JP2006022209A - Method for recovering n-substituted maleimide-olefin copolymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently recovering an N-substituted maleimide-olefin copolymer by removing a volatile component from an N-substituted maleimide-olefin copolymer solution which contains the N-substituted maleimide-olefin copolymer and a solvent and may contain a volatile component such as an unreacted monomer, a volatile by-product, and an impurity. <P>SOLUTION: The method for recovering an N-substituted maleimide-olefin copolymer comprising recovering the N-substituted maleimide-olefin copolymer from a specific N-substituted maleimide-olefin copolymer solution comprises the steps of: providing a horizontal type closed continuous kneader having a vent-port, supplying the solution from an inlet-port adjusted at the boiling point of the solvent -50°C to the boiling point +100°C into the horizontal type closed continuous kneader, and volatilizing and separating the solvent from the vent-port. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for recovering an N-substituted maleimide / olefin copolymer from an N-substituted maleimide / olefin copolymer solution having excellent transparency, and in particular, an N-substituted maleimide / olefin copolymer and a solvent. In some cases, the volatile components are removed from the N-substituted maleimide / olefin copolymer solution containing volatile components such as unreacted monomers, volatile by-products and impurities, and the N-substituted maleimide The present invention relates to a method for recovering an olefin copolymer.

  Maleimide copolymers are known to be thermoplastic resins with high heat distortion temperature and thermal decomposition temperature, and generally improve the heat resistance, impact resistance, etc. of products using other thermoplastic resins. Used to make. The maleimide copolymer is usually produced by copolymerizing a maleimide monomer and another monomer copolymerizable therewith. As the polymerization method, various polymerization methods such as solution polymerization, bulk polymerization, emulsion polymerization and suspension polymerization are employed. In solution polymerization and bulk polymerization, the polymer is produced in a dissolved state, and in emulsion polymerization and suspension polymerization, the polymer is produced in a dispersed state. When recovering the maleimide copolymer, these are produced. From this state, it is necessary to separate a volatile component such as a solvent, an unreacted monomer, a volatile by-product or an impurity to obtain a maleimide copolymer. This is because, particularly when volatile components such as solvent and unreacted monomer remain in the maleimide copolymer, it causes deterioration in physical properties such as heat resistance and poor appearance of the molded product (silver streak). This is because the physical properties of the molded product may be significantly reduced.

  Therefore, in general, in the emulsion polymerization method and the suspension polymerization method, a method for separating and recovering the polymer by aggregation, filtration operation, steam stripping, or the like has been proposed (for example, see Patent Document 1).

  In the solution polymerization method or bulk polymerization method, the reaction solution after the completion of polymerization is placed in a solvent in which only the solvent or unreacted monomer is dissolved to extract and remove the unreacted monomer or solvent, or a flash evaporator. There has been proposed a method of separating and recovering a polymer by evaporating an unreacted monomer or solvent using a solvent and then extracting the polymer in a molten state (see, for example, Patent Documents 2 and 3). .)

  Furthermore, a method has been proposed in which the reaction mixture of the maleimide copolymer after completion of the polymerization is directly or previously heated and dried and then supplied to a vent type extruder to devolatilize the polymer into a pellet. (For example, refer to Patent Documents 4 and 5.)

JP-A-62-112612 JP 58-162616 A Japanese Patent Laid-Open No. 3-205411 JP-A-2-51514 JP 2001-31710 A

  However, in the separation / recovery method of maleimide copolymer, which is processed by a vent type screw extruder proposed in Patent Document 5 to remove volatile components, the vent port is blocked by controlling the temperature of the cylinder. However, the concentration of the maleimide copolymer solution proceeds near the supply port, and in the worst case, the dried resin closes the supply port, making it difficult to recover the resin stably. There was a problem of becoming.

  Therefore, the present invention recovers the N-substituted maleimide / olefin copolymer stably and efficiently when recovering the N-substituted maleimide / olefin copolymer from the N-substituted maleimide / olefin copolymer solution. It provides a method that makes it possible.

