JP2009227721A - Method for manufacturing thermoplastic copolymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for industrially advantageously manufacturing a thermoplastic copolymer excellent in thermal stability and transparency. <P>SOLUTION: The method for manufacturing a thermoplastic copolymer containing a glutaric acid anhydride unit and (i) an unsaturated carboxylic acid alkylester unit includes a volatile component elimination step of eliminating a volatile component comprising a mixture of unreacted monomers or a mixture of unreacted monomers and an organic solvent, wherein the step includes a first-half elimination step at 760 to 1,000 Torr and a last-half elimination step under a reduced pressure of less than 200 Torr. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for continuously producing a thermoplastic copolymer containing glutaric anhydride units that are excellent in heat resistance, molding processing characteristics, and colorless transparency, and that are particularly free of foreign matters.

  Amorphous resins such as polymethyl methacrylate (hereinafter referred to as “PMMA”) and polycarbonate (hereinafter referred to as “PC”) make use of transparency and dimensional stability of optical materials, household electrical appliances, office automation equipment, automobiles, and the like. It is used in a wide range of fields including parts.

  In recent years, these resins have been widely used in higher performance optical materials such as optical lenses, prisms, mirrors, optical disks, optical fibers, liquid crystal display sheets and films, light guide plates, etc. The optical properties, moldability, and heat resistance required for these products are also higher.

  At present, these transparent resins are also used as lamp members for automobiles such as tail lamps and head lamps, but in recent years, tail lamp lenses, inner lenses, There is a tendency to reduce the distance between various light sources such as headlamps and shield beams and the light source, and to reduce the thickness of the parts, and excellent moldability is required. Further, since the vehicle is used under severe conditions, it is required to have a small shape change under high temperature and high humidity, and excellent scratch resistance, weather resistance, and oil resistance.

  However, although PMMA resin has excellent transparency and weather resistance, there is a problem that heat resistance is not sufficient. On the other hand, PC resin is excellent in heat resistance and impact resistance, but has a large birefringence, which is an optical distortion, and has optical anisotropy in the molded product, remarkably in moldability, scratch resistance, and oil resistance. There was a problem of being inferior.

  Therefore, for the purpose of improving the heat resistance of PMMA, a resin in which a maleimide monomer or a maleic anhydride monomer is introduced as a heat resistance imparting component has been developed. However, maleimide monomers are expensive and have low reactivity, and maleic anhydride has a problem of poor thermal stability.

  As a method for solving these problems, a copolymer containing an unsaturated carboxylic acid monomer unit is heated using an extruder to contain a glutaric anhydride unit obtained by a cyclization reaction. The copolymer is disclosed in, for example, Patent Documents 1 and 2, but a glutaric anhydride unit-containing copolymer obtained by heat-treating the copolymer using a suspension polymerization method or an emulsion polymerization method is However, there is a problem that a high degree of colorless transparency cannot be obtained due to the foreign matters resulting from the polymerization method.

  Therefore, if a bulk polymerization or solution polymerization without using a so-called polymerization aid such as a dispersant or an emulsifier can be applied as a polymerization method of a copolymer containing an unsaturated carboxylic acid unit as a precursor, it is required for an optical material. In addition, it is expected to obtain a highly colorless and transparent copolymer, and since continuous copolymerization makes it possible to control the copolymer composition and molecular weight distribution, intensive studies have been conducted.

  For example, as a method of obtaining a copolymer containing the glutaric anhydride unit by bulk polymerization or solution polymerization, a copolymer containing unsaturated carboxylic acid alkyl ester units and unsaturated carboxylic acid units is bulk polymerization or solution A method of polymerizing and subsequently heating the obtained polymerization solution, separating and removing unreacted monomers and unreacted monomers and solvent, and further subjecting the copolymer to a cyclization reaction by heating is disclosed in Patent Documents 3 to 3. 5 is disclosed.

  However, although the production method disclosed in Patent Document 3 describes the polymerization method (see Examples), specific description is made on the devolatilization and cyclization of the obtained polymerization solution. When the polymerization solution is heated in the “high temperature vacuum chamber” described in the examples, the unreacted monomer and solvent are completely removed under vacuum. In order to complete the cyclization reaction, heat treatment at a high temperature for a long time is required, and a great deal of labor and energy is required. Furthermore, the resulting copolymer containing glutaric anhydride units is markedly colored. There was a problem.

  Patent Document 4 discloses a production method in which a copolymer solution (a) obtained by a polymerization reaction is continuously supplied to a devolatilization tank to perform devolatilization and a cyclization reaction. Even in the case, unreacted monomers and solvents are completely removed under vacuum and the cyclization reaction is completed, requiring heat treatment at a high temperature for a long time, which requires a great deal of labor and energy. Furthermore, there is a problem that the resulting copolymer containing glutaric anhydride units is markedly colored.

  Further, Patent Document 5 discloses a solution polymerization method of a copolymer containing an unsaturated carboxylic acid alkyl ester unit and an unsaturated carboxylic acid unit, and the devolatilization and cyclization reaction using this polymerization solution is disclosed. Has not been considered.

  In view of these situations, the present inventors, as in Patent Document 6, produce a copolymer containing a specific unsaturated carboxylic acid unit under specific polymerization conditions, and then heat-treat the copolymer. Therefore, a method for producing a glutaric anhydride-containing copolymer excellent in colorless transparency and retention stability was proposed. In this proposed technique, although the coloration and residence stability of the copolymer containing glutaric anhydride obtained by continuous polymerization at a specific polymerization temperature has been greatly improved, the twin-screw extruder disclosed in Patent Document 6 has been improved. Also in the method of performing devolatilization and cyclization reaction using, in order to completely remove unreacted monomer and solvent under vacuum and complete the cyclization reaction, the ratio of screw diameter to screw length (L / D) It is necessary to perform heat treatment for a long time at a high temperature by controlling the supply amount of the copolymer and securing the residence time by using an apparatus having a very high (L / D). In addition, at the same time, there is a problem that coloring caused by thermal decomposition of the polymer chain due to shear heat generation becomes large when it is retained for a long time in a twin screw extruder.

That is, in order to use it for higher performance optical materials such as optical lenses, prisms, mirrors, optical disks, optical fibers, liquid crystal display sheets and films, and light guide plates, the manufacturing methods disclosed in Patent Documents 3 to 6 There has been a demand for a method capable of industrially advantageously producing a copolymer containing glutaric anhydride units that have not been able to be achieved and have higher colorless transparency and excellent thermal stability.
JP-A-49-85184 (page 1-2, Examples) Japanese Patent Laid-Open No. 01-103612 (page 1-2, Examples) JP 58-217501 A (page 1-2, Examples) JP-A-60-120707 (page 1-2, Examples) Japanese Patent Laid-Open No. 06-049131 (page 1-2, Examples) JP 2004-002711 A (page 1-2, Examples)

  Therefore, an object of the present invention is to propose a method capable of industrially advantageously producing a copolymer containing a glutaric anhydride unit having high colorless transparency and excellent thermal stability.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors provide a method for industrially advantageously producing a thermoplastic copolymer excellent in thermal stability with reduced residual volatile components. In addition, when devolatilizing the unreacted monomer mixture or the mixture of the unreacted monomer and organic solvent, the productivity can be greatly stabilized by reducing the pre-process to normal pressure and the post-process to reduced pressure. Furthermore, since the size of the apparatus used for devolatilization can be reduced, it has been found that labor and energy can be greatly reduced, and the present invention has been achieved.

That is, the present invention is as follows.
1. A copolymer (A) containing (I) (i) an unsaturated carboxylic acid alkyl ester unit and (ii) an unsaturated carboxylic acid unit is continuously polymerized by solution polymerization or bulk polymerization in an organic solvent, and the copolymer (A ) And an unreacted monomer mixture and / or an organic solvent, and a copolymer solution (a) having a volatile component content of 30 to 70% by weight,
(II-1) a pre-devolatilization step in which this is heated and volatilized at 760 to 1000 Torr;
(II-2) Subsequent to this, the unreacted monomer mixture and / or the organic solvent is removed from the copolymer solution (a) by a devolatilization step after heating and devolatilization under a reduced pressure of 200 Torr or less,
(III) Subsequently, the mixture is supplied to a cyclization apparatus and subjected to heat treatment, and an intramolecular cyclization reaction is performed by dehydration and / or dealcoholization reaction. (Iii) Glutar represented by the following general formula (1) A method for producing a thermoplastic copolymer, comprising producing a thermoplastic copolymer (B) comprising an acid anhydride unit and (i) an unsaturated carboxylic acid alkyl ester unit.

