JPS5830882B2 - Polyolefin Inno Seiseihouhou - Google Patents

Description

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

Specifically, the present invention relates to a novel method for deactivating halogen-containing catalysts remaining in polyolefins.

When producing polyolefins from olefins such as ethylene, propylene, and butene-1, polyolefins are usually prepared from halides of transition metals such as titanium, vanadium, and zirconium, and organometallic compounds such as alkyl aluminum or alkyl aluminum halides. A suitable catalyst is required.

Such catalysts remain in the resulting polyolefin at the end of the polymerization.

However, when the polyolefin is molded or heat treated, such residual catalyst not only causes undesirable discoloration and odor in the polymer, but also causes deterioration of the polymer and impairs its physical properties.

Therefore, it is necessary to remove residual catalyst from polyolefins.

The most common method for removing such a catalyst is to treat the polyolefin with a lower aliphatic alcohol such as methanol or isopropyl alcohol, to dissolve the catalyst in the polyolefin in the alcohol, and to wash and remove it. It is being done.

However, such a treatment method requires expensive corrosion-resistant equipment because the hydrogen halide generated by the reaction between the remaining catalyst and alcohol corrodes the equipment.

Furthermore, the stabilization of polyolefin during molding and heat treatment is not sufficient.

Therefore, there has been a desire for an inexpensive catalyst removal method that does not require corrosion-resistant equipment and can sufficiently improve the stabilization of polyolefins.

Furthermore, when the catalyst is very highly active, the amount of catalyst remaining in the polyolefin produced can be significantly reduced.

Therefore, it is also possible to omit the catalyst removal step such as the alcohol treatment.

However, even polyolefins produced in the presence of such highly active catalysts still contain trace amounts of halogen-containing catalyst.

However, due to the presence of this halogen-containing catalyst, even in a small amount, under severe heat treatment conditions such as thermoplasticization, active halogens such as hydrogen halide may be generated, causing equipment corrosion, or causing equipment corrosion. This may result in undesirably altered polyolefins.

Therefore, it has been strongly desired to solve the problem of corrosion and the stabilization of polyolefins in an industrially advantageous manner even when polyolefins are produced using catalysts with such high activity that catalyst removal can be omitted.

As a result of various studies to solve the above-mentioned problems, the inventors of the present invention deactivated the remaining catalyst by adding a specific compound to a polyolefin produced using a halogen-containing catalyst and performing a heat treatment. The present invention was achieved by discovering that corrosive active halogens can be rendered harmless and easily removed.

That is, the gist of the present invention is to apply a polyolefin containing a halogen-containing catalyst to a polyolefin having a general formula (wherein R1 represents hydrogen or has 1 to 10 carbon atoms and may contain oxygen in the carbon chain). R2 represents a hydrocarbon residue and represents a hydrocarbon group having 1 to 10 carbon atoms which may contain oxygen in the carbon chain.

Further, R1 and R2 may form a cyclic structure between R1 and R1, R1 and R2, or R2 and R2.

Moreover, n represents an integer of O to 2. ) is mixed and heat-treated.

To explain the present invention in detail, the polyolefin to which the present invention is applied includes all polyolefins in which a halogen-containing catalyst remains, but most commonly olefins such as ethylene, propylene, butene-1, etc. of,
For example, halides of transition metals of groups ■ to ■ of the periodic table,
Examples include polyolefins obtained by polymerization or copolymerization in the presence of a catalyst system consisting of an oxylogenide, etc., and an organometallic compound of Groups 1 to 2 of the same table.

Advance general formula A used in the present invention; R”n C(
OR1) 2-n(OR2) 2 (wherein, R1 represents hydrogen or a hydrocarbon residue having 1 to 10 carbon atoms which may contain oxygen in the carbon chain, and R2 represents hydrogen in the carbon chain. represents a hydrocarbon residue having 1 to 10 carbon atoms which may contain oxygen.

Further, R1 and R2 may form a cyclic structure between R1 and R1, R1 and R2, or R2 and R2.

Moreover, n represents an integer of O to 2.

) (Hereinafter, this compound is referred to as a deactivating agent) is more specifically exemplified by compounds represented by the following general formulas (1) to (2).

