CS223264B1 - Method of isolation of the dien polymere with reactive functional groups in the chain - Google Patents

Description

The ^y n ^and falsehood ^of ESI from squibs Úsobí ^{p p} ol ^y mer reakUvními with functional groups in the chain prepared by anionic polymerization in the presence organoalkylových compounds or alkali decomposition of the polymer gel obtained by functionalization of the living polymer solution.

Degradation of the gel polymer is effected by adding reagents simultaneously hnětern reacting the mixture at ^t ^ e ^p lo ^TE - ³⁰ ° to 4-8 degrees Celsius for at least 5 seconds. It works particularly under pressure of 0.1 to 4.0 MPa and the mixture treated with a minimum power of 15 W / ^{kg of} a mixture. ^{* H} o ou ^{d PU} with ^b in the perfect mixing .gel polymer with a decomposition agent, thereby achieving more complete ^gamma c ^hl ar ej ^SiH r o ^{p h by} BE uc ^h emic ^Ké rea tion between ^the two components.

The invention relates to a process for the isolation of chain-reactive diene polymers prepared by anionic polymerization in the presence of an organometallic compound or an alkali metal polymerization initiator.

Anionic polymerization of unsaturated compounds in aliphatic or aromatic solvents and ethers in the presence of initiators based on organometallic compounds or alkali metals can be prepared from unsaturated compounds, such as butadiene, isoprene, alpha-methylstyrene, styrene and others, so-called "living polymers" chain ends of the reactive organometallic group.

These living polymers react with various substances to convert the organometallic groups into reactive functional groups, for example, carboxyl, hydroxyl, mercaptan and others. Suitable functionalizing agents are, in particular, carbon dioxide, alkylene oxides, aldehydes, ketones, oxygen, sulfur and others.

The process of functionalization is described chemically in a number of publications, for example GB 1 029 451 and GB 921 803.

In the course of functionalization, carboxylic acid salts, metal alcoholates, mercaptides and the like are formed first, which associate in a low-polar environment and the solution suddenly turns into a gel. This causes problems both in the technological implementation of the functionalization process and in the subsequent polymer gel decomposition. According to known methods, the resulting gel is decomposed by hydrolysis. The resulting gel is collected at the bottom of the reaction vessel and is hydrolyzed directly therein with water or acid, or is discontinuously transported further for hydrolysis, washing and isolation from solution.

The disadvantage of this process is the high viscosity of the polymer gel, which makes it very difficult to handle it. In the initial phase, it can practically not be mixed and the reaction with the decomposition agent is therefore only controlled by diffusion. The reaction time at room temperature is then considerably long, lasting 24 L more hours. The reagent must use a considerable excess over the molar ratio of reagent to alkali metal (lithium) present in the gel. When working with larger volumes, the reaction time becomes even longer, as the volume to contact area / reactive reagent ratio decreases as the volume increases. It is therefore necessary to accelerate this reaction.

Upon dissolution of the gel, a heterogeneous mixture is formed, at the bottom of the reaction vessel, reaction products containing alkali metal salts with initiator residues and excess reagent accumulate. It is not ensured that the reagent has completely reacted with the polymer gel in its entire volume. If the reaction mixture is stirred at this stage, stable emulsions are formed very easily, stabilized by the alkali metal reaction products, which are very difficult to separate and prevent further. processing, separating the reaction products from the polymer solution, especially in the case of hydroxyl-functional polymers.

The above drawbacks eliminate the process of isolating liquid reactive diene polymers prepared by anionic polymerization in the presence of an organoalkyl metal compound or an alkali metal initiator followed by functionalization and decomposition of the obtained polymer gel by water or acid hydrolysis according to the invention, which comprises: The polymer gel is decomposed upon decomposition at a temperature of from -10 ° C to 80 ° C for at least 5 seconds to form a solution of the polymer in the hydrolyzing agent and a phase containing the initiator residues and reaction products of the hydrolyzing agent with the metal atoms contained in the initiator. The polymer is then separated and the polymer is isolated by evaporation of the hydrolyzing agent.

The decomposition of the gel can be carried out under the evacuation of the generated heat, at a pressure of 1 to 40 bar. The mixture should be applied with an energy of at least 15 Watts per 1 kg of the mixture.

An advantage of the process of the invention is that it allows for substantially better contact between the polymer gel and the degradant. The reaction proceeds considerably faster with substantially less reagent. Under these conditions, emulsion formation tendency is considerably less. By suitable choice of reaction conditions, their formation can be practically prevented.

The gel decomposition can be easily carried out as a continuous process on various kneading machines, for example, screw extruders, or screw agitators, or other mixing and milling machines which may optionally be used. adjusts.

The process of the invention is. further explained in the following 'Examples' of the embodiment.

Example 1

Initially, a solution of live polybutadiene having a molecular weight of 2100 was prepared in a manner known per se. The reaction mixture is charged into a reactor containing 84 parts by weight of a solution of 1,4-dithithiobutane in methyl tert-butyl ether. with a concentration of 0.68 mol / kg and 290% by weight. parts of toluene was added gradually with stirring over 90 ml ^. at 50 ° C, 100 parts by weight of 1,3-butadiene. The solution of live butadiene in toluene and methyl tert-butyl ether had a concentration of 22% by weight of polybutadiene and a viscosity of 105 mPa. with.