(However, R ¹ and R ² are the same or different and represent any one selected from a hydrogen atom and an alkyl group having 1 to 5 carbon atoms.)
2. The thermoplastic copolymer according to 1, comprising a devolatilization step before devolatilization until the volatile component content is 5 to 30% by weight and a devolatilization step after devolatilization until the volatile component content is less than 5% by weight. Production method.
3. The devolatilizer has a stirrer in which a cylindrical container and a large number of stirrers are attached to one or a plurality of rotating shafts, has at least one vent port at the top of the tube, and has one end of the tube The thermoplastic resin according to 1 or 2, wherein the thermoplastic resin is a device having a supply port for supplying the copolymer solution (a) and a discharge port for extracting the devolatilized copolymer (A) at the other end. A method for producing a copolymer.
4). 4. The method for producing a thermoplastic copolymer according to 3, wherein the devolatilization device is a twin screw extrusion device having a vent.
5. The method for producing a thermoplastic copolymer according to any one of 1 to 4, wherein the pre-devolatilization step is performed by a twin-screw extruder having a back vent.
6). The method for producing a thermoplastic copolymer according to any one of 1 to 5, wherein the pre-devolatilization step is performed at a temperature of not lower than the polymerization temperature and not higher than 250 ° C.
7). The post-devolatilization step is carried out at a temperature not lower than the devolatilization temperature in the pre-devolatilization step, not higher than 300 ° C, and not higher than 200 Torr. Production method.
8). The thermoplastic copolymer according to 3 to 7, wherein the ratio (L / D) of screw diameter (D) and screw length (L) of the devolatilizer in the pre-devolatilization step is 14 to 25 Manufacturing method.
9. The thermoplastic copolymer according to 3 to 8, wherein the ratio (L / D) of screw diameter (D) and screw length (L) of the devolatilizer in the post-devolatilization step is 35 to 60 Manufacturing method.

  According to the present invention, a thermoplastic copolymer excellent in thermal stability and transparency can be stably produced, and further, the size of the thermoplastic copolymer production apparatus can be reduced, and labor and energy can be reduced. It can be greatly reduced.

Examples of the best embodiment of the present invention will be described below.
The thermoplastic copolymer (B) of the present invention means (iii) a thermoplastic copolymer containing a glutaric anhydride unit represented by the following general formula (1) and (i) an unsaturated carboxylic acid alkyl ester unit. It is.

(However, R ¹ and R ² are the same or different and represent any one selected from a hydrogen atom and an alkyl group having 1 to 5 carbon atoms.)

  The method for producing a thermoplastic copolymer containing a glutaric anhydride unit represented by the general formula (1) of the present invention is basically produced by the following three steps. That is, an unsaturated carboxylic acid alkyl ester monomer and an unsaturated carboxylic acid monomer that give the glutaric anhydride unit represented by the above general formula (1) by a subsequent heating step, and other vinyl series A step (polymerization step) of producing a copolymer solution (a) containing a copolymer (A) by copolymerizing with a vinyl monomer that gives the unit when the monomer unit is included; Subsequently, the copolymer solution (a) is continuously supplied to a devolatilization device by a pump, and continuously removing and removing the unreacted monomer mixture and / or the organic solvent (devolatilization step); Furthermore, the process (cyclization) which manufactures the copolymer (A) obtained at the said devolatilization process by heat-processing and making it carry out the intramolecular cyclization reaction by (i) dehydration and / or (b) dealcoholization. Process). In this case, typically, the copolymer (A) is heated to dehydrate the carboxyl group of two (ii) unsaturated carboxylic acid units, or adjacent (ii) an unsaturated carboxylic acid unit and (I) One unit of the glutaric anhydride unit is generated by elimination of the alcohol from the unsaturated carboxylic acid alkyl ester unit.

  The feature of the method for producing the thermoplastic copolymer (B) of the present invention is that the above-mentioned devolatilization process is divided into two stages, the pre-devolatilization process is set to 760 to 1000 Torr, and the post-devolatilization process is set to less than 200 Torr. . Here, an example of a schematic process diagram of the production method of the present invention is shown in FIG. As shown in FIG. 1, the copolymer solution (a) obtained by carrying out the polymerization reaction in the polymerization tank (1) is continuously supplied to the pre-devolatilization device (2-1), and slightly pressurized or It is heated and devolatilized under normal pressure, then supplied to the post-devolatilization device (2-2) and heated under reduced pressure, and then polymerized with the unreacted monomer mixture or the unreacted monomer mixture by the post-devolatilization step. The mixture of the organic solvent (C) used sometimes (hereinafter, the unreacted monomer mixture and the organic solvent may be referred to as volatile components) is devolatilized to obtain the copolymer (A). Subsequently, the copolymer (A) is continuously supplied in a molten state to the cyclization unit (3) and is subjected to a cyclization reaction, whereby a thermoplastic copolymer (B) containing a glutaric anhydride unit. Are manufactured continuously.

  Further, in the production method of the present invention, in addition to the above “polymerization step”, “devolatilization step” and “cyclization step”, the unreacted monomer mixture separated or removed in the devolatilization step, or the unreacted monomer mixture The volatile matter recovery step (4) and the volatile matter purification step (5), which are recovered raw materials for recovering, separating and purifying a mixture of the organic solvent (C) and recycling them to the polymerization step Good.

  Hereinafter, each step will be specifically described.

[Polymerization process]
There is no restriction | limiting in particular as an unsaturated carboxylic acid monomer used at a superposition | polymerization process, Any unsaturated carboxylic acid monomer which can be copolymerized with another vinyl compound can be used. As a preferable unsaturated carboxylic acid monomer, the following general formula (2)

(However, R ³ represents any one selected from hydrogen and an alkyl group having 1 to 5 carbon atoms)
In particular, acrylic acid and methacrylic acid are preferred, and methacrylic acid is more preferred from the viewpoint of excellent thermal stability. These can be used alone or in combination. The unsaturated carboxylic acid monomer represented by the general formula (2) gives an unsaturated carboxylic acid unit having a structure represented by the following general formula (3) when copolymerized.

(However, R ⁴ represents any one selected from hydrogen and an alkyl group having 1 to 5 carbon atoms)

  Moreover, there is no restriction | limiting in particular as an unsaturated carboxylic-acid alkylester type monomer, However, As a preferable example, what is represented by following General formula (4) can be mentioned.

(Wherein R ⁵ represents any one selected from hydrogen and an alkyl group having 1 to 5 carbon atoms, and R ⁶ represents an unsubstituted or substituted C 1-6 aliphatic hydrocarbon group substituted with a hydroxyl group or halogen, and Represents any one selected from alicyclic hydrocarbon groups having 3 to 6 carbon atoms)

  Among these, an acrylate ester and / or a methacrylic ester having an aliphatic or alicyclic hydrocarbon group having 1 to 6 carbon atoms or the hydrocarbon group having a substituent is particularly preferable. The unsaturated carboxylic acid alkyl ester monomer represented by the general formula (4) gives an unsaturated carboxylic acid alkyl ester unit having a structure represented by the following general formula (5) when copolymerized.

(However, R ⁷ represents any one selected from hydrogen and an alkyl group having 1 to 5 carbon atoms, and R ⁸ is an aliphatic hydrocarbon group having 1 to 6 carbon atoms which is unsubstituted or substituted with a hydroxyl group or halogen, and Represents any one selected from alicyclic hydrocarbon groups having 3 to 6 carbon atoms)

  Preferred specific examples of unsaturated carboxylic acid alkyl ester monomers include methyl acrylate, ethyl acrylate, n-butyl acrylate, t-butyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, Examples thereof include monomers such as dodecyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, benzyl methacrylate, lauryl methacrylate, dodecyl methacrylate, and trifluoroethyl methacrylate. Of these, methyl methacrylate and ethyl methacrylate are preferable, and methyl methacrylate is particularly preferable from the viewpoint of excellent optical characteristics and thermal stability. These may be used alone or as a mixture of two or more.

  In the first step, other vinyl monomers may be used as long as the effects of the present invention are not impaired. Preferable specific examples of other vinyl monomers include fragrances such as styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, o-ethylstyrene, p-ethylstyrene, and pt-butylstyrene. Vinyl cyanide monomers such as aromatic vinyl monomers, acrylonitrile, methacrylonitrile, ethacrylonitrile, etc., but includes aromatic rings in terms of transparency, birefringence, and chemical resistance Less monomers can be used more preferably. These may be used alone or in combination of two or more.

  In the present invention, the polymerization step is a method of polymerizing in a state containing the monomer mixture, a polymerization initiator and a chain transfer agent and substantially free of a solvent (bulk polymerization method), or a copolymer (A ) Can be carried out by a polymerization method (solution polymerization method) in which an organic solvent (C) soluble in is added.

  As described above, the organic solvent (C) used in the solution polymerization method is not particularly limited as long as the copolymer (A) is a soluble organic solvent, but ketones, ethers, amides, alcohols, Preferably, one or more selected from the group consisting of acetone, methyl ethyl ketone, methyl-n-butyl ketone, methyl isobutyl ketone, ethyl isobutyl ketone, diethyl ether, tetrahydrofuran, dioxane, dimethylformamide, diethylformamide, Known solvents such as dimethylacetamide, diethylacetamide, N-methylpyrrolidone, methanol, ethanol, isopropanol, ethylene glycol, propylene glycol, 2-methoxy-2-propanol, and tetraglyme can be used. Ethyl ketone, methanol, isopropanol, and tetrahydrofuran are preferable.