More specifically, the compounds represented by formula (1) include tetraethoxymethane, tetraallyloxymethane, tetraphenoxymethane, tripropoxymethane, triethoxymethane, triisobutoxymethane, triaryloxymethane, 1, 1゜1-Trimethoxypropane, dimethoxymethane, ■, 1-ethoxyethane, 1,1-ethoxy-2-methylethane, diphenoxymethane, di(
3-methylphenoxy)methane, di(allyloxy)methane, etc. are compounds represented by the formula 2 (1゜1-
Jetoxycyclohexane, 1,1-dipropoxycyclohexane, 1,1-dibutoxycyclohexane, 1,
1-jethoxy-3-methylcyclohexane etc. (3
Compounds represented by the formula include ■, 1-jethoxycyclopentane, and ■.

Examples of compounds represented by formula (4) include 1-dibutoxycyclopentane, 2-ethoxytetrahydropyran, 2-propoxytetrahydropyran, 2-ethoxy-
Examples of compounds represented by formula (5) include 4-methyltetrahydropyran, 2,6-jethoxytetrahydrofuran, 2,6-dipropoxytetrahydropyran, etc. (compounds represented by 6X include 2-ethoxy Tetrahydrofuran, 2-ethoxy-4-methyltetrahydrofuran, 2-propoxytetrahydrofuran, etc.
(Compounds represented by formula 7 include 2,5-dimethoxytetrahydrofuran, 2,5-jethoxytetrahydrofuran, 2,5-dipropoxytetrahydrofuran, etc. (Compounds represented by formula 8 include 2-ethoxyoxetane, Examples of compounds represented by formula (9) include 2-propoxyoxetane, 2,4-jethoxyoxetane, 2,4-dipropoxyoxetane, etc., and compounds represented by four holes include trioxane, valaldehyde, etc. etc.

In the present invention, such a deactivating agent is added to the polyolefin (crude polyolefin) in which the halogen-containing catalyst remains, and heat treatment is performed to deactivate the halogen-containing catalyst and at the same time remove the corrosive halogen. This converts it into a volatile halide that can be easily removed.

However, specific methods of addition include a dry mixing method and a wet mixing method.

In the dry mixing method, for example, the crude polyolefin and the above-mentioned inactivating agent are added to a mixing or molding device such as a kneader, roll, pelletizer, vented extruder, etc., and the inactivation treatment is performed in the device to produce the polyolefin. Examples include methods for directly obtaining purified polyolefin products by removing volatile halides out of the system, for example through a vent.

In addition, as a wet mixing method, for example, in the presence of a hydrocarbon solvent, the above-mentioned deactivating agent is added to and mixed with the crude polyolefin, and after heat treatment, the polyolefin is separated by a method such as filtration, and washed if necessary. Examples include a method of drying, and a method of appropriately using acetone, alcohol, water, etc. in combination with a catalyst removal step.

In addition, in the above-mentioned wet mixing method, volatile halides generated after treatment are generally sufficiently removed during separation, washing, and drying, and at the same time, the effect of removing transition metal components in the deactivated catalyst is also remarkable. .

The amount of the deactivating agent used in the method of the present invention is o, i to 10, based on the amount of halogen in the crude polyolefin.
00 times mole, especially 1 to 500 times mole is preferable.

In addition, the heating temperature varies depending on the above-mentioned mixing treatment method, but is generally 30 to 400°C, preferably 40 to 300°C.
It is.

However, when using the above-mentioned wet mixing method, it is generally carried out at a temperature of 150°C, and when using a dry mixing method in which processing is carried out in a molding device, at least the melting point of the polyolefin is exceeded.
For example, it roars at 150 to 300 degrees Celsius.

The time required for the heat treatment can be changed as appropriate depending on the treatment temperature, and is usually 1 minute to 5 hours, preferably 5 minutes to 3 hours.
It's time.

The purification method of the present invention described above has the advantage that even if a small amount of the deactivated catalyst and deactivating agent remain in the polyolefin, the physical properties of the polyolefin are not impaired.

Therefore, for polyolefins in which extremely small amounts of catalyst remain, such as those obtained using highly active catalysts, the above-mentioned deactivating agent is added and heat treatment is performed to remove volatile compounds.
A polyolefin product of sufficient practical value can be obtained simply by vaporizing and removing the halides.

