JPS60127303A - Removal of low-boiling point component from liquid polymer - Google Patents

Abstract

PURPOSE:To efficiently remove at low temperatures under reduced pressure low- boiling component(s) as odoriferous source from a liquid polymer, that is, without impairing the properties of said polymer, by incorporating, in advance, specific amount of water or steam is said polymer. CONSTITUTION:For example, 95-60(pref. 90-80)wt% of a liquid polymer such as butadiene, isoprene or polybutene is incorporated with 5-40(pref. 10-20)wt% of water or steam followed by keeping the system at 100-130 deg.C under a pressure <=50mm.Hg, thus removing low-boiling components) (e.g. dimer, trimer as odoriferous source from said polymer. EFFECT:Furthermore, capable of eliminating water-soluble catalysts in said polymer with said catalysts accompanying the water or steam.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for removing low-boiling components from a liquid polymer, and more particularly, to a method for efficiently removing low-boiling components without changing the properties of the polymer.

The polymerization reaction product, which is liquid at room temperature, often contains low-boiling components such as by-product monomer dimers, monomers, or their rust conductors.

Therefore, problems such as low purity of the liquid polymerization reaction product and odor have occurred.

As a method for removing low boiling point components, it is generally known to strip the low boiling point components at high temperature and under reduced pressure.

However, even if the temperature in vacuum distillation is increased or the degree of vacuum is increased, the low-boiling components are not easily reduced, and large temperature increases can increase the viscosity of the polymer, causing coloration, oxidation odor, etc. There was a risk that the properties of the liquid polymerization reaction product would be altered. The inventors of the present invention have conducted intensive research to solve these conventional problems. As a result, we have found that before removing low-boiling components from the liquid polymerization reaction product under reduced pressure, we preheated the liquid polymerization reaction product with water or steam. The present inventors have discovered that low-boiling components can be efficiently removed at low temperatures, without the risk of deteriorating the polymer properties, by adding the above liquid polymerization reaction product to the liquid polymerization reaction product, and have completed the present invention. Ta.

That is, the present invention provides a method for removing low-boiling components from a liquid polymer, in which 5 to 40% by weight of water or steam is added to 95 to 6% by weight of the liquid polymer, and the temperature is 100% by weight.
The present invention provides a method for removing low-boiling point components from a liquid polymer, which is characterized in that the low-boiling point components are removed while maintaining the temperature at ~150° C. and the pressure at 50 μHg or less.

The liquid polymer to which the present invention can be applied, that is, the polymer that is liquid at room temperature, is not particularly limited and includes various polymers. Specifically, for example, butadiene, isoprene,
In addition to conjugated diene polymers such as νp-prene and olefin polymers such as polyptezo, polyethylene, and polypropylene, it can also be used for polymers such as polyethylene glycol and polypropylene glycol. It has been difficult to remove low-boiling components from conjugated diene polymers, but according to the present invention, low-boiling components can be removed without changing the product properties, and the water-soluble catalyst in the polymer can also be removed. Since it can be removed together with water or steam, the present invention can be particularly effectively used to remove low-boiling components from conjugated diene polymers. Furthermore, in the case of conjugated diene polymers, oxidation odors are particularly likely to occur when the temperature of vacuum distillation is raised to remove low-boiling components as in conventional methods, but the present invention eliminates this problem. In the present invention, the above liquid polymer is used in a proportion of 95 to 60%.
5 to 40% by weight of water or steam to 11t%, preferably 90 to 80% of the former to 10 to 2% of the latter.
Add 0 weight melon%. That is, preferably the overlapping ratio of the former to the latter is in the range of 9o,/i0 to 80/20. Here, the amount of water or steam added is 5 ftt%
If the amount is less than 40% by weight, the removal effect will be low, and if the amount of water or steam added exceeds 40% by weight, the processing density will increase and the load will be large, requiring increased capacity, which is not preferable.

As mentioned above, after adding water or steam to the liquid polymer, low boiling point components are removed while maintaining the liquid polymer under the following conditions.
20°C, pressure 50II2IHg or less, preferably 110
Process while keeping the value below 11111H. If the treatment temperature is less than 100°C, it will be difficult to sufficiently remove low-boiling components, while if it exceeds 130°C, the properties of the polymer may change, which is not preferable. On the other hand, if the pressure exceeds 50 mEg, the removal effect will be low, which is not preferable.

This heating and depressurization treatment can be performed using a closed device equipped with a stirrer as shown in Fig. 1, but IP! It is preferable to use a thin film evaporator as shown in FIG. When using this thin film evaporator, the rotation speed is adjusted so that the linear velocity is 6 to 15 m/sea.

When using the present invention to remove low-boiling components from a conjugated diene polymer, if the following treatment is performed during the production of the conjugated diene polymer, the conjugated diene polymer can be processed with almost no polymer loss. It can be efficiently produced without changing the properties of the polymer.

That is, when producing a conjugated diene monomer that is liquid at room temperature by polymerizing a conjugated diene monomer using a solvent containing alcohol as a polymerization reaction solvent and a water-soluble catalyst as a polymerization catalyst, the above-mentioned conjugate The diene monomer is polymerized, and then the reaction mixture containing the conjugated diene monomer (i.e., the reaction mixture containing the unreacted or conjugated diene spinning wheel cover added after the polymerization reaction) is conjugated with the conjugated diene polymer. An oil phase containing a diene monomer as a main component is separated, and the conjugated diene monomer is removed from the oil phase.

Polymers can be produced with good yield from K, but if the method of the present invention is applied to the conjugated diene polymers obtained in this way, low-boiling components can be added without changing the properties of the polymer. can be removed with very favorable results.

According to the present invention, low-boiling components, ie, odor components, can be removed from a liquid polymer without changing the product properties. Moreover, according to the present invention, water-soluble catalysts in the polymer can also be removed by entraining them with water or steam.

Next, the present invention will be explained using examples.

Examples 1 to 5 and Comparative Examples 1 to 3 Liquid polymers having the following compositions 1 to 3 were heated in a thin film evaporator 1 (clearance O = 1.5 m, transmission The treatment was carried out under the conditions shown in Table 1 using a heating surface of 0.1 W?). The results are shown in Table 1.

Composition ■ Conjugated diene polymer (product) - 96.5% by weight (liquid rubber R-45HT manufactured by Idemitsu Petrochemical ■) ■ Vinyl cyclohexene (low boiling point component) 6.5wt i1% Table 1 1 Paper outlet Amount of evaporation from 3・2 Product extracted from bottom outlet 4・3 Rotational speed 92 Or, push.

+14 Rotation vIi615 r, Bm In addition, in the case of comparison rows 1 to 3, the odor was stronger than in Examples 1 to 5.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one example of the apparatus used in the method of the present invention, and FIG. 2 is a partially cutaway front view showing another example of the apparatus used in the method of the present invention. 1... Thin film evaporator, 2... Stock solution inlet. 3.0. Paper outlet, 4...bottom outlet. 5...tPJ stirring blade, C...Clearance patent applicant Idemitsu Petrochemical Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] 1. In a method for removing low-boiling components from a liquid polymer, 5 to 40% by weight of water or steam is added to 95 to 60% by weight of the liquid polymer, and the temperature is 100 to 15oC. ,
A method for removing low boiling point components from a liquid polymer, the method comprising removing the low boiling point components while maintaining the pressure at 501 mlHg or less. The removal method according to claim 1, wherein the λ liquid polymer is a conjugated diene polymer.