  In the case of the solution polymerization method, the addition amount of the organic solvent (C) is based on 100 parts by weight of the monomer mixture from the viewpoint of the stability of the polymerization reaction, the recoverability in the devolatilization step, and the recyclability to the polymerization step. The amount is preferably 1 to 200 parts by weight, more preferably 10 to 150 parts by weight, and still more preferably 20 to 150 parts by weight. In addition, a bulk polymerization method substantially free of an organic solvent can be preferably used as long as the polymerization reaction can be sufficiently controlled.

  When the addition amount of the organic solvent (C) exceeds 200 parts by weight, solvent removal becomes insufficient in the subsequent devolatilization step and cyclization step, and the amount of gas generated in the thermoplastic copolymer (B) increases. Since thermal stability falls, it is not preferable. On the other hand, in order to reduce the residual solvent in order to reduce the amount of gas generated, the devolatilization and cyclization steps require treatment at high temperature for a long time, so that the thermoplastic copolymer (B) is markedly colored. Therefore, it is not preferable.

  In the present invention, it is possible to control the dissolved oxygen concentration of the polymerization liquid containing the monomer mixture to 5 ppm or less in the polymerization step, and the excellent colorless transparency and retention of the thermoplastic copolymer (B) after the heat treatment It is preferable because stability and thermal stability can be achieved. Furthermore, in order to further suppress coloring after the heat treatment, a preferable range of dissolved oxygen concentration is 0.01 to 3 ppm, and more preferably 0.01 to 1 ppm. When the dissolved oxygen concentration exceeds 5 ppm, the thermoplastic copolymer (B) after the heat treatment tends to be colored, and the thermal stability of the thermoplastic copolymer (B) is lowered. I can't reach my goal. Here, the dissolved oxygen concentration in the present invention is a value obtained by measuring dissolved oxygen in the polymerization solution using a dissolved oxygen meter (for example, DO meter B-505 manufactured by Iijima Electronics Co., Ltd., which is a galvanic oxygen sensor). is there. For the method of reducing the dissolved oxygen concentration to 5 ppm or less, a method of passing an inert gas such as nitrogen, argon or helium into the polymerization vessel, a method of bubbling an inert gas directly into the polymerization solution, or an inert gas before starting the polymerization A method of performing pressure relief once or twice after filling the polymerization vessel, a method of degassing the closed polymerization vessel before charging the monomer mixture, and then filling with an inert gas, A method of passing an inert gas through the polymerization vessel can be exemplified.

  A preferred ratio of the monomer mixture used in the polymerization step is 10 to 50% by weight of the unsaturated carboxylic acid monomer, more preferably 15 to 45% by weight, with the monomer mixture being 100% by weight. The unsaturated carboxylic acid alkyl ester monomer is preferably 50 to 90% by weight, more preferably 55 to 85% by weight. When other vinyl monomers copolymerizable with these are used, the preferred ratio is 0 to 35% by weight, and a particularly preferred ratio is 0 to 10% by weight.

  When the amount of the unsaturated carboxylic acid monomer is less than 10% by weight, the amount of glutaric anhydride units represented by the general formula (1) generated by heating the copolymer (A) is reduced, There exists a tendency for the heat resistance improvement effect to become small. On the other hand, when the amount of the unsaturated carboxylic acid monomer exceeds 50% by weight, a large amount of unsaturated carboxylic acid units tend to remain after the cyclization reaction by heating of the copolymer (A), which is colorless. There is a tendency for transparency and retention stability to decrease.

  The polymerization initiator used in the present invention uses a radical polymerization initiator having a half-life at the above-described polymerization temperature of 0.1 to 60 minutes, more preferably 1 to 30 minutes, and most preferably 2 to 20 minutes. It is preferable. If this half-life is shorter than 0.1 minutes, the radical polymerization initiator decomposes before being uniformly dispersed in the polymerization reaction tank, so that the efficiency (starting efficiency) of the radical polymerization initiator is reduced. This is not preferable because the amount increases and the thermal stability of the finally obtained thermoplastic copolymer may decrease. On the other hand, if the half-life is longer than 60 minutes, a polymerized mass (scaling) is generated in the polymerization tank, and it becomes difficult to stably operate the polymerization. Further, after the polymerization is completed, the copolymer solution (a) Since unreacted radical polymerization initiator remains, high colorless transparency may not be obtained, such as subsequent devolatilization or cyclization process, resin coloring due to residual radical polymerization initiator during molding process, etc. Yes, not preferred.

  In the present invention, the “half-life of the radical polymerization initiator” is a value described in a known product catalog such as Nippon Oil & Fats Co., Ltd. or Wako Pure Chemical Industries, Ltd.

  Examples of such radical polymerization initiators include tert-butyl peroxy-3,5,5-trimethylhexanate, tert-butyl peroxylaurate, tert-butyl peroxyisopropyl monocarbonate, tert-hexyl peroxyisopropyl. Monocarbonate, tert-butylperoxyacetate, 1,1-bis (tert-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (tert-butylperoxy) cyclohexane, tert-butylperoxy 2-ethyl hexanate, tert-butyl peroxyisobutyrate, tert-hexyl peroxy 2-ethyl hexanate, di-tert-butyl peroxide, 2,5-dimethyl-2,5-bis (tert-butyl peroxy) Oxy) hexane, lauroyl peroxide, benzoyl peroxide, t-butylperoxyneodecanate, t-butylperoxypivalate, t-butylperoxy-2-ethylhexanoate, t-butylperoxybenzoate, dic Organic peroxides such as milperoxide, or 2- (carbamoylazo) -isobutyronitrile, 1,1′-azobis (1-cyclohexanecarbonitrile), 2,2′-azobisisobutyronitrile, 2 , 2′-azobis (2-methylbutyronitrile), dimethyl 2,2′-azobisisobutyrate, 2,2′-azobis (2,4,4-trimethylpentane), 2,2′-azobis ( 2-methylpropane), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, 2,2 - the polymerization temperature from azo compounds such as azobis-2,4-dimethylvaleronitrile may be selected in consideration.

  The amount of radical polymerization initiator used is determined by the polymerization temperature, the polymerization time (average residence time), and the target polymerization rate, but is preferably 0.001 with respect to 100 parts by weight of the monomer mixture. It is -2.0 weight part, More preferably, it is 0.01-2.0 weight part, More preferably, it is 0.01-1.0 weight part.

  Further, in the present invention, for the purpose of controlling the molecular weight, a chain transfer agent such as alkyl mercaptan, carbon tetrachloride, carbon tetrabromide, dimethylacetamide, dimethylformamide, triethylamine, etc. with respect to 100 parts by weight of the monomer mixture, It is preferable to add 0.1 to 2.0 parts by weight. Examples of the alkyl mercaptan used in the present invention include n-octyl mercaptan, t-dodecyl mercaptan, n-dodecyl mercaptan, n-tetradecyl mercaptan, n-octadecyl mercaptan and the like. Among them, t-dodecyl mercaptan, n-dodecyl mercaptan is preferably used.

  By polymerizing the addition amount of the chain transfer agent within the scope of the present invention, the copolymer (A) has a weight average molecular weight (hereinafter also referred to as Mw) of 30,000 to 150,000, preferably 50,000 to 150,000, more preferably, It can be controlled to 50,000 to 130,000. In addition, the weight average molecular weight as used in the field of this invention shows the weight average molecular weight in the absolute molecular weight measured by multi-angle light scattering gel permeation chromatography (GPC-MALLS).

  Those having an Mw of 30000 or more are preferable because the thermoplastic copolymer does not become brittle and the mechanical properties are good. Also, those having an Mw of 150,000 or less are preferable because high molecular weight substances that are not sufficiently melted or dissolved in a melt-molded or solution-coated product do not remain as foreign matters, so that the defects of fish eyes and repellency do not occur.

  Further, in the present invention, the inventors select a bulk polymerization method or a solution polymerization method as the polymerization step, so that the polymerization reaction proceeds in a substantially uniform mixed state, and a co-polymer having a homogeneous molecular weight distribution. We found that coalescence was obtained. For this reason, in a preferable aspect, the molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) of the copolymer (A) is 1.5 to 3.0, and in a more preferable aspect, 1.5 to 2.5. The thing of the range of is obtained. When the molecular weight distribution is in the above range, the resulting thermoplastic copolymer (B) tends to be excellent in molding processability and can be preferably used. The molecular weight distribution (Mw / Mn) in the present invention is the weight average molecular weight (Mw) and number average molecular weight (Mn) in absolute molecular weight measured by multi-angle light scattering gel permeation chromatography (GPC-MALLS). The numerical value calculated from

  The polymerization tank (1) used in the present invention is not particularly limited, but from the viewpoint of enabling uniform mixing and obtaining a homogeneous polymerization solution (a), in each part of the polymerization tank, It is preferably a “completely mixed reaction tank” in which the composition, temperature, and the like are maintained substantially equal by the stirring action, and further, a tank reactor provided with a stirring device, and the stirring device is provided in the tank. More preferably, it is a tank reactor equipped with a stirring blade capable of bringing the solution into a substantially complete mixed state.

