JPH02178307A - Methacrylimide-containing polymer - Google Patents

Abstract

PURPOSE:To obtain the subject polymer, having structural units derived from methacrylimide ring structural units and structural units derived from an ethylenic monomer in a specific proportion with a specified value or below of iron content, excellent in transparency and heat coloring properties with time and suitable as optical fiber, etc. CONSTITUTION:For example, 90-40wt.% methacrylic acid ester, such as methyl methacrylate, alone or a mixture thereof with an ethylenic monomer, such as styrene, copolymerizable with the above-mentioned ester is mixed with 10-60wt.% inert solvent, such as benzene, 0.0001-0.5wt.% radical polymerization initiator, such as di-tert-butyl peroxide, and 0-5wt.% polymer molecular weight modifier, such as n-butyl mercaptan, and polymerization reaction is carried out. The resultant polymer is then imidated with an imidating substance (e.g. methylamine) expressed by formula I (R is H, 1-20C aliphatic hydrocarbon group, etc.) to afford the objective polymer, consisting of 2-100wt.% methacrylimide ring structural units expressed by formula II and 0-98wt.% structural units derived from the ethylenic monomer and having <=20ppm iron content.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a methacrylimide-containing polymer that has excellent transparency, heat resistance, and colorability over time under heating.

[Conventional technology]

Methyl methacrylate polymer is not only transparent but also has excellent weather resistance and mechanical properties, so it is used as a high-performance plastic optical material and decorative material, and in recent years, applications have been developed in fields such as short-distance optical communications and optical sensors. It is progressing. However, methyl methacrylate polymer has a low heat deformation temperature of around 10''C, so it is insufficient for use in fields where heat resistance is required, and there is a strong demand for improved heat resistance.

As a method for improving the heat resistance of a methyl methacrylate polymer, a method of imidizing the methyl methacrylate polymer is known. For example, (1) a polymer of acrylic acid, methacrylic acid or an ester thereof and a first A method of reacting a primary amine, ammonia, or a compound that generates a primary amine or ammonia by heating in the presence of a solvent (US Pat. No. 2,146,209, German Patent No. 1)
, No. 077, 872 and No. 1,242,369
(2) A method of reacting a methyl methacrylate polymer with a primary amine in the presence of water (U.S. Pat. No. 3.284)
, No. 425) and (3) a method of reacting an acrylic polymer with ammonia or a primary amine in an extruder (
No. 4,246,374) has been proposed.

However, in method (1) above, it is difficult to completely separate the solvent from the imidized polymer produced on a commercial scale due to the high boiling point of the solvent used, and as a result, the resulting imide The resulting polymer becomes colored and the transparency of the resulting polymer decreases.

In addition, in the method (2) above, hydrolysis of the methyl methacrylate segment occurs when attempting to obtain a partially imidized polymer due to the reaction in the presence of water, which results in the desired heat resistance. It is difficult to obtain an imidized polymer having the following properties, and it is also difficult to carry out a uniform imidization reaction. Furthermore, in the method (3) above, it is difficult to carry out a uniform imidization reaction because the imidization reaction is a reaction between a highly viscous polymer and a gaseous imidization substance. It is difficult to obtain imidized polymers.

Therefore, although the heat resistance of the imidized polymer obtained by the above method is improved, if it is attempted to be commercially produced, it may have poor transparency, a substantial decrease in molecular weight, or lack of imidization. At present, these methods have not yet been put to practical use in order to achieve uniformity.

[Problem to be solved by the invention]

The purpose of the present invention is 1? By improving the shortcomings of the prior art as described above, we have developed a method that maintains the excellent optical properties, mechanical properties, weather resistance, moldability, etc. inherent to methacrylic acid ester polymers, and also has transparency and heat resistance. In particular, it is an object to capture and provide a methacrylimide-containing polymer that has excellent coloring properties over time under heating.

