JPS608046B2 - Method for purifying 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 polymerizing olefins using a Ziegler-Natsuta type catalyst to obtain an olefin polymer, if a catalyst consisting of a magnesium compound, a halogen, a transition metal compound, an electron donor, and an organometallic compound is used, the yield of olefin polymer per transition metal can be increased. is enhanced. Therefore, the amount of transition metals in the olefin polymer is at a level that allows it to be put to practical use 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.
But pu. In the case of pyrene polymers 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 directly as a product, it causes undesirable phenomena such as rust on the molding machine and mold. The olefin polymer obtained by the Ziegler-Natta type catalyst is purified with alcohol, but it is necessary to use a large amount of alcohol for the olefin polymer, which increases the cost of regenerating the alcohol.

Tokusekki No. 49-87782 describes a method for dechlorinating olefin polymers by adding alkylene oxide in the granulation process, but this method requires a special granulation machine and requires a special granulation machine. Handling xylene oxide is dangerous.

Furthermore, in Tokkoku Sho 52-69488, a transition metal compound supported on magnesium halide is used as a soot component, and the resulting polyolefin containing catalyst residue is contacted with aromatic monocarboxylic acid, polycarboxylic acid, or oxycarboxylic acid. It describes how to do this. However, acids interact with additives such as stabilizers, and the produced pellets tend to foam. Therefore, there is a need for an effective dehalogenation method that involves adding a small amount of a more neutral compound and using simple operations. 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 is a method for reducing halogen present in an olefin polymer obtained using a catalyst consisting of a halogen-containing magnesium solid, a titanium compound, an electron donor, and an organometallic compound.
This is a method for purifying an olefin polymer, which is characterized by bringing it into contact with a lactone. The lactones (hereinafter referred to as processing agents) used in the method of the present invention include butyrolactone, y
-valerolactone, y-caprolactone, y-capryrolactone~ y-laurolactone, 2/gulumimelactone, y-stearolactone, 8-propiolactone,
Examples include crotolactone, Q-angelicalactone, 8-angelicalactone, 6-valerolactone, 8-cabrolactone, glucuronic acid lactone, L-ascorbic acid (oxidized form and reduced form), and 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 coexistence of a solvent, but it is preferably carried out in the molten state.

The temperature depends on the type of olefin polymer, but it is 160~
35,000, preferably 200 to 30,000. As equipment for melt kneading,
Conventional extruders, kneaders, Banbury mixers, etc. can be used; vented extruders give preferable results.
The processing agent can be mixed in advance with the olefin polymer, or can be added simultaneously or during the extruder. The amount of the treatment agent used is usually 0.005 to 5 parts by weight, preferably 0.01 to 2 parts by weight, per 10 G parts by weight of the olefin polymer.

If the amount is below the above range, the effect of the present invention cannot be obtained, and although it may be used above the above range, it will only increase the cost. The contact time between the olefin polymer and the treatment agent may be about 2 to 30 minutes when using an extruder, and from 1 minute to 40 minutes when using a Banbury mixer or the like. Hereinafter, the method of the present invention will be explained in detail with reference to Examples.

Examples 1 to 5 and Comparative Examples 1 to 3 Trichlorosilane 1. Organomagnesium complex NMg6. At3. , n-Bu, .
．． 91. 1 mmol of ethyl benzoate per solid was added to the solid obtained by dropping 200 ml of ethyl benzoate at 65 qo over 1 hour, and then 200 M of titanium tetrachloride was added to the solid, and the mixture was reacted at 130 qo. It was treated for 2 hours.

Thereafter, the obtained solid was pulverized in a vibrating ball mill for 5 hours, and to the resulting powder, 300% titanium tetrachloride was further added and heat treated at 11,000°C. The treatment agent shown in Table 1 was added to 100 parts by weight of polypropylene powder (chlorine content: 10%) produced using the solid catalyst thus obtained (Ti content: 2.5% by weight) as one component. After the addition, using an extruder with a vent, the pressure at the vent part was reduced to 5-side Hg or less, and the pellet was extruded into a pellet, and the residual amount of chlorine in the pellet was measured by X-ray imaging. The results are shown in Table 1. For comparison, tests were conducted with the addition of ethanol (Comparative Example 1) and methyl stearate (Comparative Example 2) as treatment agents, and with no treatment agent (Comparative Example 3). The results are shown in Table 1. Shown below. *: 3,5-turn Yabutyl 4-Hydroxytoluene In Examples 1 to 5,
The collar of the obtained pellet and the mechanical properties of the molded product were good.

Examples 6 to 9 and Comparative Example 4 The processing agents shown in Table 2 were added to the polypropylene slurry (slurry concentration 340 pm/pm) produced using the solid catalyst synthesized in Example 1 as one component, and the processing agents shown in Table 2 were added. After the slurry was treated under the following treatment conditions, 1/a amount of water was added to the slurry, heated at 3000 for 1 hour, filtered and dried, and the residual amount of monochlorine was measured by X-ray.

The results are shown in Table 2. As Comparative Example 4, a test was conducted in which no treatment agent was used. Table 2 shows the results.
Shown below. Table 2

Claims (1)

[Scope of Claims] 1. A method for reducing halogen present in an olefin polymer obtained using a catalyst comprising halogen-containing magnesium, a titanium compound, an electron donor, and an organometallic compound, comprising: 100 parts by weight of an olefin polymer; A method for purifying an olefin polymer, which comprises contacting the olefin polymer with 0.01 to 2 parts by weight of lactone in a kneaded state using an extruder or the like. 2. The method for purifying an olefin polymer according to claim 1, wherein the lactone is propiolactone, glucuronic acid lactone, or L-ascorbic acid (oxidized type and reduced type).