JP2008255139A - Method for producing acrylic resin, being small in the amount of gas formed during processing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an acrylic resin, being small in the amount of gas formed during its processing. <P>SOLUTION: This method for producing the acrylic resin comprises charging an acrylic resin and optionally a low volatile component to an extruder, and progressing a desired reaction (e.g. an imidizing reaction), while operating the extruder e.g. at ≥50 cm/s high rotation, further preferably removing a volatile component by a high vacuum (e.g. pressure of <8 kPa absolute pressure) from a vent to be able to produce the acrylic resin, such as an imidized acrylic resin with a small amount of gas formed during processing. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing an acrylic resin (for example, an imidized acrylic resin or an esterified modified imidized acrylic resin) that generates a small amount of gas during processing.

  Acrylic resins such as polymethyl methacrylate are used as optical components such as optical lenses, light diffusion plates, and light guide plates, various protective films, and optical films because of their transparency and optical properties.

  When the acrylic resin is processed into the molded product, if the oligomer component remains in the resin, the oligomer component volatilizes particularly during processing with the film, thereby causing defects in the film.

  As a method for removing volatile components in the resin, a method using a supercritical fluid is disclosed (for example, see Patent Document 1).

  As acrylic resins, polymethyl methacrylate and those obtained by copolymerizing an aromatic vinyl compound such as styrene in order to improve the hygroscopicity of methyl methacrylate are known.

  In addition, a method of introducing these acrylic resins into a high-temperature devolatilization tank to remove volatile components is also conceivable, but devolatilization passes a high-temperature devolatilization tank after polymerization and requires an apparatus other than an extruder. And inefficient.

  On the other hand, as an acrylic resin, what imidized acrylic resin is known in order to improve the heat resistance of polymethyl methacrylate.

  For example, Patent Document 2 describes a method of obtaining an acrylic resin by reacting polymethyl methacrylate with a primary amine. Patent Document 3 describes that an acrylic resin is obtained by reacting a methyl methacrylate-styrene copolymer with a primary amine, and further, an acid group and an acid anhydride of an intermediate product of imidation reaction. Since the group deteriorates the compatibility with other thermoplastic polymers, it is reacted with an esterifying agent and converted into non-acid groups and non-anhydride groups to improve compatibility when blended with other thermoplastic polymers. A method is described.

As a method for removing residual volatile components in the acrylic resin, Patent Document 2 describes that residual volatile components are removed by devolatilization at atmospheric pressure and in vacuum at the time of extrusion. Patent Document 4 describes a method in which trimethylamine in a residual volatile sentence is reduced to 30 ppm or less by devolatilizing an acrylic resin together with methanol or water. However, nothing is said about the removal of the oligomer.
JP-A-11-292921 U.S. Pat. No. 4,246,374 U.S. Pat. No. 4,727,117 US Pat. No. 5,126,409

  An oligomer component remains in an acrylic resin or a resin obtained by imidizing an acrylic resin to improve heat resistance (for example, imidized acrylic resin, esterified modified imidized acrylic resin, etc.) There has been a problem that defects occur with the generation of gas during processing, and a new production method for reducing oligomer components has been demanded.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive studies, and as a result of adding an acrylic resin and, if necessary, a low-volatile component to the extruder to proceed a desired reaction, the peripheral speed of the screw of the extruder Operating the extruder at a high rotation speed of 50 cm / s or more, and further removing the volatile matter under reduced pressure from the vent at a pressure of less than 8 kPa, thereby reducing the amount of gas generated during processing (for example, It was found that an imidized acrylic resin, an esterified modified imidized acrylic resin, etc.) can be produced, and the present invention has been completed.

That is, the present invention provides an imidization characterized in that when an acrylic resin and a primary amine are added to an extruder and an imidization reaction is performed, extrusion is performed with a peripheral speed of the extruder screw of 50 cm / s or more. A method for producing an acrylic resin (Claim 1),
An esterification-modified imide, characterized in that when an imidized acrylic resin and an esterifying agent are added to an extruder to carry out an esterification-modifying reaction, extrusion is performed with a peripheral speed of the extruder screw of 50 cm / s or more. A method for producing a fluorinated acrylic resin (Claim 2),
A method for producing an esterified modified imidized acrylic resin, characterized in that an esterified modified imidized acrylic resin is added to an extruder and devolatilized and extruded at a peripheral speed of an extruder screw of 50 cm / s or more (claim). It relates to 3).

