JPS5830884B2 - Method for producing polyolefin polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polyolefin polymer having excellent heat aging resistance, weather resistance, and good hue.

More specifically, the present invention relates to a method for easily rendering harmless a small amount of catalyst residue remaining in a polymer even after a catalyst deactivation operation.

When one or more 1-olefins such as ethylene, propylene, butene-1, pentene-1, and hexene-1 are polymerized using a Ziegler-Natsuta type composite catalyst, is the removal of catalyst residues insufficient? Alternatively, if the catalyst residue is not removed, thermal deterioration may occur during heat treatment of the product, the hue may deteriorate, and the heat aging resistance and weather resistance of the product may also be impaired.

The allowable amount of residual catalyst is 30 ppm (preferably 10 ppm) or less as a transition metal content, but the degree of influence on polymer quality varies greatly depending on the catalyst system and/or deactivator used.

In the conventional method, the catalyst components are decomposed and dissolved using a large amount of alcohol after polymerization, and then washed.
The recovery and purification process for chemicals such as alcohol and cleaning fluids has significantly impaired the economic efficiency of industrial production of polyolefins.

The method of the present invention eliminates the need for an expensive catalyst residue removal step as in conventional methods, and also eliminates restrictions placed on the selection of catalyst systems and deactivators.

That is, for a polyolefin polymer polymerized using a Ziegler-Chick type composite catalyst and then deactivated under non-aqueous conditions, 0.1 to 10% by weight φ weight and 0.01 to 10% by weight for water. More than 30% by weight of surfactant is mixed and heated to a temperature higher than the melting temperature of the polyolefin polymer using a bed extruder in the presence or absence of a stabilizer to form a polymer while removing volatile components from the vent part. This is a method for producing a polyolefin polymer, which is characterized by extruding a polyolefin polymer.

Here, the Ziegler-Natsuta type composite catalyst means Ti or ■
It is a catalyst whose main components are a transition metal component consisting of and an organoaluminum component.

Transition metal components include titanium tetrachloride, triangular titanium,
Titanium tetrachloride or titanium trichloride supported on a magnesium compound carrier, or a complex of these with an electron-donating compound, vanadium tetrachloride, vanadium oxychloride, vanadium tetrachloride or vanadium oxychloride supported on a magnesium compound carrier, or these. A mixture of

Organic aluminum components include trialkyl aluminum, dialkyl aluminum hydride, dialkyl aluminum chloride, imprenyl aluminum,
Bis(dialkylaluminum) oxide, bis(dialkylaluminum) sulfuric acid, or a reaction product of these with an alcohol is used.

The third precept is silicon compounds, N, P, 0. An organic compound containing S or the like may be added.

After the polymerization reaction is completed, the product can either stop the polymerization by removing the monomer without adding a deactivating agent, or add a deactivating agent to stop the polymerization, but alcohols (methanol: Ethanol: n- or 1so
- propatools: n, sec, or 1so-butanol, etc.), ketoesters (methyl acetoacetate, ethyl acetoacetate, etc.), epoxides (propylene oxide,
butylene oxide, cyclohexene oxide, etc.), amines (
laurylamine, etc.), fatty acids (stearic acid, etc.),
Examples include diketones (acetylacetone, etc.).

The surfactant may be cationic or anionic, but nonionic surfactants give the best results.

Ethylene oxide adducts of alkyl or alkylaryl alcohols and alkyl or cycloaliphatic esters give excellent results.

The amount of water used is generally 0.1-1 based on the polymer.
It is necessary to limit the amount of water to 10 weight φ.
If the extruder exceeds surging, it becomes difficult to operate the extruder, and a weight multiplicity f of 0.1 is insufficient to render the catalyst residue harmless.

Generally, the amount of surfactant should be kept at 0.01 to 30% by weight relative to water; if the amount used is less than 0.01% by weight, the polymer will not leak out and the polymer will get stuck in the extruder. In addition, when the polymer is heated in the extruder, vaporized water flows back into the feeder, making operation difficult.

