JPS6031855B2 - Method for producing particulate atactic polypropylene - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing particulate atactic polypropylene.

More specifically, the present invention relates to a method for converting coarse atactic polypropylene containing a relatively large amount of catalyst residue into particulate atactic polypropylene at the same time as removing the catalyst residue.

When producing stereoregular polypropylene or a copolymer of propylene with other Q-olefins, the so-called atactic polypropylene, which is reactive, impairs the physical properties of stereoregular polypropylene or a copolymer of propylene with other Q-olefins. Therefore, it is removed from the product polypropylene.

As a method for removing the accessory atactic polypropylene, a solvent polymerization method using a transparent polymerization medium yields the stereoregular polymer as an insoluble part in the polymerization medium and the accessory atactic polypropylene as a soluble part. After polymerization, the catalyst residue is solubilized with alcohol, etc., and then extracted with water, so it is rich. There are few catalyst residues in the reactive polypropylene. The stereoregular polymer is then removed by a method such as filtration, and the secondary atactic polypropylene is
Obtained by removing the solvent by distillation or the like. The obtained atactic polypropylene is so viscous that it cannot be obtained in pellet form using an ordinary extruder, and is usually shipped in plate form. On the other hand, with recent improvements in catalyst performance, it is now possible to remove the medium and the atactic polypropylene soluble in the medium by filtering the stereoregular polymer without solubilizing the catalyst residue or extracting it with water. It is becoming possible to provide usable stereoregular polymers for general applications.

Also, without using an inert medium. In the bulk polymerization method using pyrene itself as a medium, the amount of polymer obtained per catalyst is larger than when using the above-mentioned inert medium, so it is necessary to solubilize the catalyst residue with alcohol etc. It is known that a product with less catalyst residue can be obtained by recovering the stereoregular polymer as a solid portion, such as by using a method such as the following. With these methods, it is possible to keep the amount of catalyst residue in the stereoregular polymer at a fairly low level, but soluble atactic polypropylene has side effects when recovered by evaporating the medium (inert medium or propylene). Catalyst residues will be concentrated in the atactic polypropylene.

Atactic polypropylene, which is produced as a by-product during the production of stereoregular polypropylene or stereoregular polypropylene-Q olefin copolymer, is usually incinerated as a fuel, or
Alternatively, it is blended and crosslinked with polymers containing other unsaturated bonds and used for various purposes, but when incinerated as a fuel, the halogen content of the catalyst residue must be extremely high. It is not practical to reduce the number to a small level, for example, 5 or less, because the incinerator will be damaged. On the other hand, regarding the use of molded products, the halogen content must be low even in the catalyst residue, and furthermore, it is necessary to blend it with other polymers,
For molding, it needs to be easy to handle. As a result of various studies, the inventor of the present invention has found that by treating atactic polypropylene containing a relatively large amount of catalyst residue using a specific method, particulate atactic polypropylene with less catalyst residue can be obtained. The present invention was completed based on these findings.

In the present invention, after contacting atactic polypropylene with water, a surfactant, and carboxylic acid in a molten state in the presence or absence of a solvent,
The present invention relates to a method for producing particulate atactic polypropylene, which is characterized in that, if a solvent is present, the solvent is removed by distillation, then cooled under a rope sieve, and separated. There are no particular restrictions on the atactic polypropylene to which the method of the present invention is applied, but the intrinsic viscosity measured with a 135 oo tetralin solution is 0.05 to 2.0, usually 0.1 to 1.
0, and may contain comonomers such as ethylene, butene, butadiene, isoprene, etc. in addition to propylene.

The catalyst residue used is usually 30 to 2,000 blood, the halogen content is usually 30 to 2,000, and the metal content is Ti, mountain, Mg, etc. That's fine. Preferably, the metal content is 5 x 10-6 moles or more and the chlorine content is 5 x 10 moles or more.
-6 moles to lk9 atactic polypropylene or more.

There are no particular restrictions on the surfactant used in the method of the present invention, but when the reaction is carried out under acidic conditions, an acid-resistant surfactant is used, and when the reaction is carried out under alkaline conditions, an alkali-resistant surfactant is used. It is preferable to use Various carboxylic acids are used as the carboxylic acid used in the method of the present invention, but generally have a general formula R-C having 1 to 40 carbon atoms.
Monobasic acid represented by OO (in the formula, R is hydrogen or a hydrocarbon residue having 1 to 39 carbon atoms) or R- having 2 to 40 carbon atoms
A dibasic acid represented by (COOH)2 or the like is used.

Further, the above carboxylic acid can also be used in the form of a metal salt. The method of contacting water with the above-mentioned surfactant, carboxylic acid, or atactic polypropylene is described in detail below; the presence of a hydrocarbon solvent such as hexane, heptane, kerosene, toluene, or It is also possible to have an alkali such as , NaOH, Ca(OH)2, KOH, NH40, etc. present.

The contact treatment temperature of surfactant, carboxylic acid, atactic polypropylene and water may be at least the melting temperature of atactic polypropylene, preferably 80 to 200 oo when no solvent is present, and 40 oo when solvent is present.
~150qo.

The contact treatment time is 1 generation to 1 feeding time, and the preferred time varies depending on the shape of the contact treatment device and the degree of fly worship, but is usually 30 minutes to 5 hours. The amount of water used is 0.5 to 50 times the amount of atactic polypropylene, usually 1 to 2 times the amount of atactic polypropylene.

The amount of surfactant used varies depending on the type of surfactant, but is usually 0.1 to 5 wt% of water, and the amount of carboxylic acid used is from the same mole as the metal present in the atactic polypropylene to 10% by weight. It is preferably used in an amount of 0.1 to 5 wt % based on moles of moss or atactic polypropylene. After the above-mentioned contact treatment, if a solvent is used, remove the solvent, or if not, cool it while cooling it, usually below 100 qo, preferably 50 to 80 qo, and then remove the solvent. Separation of atactic polypropylene from water usually yields atactic polypropylene as spherical particles with a radius of 1 to 1 Q rib.

By the above operation, atactic polypropylene is obtained in a purified state and in the form of approximately spherical particles, which is extremely effective industrially.

The present invention will be explained in more detail with reference to Examples below. Examples and Comparative Examples Chlorine 1.1 wt%, total ash 3.64 M% (M
%, N2032.1wt%, Ti0230) containing atactic polypropylene, intrinsic viscosity 0.5 (13
The samples were treated under the conditions shown in Table 1 in a two-piece autoclave (equipped with a fly azusa machine) whose interior was lined with glass.

As is clear from the results, the combination of surfactant and carboxylic acid is spherical, and both chlorine and total ash can be removed efficiently. Shameful discussion.

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Claims (1)

[Scope of Claims] 1 Atactic polypropylene is subjected to a contact treatment with water, a surfactant, a carboxylic acid, and a molten state of atactic polypropylene in the presence or absence of a solvent with stirring, and then, if a solvent is present, A method for producing particulate atactic polypropylene, which comprises distilling off the solvent, followed by cooling and separation with stirring. 2. A patent in which the atactic polypropylene before treatment contains at least 5x10^-^6 mol/kg or more of a metal selected from Al, Ti, and Mg and 5x10^-^6 mol/kg or more of chlorine. The manufacturing method according to claim 1.