(Means for Solving the Problems) The methacrylimide-containing polymer according to the present invention has 10 to 10 methacrylimide ring structural units represented by the following formula (1).
A thermoplastic polymer consisting of 0 to 90% by weight of structural units derived from 100% by weight and an ethylenic monomer, characterized in that the iron content in the polymer is 20 pp11 or less.

(wherein R is a hydrogen atom or an aliphatic group having 1 to 20 carbon atoms,
The methacrylimide-containing resin polymer according to the present invention (representing an aromatic or alicyclic hydrocarbon group) can be obtained by the following method. That is, methacrylic resin obtained from monomers with a specific composition and the general formula % formula % () (wherein R is a hydrogen atom or an aliphatic group having 1 to 20 carbon atoms,
Or represents an aromatic or alicyclic hydrocarbon group. ) with one or more types of compounds (hereinafter abbreviated as "imidized substances") in the presence of a specific solvent, volatiles are removed from the resulting reaction solution, and extrusion molding is performed under specific conditions. . This method may be either batchwise or continuous.

In a more preferred embodiment, the methacrylimide-containing resin polymer of the present invention is produced continuously as follows. That is, 10-60% by weight of an inert solvent, 90-40% by weight of a methacrylic ester or a mixture of a methacrylic ester and a copolymerizable monomer, 0.0001-0.
．． A solution consisting of 5% by weight radical initiator, 0-5% by weight polymer molecular weight modifier is continuously introduced into the substantially uniformly mixed first reaction zone, followed by a plug flow stream. After converting at least 80% by weight of the initial monomer into a polymer at a temperature of 80 to 170"C in a second reaction zone with a・An imidization reaction is carried out with the imidized substance at a temperature of 150 to 350 °C in a third multi-stage reaction zone having at least two zones, and the final temperature is 150 to 350 °C.
The reaction solution heated to a temperature of 'C is introduced into a retention zone below atmospheric pressure, volatile matters are continuously separated and removed by flashing, and the flushed polymer is continuously received by a specific extruder screw. By shaping using a specific extruder, a desired polymer having an iron content of 2 oppm or less can be obtained.

Hereinafter, the methacrylimide-containing polymer of the present invention and the method for producing the same will be explained in more detail.

The monomer used in the production of the methacrylimide-containing resin polymer of the present invention is methacrylic acid ester alone, or
methacrylic esters and other methacrylic esters,
Acrylic acid ester (mixture with copolymerizable ethylenic monomers such as acrylic acid, methacrylic acid, styrene, α-methylstyrene, and other substituted styrenes.Methacrylic acid esters include, for example, methyl methacrylate, methacrylate, etc. ethyl acid, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate,
Examples include norbornyl methacrylate, 2-ethylhexyl methacrylate, and benzyl methacrylate. Examples of acrylic esters include methyl acrylate,
Ethyl acrylate, propyl acrylate, acrylic acid n
-butyl, isobutyl acrylate, ter acrylate
Examples include t-butyl, cyclohexyl acrylate, norbornyl acrylate, 2-ethylhexyl acrylate, and benzyl acrylate. These monomers may be used alone or in combination of two or more.

Among these monomers, in the production of the methacrylimide-containing resin polymer of the present invention, methyl methacrylate alone or 25% by weight or more of methyl methacrylate and 75% by weight or less of the above-mentioned copolymerizable ethylenic monostars are used. Although a mixture is preferred, methyl methacrylate alone is particularly preferred from the viewpoint of transparency of the resulting polymer.

The polymerization reaction and imidization reaction are performed in the presence of a solvent. The inert solvent used must not inhibit the progress of the polymerization reaction or imidization reaction and must not substantially react with the reaction mixture. In addition, in the case of a partial imidization reaction, it must not cause any change in the methyl methacrylate or methacrylate segment. Furthermore, it must be able to be easily separated and removed from the produced imidized polymer.