  The shape of such a stirring blade includes known stirring blades such as double helical blades, paddle blades, turbine blades, propeller blades, bull margin blades, multistage blades, anchor blades, Max blend blades, paddle blades, MIG (Mig) A wing, a full zone wing manufactured by Shinko Environmental Solution Co., Ltd., a log bone wing, and the like can be preferably exemplified. Among them, a double helical ribbon wing is more preferable from the viewpoint of obtaining a higher complete mixing property. In order to enhance the stirring effect, it is preferable to attach a baffle in the polymerization tank.

  Moreover, since heat_generation | fever by a polymerization reaction and stirring arises, superposition | polymerization temperature is controlled by removing heat and depending on the case. Examples of the temperature control include a jacket, heat transfer heat removal or heating by circulation of a heat medium, cooling supply of a monomer mixture, and heating supply.

  The polymerization temperature is preferably in the range of 60 ° C to 160 ° C. By controlling the polymerization temperature within the above range, the acceleration phenomenon of the polymerization rate due to the gel effect can be suppressed, so that the thermoplastic copolymer (B) having excellent thermal stability can be produced efficiently.

  The polymerization time is determined by the target polymerization rate, polymerization temperature, and type / amount of initiator used, but is preferably in the range of 1 to 7 hours, more preferably 1 to 6 hours. By setting it within this range, the polymerization control is stabilized, and a high-quality thermoplastic copolymer (B) can be produced. If the residence time is shorter than 1 hour, it is necessary to increase the amount of radical polymerization initiator used, and it becomes difficult to control the polymerization reaction. Preferably, it is 2 hours or more. Since productivity will fall when it exceeds 7 hours, More preferably, it is 6 hours or less.

  Here, for the average residence time of the copolymer solution (a) in the polymerization tank corresponding to the polymerization time when the production method of the present invention is the above-mentioned continuous polymerization method, the target polymerization rate, Although it is determined by the polymerization temperature and the type and amount of initiator used, it is preferably 1 to 7 hours, more preferably 1 to 6 hours. By setting it within this range, it is possible to produce a high-quality thermoplastic copolymer (B) while stabilizing the polymerization control even in the continuous polymerization method.

  Further, since the solution viscosity of the copolymer solution (a) obtained under the polymerization conditions of the present invention is in the range of 0.1 to 100 Pa · s, the polymerization rate (φ) is at a high polymerization rate of 50 to 80%. However, since the acceleration reaction of the polymerization due to the increase in viscosity, the so-called gel effect can be suppressed, the polymerization can be performed stably. Further, since the solution viscosity is in the above range, the pump can be easily used in the devolatilization step. It becomes possible to supply to the devolatilizer. Here, the solution viscosity of the copolymer solution (a) in the present invention is the viscosity of the copolymer solution (a) at 30 ° C. using a vibration viscometer (VM-100A manufactured by CBC Materials Co., Ltd.). It is a numerical value measured by holding, and the polymerization rate (φ) indicates a value calculated from the unreacted monomer quantified by gas chromatography.

  In the present invention, the volatile component content of the copolymer solution (a) (content of the unreacted monomer mixture and / or organic solvent with respect to the copolymer solution (a)) is 30 to 70% by weight. Thus, it is necessary to send the solution to the next devolatilization step. Here, the volatile component content is a value measured by the following method.

1 g of the copolymer solution (a) before being introduced into the devolatilization step is dissolved in 20 g of tetrahydrofuran, and the remaining unreacted monomer and / or organic solvent (C) is quantified by gas chromatography, and the volatile component is calculated from the following formula. The content of was calculated.
Volatile component content (% by weight) = {(α + β) / P1} × 100
Each symbol indicates the following numerical value.
α = weight of unreacted monomer determined by gas chromatography (g)
β = weight of organic solvent (C) determined by gas chromatography (g)
P1 = weight (g) of the sampled copolymer solution (a)

[Volatilization process]
In the production method of the present invention, the copolymer solution (a) obtained in the polymerization step is devolatilized in the subsequent devolatilization step, and the obtained copolymer (A) is cyclized in another step. (A) A thermoplastic copolymer (B) is produced by dehydration and / or (b) dealcoholization reaction.

  By separating the devolatilization step and the cyclization step, the volatile content of the copolymer (A) supplied to the cyclization step is reduced, and (i) dehydration and / or (b) dealcoholization reaction is efficiently performed. The volatile matter of the thermoplastic copolymer (B) that occurs and is finally obtained can be reduced, and the thermal stability is also excellent.

  Further, in the production method of the present invention, the devolatilization step and the cyclization step are separated and carried out in different apparatuses, whereby the unreacted monomer separated or removed in the devolatilization step, or the unreacted monomer and the organic The mixture of the solvent (C) and the water or methanol produced as a by-product in the cyclization step can be recovered separately, and the unreacted monomer or the mixture of the unreacted monomer and the organic solvent (C) can be easily obtained. It can be recovered, purified, and recycled in the polymerization process.

  Moreover, in the devolatilization step in the production method of the present invention, it is important to adopt a method of devolatilization with two devolatilizers, and the residual volatile components of the copolymer (A) obtained after devolatilization are used. Can be reduced. That is, the devolatilization process of the present invention includes a pre-devolatilization process and a post-devolatilization process.

  Generally, when volatile components are devolatilized with an extruder or the like, if there is a large amount of volatile components, the larger the screw diameter, the higher the processing capacity. The processing capacity increases as / D increases. That is, in order to completely devolatilize a resin solution with many volatile components with one apparatus, the screw diameter and L / D must be increased. However, as in the present invention, devolatilization is performed in two stages, and by using two apparatuses, the screw diameter of the extruder in the pre-devolatilization step for processing a solution with a large amount of volatile matter is increased, and the L / D is decreased. In addition, L / D can be increased by reducing the screw diameter in the post-devolatilization step. Therefore, when selecting the extruder size, the selection range is widened, and the extruder can be downsized.

  The feature of the present invention is that the copolymer solution (a) obtained by the polymerization step is continuously added to the devolatilization step characterized in that the pre-devolatilization step is 760 to 1000 Torr and the post-devolatilization step is reduced in pressure. By supplying, it is possible to separate and remove the unreacted monomer mixture or the mixture of the unreacted monomer mixture and the organic solvent (C) without abrupt pressure reduction, thereby preventing vent-up. For this reason, it has been found that the thermoplastic copolymer (B) can be stably produced and the present invention has been reached.

  If the unreacted monomer mixture or the mixture of the unreacted monomer mixture and the organic solvent (C) cannot be separated and removed sufficiently in the devolatilization step, the efficiency of dehydration and demethanol reaction in the cyclization step Becomes worse and is not preferable.

  In the pre-devolatilization step of the present invention, it is important that the pressure is 760 to 1000 Torr. When the pressure in the pre-devolatilization step is less than 760 Torr, the unreacted monomer or the mixture of the unreacted monomer and the organic solvent (C) is involved in volatilization, and at the same time, the copolymer (A) Is sucked into the volatile matter recovery step and accumulates in the flow path of the unreacted monomer or the mixture of the unreacted monomer and the organic solvent (C), and the flow path is blocked (hereinafter referred to as vent-up). The entire process must be frequently stopped and disassembled, washed, and assembled, and productivity is reduced, and the object of the present invention cannot be achieved.

  As a continuous devolatilizer for performing such devolatilization, it has a cylindrical vessel and a stirring device with one or more stirring elements attached to a rotating shaft, and at least one vent port at the top of the cylindrical portion And an apparatus having a supply port for supplying the copolymer solution (a) to one end of the cylindrical portion and a discharge port for extracting the devolatilized copolymer (A) to the other end can be preferably used.

  Although there is no restriction | limiting in the number of rotating shafts, Usually, it is 1-5, Furthermore, 2-4 are preferable, More preferably, the apparatus which has two rotating shafts is preferable.

  Moreover, it is preferable that the ratio (L / D) of the screw diameter (D) and the screw length (L) in the devolatilization apparatus in the pre-devolatilization step is 14 to 25.

  The number of stirring elements is preferably 10 to 50, and more preferably 20 to 30. The shape of the stirring element is not particularly limited, and may be a multi-leaf shape (for example, a clover leaf shape), may have holes or irregularities as appropriate, and may have a shape like a ship screw or a fan blade, Various other applications are possible. Moreover, since the effect | action which sends a reaction material will be obtained if a stirring element is made into a screw shape, it can use preferably.

  Specifically, a continuous twin screw extruder or a batch type melt kneader having a vent is preferable. A single screw extruder, twin screw extruder, twin screw / single screw combined type continuous kneading equipped with a “unimelt” type screw. Mention may be made of extruders, triaxial extruders, continuous or batch kneader type kneaders, in particular equipped with a biaxial extruder with vents, a plurality of convex lens and / or elliptical plate-like paddles A continuous biaxial reactor can be preferably used.

  In the devolatilization apparatus in the pre-devolatilization step, there is no particular limitation, but the vent position is preferably on the side opposite to the resin feed direction (back vent) with respect to the resin solution supply port. By using the back vent, only the volatile component of the resin solution supplied into the devolatilizer can be efficiently devolatilized, and vent-up can be suppressed.