  Add acrylic resin and low volatile components to the extruder as needed, and proceed with the desired reaction. While operating the extruder at high speed, remove the volatiles from the vent under high vacuum. By doing so, an acrylic resin with a small amount of gas generated during processing can be produced.

  The production method of the present invention is an acrylic resin containing a repeating unit represented by at least the following general formulas (1) and (2) (in the present specification, the raw material is not clarified particularly from the context). The term “acrylic resin” is a production method applicable to imidized acrylic resins such as imidized acrylic resins and esterified modified imidized acrylic resins).

(Here, R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ³ represents an alkyl group having 1 to 18 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms. Or an aryl group having 6 to 10 carbon atoms.)

(Here, R ⁴ and R ⁵ each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁶ represents an alkyl group having 1 to 18 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms. Or an aryl group having 6 to 10 carbon atoms.)

(Here, R ⁷ represents hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁸ represents an aryl group having 6 to 10 carbon atoms.)
As a 1st structural unit which comprises the said acrylic resin, it is a glutarimide unit represented by following General formula (1).

(Here, R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ³ represents an alkyl group having 1 to 18 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms. Or an aryl group having 6 to 10 carbon atoms.)
As a preferable glutarimide unit, R ¹ and R ² are hydrogen or a methyl group, and R ³ is hydrogen, a methyl group, or a cyclohexyl group. The case where R ¹ is a methyl group, R ² is hydrogen, and R ³ is a methyl group is particularly preferable.

The glutarimide unit may be of a single type or may include a plurality of types in which R ¹ , R ² and R ³ are different.

  As a 2nd structural unit which comprises the said acrylic resin, it is an acrylic ester or methacrylic ester unit represented by following General formula (2).

(Here, R ⁴ and R ⁵ each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁶ represents an alkyl group having 1 to 18 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms. Or an aryl group having 6 to 10 carbon atoms.)
The (meth) acrylic acid compound or (meth) acrylic acid ester compound is not particularly limited. For example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate , T-butyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate and the like. In addition, acid anhydrides such as maleic anhydride or half esters of these and linear or branched alcohols having 1 to 20 carbon atoms; acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, Α, β-ethylenically unsaturated carboxylic acids such as crotonic acid, fumaric acid and citraconic acid can also be imidized and used in the present invention. Of these, methyl methacrylate is particularly preferred.

These second structural units may be of a single type, and may include a plurality of types in which R ⁴ , R ⁵ , and R ⁶ are different.

  Furthermore, the acrylic resin to which the production method of the present invention can be applied may contain an aromatic vinyl unit represented by the following general formula (3).

(Here, R ⁷ represents hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁸ represents an aryl group having 6 to 10 carbon atoms.)
Preferred aromatic vinyl structural units include styrene, α-methylstyrene, and the like. Of these, styrene is particularly preferred.

These third structural units may be of a single type, and may include a plurality of types in which R ⁷ and R ⁸ are different.

  The content of the glutarimide unit represented by the general formula (1) in the acrylic resin is preferably 1% by weight or more of the acrylic resin. The preferable content of the glutarimide unit is 1 to 95% by weight, more preferably 1.5 to 90% by weight, and still more preferably 2 to 80% by weight. When a glutarimide unit is smaller than this range, the heat resistance of the acrylic resin obtained may be insufficient, or transparency may be impaired. On the other hand, if it exceeds this range, the heat resistance is unnecessarily increased and it becomes difficult to mold, and the mechanical strength of the resulting molded body becomes extremely brittle, and the transparency may be impaired.

  The content of the aromatic vinyl unit represented by the general formula (3) in the acrylic resin is preferably 80% by weight or less based on the total repeating units of the acrylic resin. The preferred content of the aromatic vinyl unit is 1 to 80% by weight, more preferably 1.5 to 70% by weight, and still more preferably 2 to 60% by weight. When the aromatic vinyl unit is larger than this range, the heat resistance of the resulting acrylic resin may be insufficient and the photoelastic coefficient may be small.

  Furthermore, the fourth structural unit may be copolymerized in the acrylic resin to which the production method of the present invention can be applied, if necessary. A constitution obtained by copolymerizing a nitrile monomer such as acrylonitrile and methacrylonitrile, and a maleimide monomer such as maleimide, N-methylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide as the fourth structural unit Units can be used. These may be directly copolymerized in an acrylic resin or may be graft copolymerized.