Preferred examples of inert solvents include those having a boiling point of 50 to 50 at normal pressure.
150"C and a mixed solvent of a poor solvent that is difficult to dissolve the methacrylic polymer at room temperature and a good solvent that is easy to dissolve the methacrylic polymer. Particularly, such a mixed solvent is used in the imidization reaction stage in the third reaction zone. A mixed solvent is preferable, and at least one of them (either a poor solvent or a good solvent may be used) can be used in the reaction zone before that.A preferable poor solvent has a solubility parameter δ value of 14.0 to 19.
．． 5 (ca 1/cd)! , is in the range of 4,
In addition, a good solvent has a solubility parameter δ value of 8.0 to 13.
It is in the range of 9 (cal/c+d) y2. Examples of poor solvents include methanol, and examples of good solvents include alcohols such as ethanol, propatool, and isopropanol butanol, aromatic hydrocarbons such as benzene, toluene, xylene, and ethylhexyl, methyl ethyl ketone, glyme, Examples include ketones and ethers such as 12-jethoxyethane, dioxane and tetrahydrofuran, among which benzene and toluene are preferred.

The solubility parameter δ value referred to in the present invention is as described in Polymer Handbook, 2nd edition, G.I. Butendorp, E.H. Inmargt, John Wiley & Sons, New York (Polymer tran).
dbook, 5econd Ed, J, Brand
rup, E, H.

ImmerguL, John, W eye and 5
ons, Nely York, 1975).

In the mixed solvent used in the preferred production method, if the boiling point of the poor solvent and good solvent exceeds 150°C at normal pressure, volatile substances mainly composed of the solvent may be extracted from the reaction product obtained by the imidization reaction. It becomes difficult to remove it sufficiently. If the temperature is less than 50°C, the imidization reaction temperature cannot be raised due to an increase in the internal pressure of the reaction system, so a sufficient imidization reaction cannot be performed.
Furthermore, when volatile substances are separated and removed from the reaction product, they volatilize suddenly, making it difficult to control the devolatilization operation. In addition, if the solubility parameter δ value of the poor solvent and good solvent is a combination outside the above range, it will be difficult to perform a uniform polymerization reaction and a uniform imidization reaction, and it will be difficult to perform a uniform polymerization reaction and a uniform imidization reaction. Difficult to combine.

The amount of solvent used is 1 based on the total weight of solvent and monomer.
It is 0 to 60% by weight. If the amount of solvent used is less than 10% by weight, the viscosity of the reaction system becomes too high, which not only makes handling difficult, but also causes the polymerization or imidization reaction to proceed unevenly, resulting in poor quality of the obtained polymer. descend.

If the amount of solvent used exceeds 60% by weight, not only will it be difficult to separate the solvent from the polymer, but the amount of polymer obtained will be small, which will be industrially disadvantageous. Preferably, the amount of solvent used is 20-50% by weight.

In addition, when using a mixed solvent, the ratio of poor solvent to good solvent is 99/1 to 1/99, preferably 90/10 to 10.
/90 (weight ratio).

In the imidization reaction, the inert solvent to be used allows the imidization substance to easily diffuse between the methacrylic polymers, allowing the imidization reaction to occur uniformly and quickly, and also to effectively remove the heat generated by the reaction. This makes it possible to obtain a meccrylimide-containing polymer that is transparent and has excellent heat resistance as a desired optical material.