  As temperature at the time of performing devolatilization in the pre-devolatilization step, the temperature is preferably not less than the polymerization temperature and not more than 250 ° C, more preferably not less than the polymerization temperature and not more than 200 ° C.

  In the post-devolatilization step of the present invention, it is important that the pressure is a reduced pressure of less than 200 Torr.

  As a continuous devolatilizer for performing such devolatilization, it has a cylindrical vessel and a stirring device with one or more stirring elements attached to a rotating shaft, and at least one vent port at the top of the cylindrical portion And an apparatus having a supply port for supplying the copolymer solution (a) to one end of the cylindrical portion and a discharge port for extracting the devolatilized copolymer (A) to the other end can be preferably used.

  Although there is no restriction | limiting in the number of rotating shafts, Usually, it is 1-5, Furthermore, 2-4 are preferable, More preferably, the apparatus which has two rotating shafts is preferable.

  Moreover, it is preferable that the ratio (L / D) of the screw diameter (D) and the screw length (L) in the devolatilization apparatus in the pre-devolatilization step is 35-60.

  The number of stirring elements is preferably 10 to 50, and more preferably 20 to 30. The shape of the stirring element is not particularly limited, and may be a multi-leaf shape (for example, a clover leaf shape), may have holes or irregularities as appropriate, and may have a shape like a ship screw or a fan blade, Various other applications are possible. Moreover, since the effect | action which sends a reaction material will be acquired if a stirring element is made into a screw form, it can use preferably.

  Specifically, a continuous twin screw extruder or a batch type melt kneader having a vent is preferable. A single screw extruder, twin screw extruder, twin screw / single screw combined type continuous kneading equipped with a “unimelt” type screw. Mention may be made of extruders, triaxial extruders, continuous or batch kneader type kneaders, in particular equipped with a biaxial extruder with vents, a plurality of convex lens and / or elliptical plate-like paddles A continuous biaxial reactor can be preferably used.

  As temperature at the time of performing devolatilization in the devolatilization apparatus in the post-devolatilization step, it is preferable to set the temperature to be equal to or higher than the temperature of the pre-devolatilization step, more preferably 200 ° C to 300 ° C.

  An example of devolatilization using such a plurality of devolatilizers will be described with reference to a schematic process diagram shown in FIG. As shown in FIG. 1, two devolatilizers are arranged in series in the devolatilization process, and the devolatilizer connected to the polymerization tank (1) is connected to the pre-devolatilization process and the cyclization apparatus. Let the device be a post-devolatilization step. Specifically, the copolymer solution (a) obtained in the polymerization step is continuously added to the devolatilization apparatus (2-1) in the pre-devolatilization step in which the temperature is raised to the polymerization temperature or higher and 250 ° C. or lower. The devolatilization apparatus in the devolatilization step is performed after the temperature of the copolymer (A) obtained in the pre-devolatilization step is raised to 200 ° C. or higher and 300 ° C. or lower. After supplying continuously to (2-2) and performing a post-devolatilization process, the obtained copolymer (A) is continuously supplied to the cyclization apparatus (3) of a cyclization process.

  Thus, the copolymer (A) obtained through the devolatilization step has a volatile component content (content of the remaining unreacted monomer mixture or the mixture of the unreacted monomer mixture and the polymerization solvent) before devolatilization. 5 to 30% by weight in the step, 5 to 25% by weight in the preferred embodiment, and less than 5% by weight in the post-devolatilization step, and less than 4% by weight in the preferred embodiment. In order not to reduce the pressure in the process, vent-up is suppressed, and further sufficient devolatilization is performed in the post-devolatilization process, so that (i) dehydration and / or (b) dealcoholization can proceed efficiently in the subsequent cyclization process Is possible. Although there is no restriction | limiting in particular in the minimum of content of the volatile component in the copolymer (A) after a devolatilization process, It is 0.1 weight% or more substantially.

  Moreover, since the copolymer (A) after the devolatilization step can be introduced into the next cyclization step as a high-temperature melt, and can be continuously subjected to the cyclization reaction, it is economically advantageous. It became possible to produce a thermoplastic copolymer (B).

  Moreover, in the manufacturing method of the thermoplastic copolymer (B) of this invention, the unreacted monomer isolate | separated and removed by the devolatilization process, or the mixture of an unreacted monomer and an organic solvent (C) is said polymerization process. The volatile matter recovery step (4) and the volatile matter purification step (5) to be recycled may be included. In the present invention, the unreacted monomer removed in the devolatilization step or a mixture of the unreacted monomer and the organic solvent (C) may be recovered and reused in the polymerization step.

[Cyclization process]
In the present invention, the copolymer (A) obtained in the devolatilization step is heated, subjected to intramolecular cyclization by dehydration and / or dealcoholization, and a thermoplastic resin composition containing glutaric anhydride ( A process for producing B) is required.

  In the cyclization step, it is preferable to carry out the reaction in the range of 200 to 350 ° C., more preferably 250 to 330 ° C., using a continuous kneading extruder. When the cyclization temperature is 200 ° C. or lower, the cyclization reaction becomes insufficient, the thermal stability of the resulting thermoplastic copolymer (B) decreases, and when the cyclization reaction is attempted to be completed at the temperature, Since the cyclization reaction takes a long time, the resin is colored due to thermal degradation. On the other hand, when the cyclization temperature is 350 ° C. or higher, the resin is colored due to thermal deterioration, and high colorless transparency cannot be obtained. The cyclization temperature is preferably higher than the temperature in the post-devolatilization step, more than 300 ° C. and 350 ° C. or less, more preferably more than 300 ° C. and 330 ° C. or less.

  In the production method of the present invention, the pressure condition of the cyclization step is 100 Torr or less, preferably 50 Torr or less, more preferably 30 Torr or less, and most preferably 10 Torr or less, and the cyclization can proceed. It is preferable because the thermoplastic copolymer (B) having excellent thermal stability and color tone can be produced. The lower limit of the pressure is not limited, but is usually about 0.1 Torr. By controlling the pressure condition to 100 Torr or less, water and / or alcohol by-produced by the cyclization reaction can be efficiently removed.

  On the other hand, when the pressure condition is 100 Torr or more, since the degree of vacuum is insufficient, the cyclization reaction becomes insufficient, and not only the thermal stability of the resulting thermoplastic copolymer (B) is lowered, but also in the system. Due to the oxygen present, the polymer deteriorates during cyclization and tends to color, which is not preferable. Even if the reaction is carried out in an inert gas atmosphere without reducing the pressure, water and / or alcohol by-produced during cyclization cannot be sufficiently removed, and the resulting thermoplastic copolymer (B ) Is unfavorable because the thermal stability is reduced.

  In the present invention, the heat treatment time in the cyclization step is preferably 1 minute to 120 minutes, more preferably 20 minutes to 120 minutes, still more preferably 30 minutes to 120 minutes, and most preferably 30 to 90 minutes. The range of minutes. When the heat treatment time is 20 minutes or less, the cyclization reaction rate is low, it is difficult to make the composition of the resulting thermoplastic copolymer (B) within the scope of the present invention, and unreacted unsaturation. Since a large amount of carboxylic acid units remain, the reaction proceeds again during thermoforming, water and / or alcohol by-produced by the cyclization reaction evaporates, and radial silver marks, so-called silver, are generated on the surface of the molded body. To do. Alternatively, bubbles are generated on the surface of the molded body, both of which are not preferable because they cause poor appearance, and are not preferable because of poor thermal stability.

  The cyclization apparatus used for the cyclization reaction is an apparatus capable of continuously cyclizing the copolymer (A) supplied from the devolatilization apparatus as the previous step, and the conditions of the temperature, pressure, and time described above. There is no particular limitation as long as the above can be satisfied, but it has a stirring device in which a cylindrical container and a plurality of stirring elements are attached to the rotating shaft, and has at least one vent port at the top of the cylindrical portion, A horizontal stirrer having a supply port for supplying the copolymer (A) at one end and a discharge port for taking out the thermoplastic copolymer (B) at the other end can be preferably used.

  In a more preferred embodiment, as a horizontal stirring device, water / methanol produced as a by-product in the cyclization reaction can be efficiently removed from the molten thermoplastic copolymer (A). And a supply port for supplying the copolymer (A) to one end of the container, and a thermoplastic copolymer ( B) has a discharge port for taking out, and has at least two stirring shafts inside thereof, and a plurality of scraping blades are attached to the shafts, and when the shafts rotate in the same direction or different directions The blades are mounted so as to be offset from each other so that the blades attached to each shaft do not collide with each other, and the blade tips rotate while making contact with the inner surface of the container and the empty stirring shaft surface with a slight clearance. The blades attached to each shaft are arranged so as to be aligned on the same plane perpendicular to the axial direction, and the blade tips rotate while contacting the inner surface of the container and the surface of the other blade with a slight clearance. Thus, it is possible to use a horizontal stirrer having a function of kneading the copolymer (A) in a molten state and constantly updating the surface thereof to advance the cyclization reaction. As a specific example of such a horizontal stirrer, a horizontal stirrer with good surface renewability shown in Japanese Patent Publication No. 58-11450 and Japanese Patent Publication No. 61-52850 is suitable, which is manufactured by Hitachi, Ltd. Preferred examples include glasses blade polymerization machine, lattice blade polymerization machine, SCR manufactured by Mitsubishi Heavy Industries, Ltd., NSCR type reactor, KRC kneader manufactured by Kurimoto Steel Works, SC processor, Sumitomo Heavy Industries, Ltd. BIVOLAK, etc. Can do.