  The methyl methacrylate-styrene copolymer to which the production method of the present invention can be applied is a (meth) acrylic acid-based compound or a (meth) acrylic acid ester-based compound capable of imidization reaction alone or a copolymer thereof. If a (meth) acrylic acid compound or a (meth) acrylic acid ester compound and a styrene compound are included as essential components, even a linear (linear) polymer, a block polymer, a core-shell polymer, a branched polymer, A ladder polymer or a crosslinked polymer may be used. The block polymer may be an A-B type, A-B-C type, A-B-A type, or any other type of block polymer. There is no problem even if the core-shell polymer is composed of only one core and only one shell, or each layer is a multilayer.

  The imidizing agent used in the present invention is not particularly limited as long as the methyl methacrylate-styrene copolymer can be imidized. For example, methylamine, ethylamine, n-propylamine, i-propylamine, n-butylamine Aliphatic hydrocarbon group-containing amines such as i-butylamine, tert-butylamine, and n-hexylamine, aromatic hydrocarbon group-containing amines such as aniline, toluidine, and trichloroaniline, and alicyclic hydrocarbon groups such as cyclohexylamine Contains amines. In addition, urea compounds that generate these amines by heating, such as urea, 1,3-dimethylurea, 1,3-diethylurea, and 1,3-dipropylurea can also be used. Of these imidizing agents, methylamine is preferable from the viewpoint of cost and physical properties.

  The amount of the imidizing agent added is determined by the imidization rate for expressing necessary physical properties.

  In addition, acrylic resins (including imidized acrylic resins, esterified modified imidized acrylic resins, etc.) that can be produced by the production method of the present invention have a weight average molecular weight of 10,000 to 200,000 in particular. Is preferred. When the weight average molecular weight is not more than the above value, the mechanical strength of the molded product is insufficient. When the weight average molecular weight is not less than the above value, the viscosity at the time of melting is high, and the productivity at the time of molding may be reduced. .

  The glass transition temperature of acrylic resins (including imidized acrylic resins and esterified modified imidized acrylic resins) that can be produced by the production method of the present invention is preferably 100 ° C. or higher, and 110 ° C. or higher. It is more preferable that the temperature is 115 ° C. or higher.

  In addition, other acrylic resins may be added to the acrylic resins (including imidized acrylic resins, esterified modified imidized acrylic resins, etc.) that can be produced by the production method of the present invention. Can do.

  In addition, in the acrylic resin that can be produced by the production method of the present invention, unnecessary volatile components composed of unreacted primary amines and various by-products may be generated during the imidization reaction. Volatile components in the imidization reaction when monomethylamine is treated on polymethyl methacrylate resin include amines such as monomethylamine, dimethylamine, and trimethylamine, methanol, water, resin monomers and oligomers, and the like. Also when other acrylic resins and other primary amines are used, volatile components such as various amines, various alcohols, water, resin monomers and oligomers are generated.

  These volatile components are removed after the imidization reaction. U.S. Pat. No. 4,246,374 describes that an acrylic resin is contacted with a primary amine in an extruder to undergo an imidization reaction, and then a volatile component is removed by vacuum devolatilization.

  If the acid group and acid anhydride group of the intermediate product of the imidization reaction remain in the acrylic resin of the present invention, foaming occurs during melt processing, surface defects occur in the molded product, and other thermoplastic polymers Compatibility becomes worse. Therefore, it is desirable to react with an esterifying agent as necessary to convert it into a non-acid group and a non-anhydride group.

  Examples of the esterifying agent used in the present invention include dimethyl carbonate, dimethoxypropane, dimethyl sulfoxide, trimethylaltoformate, triethylaltoformate, etc., but ester of acid group and acid anhydride group of imidized acrylic resin However, this is not necessary as long as it can be efficiently performed. A small amount of catalyst may be added in order to promote the esterification reaction by the esterifying agent.

  Examples of the esterifying agent catalyst used in the present invention include trimethylamine and triethylamine.

  Of these esterifying agents, dimethyl carbonate is preferred from the viewpoint of cost and physical properties.

  In order to suppress molding defects such as foaming during resin processing, the acrylic resin of the present invention is preferably further devolatilized after imidization and esterification modification to remove residual volatile components.