The radical polymerization initiator used during polymerization is one that actively decomposes at the reaction temperature and generates radicals.
ert-butyl peroxide, dicumyl peroxide, methyl ethyl ketone peroxide, di-te
r lebutyl barphthalate, di-tert-butyl perbenzoate, tert-butyl peracetate, 2.
5-dimethyl-2,5-di(tert-butylperoxy)hexane, di-terreamyl peroxide, 2
, 5-dimethyl-2,5-di(tert-butylperoxy)hexane, organic peroxides such as benzoyl peroxide and lauryl peroxide, and azobisisobutanol diacetate, 1,1-abbiscyclohexane carbonitrile. , 2-phenylazo-2
, 4-dimethyl-4-methoxyvaleronitrile, 2-cyano-2-propylazoformamide and 2,2'-
Examples include ab compounds such as azobisisobutyronitrile. These radical polymerization initiators can be used alone or in combination of two or more. The amount of radical polymerization initiator used is 0.0001 to 0 for the solution containing the monomer.
．． It is selected within the range of 5% by weight. Examples of the polymer molecular weight regulator include commonly used mercaptans and others. Specific examples of mercaptans used include primary mercaptans having an alkyl group or substituted alkyl group;
Secondary and tertiary mercaptans, such as n-butyl, isobutyl, n-octyl, n-dodecyl, 5ec-butyl, 5ec-dodecyl, tert-butylmercaptan; aromatic mercaptans, such as phenylmercaptan, thiocresol, Examples include mercaptans having 3 to 18 carbon atoms, such as 4-tert-butyl-0-thiocresol; thioglycolic acid and its ester; and ethylene glycol. Additionally, non-mercaptan polymer molecular weight modifiers can also be used. Examples include at least one of β-terbinolene, tilpinol, and alkyl-substituted-1,4-cyclohexadiene. As the alkyl-substituted l,4-cyclohexadiene, T-
Terpinene, 2-methyl-1,4-cyclohexadiene, 2,6-dimethylcyclohexadiene, 2゜5-dimethylcyclohexadiene, 2-isopropyl-1,4-
Examples include cyclohexadiene, 2-ethyl 1,4-cyclohexadiene, and the like.

The substantial amount of the polymer molecular weight regulator used is 5% by weight or less. In a preferred continuous method for the production of methacrylic acid esters, the monomer solution described above is introduced into a first substantially uniformly mixed reaction zone, and at a temperature of 60 to 190°C, at least the monomers are dissolved. 40% by weight of is converted into polymer. If the polymerization temperature in the first reaction zone is less than 60°C, the viscosity of the polymer will increase and it will be difficult to achieve uniform mixing. When the polymerization temperature exceeds 190°C, the formation of side reaction products increases. Therefore, the polymerization temperature in the first reaction zone is 60
-190°C, preferably 70-180°C.

The conversion of monomer to polymer in the first reaction zone is 4
It has been found that when the amount is less than 0% by weight, the heat decomposition resistance of the finally obtained methacrylimide-containing polymer decreases.

Although the cause of this is not clear, it is presumed that it is due to a change in the terminal structure of the polymer molecule related to the polymerization termination reaction mechanism. When the thermal decomposition resistance of a polymer decreases, defects called silver streaks occur due to decomposition products during molding, which not only impairs the appearance but also deteriorates physical properties. Therefore, the polymerization conversion of the monomers in the first reaction zone is at least 40% by weight, preferably at least 60% by weight. The first reaction zone is not substantially uniformly mixed, and the polymerization conversion rate is 40% by weight in some parts.
If less than 100% of the total amount is present, a polymer with poor thermal decomposition resistance will be partially produced, so it is necessary to sufficiently mix and maintain a substantially uniform state in the first reaction zone. A substantially uniformly mixed reaction zone is typically achieved by using an agitated mixing vessel equipped with an anchor-type, helical-ribbon-type, screw-type, and paddle-type agitator.

The polymerization solution leaving the first reaction zone is subsequently passed through a second reaction zone with plug flow to polymerize at least 80% by weight of the initial monomers at a temperature of 80°C-170''C. converts into

The imidized substance shown in (II) 2 used in the third reaction zone partially reacts when the monomer remains to generate a high boiling point by-product amide derivative. If a large amount of unconverted monomer remains in the second reaction zone and enters the third reaction zone, the generation of the high-boiling byproduct amide derivative increases, making it difficult to separate it from the polymer. If the high-boiling by-product amide derivative remains in the polymer, it will cause coloring or deterioration of the quality of the polymer. The polymerization conversion of the initial monomer in the second reaction zone is at least 80% by weight, preferably at least 90% by weight.

In order to achieve a high polymerization conversion in the second reaction zone, a reactor with plug flow flow, i.e. a reactor having a relatively long shape, configured with feed from one end and discharge from the other end, is required. There is a need for a reactor that is designed so that there is no substantial mixing along the length of the device. Examples of this include the screw extruder type reactor described in U.S. Pat. No. 3,234,303;
2,950, U.S. Pat. No. 2,784
Examples include a tubular reaction device with a built-in baffle plate and a hollow pipe-like reaction device described in No. 31.