In addition, an infrared spectrophotometer or a proton nuclear magnetic resonance ( ¹ H-NMR) measuring instrument is generally used for quantification of each component unit in the thermoplastic copolymer of the present invention. In infrared spectroscopy, glutaric anhydride units, absorption of 1800 cm ^-1 and 1760 cm ^-1 are characteristic can be distinguished from unsaturated carboxylic acid units and unsaturated carboxylic acid alkyl ester unit. In the ¹ H-NMR method, for example, in the case of a copolymer consisting of a glutaric anhydride unit, methacrylic acid, and methyl methacrylate, the attribution of the spectrum in dimethyl sulfoxide heavy solvent is 0.5 to 1.5 ppm. Peak of methacrylic acid, methyl methacrylate and glutaric anhydride ring compound α-methyl group hydrogen, 1.6 to 2.1 ppm peak of polymer main chain methylene group hydrogen, 3.5 ppm peak of methacrylic acid Copolymer composition can be determined from hydrogen of carboxylic acid ester of methyl acid (—COOCH ₃ ), a peak of 12.4 ppm and hydrogen of carboxylic acid of methacrylic acid and an integral ratio of the spectrum. In addition to the above, when styrene is contained as another copolymerization component, hydrogen in the aromatic ring of styrene is found at 6.5 to 7.5 ppm, and the copolymer composition is similarly determined from the spectral ratio. can do.

  Further, the thermoplastic copolymer of the present invention contains an unsaturated carboxylic acid unit and / or another copolymerizable vinyl monomer unit in addition to the components (i) and (ii). Can do.

  In the present invention, the amount of the unsaturated carboxylic acid unit contained in the thermoplastic copolymer is 10% by sufficiently carrying out (i) dehydration and / or (b) dealcoholization reaction of the copolymer (A). % Or less, that is, 0 to 10% by weight, more preferably 0 to 5% by weight. When the unsaturated carboxylic acid unit exceeds 10% by weight, colorless transparency and residence stability tend to be lowered.

  The amount of other copolymerizable vinyl monomer units is preferably 0 to 35% by weight, more preferably 10% by weight or less, that is, 0 to 10% by weight, further preferably 0 to 0% by weight. 5% by weight. In particular, when an aromatic vinyl monomer unit such as styrene is contained, if the content is too large, the colorless transparency, optical isotropy, and chemical resistance tend to decrease.

  The thermoplastic copolymer (B) of the present invention has a weight average molecular weight (hereinafter also referred to as Mw) of 30,000 to 150,000, preferably 50,000 to 150,000, and more preferably 50,000 to 130,000. In addition, the weight average molecular weight as used in the field of this invention shows the weight average molecular weight in the absolute molecular weight measured by multi-angle light scattering gel permeation chromatography (GPC-MALLS).

  In the present invention, a copolymer (A) having a homogeneous molecular weight distribution is achieved by selecting a bulk polymerization method or a solution polymerization method as the polymerization step so that the polymerization reaction proceeds in a substantially homogeneously mixed state. In a preferred embodiment, the molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) of the thermoplastic copolymer (B) is 1.5 to 3.0, and in a more preferred embodiment 1.5 to 3.0. It has been found that a range of 2.5 can be obtained. When the molecular weight distribution is in the above range, the resulting thermoplastic copolymer (B) tends to be excellent in molding processability and can be preferably used. The molecular weight distribution (Mw / Mn) in the present invention is the weight average molecular weight (Mw) and number average molecular weight (Mn) in absolute molecular weight measured by multi-angle light scattering gel permeation chromatography (GPC-MALLS). The numerical value calculated from

  The thermoplastic copolymer (B) of the present invention thus obtained has excellent heat resistance with a glass transition temperature of 120 ° C. or higher, and is preferable in terms of practical heat resistance. Further, in a preferred embodiment, the glass transition temperature is 125 ° C. or higher and extremely excellent heat resistance. Moreover, as an upper limit, it is about 160 degreeC normally. The glass transition temperature here is a glass transition temperature measured at a heating rate of 20 ° C./min using a differential scanning calorimeter (DSC-7 manufactured by Perkin Elmer).

  Further, the thermoplastic copolymer (B) produced by the production method of the present invention has a preferred embodiment in which the color of the pellet has a yellowness index of 20 or less, and coloring is suppressed. It has the following and extremely high colorless transparency. In the above, the yellowness is a value obtained by measuring the YI value of the pellets according to JIS-K7105 (1981 version). The lower limit of the yellowness is not particularly limited and is preferably as low as possible, but is usually about 1.

  The thermoplastic copolymer (B) produced by the production method of the present invention is a residual unreacted monomer or a mixture of unreacted monomer and organic solvent (C) (hereinafter collectively referred to as “reacted monomer”). The content of volatile components is sometimes suppressed to 5% by weight or less, and in a preferred embodiment, 3% by weight or less. Further, the heating loss when heated at a glass transition temperature + 130 ° C. for 30 minutes (hereinafter referred to as gas generation) In a preferred embodiment, it is 1.0 wt% or less, in a more preferred embodiment 0.5 wt%, most preferably 0.3 wt% or less, which could not be achieved by conventional methods. High thermal stability. The lower limit of the volatile component content and gas generation amount is not particularly limited and is preferably as low as possible, but is usually about 0.1% by weight.

  In the thermoplastic copolymer (B) of the present invention, the melt viscosity measured at a glass transition temperature + 130 ° C. and a shear rate of 12 / second is 100 to 10,000 Pa · s or less in a preferred embodiment, and in a more preferred embodiment. It has a high fluidity of 100 to 5000 Pa · s, and in the most preferred embodiment 100 to 2000 Pa · s or less, and is excellent in molding processability. The melt viscosity referred to here is the melt viscosity (Pa · s) measured at the above temperature and shear rate using a Capillograph type 1C (die diameter φ1.0 mm, die length 5.0 mm) manufactured by Toyo Seiki Co., Ltd. .

  The thermoplastic copolymer (B) produced according to the present invention makes use of its excellent heat resistance, colorless transparency and retention stability, and is used for electrical / electronic parts, automobile parts, mechanical mechanism parts, OA equipment, home appliances. It can be used for various uses such as housings and their parts and general sundries.

  In addition, the thermoplastic copolymer (B) obtained by the above method is excellent in mechanical properties and molding processability and can be melt-molded, so that extrusion molding, injection molding, press molding, etc. are possible. And can be used after being formed into a film, sheet, tube, rod, or other molded article having any desired shape and size.

  In particular, a known method can be used as a method for producing a film made of the thermoplastic copolymer (B). That is, production methods such as an inflation method, a T-die method, a calendar method, a cutting method, a casting method, an emulsion method, and a hot press method can be used. Preferably, an inflation method, a T-die method, a cast method or a hot press method can be used. In the case of a production method using an inflation method or a T-die method, an extruder type melt extrusion apparatus equipped with a single screw or twin screw can be used. The melt extrusion temperature for producing the film of the present invention is preferably 150 to 350 ° C, more preferably 200 to 300 ° C. Moreover, when melt-kneading using a melt-extrusion apparatus, it is preferable to perform the melt-kneading under reduced pressure or the melt-kneading under nitrogen stream from a viewpoint of coloring suppression. When the film of the present invention is produced by the casting method, solvents such as tetrahydrofuran, acetone, methyl ethyl ketone, dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone can be used. Preferred solvents are acetone, methyl ethyl ketone, N-methylpyrrolidone and the like. The film is prepared by dissolving the thermoplastic resin composition of the present invention in one or more of the above solvents, and using the solution with a bar coater, a T die, a T die with a bar, a die coat, etc. It can be produced by casting on a flat plate or curved plate (roll) such as a film, steel belt, or metal foil and using a dry method in which the solvent is removed by evaporation, or a wet method in which the solution is solidified with a coagulating liquid.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. Each measurement and evaluation was performed by the following method.