  Examples of the extruder used in the present invention include a single-screw extruder, a twin-screw extruder, and a multi-screw extruder, and a twin-screw extruder having good devolatilization efficiency is preferable. The twin screw extruder includes a non-meshing type same direction rotating type, a meshing type same direction rotating type, a non-meshing type different direction rotating type, and a meshing type different direction rotating type. Among the twin screw extruders, the meshing type co-rotating type is preferable because high speed rotation is possible and the production amount can be increased. These extruders may be used alone or connected in series. Moreover, it is preferable to install one or more vent ports that can be depressurized to atmospheric pressure or less in the extruder.

  The extrusion temperature for removing the oligomer component from the acrylic resin is in the range of 150 to 350 ° C. 200-330 degreeC is more preferable, and 250-310 degreeC is further more preferable. Below 150 ° C, the melt viscosity of the polymer becomes high, and a large load is imposed on the operation of the apparatus, and the oligomer is not sufficiently volatilized.

  The internal pressure of the extruder is usually in the range of atmospheric pressure to 15 MPa, and more preferably in the range of 0.5 MPa to 10 MPa. If the pressure is 0.5 MPa or less, the reaction efficiency of the imidizing agent or the esterifying agent becomes low, and the reaction hardly proceeds. If it is 10 MPa or more, an extreme screw configuration for resin sealing is required, the resin temperature becomes high, and the resin is decomposed and colored.

  The number of revolutions of the extruder is preferably 10 rpm to 2000 rpm, and more preferably 20 rpm to 1000 rpm. If it is 10 rpm or less, productivity and devolatilization efficiency are deteriorated, and if it is 2000 rpm or more, the electric energy of the extruder main motor becomes large, and further heat generation of the resin becomes intense, resulting in resin deterioration.

  In order to efficiently perform devolatilization, it is necessary to increase the resin temperature to facilitate evaporation of volatile components, and to increase the renewal of the resin surface of the vent portion by speeding up the extruder. The peripheral speed of the screw of the extruder is used as an index that serves as both.

  The peripheral speed of the screw of the extruder is preferably 10 cm / s to 200 cm / s, more preferably 20 to 180 cm / s, and even more preferably 50 to 150 cm / s. When the peripheral speed is 10 cm / s, kneading is insufficient and devolatilization is not sufficient. On the other hand, when the peripheral speed is higher than 200 cm / s, heat generation of the resin becomes intense and the resin deteriorates.

  It is preferable to install a plurality of vents for removing volatile components from the extruder. In order to increase efficiency, it is preferable to provide a vent that is open to the atmosphere on the upstream side, and a vent that is connected to a vacuum pump on the downstream side to increase the degree of pressure reduction.

  The lower the pressure at the time of residual volatile matter removal, the higher the removal rate, which is preferable. The absolute pressure is preferably 30 kPa or less, and more preferably 8 kPa or less. When the absolute pressure is 30 kPa or more, the remaining volatile components cannot be sufficiently removed.

  The acrylic resin according to the present invention is characterized in that less gas is generated during resin processing.

  As the gas amount, the gas amount by the heat desorption apparatus is used as an index. The total amount of gas generated when heated at 280 ° C. for 30 minutes in a helium atmosphere is preferably 2000 μg or less per 1 g of resin, more preferably 1500 μg or less.

  In the acrylic resin, generally used catalysts, antioxidants, heat stabilizers, plasticizers, lubricants, ultraviolet absorbers, antistatic agents, colorants, shrinkage inhibitors, etc. are not impaired. You may add in the range.

  The acrylic resin according to the present invention has properties such as high tensile strength and bending strength, solvent resistance, thermal stability, good optical properties, and weather resistance.

  The acrylic resin obtained in the present invention may be used by itself or may be blended with other thermoplastic polymers. Acrylic resins alone or blends with other thermoplastic resins can be processed into various molded products by various plastic processing methods such as injection molding, extrusion molding, blow molding, compression molding and the like. It can also be molded by a casting method using a polymer solution obtained by dissolving an acrylic resin obtained in the present invention such as methylene chloride in a solvent that dissolves the acrylic resin.

  When molding, generally used antioxidants, heat stabilizers, plasticizers, lubricants, UV absorbers, antistatic agents, colorants, shrinkage inhibitors, etc. are added within the range that does not impair the purpose of the present invention. May be.