The polymerization temperature in the second reaction zone is below 170'C.

For the reasons stated above, the polymerization conversion in the second reaction zone should be at least 80%, but the highest polymerization rate achievable is
The equilibrium between the growth and reverse growth reactions of the active polymer at a given temperature, i.e., governed by the polymerization temperature,
When the polymerization temperature exceeds 170°C, it becomes difficult to achieve a polymerization rate of 80%. On the other hand, if the polymerization temperature is less than 80°C, the polymerization rate will decrease and it will be uneconomical, and the viscosity will increase, making it difficult to transfer the reaction liquid. Therefore, the reaction temperature in the second reaction zone is 80-170°C, preferably 90-160°C.

The above-mentioned formula (II) is applied to the polymerization reaction liquid exiting the second reaction zone.
The imidized substance indicated by is added and led to the third reaction zone. The imidized substance may be used alone or may be dissolved and diluted in the above-mentioned inert solvent. The methacrylic polymer obtained in the second reaction zone and the imidized material are mixed and then reacted in the third reaction zone.

This third reaction zone is preferably composed of at least two reaction zones. One zone is a reaction zone where the methacrylic polymer and the imidized substance are reacted to cause a condensation reaction between the polymer side chains of the methacrylic polymer, and the other zone contains the imidized polymer. This is an aging reaction zone where the reaction product is further heated to further promote the imidization reaction.

Furthermore, if necessary, a plurality of reaction zones and/or a plurality of ripening zones can be used in combination.

The reaction between the methacrylic polymer and the imidized material in the reaction zone is carried out at a temperature of 150'C to 350''C.

If the reaction temperature is less than 150°C, the imidization reaction will be slow;
If the temperature exceeds 350"C, a decomposition reaction of the raw material methacrylic polymer occurs simultaneously.The reaction time in the reaction zone is not particularly limited, but from the viewpoint of production, the shorter the better, it is in the range of 20 minutes to 5 hours.The reaction is carried out continuously. Similarly, the average stay time is in the range of 20 minutes to 5 hours.

If water is present in the reaction system during the imidization reaction, the ester moiety of the methacrylic polymer will
Hydrolysis with water occurs as a side reaction, and as a result, methacrylic acid is produced in the resulting methacrylimide-containing polymer, making it difficult to obtain a methacrylic acid-containing polymer having the desired amount of imidization, which is the object of the present invention. Therefore, this reaction is carried out under conditions in which the reaction system does not substantially contain water, that is, the water content is 1% by weight or less, preferably under anhydrous conditions.

Further, as the atmosphere of the reaction system, it is preferable to carry out the reaction under an inert gas atmosphere in which nitrogen, helium, argon gas, etc. are present, from the viewpoint of the colorability of the imidized polymer obtained.

Specific examples of the imidized substance represented by formula (II) include aliphatic primary amines such as methylamine, methylamine, and propylamine, 1,3-dimethylurea, 1,3-
Examples include compounds that generate aliphatic primary amines when heated, such as diethyl urea and 1,3-dipropylurea, ammonia, and urea. Further examples include aromatic amines such as aniline, toluidine, and trichloroaniline, and alicyclic amines such as cyclohexylamine and bornylamine. Among the imidized substances used, methylamine, ammonia, and cyclohexylamine are preferred from the viewpoint of heat resistance and transparency.

The amount of imidization substance to be used cannot be absolutely limited depending on the amount to be imidized, but methacrylic acid ester polymer 10
The amount is 1 to 250 parts by weight relative to 0 parts by weight. If it is less than 1 part by weight, no obvious improvement in heat resistance can be expected. Also, 2
If it exceeds 50 parts by weight, it is unfavorable from the economic point of view.