(1) Polymerization rate (φ)
The unreacted monomer concentration (% by weight) in the copolymer solution (a) and the charged raw material solution was quantified by gas chromatography, and calculated from the following formula.
Polymerization rate (φ) = 100 × (1−M1 / M0)
Each symbol indicates the following numerical value.
M1 = Unreacted monomer concentration (% by weight) in the copolymer solution (a)
M0 = monomer concentration in the charged raw material solution (wt%)

(2) Content of Volatile Component 1 g of each of the copolymer (A) or thermoplastic copolymer (B) containing the sampled volatile components is dissolved in 20 g of tetrahydrofuran, and unreacted monomers remaining by gas chromatography The organic solvent (C) was quantified, and the content of volatile components was calculated from the following formula.
Volatile component content (% by weight) = {(α + β) / P1} × 100
Each symbol indicates the following numerical value.
α = weight of residual monomer determined by gas chromatograph (g)
β = weight of organic solvent (C) determined by gas chromatography (g)
P1 = weight (g) of copolymer (A) or thermoplastic polymer (B) containing sampled volatiles

(3) Weight average molecular weight / molecular weight distribution 10 mg of the obtained copolymer (A) and thermoplastic copolymer (B) were dissolved in 2 g of tetrahydrofuran to prepare a measurement sample. Gel permeation chromatograph (pump: model 515, manufactured by Waters, column: TSK-gel-GMHXL, manufactured by Tosoh Corporation) equipped with a DAWN-DSP type multi-angle light scattering photometer (manufactured by Wyatt Technology) using tetrahydrofuran as a solvent. ) Was used to measure the weight average molecular weight (absolute molecular weight) and the number average molecular weight (absolute molecular weight). The molecular weight distribution was calculated by weight average molecular weight (absolute molecular weight) / number average molecular weight (absolute molecular weight).

(4) Composition analysis of each component ¹ H-NMR was measured at 30 ° C. in deuterated dimethyl sulfoxide to determine the composition of each copolymer unit.

(5) Glass transition temperature (Tg)
Using a differential scanning calorimeter (DSC-7 manufactured by Perkin Elmer), the measurement was performed at a temperature increase rate of 20 ° C./min in a nitrogen atmosphere.

(6) Yellowness Index
The YI value of the obtained thermoplastic copolymer pellets was measured using a spectrocolorimeter SE2000 (manufactured by Nippon Denshoku).

(7) Gas generation amount during residence 5 g of the obtained thermoplastic copolymer (B) pellets were pre-dried at 80 ° C. for 12 hours and heat-treated for 30 minutes in a heating furnace adjusted to a glass transition temperature of + 130 ° C. The weight before and after was measured, and the weight reduction rate calculated by the following equation was evaluated as the amount of gas generated during residence.
Weight reduction rate (% by weight) = {(W0−W1) / W0} × 100
Each symbol indicates the following numerical value.
W0 = weight (g) of thermoplastic copolymer (B) before heat treatment
W1 = weight (g) of the thermoplastic copolymer (B) after the heat treatment

(8) Melt viscosity of thermoplastic copolymer (B) The obtained thermoplastic copolymer (B) pellets were pre-dried at 80 ° C. for 12 hours, and Capillograph 1C type (die diameter φ1 mm, die length 5 mm, manufactured by Toyo Seiki Co., Ltd.) ) At a glass transition temperature of + 130 ° C. and a shear rate of 12 / sec.

  Below, it demonstrates in order, referring FIG.

(1) Polymerization step <Reference Example 1>
To a stainless steel autoclave having a capacity of 20 liters and equipped with a double helical stirring blade, a raw material mixture of the following formulation bubbled with nitrogen gas at 20 L / min for 15 minutes was continuously supplied at a rate of 8.0 kg / h. The mixture was stirred at 50 rpm, the internal temperature was controlled at 130 ° C., and continuous polymerization was carried out with an average residence time of 3 hours. As a result of sampling and analyzing the obtained copolymer solution (a), the polymerization rate was 88%, and the volatile content in the copolymer solution (a) was 30% by weight. Moreover, as a result of measuring the solution viscosity of the obtained copolymer solution (a-1) at 30 degreeC, it was 70 Pa.s.
Methacrylic acid 15 parts by weight Methyl methacrylate 85 parts by weight Methyl ethyl ketone 25 parts by weight 1,1-di-t-butylperoxycyclohexane 0.1 part by weight n-dodecyl mercaptan 0.3 part by weight.

<Reference Example 2>
To a stainless steel autoclave having a capacity of 20 liters and equipped with a double helical stirring blade, a raw material mixture of the following formulation bubbled with nitrogen gas at 20 L / min for 15 minutes was continuously supplied at a rate of 8.0 kg / h. The mixture was stirred at 50 rpm, the internal temperature was controlled at 130 ° C., and continuous polymerization was carried out with an average residence time of 3 hours. As a result of sampling and analyzing the obtained copolymer solution (a), the polymerization rate was 75%, and the volatile content in the copolymer solution (a) was 70% by weight. Moreover, as a result of measuring the solution viscosity of the obtained copolymer solution (a-2) at 30 degreeC, it was 30 Pa.s.
Methacrylic acid 15 parts by weight Methyl methacrylate 85 parts by weight Methyl ethyl ketone 150 parts by weight 1,1-di-t-butylperoxycyclohexane 0.1 part by weight n-dodecyl mercaptan 0.3 part by weight.

(2) Volatilization process and cyclization process <Examples 1-2>
The copolymer solutions (a-1, a-2) obtained in Reference Examples 1 and 2 were mixed with a 58 mmφ twin screw extruder (TEX-54 (manufactured by Nippon Steel Works, L / D = 14.0, Back vent part: 1 place, fore vent part: none) continuously at a feed rate of 10 kg / h, screw rotation speed 400 rpm, cylinder temperature 150 ° C., no pressure reduction operation from the vent part, pressure 760 Torr Table 2 shows the results of sampling the devolatilized copolymer (A) and measuring the volatile components contained at this point.

  Next, the copolymer (A) obtained in the pre-devolatilization step was further subjected to a 32 mmφ twin screw extruder (TEX-30 (manufactured by Nippon Steel Works, L / D = 56.0, back vent part: 1 point, forevent: 3 places), the screw rotation speed was 300 rpm, the cylinder temperature was 260 ° C., the pressure was reduced from the forevent part, and post-devolatilization was performed at a pressure of 20 Torr. Table 2 shows the results of sampling the volatile copolymer (A) and measuring the volatile components contained.

  Subsequently, the copolymer (A-1 to 2) obtained in the above step was subjected to a spectacle blade horizontal biaxial agitator (“Hitachi spectacle blade polymerizer (trade name)” manufactured by Hitachi, Ltd., capacity 24 L, vent Part: 1 location) at a supply rate of 10 kg / h, screw rotation speed 10 rpm, cylinder temperature 300 ° C., decompression from the vent, cyclization reaction at 10 Torr pressure, pelletized by strand cutter A thermoplastic copolymer (B-1 to 2) was produced at a rate of 9.8 kg / h. The average residence time of the cyclizer at this time was 60 minutes.

The obtained pellets of (B-1 to 2) are dried at 100 ° C. for 8 hours, and each copolymer component composition and various characteristics evaluation results determined by ¹ H-NMR are shown in Table 3.

<Examples 3 to 4>
The copolymer solutions (a-1, a-2) obtained in Reference Examples 1 and 2 were mixed with a 58 mmφ twin screw extruder (TEX-54 (manufactured by Nippon Steel Works, L / D = 14.0, Back vent part: 1 place, fore vent part: none) continuously at a feed rate of 10 kg / h, screw rotation speed 400 rpm, cylinder temperature 150 ° C., adjusting the valve opening of the vent part The pre-devolatilization treatment was performed under a slightly pressurized condition of 960 Torr, and at this time, the copolymer (A) after devolatilization was sampled, and the results of measuring the volatile components contained are shown in Table 2.

  Next, the copolymer (A) obtained in the pre-devolatilization step was further subjected to a 32 mmφ twin screw extruder (TEX-30 (manufactured by Nippon Steel Works, L / D = 56.0, back vent part: 1 point, forevent: 3 places), the screw rotation speed was 300 rpm, the cylinder temperature was 260 ° C., the pressure was reduced from the forevent part, and post-devolatilization was performed at a pressure of 20 Torr. Table 2 shows the results of sampling the volatile copolymer (A) and measuring the volatile components contained.

  Subsequently, the copolymer (A-3 to 4) obtained in the above step was subjected to a spectacle blade horizontal biaxial stirrer (“Hitachi spectacle blade polymerizer (trade name)” manufactured by Hitachi, Ltd., capacity 24 L, vent Part: 1 location) at a supply rate of 10 kg / h, screw rotation speed 10 rpm, cylinder temperature 300 ° C., decompression from the vent, cyclization reaction at 10 Torr pressure, pelletized by strand cutter A thermoplastic copolymer (B-3-4) was produced at a rate of 9.8 kg / h. The average residence time of the cyclizer at this time was 60 minutes.

The obtained pellets of (B-3 to 4) are dried at 100 ° C. for 8 hours, and each copolymer component composition and various characteristics evaluation results determined by ¹ H-NMR are shown in Table 3.

<Comparative Examples 1-2>
The copolymer solutions (a-1, a-2) obtained in Reference Examples 1 and 2 were mixed with a 58 mmφ twin screw extruder (TEX-54 (manufactured by Nippon Steel Works, L / D = 14.0, Back vent part: 1 place, fore vent part: none) continuously at a supply speed of 10 kg / h, screw rotation speed of 400 rpm, cylinder temperature of 150 ° C., decompression from the back vent part, and pre-desorption at a pressure of 20 Torr At this time, the copolymer (A) after devolatilization was sampled, and the results of measuring the volatile components contained are shown in Table 2.