If the amount used is more than 30 weight φ, it becomes viscous and difficult to handle, and a large amount of surfactant remains in the product polymer, which may cause problems in some cases.

Japanese Patent Publication No. 44-2227 proposes a method of deactivating the remaining catalyst in the polymerized polyolefin by treating it with an alkaline aqueous solution in an extruder under softening conditions.

However, in this case it was found that the polymer was susceptible to thermal degradation in the extruder and the color of the product was also unsatisfactory.

Japanese Patent Publication No. 49-38035 describes small amounts of epoxy group-containing compounds, esters of phosphoric acid, phosphorous acid, boric acid or carbonic acid,
It is stated that if the catalyst is inactivated with oxygen or steam and is extruded at 250°C or higher, the molecular weight of the polymer will decrease significantly due to thermal decomposition, and the heat aging resistance of the product will also be poor. was recognized.

Japanese Patent Publication No. 39-18947 used diketone-treated polymers at 220
This method involves contacting with water vapor at a temperature of 104 to 135°C (104 to 135°C), but is limited to specific deactivators and requires equipment for contacting with water vapor.

Japanese Patent Publication No. 49-32313 proposes a method in which the catalyst residue after polymerization is brought into contact with a small amount of the vapor phase of an epoxy compound or alcohol, and then with water vapor, without performing an elution treatment.

However, as stated in the specification, it requires a long time (about 30 minutes) for contact with water vapor, and furthermore, it requires drying of the polymer, resulting in a rather large-scale equipment.

According to the method of the present invention, the polymer, which has been previously treated with a deactivating agent under non-aqueous conditions or without being treated with a deactivating agent and, if necessary, washed with a non-aqueous detergent, is treated with a surfactant. The mixture is mixed with water containing the agent and fed to a vented extruder.

Due to the action of the surfactant, water is uniformly dispersed and mixed with good affinity for the polymer, bringing the polymer into a wet state.

In the extruder, water evaporates due to the action of heat, and at this time it reacts with the catalyst residue in the polymer, completely rendering the residue harmless, thus preventing thermal decomposition and color deterioration of the polymer in the melt extruder.

The heated water is discharged through the ventro.

Volatile components such as solvents, deactivators, catalyst decomposition products, and catalyst additives that are contained in the polymer and are entrained in the polymer before being treated with the method of the present invention are evaporated from the vent part along with water, so they are not volatile in the product polymer. It also has the effect of keeping the water at a low level and eliminating odors.

The invention can also be extended by separately charging the extruder with the polymer and the water containing the surfactant.

According to the method of the present invention, the selection range of deactivating agents is widened, and deactivating agents that, in the conventional method, had a large deashing effect but were unsatisfactory in terms of color and thermal stability of the product, for example, Good quality products can be obtained even when using compounds that tend to color the polymer, such as diketones and higher amines.

In the production of polyolefins, stabilizers such as heat stabilizers, hydrochloric acid absorbers, ultraviolet absorbers, slip agents, and antistatic agents are usually added.

The stabilizer may be added to the polymer before mixing with water or after the water removal operation in a ventro.

The latter is preferred in the case of readily volatile stabilizers. The vented extruder used in the process of the invention may be a single-screw or twin-screw machine customarily used for pelletizing polyolefins.

The vent may be either one stage or two stages, but a single stage vent is sufficient if operating conditions are appropriately selected.

Although the extrusion temperature varies depending on the type of polymer, it is generally at least the melting temperature of the polymer and at most 300° C. from the polymer feedthrough to the ventro.

If the temperature of the polymer near the vent hole is low, the color of the product will be poor, and if it is too high, venting will occur and operation will become impossible.

The residence time of the polymer in the extruder is usually 1 to 7 minutes, within which time the effects of the invention are fully achieved.

As can be seen from the above description, the method of the present invention can be carried out without significant additional equipment and, in combination with polymerization using recently developed highly active catalysts, simplifies the deactivation, washing and drying steps. It is effective for

The present invention will be explained in detail below with reference to Examples.