Next, the imidization reaction product taken out from the reaction zone is supplied to the aging reaction zone. The reaction in this aging reaction zone is carried out at a temperature of 150°C or more and 350°C or less, preferably 170°C or more and 300°C or less, similar to the reaction in the previous step.

The aging time in the aging reaction zone is required to be at least 5 minutes, and when the aging is carried out continuously, the average residence time is also required to be 5 minutes or more. If the aging reaction takes less than 5 minutes, no obvious aging effect can be expected. Although the reason for the effect of the aging reaction itself contributing to the product is not clear, if the ripening reaction is insufficient, unreacted amide segments remain in the imidized polymer product. Therefore, the heat resistance, heat decomposition resistance, and yellowing degree of the product itself after exposure to heat become remarkable.

The amount of imidization of the methacrylic polymer in the method of the present invention is from 10 to 100%, preferably 3% by weight, from the viewpoint of heat resistance.
The amount is in the range of 0 to 100% by weight, more preferably 50 to 100% by weight.

Examples of the reaction device used in the reaction zone in the third reaction zone include the above-described stirred mixing tank reactor, a reactor having at least two or more reaction zones in one reactor,
Examples include a screw extruder type reactor, a columnar reactor, and a tubular reactor, and among these, a combination of a stirring mixing tank reactor is particularly preferred. By using a stirred mixing tank reactor, the polymer is uniformly imidized, and a methacrylimide-containing polymer with excellent transparency and heat resistance can be obtained.

The resulting methacrylimide-containing resin polymer has an intrinsic viscosity of 0.
．． 02 to 4.5 (measured at 25±0.1'C on a dimethylformamide solution with a polymer concentration of 0.5% by weight).

After the imidization reaction is completed, the volatile matter is separated from the reaction solution to obtain the desired polymer. A reaction composition containing a large number of volatile substances can be vacuum flushed while being kept in a stable fluid state, and the volatile substances can be efficiently separated. That is, the reaction composition is heated to 180 to 300°C, preferably 200 to 250°C.
”Heat to a temperature of 20 to 1
Flushing is carried out in a tank regulated under a vacuum of 0.00 Torr. The flashed polymer is received by an extruder screw and passed through the extruder to be obtained in the form of a strand from the die opening. However, in the case of a screw type extruder, iron contamination occurs due to contact with the barrel due to wobbling of the rotating shaft or corrosion of a portion of the screw or barrel.

As a result of extensive studies, the inventor of the present invention found that the inclusion of iron tends to promote coloration of polymers by heating, and that when exposed to a high temperature atmosphere for a long time, the color changes to yellow, impairing the appearance of the product and reducing transparency. It started.

This discoloration due to heat exposure is due to the iron content in the polymer being 2.
It becomes noticeable when it exceeds 0 ppm. Therefore, the iron content needs to be 20 ppm or less. More preferably, it is 10 ppm or less. 20ppm iron contamination
In order to achieve the following, a part of the extruder screw needs to be coated with corrosion-resistant chrome plating, and the screw part itself needs to be made of superhard steel to prevent rotational shaft wobbling. Additionally, the barrel needs to be made of corrosion-resistant stainless steel.

In addition, when separating and removing most of the volatile substances from the above-mentioned methacrylimide-containing polymer reaction solution, separation is carried out so that the content of residual volatile substances in the polymer is 2% by weight or less, preferably 1% by weight or less. Remove.

In the method of the present invention, an antioxidant,
Additives such as plasticizers and ultraviolet absorbers can be added.

[Effects of the Invention] As explained above, the methacrylimide-containing polymer of the present invention has excellent transparency, heat resistance, and heat colorability.

Therefore, the above-mentioned characteristics are required in fields such as optical fibers, optical disks, CRT filters, meters, displays of digital display boards, lighting optics, automobile headlamp light covers, lenses, electrical parts, and other fields. Can be used in a wide range of molding materials by blending with resin.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the Examples.

All references to "r parts" and "r%" used in the examples are by weight.

In the following examples, the physical properties of the polymer were measured by the following method.