  Subsequently, the copolymer (A) obtained in the pre-devolatilization step was subjected to a 32 mmφ twin screw extruder (TEX-30 (manufactured by Nippon Steel Works, L / D = 56.0, back vent part: 1 place) with a gear pump. , Forevent: 2 locations), and after that, after the devolatilization process, the pressure was reduced from the forevent part at a screw speed of 300 rpm, a cylinder temperature of 260 ° C., and a pressure of 20 Torr. Table 2 shows the results of sampling the copolymer (A) and measuring the volatile components contained therein.

  Subsequently, the copolymer (A-5 to 6) obtained in the above step was subjected to a spectacle blade horizontal biaxial agitator (“Hitachi spectacle blade polymerizer (trade name)” manufactured by Hitachi, Ltd., capacity 24 L, vent Part: 1 location) at a supply rate of 10 kg / h, screw rotation speed 10 rpm, cylinder temperature 300 ° C., decompression from the vent, cyclization reaction at 10 Torr pressure, pelletized by strand cutter A thermoplastic copolymer (B-5 to 6) was produced at a rate of 9.8 kg / h. The average residence time of the cyclizer at this time was 60 minutes.

The obtained pellets of (B-5 to 6) are dried at 100 ° C. for 8 hours, and each copolymer component composition and various characteristics evaluation results determined by ¹ H-NMR are shown in Table 3.

<Comparative Examples 3-4>
The copolymer solution (a-1, a-2) obtained in Reference Examples 1 and 2 was subjected to a 32 mmφ twin screw extruder (TEX-30 (manufactured by Nippon Steel Works, L / D = 56.0, Back vent part: 1 place, fore vent: 3 places) at a feed rate of 10 kg / h, continuously screwed at 400 rpm, cylinder temperature 260 ° C., depressurized from the fore vent part, and devolatilized at a pressure of 20 Torr Table 2 shows the results of sampling the devolatilized copolymer (A) and measuring the volatile components contained.

  Subsequently, the copolymer (A-7) obtained in the above step was subjected to a spectacle blade horizontal biaxial stirrer (“Hitachi Glasses blade polymerizer (trade name)” manufactured by Hitachi, Ltd., capacity 24 L, vent part: 1 place) at a supply rate of 10 kg / h continuously, screw rotation speed of 10 rpm, cylinder temperature of 300 ° C., decompression from the vent, cyclization reaction at a pressure of 10 Torr, pelletized by a strand cutter, A plastic copolymer (B-7) was produced at a rate of 9.8 kg / h. The average residence time of the cyclizer at this time was 60 minutes.

The obtained pellets of (B-7) were dried at 100 ° C. for 8 hours, and each copolymer component composition and various characteristics evaluation results determined by ¹ H-NMR are shown in Table 3.

<Comparative Examples 5-6>
The copolymer solution (a-1, a-2) obtained in Reference Examples 1 and 2 was subjected to a 58 mmφ twin screw extruder (TEX-54 (manufactured by Nippon Steel Works, L / D = 56.0, Back vent part: 1 place, fore vent: 3 places) at a feed rate of 10 kg / h, continuously screwed at 400 rpm, cylinder temperature 260 ° C., depressurized from the fore vent part, and devolatilized at a pressure of 20 Torr Table 2 shows the results of sampling the devolatilized copolymer (A) and measuring the volatile components contained.

  Subsequently, the copolymer (A-8-9) obtained in the above step was subjected to a spectacle blade horizontal biaxial agitator (“Hitachi Glasses blade polymerizer (trade name)” manufactured by Hitachi, Ltd., capacity 24 L, vent Part: 1 location) at a supply rate of 10 kg / h, screw rotation speed 10 rpm, cylinder temperature 300 ° C., decompression from the vent, cyclization reaction at 10 Torr pressure, pelletized by strand cutter A thermoplastic copolymer (B-8 to 9) was produced at a rate of 9.8 kg / h. The average residence time of the cyclizer at this time was 60 minutes.

The obtained pellets of (B-8 to 9) were dried at 100 ° C. for 8 hours, and each copolymer component composition and various characteristic evaluation results determined by ¹ H-NMR are shown in Table 3.

  When the number of devolatilizers is one, as in Comparative Examples 3 and 4, if the cylinder diameter is small, the process cannot catch up, so that the venting is easily performed. Further, as in Comparative Examples 5 to 6, although the treatment becomes possible when the cylinder diameter is increased, the copolymer powder is splattered to the vent and control is not easy, so the object of the present invention cannot be achieved.

  As in Comparative Examples 1 and 2, by using two devolatilizers, the size of the devolatilizer can be reduced, and when the pre-devolatilization step and the post-devolatilization step are reduced in pressure, the devolatilization efficiency is also good. became. However, in the pre-devolatilization step, the copolymer powder is splattered into the vent by abruptly depressurizing the copolymer solution, and the control is not easy, so the object of the present invention cannot be achieved.

As in Examples 1 to 4, by using two devolatilizers, the size of the devolatilizer can be reduced. Further, the pre-devolatilization step is performed under a reduced pressure of 760 to 1000 Torr, and the post-devolatilization step is performed under a pressure of less than 200 Torr. By doing so, it is possible to remarkably suppress the scattering of the copolymer powder to the vent in the pre-devolatilization step, and in the post-devolatilization step until the volatile content is sufficiently high to be sent to the cyclization step. Since it can be devolatilized, the object of the present invention can be achieved.

  The present invention is a method for industrially producing a copolymer containing glutaric anhydride units having excellent transparency and thermal stability, and the copolymer obtained by this method is an optical lens, prism, mirror, optical disk It can be used for optical materials such as optical fibers, liquid crystal display sheets and films, and light guide plates.

It is a schematic process drawing which shows an example of the manufacturing process of the thermoplastic copolymer of this invention.

Explanation of symbols

1: polymerization tank 2-1: devolatilizer in the pre-devolatilization step 2-2: devolatilizer in the post-devolatilization step 3: cyclization device 4: volatile component recovery step 5: volatile component purification step 6: thermoplastic Polymer (B)

Claims (9)

(I) A copolymer (A) containing (i) an unsaturated carboxylic acid alkyl ester unit and (ii) an unsaturated carboxylic acid unit is continuously polymerized by solution polymerization or bulk polymerization, and the copolymer (A) and unreacted A copolymer solution (a) containing a monomer mixture and / or an organic solvent and having a volatile component content of 30 to 70% by weight,
(II-1) a pre-devolatilization step in which this is heated and volatilized at 760 to 1000 Torr;
(II-2) Subsequent to this, the unreacted monomer mixture and / or the organic solvent is removed from the copolymer solution (a) by a devolatilization step after heating and devolatilization under a reduced pressure of 200 Torr or less,
(III) Subsequently, the mixture is supplied to a cyclization apparatus and subjected to heat treatment, and an intramolecular cyclization reaction is performed by dehydration and / or dealcoholization reaction. (Iii) Glutar represented by the following general formula (1) A method for producing a thermoplastic copolymer, comprising producing a thermoplastic copolymer (B) comprising an acid anhydride unit and (i) an unsaturated carboxylic acid alkyl ester unit.

(However, R ¹ and R ² are the same or different and represent any one selected from a hydrogen atom and an alkyl group having 1 to 5 carbon atoms.) The thermoplastic copolymer according to claim 1, comprising a pre-devolatilization step for devolatilization until the volatile component content is 5 to 30% by weight, and a post-devolatilization step for devolatilization until the volatile component content is less than 5% by weight. Manufacturing method of coalescence. The devolatilizer has a stirrer in which a cylindrical container and a large number of stirrers are attached to one or a plurality of rotating shafts, has at least one vent port at the top of the tube, and has one end of the tube 3. The apparatus according to claim 1, wherein the apparatus has a supply port for supplying the copolymer solution (a) to the inside and a discharge port for taking out the devolatilized copolymer (A) at the other end. A method for producing a thermoplastic copolymer. The method for producing a thermoplastic copolymer according to claim 3, wherein the devolatilization apparatus is a twin-screw extrusion apparatus having a vent. The method for producing a thermoplastic copolymer according to any one of claims 1 to 4, wherein the pre-devolatilization step is performed by a twin-screw extruder having a back vent. The method for producing a thermoplastic copolymer according to any one of claims 1 to 5, wherein the pre-devolatilization step is performed at a temperature of not lower than the polymerization temperature and not higher than 250 ° C. The thermoplastic co-polymerization according to any one of claims 1 to 6, wherein the post-devolatilization step is carried out at a temperature not lower than the devolatilization temperature in the pre-devolatilization step, not higher than 300 ° C, and not higher than 200 Torr. Manufacturing method of coalescence. The ratio of the screw diameter (D) to the screw length (L) (L / D) of the devolatilizer in the pre-devolatilization step is 14 to 25, and the thermoplastic co A method for producing a polymer. The thermoplastic copolymer according to claim 3, wherein the ratio (L / D) of the screw diameter (D) and the screw length (L) of the devolatilizer in the post-devolatilization step is 35-60. A method for producing a polymer.

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