time (sec) required for discharging the entire amount was measured.

(3) Room temperature p-xylene soluble matter About 1 g of polyolefin particles were weighed (weight A), added to 100 ml of p-xylene, heated to 130 ° C. while stirring, and further stirred for 30 minutes. A homogeneous p-xylene solution was prepared. After cooling to room temperature (23 ° C.)
Left for hours. The precipitated gel was filtered off, and the amount of soluble matter (weight B) was determined by completely volatilizing p-xylene, which was calculated by the following equation.

Room temperature p-xylene soluble matter (wt%) = B / A × 100 Example 1 1 liter of liquid propylene was charged into a 2 liter autoclave subjected to N ₂ substitution, and diethyl aluminum chloride (100%, The undiluted solution) was charged so as to be 8 times the molar amount of titanium trichloride, and the temperature was raised to 70 ° C., and then poly1-butene containing titanium trichloride (poly1-butene 10 g / g-Ti
Cl ₃ ) was charged as a slurry of 0.3 ml of hexane so as to obtain 30 mg of titanium trichloride. 30 at 70 ° C
After polymerizing propylene for 1 minute, dilute ethyl aluminum sesquiethoxide and methyl methacrylate in a hydrocarbon solvent having 6 or more carbon atoms in a molar amount of 0.7 times and 0.02 times, respectively, of diethyl aluminum chloride. Without charging, the internal temperature of the autoclave was lowered to 55 ° C., and ethylene was fed. Ethylene was fed by gas chromatography so that the concentration of ethylene in the gas phase became 10 mol%, and polymerization was performed at 55 ° C. for 90 minutes.

In this polymerization system, hexane is 0.3 ml per liter of propylene medium, and hexane in the polymerization medium is 0.03% by volume.

After completion of the polymerization, unreacted monomers were purged, and the polymer yield was 200 g and the ethylene content was 31 mol.
1% and p-xylene solubles of 62 wt% were obtained. The results are shown in Table 1.

Examples 2 to 4 and Comparative Examples 1 to 3 In the same manner as in Example 1, polymerization was carried out in a medium containing a hydrocarbon solvent having 6 or more carbon atoms as shown in Table 1. The results are shown in Table 1. Although the particles obtained in the examples had a smooth feeling, the particles obtained in the comparative example were:
The particles were in a state where they adhered to each other.

[0023]

[Table 1]

Claims (1)

(57) [Claims] 1. A polyolefin characterized in that an olefin is polymerized in a liquid medium of a polymerization monomer having 3 to 5 carbon atoms itself, the content of a hydrocarbon solvent having 6 or more carbon atoms being 0.1% by volume or less. Method for producing particles.