JPS608045B2 - Purification method of olefin polymer - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for purifying olefin polymers.

That is, halogen-containing magnesium solids, titanium compounds,
The present invention relates to a method for removing halogen components contained in an olefin polymer obtained using a catalyst consisting of an electron donor and an organometallic compound. When obtaining an olefin polymer using a Ziegler-Natta type catalyst, a magnesium compound, c. When a catalyst consisting of a transition metal compound, an electron donor, and an organometallic compound is used, the amount of olefin polymer per transition metal can be increased. Therefore, the transition metal content in the olefin polymer is at a level that can be used as a product as it is. For example, in the case of ethylene polymer,
It is used as a product without post-treatment after polymerization. However, in the case of polypropylene and the like, since it is necessary to maintain high stereoregularity, polymerization can be carried out by slightly lowering the catalyst activity and lowering the amount of transition metal, etc. Therefore, the halogen content increases, and when used as a product as is, it causes undesirable phenomena such as rust on the molding machine and mold. Olefin polymers obtained using Ziegler-Natta type catalysts are purified by removing catalyst residue with alcohol, etc.
It is necessary to use a large amount of alcohol, and costs such as alcohol regeneration are incurred.

Samurai Kaisho 49-187782 describes a method for dechlorinating olefin polymers by adding alkylene oxide in the granulation process, but in addition to requiring a special granulator, alkylene Handling oxides is dangerous.

In addition, Tokukan Sho 52-69488 discloses that a polyolefin containing catalyst residue obtained by using a transition metal compound supported on magnesium halide as a catalyst component can be used as an aromatic monocarboxylic acid, a polycarboxylic acid or an oxycarboxylic acid. A method of contacting with a carboxylic acid is described. However, acids interact with additives such as stabilizers, and the pellets produced tend to foam. Therefore, there is a need for an effective halogenation method that involves adding a small amount of a more neutral compound and that is simple and easy to operate. The method of the present invention was discovered as a result of intensive studies with the above points in mind.

That is, the method of the present invention can reduce the amount of hydrogen present in an olefin polymer obtained by using a catalyst consisting of a magnesium solid containing haq-gen, a titanium compound, an electron donor, and an organometallic compound, such as the catalyst disclosed in JP-A-54-15893. This is a method for purifying an olefin polymer, which comprises bringing the olefin polymer into contact with a carbonate ester. The amount of carbonate ester (hereinafter referred to as a processing agent) used in the method of the present invention is usually 0.005% to 5% by weight, preferably 0.01% to 10% by weight of the olefin polymer. 2 parts by weight.

If the amount is below the above range, the effect of the present invention cannot be obtained, and if it is above the above range, it may be used, but it will only increase the cost.
The contact time between the olefin polymer and the treatment agent may be about 2 minutes to 30 minutes when using an extruder, and 1 minute to 40 minutes when using a Banbury mixer or the like. Further, examples of the processing agent include dimethyl carbonate, jetyl carbonate, dipropyl carbonate, dibutyl carbonate, diphenyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, etc., with ethylene carbonate and propylene carbonate being preferred, and ethylene carbonate being particularly preferred. .

Incidentally, the carbonate ester can also be used in the form of a mixture, adduct, masterbatch, or the like. The contact between the olefin polymer and the treating agent in the method of the present invention can be carried out in the molten state of the olefin polymer or in the presence of a solvent, but it is preferably carried out in the molten state.

The temperature depends on the type of olefin polymer, but the temperature is 160°C.
The melting and kneading contact is preferably carried out at ~350 qo, preferably from 170 to 300 qo. As a device for melt-kneading, a conventional single-screw or twin-screw (eg, FCM, CM) extruder, kneader, Banbury mixer, or the like can be used, and a vented extruder gives preferable results. The processing agent can be mixed with the olefin polymer in advance, or added simultaneously or during the extruder. Hereinafter, the method of the present invention will be explained in detail with reference to Examples.

Examples and Comparative Examples Organomagnesium body AIM saddle in 10 moles of trichlorosilane (heptane solution). Ship t2.9nBu, 2.
, 10 hmol of titanium tetrachloride was added dropwise over 1 hour at 65 qo, and 1 mmol of ethyl benzoate was added and reacted.
0I was added and treated at 130oo for 2 hours.

The obtained solid was then ground in a vibrating ball mill for 5 hours.
The obtained powder was further treated by adding 70% of titanium tetrachloride. Polypropylene powder 1 produced using the thus obtained solid catalyst (Ti content: 3.1% by weight)
After adding the processing agent shown in Table 1 to 0 parts by weight (chlorine content 10 flower blood), using a vented extruder, reduce the pressure at the vent part to 5 side Hg or less, knead and extrude to form pellets. And so. The amount of chlorine remaining in this pellet was measured using X-rays. The results are shown in Table 1. For comparison, tests were conducted in which ethanol (Comparative Example 1) and methyl stearate (Comparative Example 2) were added as compounds, and in which no treatment agent was used.

The results are shown in Table 1. Table 1 In Examples 1 to 5, the collars of the pellets obtained and the mechanical properties of the molded products thereof were good.

Claims (1)

[Scope of Claims] 1 ``In a method for reducing halogen present in an olefin polymer obtained using a catalyst consisting of halogen-containing magnesium, a titanium compound, an electron donor, and an organometallic compound, For the department,
1. A method for purifying an olefin polymer, which comprises contacting 0.01 to 2 parts by weight of a carbonate ester in a kneaded state using an extruder or the like. 2. The method for purifying an olefin polymer according to claim 1, wherein the carbonate ester is ethylene carbonate.