  The molded product obtained from the acrylic resin of the present invention is used for, for example, video fields such as a camera, a VTR, a projection lens for a projector, a finder, a filter, a prism, a Fresnel lens, an optical disk such as a CD player, a DVD player, and an MD player Information on lens fields such as pickup lenses, optical recording fields for optical discs such as CD players, DVD players, and MD players, liquid crystal light guide plates, liquid crystal display films such as polarizer protective films and retardation films, and surface protective films Equipment field, optical communication field such as optical fiber, optical switch, optical connector, etc., automotive field such as automobile headlight, tail lamp lens, inner lens, instrument cover, sunroof, glasses, contact lens, lens for internal vision, sterilization treatment necessary Medical equipment field such as medical supplies, road translucent plates, paired glass lenses, lighting windows and carports, lighting lenses and covers, building material fields such as sizing for building materials, microwave cooking containers (tableware), home appliances Can be used for product housing, toys, sunglasses, stationery, etc.

  EXAMPLES Although this invention is demonstrated further in detail based on an Example, this invention is not limited only to these Examples. In addition, each measuring method of the physical property measured in the following Examples and Comparative Examples is as follows.

(1) Measurement of the amount of volatile gas by a thermal desorption apparatus Gas chromatography (6890plus manufactured by Agilent Technologies) / mass spectrum (5973 manufactured by Agilent Technologies) equipped with a thermal desorption apparatus TurboMatrix ATD manufactured by PerkinElmer using the pellets of the product as they are. (GC / MS).

  About 20 g of pellets are put into a sample tube, both ends are fixed with quartz wool, heated at 280 ° C. for 30 minutes with a heat desorption device, and the generated gas component is collected at −30 ° C. with a Tenax tube, and then at 280 ° C. The sample was heated and desorbed to perform GC / MS measurement. The GC / MS conditions were as follows: column: DB-5MS (0.25 mm ID × 30 m), oven temperature: 40 ° C. (5 min hold) → 10 ° C./min→320° C. (10 min hold), carrier gas: He). A calibration curve was prepared using styrene, and the amount of volatile gas (μg / g) was calculated from the total area of the total ion chromatogram (TIC) obtained by GC / MS. .

(2) Measurement of imidation ratio IR spectrum was measured at room temperature from resin pellets using TravelIR manufactured by SensIR Technologies. From the obtained spectrum was determined and the absorption intensity assignable to the ester carbonyl group of 1720 cm ^-1, the imidization ratio from the ratio of the absorption intensity assignable to an imide carbonyl group 1660 cm ^-1. Here, the imidation rate refers to the proportion of the imide carbonyl group in all carbonyl groups.

(3) Measurement of acid value 0.3 g of resin was dissolved in 75 cm ³ of a methanol / methylene chloride mixed solution, and 5 ml of 0.1 kmol / m ³ sodium hydroxide was added dropwise to remove the acid and acid anhydride components in the resin. After neutralization, excess sodium hydroxide is back titrated with 0.1 kmol / m ³ hydrochloric acid. In addition, methanol / methylene chloride mixed solution as a blank was similarly subjected to back titration, and the number of moles of hydrochloric acid used for neutralization of acid and acid anhydride was determined from the difference in hydrochloric acid titration between the blank and the resin. The acid value per unit was calculated.

Example 1
A commercially available polymethyl methacrylate-styrene copolymer resin (Estyrene MS-800 manufactured by Nippon Steel Chemical Co., Ltd.) and monomethylamine as a primary amine were used to produce an imidized acrylic resin by reactive extrusion. The extruder used was a mesh type co-rotating twin screw extruder with a caliber diameter of 40 mm and L / D = 90. Extrusion was performed at a temperature setting of 230 ° C. in each temperature control zone of the extruder, a screw rotation speed of 300 rpm, a supply amount of polymethyl methacrylate-styrene copolymer resin of 20 kg / h, and a supply amount of monomethylamine of 4 kg / h. It was. The peripheral speed of the extruder screw at this time was 63 cm / s. The by-product after the reaction and unreacted methylamine were separated and removed from the first vent opened to the atmosphere and the second vent whose pressure was reduced to 5 kPa with a vacuum pump to obtain an imidized acrylic resin. The resin temperature at the exit of the extruder was 302 ° C. The imidation ratio of this resin was 76%, the acid value was 0.62 mmol / g, and the amount of volatile gas by a heat desorption apparatus was 480 μg / g.