(1) The infrared absorption spectrum is measured using an infrared spectrophotometer (■
It was measured by the KBr disk method using Hitachi, Ltd. Model 285).

(2) Heat distortion temperature was measured based on ASTM D-648.

(3) What is the total light transmittance (%) of the molded product? I 0-
It was measured by the 1003 method.

The sample used was an injection molded flat plate measuring 40 x 40 x 3 mm.

(4) The yellowness index (Yl value) was calculated using a color difference meter color analyzer (Hitachi Model 307).
Measured according to 7103.

A 40x40x3 injection molded flat plate was used as the sample.

Calculated from x, y, z stimulus values.

(5) The degree of yellowing (ΔYl) is 130'C100 for an injection molded flat plate (3 mm plate) of the above methacrylimide-containing polymer.
Measurements were taken after exposure to air for 0 hours.

ΔYI=YI−YIO ΔY1 Yellowing degree YIBl Yellowness after dew YIO Yellowness of test sample or test piece (6) Iron content in polymer Weigh out 5 g of polymer, and after burning it with a gas burner, 6 After dissolving in normal hydrochloric acid water and making it into 0.1N hydrochloric acid water solution, high frequency plasma emission spectrometer (Aji Nippon Jarrel Ash)
The iron content was determined by measurement.

(7) Elemental analysis of the nitrogen content of 1t (X%) of the imidization rate polymer (measuring device CH
N coder, MT-3, manufactured by Yanagimoto Seisakusho), and the imidization rate was calculated.

Example) 1γ imidization rate imidization rate: X The intrinsic viscosity of the polymer is
Measure the flow time (ts) of a dimethylformamide solution with a sample polymer concentration of 0.5% by weight and the flow time (t0) of dimethylformamide using a viscometer at a temperature of 25) -0.1°C. Shi, Shi s/l.

Determine the relative viscosity ηrel of the polymer from the clay, and then,
It is calculated from the following formula.

(Wherein, C represents the number of grams of polymer per 100 of solvent.) Example 1 65 parts of methyl methacrylate, 30 parts of toluene, 5 parts of methanol, 0.08 part of 1.1'-azobiscyclohexanecarbonitrile, 2 A polymerization feed liquid consisting of 0.0325 parts of 2-abbisisobutyronitrile and 0.3 parts of n-octylmercaptan was continuously fed into the first stirred tank reactor having an internal volume of 20 I7 at a rate of 4 L/! (It was fed continuously at a rate of r.) The polymerization conversion rate was measured immediately after leaving the reactor and was found to be 65%.

This polymerization liquid was subjected to the second reaction 2 of the heat exchange type with multiple tubes; (
Straight pipe 30 with inner diameter 12.7ml and length 1000 + m++
95% at a temperature of 140°C
The polymerization was advanced to a polymerization conversion rate of . Furthermore, this polymerization liquid was mixed with the imidized substance described below and supplied to the stirred tank type reactor in the third reaction zone.

On the other hand, methylamine was added to a mixed solvent (toluene methanol - 1:1 weight ratio) in which the imidized substance (methylamine) was dissolved and diluted, and the concentration was adjusted to 40% by weight, l, 2L/I (r
The mixture was mixed with the polymerization solution and supplied to the third reaction zone. Polymerization solution and imidization'! ! The mixed liquid with 711t is transferred to the third reaction zone (inner volume 15I1, temperature 230°C)
After the imidization reaction was carried out, the reaction solution leaving the reaction zone was supplied to a stirred tank reactor having an internal volume of 3 L and a temperature of 230° C., which served as an aging reaction zone. The reaction liquid exiting these reaction zones is flushed from the nozzle 1 into a tank regulated under a vacuum of 100 torr, and the flushed polymer is transferred to a screen of L/D 20, z--
h, and was extruded into a strand shape using a twin screw extruder with a 30Φ double hent to form a bellet. The extruder with double vent has a vent part vacuum level of 5mm, 11g, and a temperature of 260℃.
°C, metal ring temperature 270°C, die temperature 25
It was set to 5°C.