Example 1 A stainless steel autoclave with an internal volume of 500 L was charged with 150 kg of liquefied propylene, titanium tetrachloride was reduced with aluminum as a catalyst, and 10 parts by weight of diethyl ether was added and co-pulverized to produce 20 g of titanium trichloride.
, diethylaluminium monochloride 40.9 and ethyl anisate 2g were added and reacted at 60°C for 4 hours,
Then, isobutyl alcohol 2509 was used as a deactivator.
and 150 g of propylene oxide were added and treated at the same temperature for 30 minutes.

After repeated washing with approximately 150 to 9 liquefied propylene,
The slurry was flashed from a high pressure area to a low pressure area through a heated flash tube to evaporate propylene, yielding 74 kg of dry polypropylene powder.

The ash content of the powder is 50ppmTE, the Ti content is 7ppm,
Moreover, MI was 5.0.

To 100 parts of this polypropylene, 2 parts of distilled water and 0.0 of Neugen EA-92 (polyethylene glycol octylphenyl ether, manufactured by Dai-Koyaku ■) as a surfactant.
0.02 parts, 0.2 parts of calcium stearate and 0.1 parts of 2.6-di-tert-butyl cresol as stabilizers were added and mixed for 5 minutes at room temperature in a Henschel mixer, and then mixed in a 65 mm diameter one-stage vent type. Extruder (screw diameter D
m m and screw length Lmm, L/D=2
6. The ventro is located at 16D from the hopper.

) at a speed of 30 kg for 1 hour.

During the extrusion operation, the Ventro continued suction with a vacuum pump.

The resin temperature at the die exit was 210'C.

The polymer released from the die opening was immediately introduced into cold water, solidified, and then cut to obtain colorless pellets.

The MI of this product was 5.2, the volatile content was 0.2% (water content was 92 ppm), the Ti content was 7 ppm, and the chlorine content was 7 ppm.

The pellets were dipped in hot water at 80°C and smelled, but no odor was detected.

Regarding injection sheet, heat aging resistance (JISK
-6301) and weather resistance (J I 5A-1415).

Comparative pellets were obtained in exactly the same manner except that water and surfactant were not used during pelletization.

Table 1 shows a comparison of physical properties. In addition, the Ti content of Comparative Example-1 was 7
The chlorine content per ppm was 20 ppm.

Example 2 Using 174 kg of butane as a solvent, 3 g of a solid catalyst obtained by co-pulverizing 77 parts of magnesium chloride, 15 parts of diphenyl ether, and 8 parts of titanium tetrachloride, and 25.9 g of triethylaluminum co-catalyst were added, and after adding 350 ONl of hydrogen, ethylene was added. was polymerized at 85° C. under condition F of 30 ky/− for 3 hours.

After stopping the reaction with 16g of propylene oxide, it was flash dried to produce 95k of white powdered polyethylene with an MI of 5.5.
I got g.

To 100 parts of this polyethylene, 5 parts of distilled water, 0.005 part of cationic surfactant Electrostripper 771 (manufactured by Kao Atlas ■, polyamide type), 0.1 part of calcium stearate, and 2.6-ditertiarybutyl. 0.03 part of cresol was added and mixed for 5 minutes at room temperature using a Henschel mixer.

120mm diameter twin screw extruder (Japan Steel Works CIM120
), and after melting and kneading (resin temperature 180'C) while vacuuming the volatile components from the chute, the pellets had an MI of 53 and were volatilized using an extruder (P-150 manufactured by Japan Steel Works, Ltd.). The water content is 0.16% (moisture content is 160 ppm)
)Met.

Pellets with an MI of 4.8 were obtained by performing the same procedure except that water and surfactant were not used during pelletization.

A comparison of physical properties is shown in Table 2 as Comparative Example-2.

Claims (1)

[Claims] 1 for a polyolefin polymer polymerized using a Ziegler-Natsuta type composite catalyst and then deactivating the catalyst under non-aqueous conditions. l to 10% by weight of water and 0.
01 to 30% by weight of surfactant is mixed, heated to a temperature higher than the melting temperature of the polyolefin polymer using a bed type extruder, and the polymer is extruded while removing volatile components from the bed part. A method for producing a polyolefin polymer.