(Example 2)
Using the imidized acrylic resin obtained in Example 1, dimethyl carbonate as an esterifying agent, and triethylamine as a catalyst, the imidized acrylic resin was ester-modified by reactive extrusion. The extruder used was a mesh type co-rotating twin-screw extruder with a diameter of 44 mm and L / D = 42 manufactured by Nippon Steel. Set temperature of each temperature control zone of the extruder is 230 ° C., screw rotation speed is 300 rpm, supply amount of imidized acrylic resin is 15 kg / h, mixed solution of dimethyl carbonate and triethylamine as esterifying agent (4: 1) Extrusion was carried out at a supply rate of 1.5 kg / h. The peripheral speed of the extruder screw at this time was 68 cm / s. The by-product after the reaction was separated and removed from the first vent opened to the atmosphere and the second vent whose pressure was reduced to 4 kPa with a vacuum pump to obtain a modified imidized acrylic resin. The resin temperature at the exit of the extruder was 286 ° C. The imidation ratio of this resin was 66%, the acid value was 0.07 mmol / g, and the amount of volatile gas by a heat desorption apparatus was 370 μg / g.

(Example 3)
Using the modified imidized acrylic resin obtained in Example 2, devolatilization extrusion was performed. The extruder used was a mesh type co-rotating twin-screw extruder with a diameter of 44 mm and L / D = 42 manufactured by Nippon Steel. Extrusion was carried out at a preset temperature of each temperature control zone of the extruder of 240 ° C., a screw speed of 300 rpm, and a supply amount of the modified imidized acrylic resin of 10 kg / h. The peripheral speed of the extruder screw at this time was 68 cm / s. The residual volatile matter was separated and removed from the first vent opened to the atmosphere and the second vent whose pressure was reduced to 3 kPa with a vacuum pump to obtain a modified imidized acrylic resin. The resin temperature at the exit of the extruder was 296 ° C. The imidation ratio of this resin was 67%, the acid value was 0.1 mmol / g, and the amount of volatile gas by a heat desorption apparatus was 320 μg / g.

(Comparative Example 1)
The same operation as in Example 1 was performed except that the screw speed of the extruder was 150 rpm. At this time, the peripheral speed of the extruder screw was 31 cm / s. The resin temperature at the exit of the extruder was 284 ° C. The imidation ratio of this resin was 74%, the acid value was 0.6 mmol / g, and the amount of volatile gas by a heat desorption apparatus was 1700 μg / g.

(Comparative Example 2)
The amount of volatile gas by a heat desorption apparatus of a commercially available polymethyl methacrylate-styrene copolymer resin (Estyrene MS-800 manufactured by Nippon Steel Chemical Co., Ltd.) was 4300 μg / g.

Claims (6)

  A method for producing an imidized acrylic resin, characterized in that, when an imidization reaction is carried out by adding an acrylic resin and a primary amine to an extruder, the extrusion is performed with a peripheral speed of an extruder screw of 50 cm / s or more. .   An esterification-modified imide, characterized in that when an imidized acrylic resin and an esterifying agent are added to an extruder to carry out an esterification-modifying reaction, extrusion is performed with a peripheral speed of the extruder screw of 50 cm / s or more. For producing a fluorinated acrylic resin.   A method for producing an esterified modified imidized acrylic resin, comprising adding an esterified modified imidized acrylic resin to an extruder and performing devolatilization extrusion at a peripheral speed of an extruder screw of 50 cm / s or more.   4. The production of an imidized acrylic resin or an esterified modified imidized acrylic resin according to any one of claims 1 to 3, wherein volatile components are removed under reduced pressure from the vent at a pressure of less than 8 kPa in absolute pressure. Method.   The imidized acrylic resin or esterified modified imidized acrylic according to any one of claims 1 to 4, wherein the acrylic resin contains 1% by weight or more of an aromatic vinyl monomer. Method for production of resin.   The imidized acrylic resin or ester according to any one of claims 1 to 5, wherein the total amount of gas generated when heated at 280 ° C for 30 minutes in a helium atmosphere is 1500 µg or less per 1 g of the resin. Of a modified modified imidized acrylic resin.