JPS62164B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for processing crude atactic polypropylene containing relatively large amounts of chlorine as catalyst residue to obtain non-corrosive atactic polypropylene. So-called atactic polypropylene, which is a by-product during the production of stereoregular polypropylene or copolymers of propylene with other olefins, is removed from the product polymer because it impairs the physical properties of the stereoregular polymer. In the method of damaging stereoregular polymers by polymerization using a chlorine-containing catalyst, in the usual solvent method, the polymer slurry is treated with alcohol, water, etc. to remove catalyst residue, and then the product polymer remains as an insoluble part. can get. On the other hand, a solution of atactic polypropylene is obtained as the part soluble in the solvent, and then the atactic polypropylene obtained by evaporating and removing the solvent usually contains no chlorine.
100-300ppm or less than 50ppm can be obtained in some cases. However, with recent improvements in catalyst performance, the method for removing catalyst residues from the produced polymer slurry has been simplified, and the catalyst residues can be simply solubilized in a solvent and separated from the solvent by a method such as filtration. It has become possible to obtain products with In addition, in the polymerization method using propylene itself as a medium, since the yield per catalyst is relatively large, the catalyst residue is solubilized in propylene and then separated from the medium by filtration to remove the propylene-insoluble parts. You can get the product as. With the above method, it is possible to reduce the amount of catalyst residue in the product, but on the other hand, since the catalyst residue is concentrated in the atactic polypropylene medium solution after separation, it is not possible to simply evaporate this medium. If only the catalyst is removed, the resulting atactic polypropylene will contain a large amount of catalyst residue. Atactic polypropylene is used as a blend material with other resins or in adhesives, etc. However, if it contains a large amount of chlorine, its use is limited due to its corrosive nature, so atactic polypropylene, which is not corrosive, is used. The development of a purification method is desired. The present inventors investigated a method of processing atactic polypropylene, which has a relatively high chlorine content, to obtain non-corrosive atactic polypropylene, and found that by carrying out a specific treatment method, corrosion can be achieved extremely easily. The present invention was completed based on the discovery that it is possible to obtain atactic polypropylene with no chemical properties. An object of the present invention is to provide a non-corrosive atactic polypropylene by treating atactic polypropylene containing a relatively large amount of chlorine. In the present invention, atactic polypropylene containing a relatively large amount of chlorine as a catalyst residue is treated with an oxide, hydroxide or This invention relates to a method for producing non-corrosive atactic polypropylene, which comprises adding a carbonate and carrying out a contact treatment at a temperature of 100°C or higher. There are no particular restrictions on the atactic polypropylene to which the method of the present invention is applied, but the intrinsic viscosity measured in a tetralin solution at 135°C is 0.05 to 5.0.
It is preferably 0.1 to 3.0, and may contain comonomers such as ethylene, butene, butadiene, isoprene, etc. in addition to propylene. The catalyst residue contained is a relatively large amount of chlorine, for example 1000 ppm.
It contains about 1,000 to 50,000 ppm of ash. As the oxides, hydroxides, and carbonates of metals in Groups 1 and 2 of the periodic table used in the contact treatment, anhydrides are preferably used. Specifically, Li ₂ O,
Na ₂ O, K ₂ O, MgO, GaO, LiOH, NaOH,
KOH, Mg(OH) ₂ , Ca(OH) ₂ , Li ₂ CO ₃ ,
They are _Na2CO3 , _K2CO3 , _MgCO3 , _{and CaCO3 .} The usage ratio is 0.5 equivalent or more, preferably 1 to 3 equivalents, relative to the chlorine content in the atactic polypyrene. If the amount is less than 0.5 equivalent, the corrosion resistance will be poor, and even if it is more, the corrosion resistance effect will be almost negligible. It doesn't change. The temperature of the contact treatment is 100°C or higher, and the preferred temperature varies depending on the properties of the atactic polypropylene, but is usually higher than the softening point determined by the ring and ball method. In the contact treatment, it is preferable to achieve as good contact as possible, and it is preferable to use strong stirring means. The contact time should be set to an appropriate time depending on the above-mentioned contact means and the viscosity of the atactic polypropylene. By the above-mentioned operation, it is possible to obtain atactic polypropylene with good corrosion resistance, and it is of great industrial significance. The present invention will be explained in more detail with reference to Examples below. In Examples and Comparative Examples, the generated hydrochloric acid was obtained by placing 10 g of the polymer in a 100 ml flask, keeping it at 250°C, entraining the generated hydrochloric acid or chlorine with nitrogen and absorbing it into water, and quantifying the absorbed Cl ions. and measured. Corrosion is determined by placing a 2 cm x 10 cm copper plate in a test tube with an inner diameter of 3 cm, adding 30 g of attic polypropylene, heating in air at 200°C for 10 hours, and visually determining the degree of corrosion of the copper plate. Chlorine content 10ppm,
Atactic polypropylene containing 3 ppm of generated hydrochloric acid is 1, and atactic polypropylene before treatment (chlorine content 1.2 wt%, generated hydrochloric acid 400 ppm) is 5.
It was evaluated on a five-point scale. Examples 1 to 3 Atactic polypropylene with chlorine content of 1.2 wt% (homopolypropylene with intrinsic viscosity number of 0.23) 100
Add the additives listed in Table 1 and heat to 150°C.
The mixture was treated with stirring for 30 minutes. The treated atactic polypropylene thus obtained was tested for hydrochloric acid generation and corrosivity. Comparative Example 1 Atactic polypropylene was tested for corrosion before treatment. Examples 4 to 5 and Comparative Example 2 Using 100 g of atactic polypropylene with a chlorine content of 0.8 wt% and an ethylene content of 35 wt%, the additives shown in Table 2 were added and treated at 200°C for 30 minutes with stirring. A similar test was conducted using the treated atactic polypropylene obtained. 【table】

Claims (1)

[Scope of Claims] 1 Atactic polypropylene containing a relatively large amount of chlorine as a catalyst residue,
100 by adding oxides, hydroxides or carbonates of metals from Groups 1 to 2 of the periodic table in a proportion of 0.5 equivalent or more.
A method for producing non-corrosive atactic polypropylene, characterized by carrying out a contact treatment at a temperature of ℃ or higher. 2. The method according to item 1, using an oxide of a metal of Groups 1 to 2 of the Periodic Table. 3. The method according to item 1, wherein the contact treatment is carried out at a temperature equal to or higher than the softening point of the atactic polypropylene.