  As a result of intensive studies to solve the above problems, the present inventors used a horizontal closed continuous kneader, and N-substituted under specific conditions from the supply port of the horizontal closed continuous kneader. It has been found that by supplying a solution of a maleimide / olefin copolymer, the N-substituted maleimide / olefin copolymer can be stably recovered, and the present invention has been completed.

  That is, the present invention provides an N-substituted maleimide / olefin copolymer solution comprising an olefin residue unit represented by the following formula (I) and an N-substituted maleimide residue unit represented by the following formula (II). -When recovering the substituted maleimide / olefin copolymer, using a horizontal closed continuous kneader having a vent port, the solution was sealed from the supply port prepared at a boiling point of -50 ° C to a boiling point + 100 ° C of the solvent. The present invention relates to a method for recovering an N-substituted maleimide / olefin copolymer, characterized in that the solvent is supplied to a continuous kneader and volatilely separated from a vent port.

(Here, R1 and R2 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms.)

(R3 represents an aromatic group substituted by an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an aromatic group having 6 to 24 carbon atoms, or an alkyl group having 1 to 4 carbon atoms.)
The present invention will be described in detail below.

  The N-substituted maleimide / olefin copolymer constituting the present invention includes a copolymer comprising an olefin residue unit represented by the above formula (I) and an N-substituted maleimide residue unit represented by the above formula (II). It is. Here, R1 and R2 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms include, for example, a methyl group , An ethyl group, a propyl group, a butyl group, a heptyl group, a hexyl group, and the like. Examples of the cycloalkyl group having 3 to 6 carbon atoms include a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group. it can. R3 is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an aromatic group having 6 to 24 carbon atoms, or an alkyl group-substituted aromatic group. Examples of the group include a methyl group, an ethyl group, a propyl group, a butyl group, a heptyl group, a hexyl group, and an octyl group. Examples of the cycloalkyl group having 3 to 8 carbon atoms include a cyclopropyl group, A cyclobutyl group, a cyclohexyl group, etc. can be mentioned, As an aromatic group which a C6-C24 aromatic group or a C1-C4 alkyl group substituted, for example, a phenyl group, o-methylphenyl group, o -Ethylphenyl group, o-propylphenyl group, m-methylphenyl group, m-ethylphenyl group, m-propylphenyl group, p-methylphenyl group, p-ethylphenyl group p- propylphenyl group, o, p- dimethylphenyl group, o, p- diethyl phenyl group, o, p- dipropyl phenyl group and a naphthyl group.

  Specific examples of the N-substituted maleimide / olefin copolymer include N-phenylmaleimide / isobutene copolymer, N-phenylmaleimide / ethylene copolymer, N-phenylmaleimide / 2-methyl-1-butene copolymer, and the like. Polymer, N- (2-methylphenyl) maleimide / isobutene copolymer, N- (2-methylphenyl) maleimide / ethylene copolymer, N- (2-methylphenyl) maleimide / 2-methyl-1-butene Copolymer, N- (2-ethylphenyl) maleimide / isobutene copolymer, N- (2-ethylphenyl) maleimide / ethylene copolymer, N- (2-ethylphenyl) maleimide / 2-methyl-1- Butene copolymer, N-methylmaleimide / isobutene copolymer, N-methylmaleimide / ethylene copolymer, N-methyl Reimide / 2-methyl-1-butene copolymer, N-cyclohexylmaleimide / isobutene copolymer, N-cyclohexylmaleimide / ethylene copolymer, N-cyclohexylmaleimide / 2-methyl-1-butene copolymer, etc. Among them, N-phenylmaleimide / isobutene copolymer, N-methylmaleimide / isobutene copolymer, and N-cyclohexylmaleimide are copolymers that are particularly excellent in heat resistance, transparency, and mechanical properties. -An isobutene copolymer is preferred.

  The N-substituted maleimide / olefin copolymer includes an olefin compound derived from the olefin residue unit represented by the formula (I) and a maleimide compound derived from the N-substituted maleimide residue unit represented by the formula (II). Can be obtained by utilizing a known polymerization method. Examples of the polymerization method at that time include a bulk polymerization method, a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method. The N-substituted maleimide / olefin copolymer can also be obtained by a method of dehydrating and ring-closing imidizing an amide oxide obtained by reacting maleic anhydride / olefin copolymer with ammonia and an amine compound. is there.