The detailed mechanism of how the deactivating agent used in the present invention reacts with the halogen-containing catalyst to give the above-mentioned desired result is currently unknown, but the following reaction can be assumed, for example. It seems so.

In other words, catalyst components such as transition metal halides, hydrogen halides, and alkyl metal halides, or halogen-containing substances produced by separation from the catalyst, react in the same way to form alkyl halides, rendering the halogens that cause corrosion harmless. It is thought that it was caused by

In addition, active Ti causes thermal deterioration and coloration of polymers.
It is thought that it acts as an inactivating agent by cleaving -Cl bonds and producing stable Ti-C- bonds.

The treatment according to the present invention does not require expensive corrosion-resistant equipment and is economical, and the resulting polyolefin is stable to heat and can be easily molded without impairing its physical properties.

In addition, for polyolefins obtained using highly active catalysts, it is possible to omit the complicated catalyst removal process by simply vaporizing and removing volatile halides as described above, and the industrial significance of this point is There are many things.

EXAMPLES The present invention will be explained in more detail with reference to examples below, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

Example I 10 lppm each as Ti and C1, 520p
Crystalline polypropylene powder containing pm residual catalyst 30
100f of n-hebutane was added to 1, and triethoxymethane was added 50 times the mole based on the amount of CI to make 80
After treatment at ℃ for 1 hour, the polymer changed from pale pink to white.

Afterwards, the polymer was washed three times with n-hebutane 100S'.
After filtration and drying under reduced pressure at room temperature, a white powder was obtained.

Analysis using fluorescent X-rays revealed that Ti remaining in the polymer
and the CI amount was 56 ppm and 86 ppm.

Vehicle Transfer Example 1 In Example 1, triethoxymethane was not used, but otherwise the same treatment as in Example 1 was carried out.

As a result, Ti and CC1 remaining in polypropylene
were 100 ppm and 506 ppm, respectively, and it was found that there was almost no difference from the untreated product.

Example 1 and Comparative Example 1 show that triethoxymethane is extremely effective in removing Ti and CI from polypropylene.

Examples 2 to 6 and Comparative Example 2 Crystalline polypropylene powder containing 146 ppm of residual catalyst as CI 60? 200 Da of n-hebutane was added to the solution, and further a specified inactivating agent was added in moles of 5 times the CI content, and the mixture was treated at 80°C for 1 hour, after which the n-hebutane was filtered and the mixture was heated under reduced pressure. It was dried at 30° C. and the results shown in Table 1 were obtained.

For comparison, the results obtained when no deactivating agent was added (Comparative Example 2) are also shown in Table 1.

Example 7 60 ppm and 83 ppm as Ti and C1, respectively
Polyethylene powder containing residual catalyst of 30? For n
- As a result of adding 100P of hexane and otherwise treating in the same manner as in Example 1, TI and C remaining in polyethylene were obtained.
I is 43 ppm and 42 ppm S':)? =Example 8
~13 and Comparative Example 3 Crystalline polypropylene powder containing 164 ppm of residual catalyst as CI 100? 2,6 as an antioxidant against
- Di-t-butyl-P-methylphenol 0.12P dilauryl thiodipropionate 0.22 was added, and a predetermined deactivating agent was added in 10 times the mole relative to the CI content, and then heated to 200 to 220°C. The mixture was kneaded for 10 minutes using a vented extruder.

The polypropylene was then pressure-molded into a 3'I/1m disc at 230°C, the degree of coloring of the polypropylene was determined, and the amount of C1 remaining in the polypropylene was measured using fluorescent X-rays. The results are shown in Table 2. Obtained.

For comparison, the results obtained when no deactivating agent was added (Comparative Example 3) are also shown in Table 2.

Claims (1)

[Scope of Claims] 1. The residual polyolefin of the halogen-containing catalyst is treated with a polyolefin having a general formula (wherein R1 represents hydrogen or has a carbon number of 1 to 10 and may contain oxygen in the carbon chain). Represents a hydrocarbon residue, and R2 represents a hydrocarbon residue having 1 to 10 carbon atoms that may contain oxygen in the carbon chain. R1 and R2 represent R1 and R1, R1 and R2, or R2 and R2 may mutually form a cyclic structure. Also, n is an integer of O to 2. .