When the infrared spectrum of the obtained pellet-like polymer was measured, the wave was ¥1.1720 cm-' and 1663 cm.
Absorption peculiar to methacrylimide was observed at 750c+++-' and 750c+++-', and it was confirmed that the polymer was a methacrylimide-containing polymer. A part of the screw inside the extruder was made of Kuro 1 and Menki pressure, and the barrel part was made of stainless steel.

The physical properties of the polymer are as follows.

Total light transmittance (%) 93 Heat distortion temperature ('c) 145 Imidization rate (
%) 80 Yl 0.5ΔYl
0.9 Iron content in the polymer (pp
m) 0.8 As described above, a methacrylimide-containing polymer was obtained which had excellent transparency and heat resistance, and was also excellent in heat coloring and coloring properties over time.

Comparative Example 1 In Example 1, 0.5% of tert-dodecyl mercaptan was used as a polymerization degree regulator, the barrel part in the extruder was made of nitrided steel, and a part of the screw was not processed to be threaded [1]. The same equipment and operations as in 1 were employed.

The physical properties of the obtained polymer are as follows.

Total light transmittance (%) 92 Heat distortion temperature ('C) 145
(%)80 YI 3.2Δ
Y r 9.0 Iron content in polymer (ppm) 23.0 As mentioned above, although it had excellent transparency and heat resistance, it was extremely poor in coloration over time when heated.

Example 2 100 parts of methyl methacrylate monomer, 0.1 part of 1,1'azobiscyclohexane carbonitrile polymerization initiator,
A monomer mixture containing 0.5 parts of a terpinolene polymerization degree regulator was heated at 100°C for 17 hours to obtain a raw material (methacrylic resin). The polymerization conversion rate was 99%.

A mixture of 100 parts of the above methacrylic resin, 80 parts of toluene and 20 parts of methanol as a solvent was placed in an IOL reactor equipped with a paddle spiral stirrer, a pressure gauge, a sample injection container, and a jacket heater, and the mixture was thoroughly purged with nitrogen. ,
The temperature was raised to 230°C and stirred to dissolve the polymer.Next, 18.6 parts of methylamine (0.6 molar ratio) was dissolved in methanol to form a 50% solution in a reagent injection container, and the temperature inside the reaction container was lowered. It was added at 230°C. Internal pressure 60kg/
The reaction was carried out at c+a・G for 3.0 hours.

After the reaction is completed, the N-methylmethacrylimide-containing polymer?
'8? Pi was flashed from the nozzle opening into a tank adjusted to a reduced pressure of 100 torr, and the flan-tanked polymer was fed onto a 20Φ hex-type extruder screw with L/D 20, and the extruder turned it into a strand. Shaped.

When the infrared absorption spectrum of the obtained polymer was measured, the wave numbers were 1~20c+c', 1663cm-', and 7.
Absorption peculiar to methacrylimide-containing polymers was observed at 50 cl'.

A part of the screw inside the extruder was made with chrome plating, and the barrel part was made with stainless steel. The extrusion conditions are: degree of vacuum at the hent section: 5 mm, 1 g, temperature: 260°
C, metal ring part temperature 270'C, die part temperature 255
℃.

The physical properties of the obtained polymer are as follows.

Total light transmittance (%) 93 Heat distortion temperature (“C) 145 Imidization rate (
%) 80 Yl 1.5ΔYl
1.3 Iron content in polymer (pp
m) 1.0 As described above, a methacrylimide-containing polymer having excellent transparency and heat resistance, and excellent coloring property over time by heating was obtained.

Claims (1)

[Claims] 1. General formula (I) ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (I) (In the formula, R is a hydrogen atom or an aliphatic group having 1 to 20 carbon atoms,
A thermoplastic polymer consisting of 2 to 100% by weight of structural units represented by (representing an aromatic or alicyclic hydrocarbon group) and 0 to 98% by weight of structural units derived from an ethylenic monomer, the polymer A methacrylimide-containing polymer having an iron content of 20 ppm or less.