  The solvent constituting the N-substituted maleimide / olefin copolymer solution in the present invention may be any solvent as long as it dissolves the N-substituted maleimide / olefin copolymer, for example, N-substituted maleimide / olefin copolymer. Examples of the solvent used for polymerization of the polymer include aromatic solvents such as toluene, xylene and ethylbenzene; ketone solvents such as ethyl methyl ketone and methyl isobutyl ketone; dimethyl sulfoxide. , Polar solvents such as dimethylacetamide and ethyl acetate.

  Examples of the solution include not only a solution obtained by dissolving an N-substituted maleimide / olefin copolymer in a solvent, but also a polymerization solution obtained at the time of producing the N-substituted maleimide / olefin copolymer. The solution may also contain, for example, unreacted monomers, volatile byproducts or impurities.

  FIG. 1 shows an example of a horizontal closed continuous kneader suitable for the recovery method of the present invention. Here, 1 is a horizontal closed continuous kneader, 2 is a supply port, 3 is a vent port, 4 is a discharge port, 5 is a heat medium outlet, 6 is a paddle drive unit, 7 is a tank, 8 is a heat medium inlet , 9a to 9d are cylinders, and 10 is a jacket heating medium bypass line. In the horizontal closed continuous kneader, the cylinder is composed of a plurality of areas, and each area can individually control the temperature by circulating a heat medium through the jacket. Enables fine control during the recovery of the N-substituted maleimide / olefin copolymer, and in the present invention, it is preferable to use such a horizontal closed continuous kneader. Examples of the horizontal closed continuous kneader include, for example, a biaxial co-directional meshing kneader (manufactured by Kurimoto Steel Co., Ltd., trade name: S5KRC kneader).

  In the recovery method of the present invention, the N-substituted maleimide / olefin copolymer from which the solvent has been removed by volatilization is sucked into the vent port, so that the recovery efficiency of the N-substituted maleimide / olefin copolymer may be extremely reduced. Therefore, it is preferable to use a horizontal closed continuous kneading machine having a vent port upstream of the supply port with respect to the flow of the kneaded product, because it is possible to recover the stable N-substituted maleimide / olefin copolymer. .

  In the recovery method of the present invention, the solution of the N-substituted maleimide / olefin copolymer is brought to the range of the boiling point of the solvent from −50 ° C. to the boiling point + 100 ° C., preferably from 1 ° C. to 100 ° C., particularly preferably from 10 ° C. to 40 ° C. The N-substituted maleimide / olefin copolymer is recovered by supplying from the supply port of the prepared horizontal closed continuous kneader. Here, when the boiling point is higher than + 100 ° C., when the solution of the N-substituted maleimide / olefin copolymer is supplied from the supply port, the volatilization of the solvent is severe, and as a result, the supply port is easily blocked. The coalescence recovery efficiency is poor. On the other hand, when the boiling point is lower than −50 ° C., the solution viscosity of the solution of the N-substituted maleimide / olefin copolymer is high and the recovery efficiency of the N-substituted maleimide / olefin copolymer is poor because the supply port is easily blocked. It becomes.

  In addition, the N-substituted maleimide / olefin copolymer solution supplied to the horizontal closed continuous kneading machine has a polymer concentration of 10 to 80% by weight because of excellent efficiency in supply and volatilization efficiency of the solvent. A solution of an N-substituted maleimide / olefin copolymer is preferred.

  And since it becomes the recovery method of the N-substituted maleimide / olefin copolymer excellent in efficiency at the time of supply and solvent volatilization efficiency in particular, the operating condition of the horizontal closed continuous kneader is the atmospheric pressure or The pressure is preferably reduced, the vent port is preferably at a pressure of 300 to 760 mmHg, the pressure at the polymer outlet 4 is preferably 600 mmHg or less, and particularly preferably 400 mmHg or less.