The living polymer solution was fed to a screw reactor in which a temperature of 5 ° C was maintained. At the same time, a solution of ethylene oxide in toluene at a concentration of 60% by weight of ethylene oxide was added in an amount to maintain a one molar excess of ethylene oxide relative to the active lithium in the living polymer. The residence time of the mixture was 45 s. A solid gel in the form of a string emerged from the screw reactor. Originated

The gel was then decomposed by addition of water in a 5 molar excess to the C-Li bonds. The polymer gel was only overlaid with water and then allowed to stand overnight. After about 20 hours of standing, the polymer gel disintegrated and a low viscosity polymer solution was formed which appeared to be clearly inhomogeneous. A water layer has formed at the bottom of the vessel with a fuzzy interface between the polymeric and aqueous phases. Since the system was not mixed with water, neither the homogeneity of the polymer solution nor the guarantee that it reacted well with water is guaranteed. Therefore, the obtained solution was mixed by hand with a glass rod. The sediment settled at the bottom of the vessel and formed an emulsion, which was then separated by centrifugation at 15 ° C and 2000 G under these conditions. the amount of sediment in which a significant portion of the alkali compounds derived from the initiator residues were concentrated. The polymer solution thus obtained had a further 164 mmol / l. After extraction with water, the alkalinity was reduced to 27 mmol / l (titrated to acid-base indicator neutral red).

Example 2

The polymer gel obtained according to Example 1 was decomposed with a 5 molar excess of water to the C-Li bonds in a Sfinx cast iron screw extruder with a manual drive. Said machine is used in a household jgko meat grinder. Its worm length 140 mm and diameter 50 mm contains 5 turns. The distance between the threads is 23 mm. The cylinder has a length of 150 mm and an inner diameter of 55 mm. At the outlet, the movement is equipped with a cross-cutting rotor, which ensures mixing and extrusion of the kneaded material and passaging through a series of holes of about 3 mm diameter.

The solid polymer gel was fed into the screw machine by hand using a metal trowel and at the same time the water needed for hydrolysis was dosed using a Unipan 335 A metering pump. A polymer solution with a small amount of thin gel was discharged from the screw mixer and returned to the machine. After homogenization, a practically clear polymer solution was formed and an aqueous phase having a volume of about 2 percent by volume polymer phase was deposited at the bottom of the vessel.

Example 3

The living polybutadiene solution was prepared

264 out in the same manner as in Example 1, except that methyl tert-butyl ether was used as the polymerization solvent. The polymerization batch consisted of 76 parts by weight of methyl tert-butyl ether and 4.3 parts by weight of 1,4-dilithiobutane. 100 parts by weight of 1,3-butadiene were gradually added to the batch over 75 minutes. The temperature was maintained at 30 ° C.

A solution of living polybutadiene having a concentration of 51% polybutadiene was obtained, which had a viscosity of 130 mPa.s at 30 ° C. Functionalization in the screw device with ethyleneidide, as in Example 1, produced a gel which was decomposed in the screw device by the addition of a 4 molar excess of water to the present C-Li bonds.

A polymer solution with a small amount of thin gel was discharged from the screw mixer, which was dosed through a polyamide screen into a collection vessel. The thin gel was largely dissolved by passing the polymer solution, and the remainder was returned to the screw device. A low-viscosity polymer solution was already emerged from there.

Example 4

The living polybutadiene solution prepared in the same manner as in Example 1 was carboxylated in a known manner by treatment with gaseous carbon dioxide. The resulting gel was fed into the screw machine by hand using a metal trowel and at the same time the HCl solution needed to decompose the gel was dosed by means of a metering pump. A polymer solution with a small amount of thin gel was discharged from the screw mixer and returned to the machine. After homogenization, a practically clear polymer solution was formed and an aqueous phase having a volume of about 2% by volume of the polymer phase was deposited at the bottom of the vessel.

Example 5

The carboxylated polybutadiene gel prepared in the same manner as in Example 4 was fed into the screw machine by hand using a metal trowel, and at the same time a solution of HCl in toluene needed to decompose the gel was dosed by means of a metering pump. A polymer solution with a small amount of thin gel was discharged from the screw mixer and returned to the machine. After homogenization, a practically clear polymer solution was formed and a sediment containing decomposition products from the initiator settled at the bottom of the vessel.

Claims (4)

OBJECT OF INVENTION Process for the isolation of chain-reactive diene polymers prepared by anionic polymerization of dienes in the presence of an organometallic compound or an alkali metal initiator, followed by functionalization and decomposition of the obtained polymer gel by hydrolysis with water or acid, characterized in kneaded at a temperature of -10 to - ^L 80 ° C for at least 5 seconds to form a polymer solution and the hydrolyzing agent phase containing residues of initiator and reaction products of the hydrolysis agent with the metal atoms contained in the initiator, these are then separated from one another and the polymer is is isolated by evaporation of the hydrolyzing agent. 2. Process according to claim 1, characterized in that the kneading is carried out at a pressure of 0.1 to 4.0 MPa. 3. A method according to claim 1 or 2, characterized in that kneading is applied to the mixture with at least 15 W of energy per kg of mixture. 4. Method according to claims 1 to 3, characterized in that the kneading is carried out with removal of the heat produced.