  Volatile components from an N-substituted maleimide / olefin copolymer solution, which also contains volatile components such as N-substituted maleimide / olefin copolymer and solvent, and possibly unreacted monomers, volatile by-products, impurities, etc. And the N-substituted maleimide / olefin copolymer can be efficiently recovered.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Synthesis Example 1 (Production Example of N-Phenylmaleimide / Isobutene Copolymer Solution)
In a 30 liter autoclave equipped with a stirrer, pressure gauge, thermometer, nitrogen introduction tube, olefin introduction tube and degassing tube, 3596.4 g (20.8 mol) of N-phenylmaleimide, 9.24 g of t-butylperoxypivalate ( 0.05 mol) and 13916 g of ethyl methyl ketone (boiling point 79.6 ° C.) were purged several times with nitrogen, and then 4154 ml (41.54 mol) of liquefied isobutene was charged and reacted at 60 ° C. for 5 hours to give a polymer concentration of 24 A 6 wt% N-phenylmaleimide / isobutene copolymer solution was obtained.

Example 1
As a horizontal closed continuous kneading machine, 2-axis co-directional kneading machine (made by Kurimoto Steel Works, trade name S5KRC Kneader No. 42; screw diameter (D) 125 mm, cylinder length (L) 1250 mm, L / N-phenylmaleimide / isobutene obtained in Synthesis Example 1 was used under the conditions of D = 10, vent number 1), screw rotation speed 54 rpm, internal temperature 200 ° C., supply port temperature 35 ° C., supply port pressure 675 Torr. An N-phenylmaleimide / isobutene copolymer was recovered by supplying a polymer solution at a rate of 20 kg / hour and volatilizing and separating a volatile component such as ethyl methyl ketone as a solvent from a vent port.

  The N-phenylmaleimide / isobutene copolymer was stably recovered, and no large particles of 10 mm or more were observed in the obtained N-phenylmaleimide / isobutene copolymer.

Comparative Example 1
The N-phenylmaleimide / isobutene copolymer was recovered in the same manner as in Example 1 except that the supply port temperature was set to 200 ° C instead of the supply port temperature of 35 ° C. The blockage proceeded, and it was impossible to continuously recover the N-phenylmaleimide / isobutene copolymer.

; Is a schematic view of a horizontal closed continuous kneading machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Horizontal closed continuous kneading machine 2; Supply port 3; Vent port 4; Discharge port 5; Heat medium outlet 6; Paddle drive part 7; Tank 8; Heat medium inlet 9a-9d; Bypass line

Claims (4)

From the solution of an N-substituted maleimide / olefin copolymer comprising an olefin residue unit represented by the following formula (I) and an N-substituted maleimide residue unit represented by the following formula (II), the N-substituted maleimide / olefin copolymer When recovering the polymer, a horizontal closed continuous kneader having a vent port is used, and the horizontal closed continuous kneader is fed from a supply port prepared by boiling the solution at a boiling point of −50 ° C. to a boiling point of + 100 ° C. And recovering the N-substituted maleimide / olefin copolymer by evaporating and separating the solvent from the vent port.

(Here, R1 and R2 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms.)

(R3 represents an aromatic group substituted by an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an aromatic group having 6 to 24 carbon atoms, or an alkyl group having 1 to 4 carbon atoms.) The N-substituted maleimide / olefin copolymer solution according to claim 1, wherein a solution of the N-substituted maleimide / olefin copolymer is supplied to a horizontal closed continuous kneader from a supply port prepared at 1 ° C to 100 ° C. A method for recovering an olefin copolymer. The horizontal closed continuous kneader is a horizontal closed continuous kneader having a vent port upstream from the supply port with respect to the flow of the kneaded product, and has a polymer concentration of 10 at the supply port maintained under atmospheric pressure or reduced pressure. The method for recovering an N-substituted maleimide / olefin copolymer according to claim 1, wherein a solution of ˜80 wt% N-substituted maleimide / olefin copolymer is supplied. 4. The N-substituted maleimide / olefin copolymer according to claim 1, wherein the horizontal closed continuous kneader is a horizontal closed continuous kneader capable of independently adjusting the temperature control of the supply port. Recovery method.

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