JPH0242363B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing a methacrylimide-containing polymer having excellent transparency and heat resistance. [Prior Art] Methyl methacrylate polymer is used as a high-performance plastic optical material and decorative material because it has excellent not only transparency but also mechanical properties and weather resistance.In recent years, it has been used in fields such as short-distance optical communication and optical sensors. Application development is underway. However, methyl methacrylate polymer
Because the heat distortion temperature is around 100°C, which is insufficient for heat resistance, its use is restricted in many fields, and there is a strong demand for improved heat resistance. As a method for improving the heat resistance of a methyl methacrylate polymer, there is a method of imidizing the methyl methacrylate polymer. 2416209), a method of reacting a methyl methacrylate polymer with ammonium hydroxide, ammonium phosphate and an alkyl amine (British Patent No. 926629), and a method of reacting an acrylic acid polymer with ammonia or a primary amine ( No. 4,246,374) has been proposed. [Problems to be Solved by the Invention] However, the imidized polymer obtained by the above-mentioned proposed method still has some points to be improved, and therefore has excellent optical properties and mechanical properties. There is a desire for the emergence of methacrylimide-containing polymers that have properties such as weather resistance and moldability, as well as high transparency and heat resistance. [Means for Solving the Problems] The method for producing a methacrylimide-containing polymer according to the present invention is capable of copolymerizing with a methacrylic ester homopolymer or methacrylic ester having an intrinsic viscosity of 0.01 to 3.0 in an amount of 25% by weight or more. (hereinafter, such homopolymers and copolymers are referred to as "methacrylic resins") with 75% by weight or less of other monomers and the general formula R-NH ₂ () (wherein, R represents a hydrogen atom or an aliphatic, aromatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms)
and one or more of the compounds shown below, with a boiling point of 50 to 135°C under normal pressure and a solubility parameter δ value.
A reaction zone where a condensation reaction occurs between polymer side chains in the presence of a solvent of 10.0 to 19.5 (cal/cm ³ ) ^1/2 , and a reaction zone where a condensation reaction between polymer side chains occurs by heating the reaction product. The reaction is carried out at a temperature of 100°C or higher and 350°C or lower through at least two reaction zones, including a ripening reaction zone, and then volatile substances are separated and removed from the resulting reaction product, and the reaction product obtained by the general formula (In the formula, R is as described above.) A methacrylimide-containing polymer with excellent transparency and heat resistance consisting of 2 to 100% by weight of the structural unit represented by the formula (wherein R is as described above) and 0 to 98% by weight of the ethylenic monomer structural unit. Characterized by obtaining union. In the method of the present invention, a compound represented by the general formula R-NH ₂ () (hereinafter referred to as "imidized substance") is reacted with a methacrylic resin in the presence of a specific solvent. here,
R represents a hydrogen atom or an aliphatic, aromatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms. Specific examples of imidized substances include ammonia; aliphatic primary amines such as methylamine, ethylamine, and propylamine; aromatic amines such as aniline, toluidine, and trichloroaniline; and alicyclic amines such as cyclohexylamine and bornylamine. There are many types. It is also possible to use compounds that easily generate primary amines by heating or other means, such as urea, 1,3-dimethylurea, 1,3-diethylurea, and 1,3-dipropylurea. The amount of these imidized substances to be used varies depending on the degree of imidization, so it cannot be determined unconditionally, but generally it is 1 part by weight per 100 parts by weight of methacrylic resin.
~250 parts by weight. If it is less than 1 part by weight, no obvious improvement in heat resistance can be expected. Moreover, if it exceeds 250 parts by weight, it is not preferred from the economic point of view. Among the imidizing agents used in the present invention, methylamine and ammonia are particularly preferred from the viewpoint of heat resistance and transparency. "Methacrylic resin" used in the present invention
is a methacrylic ester homopolymer or methacrylic ester and other methacrylic esters, acrylic ester, acrylic acid, methacrylic acid, styrene, 2-
A copolymer with substituted styrene such as methylstyrene. Examples of methacrylic esters constituting the homopolymer and copolymer include methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, Examples of acrylic esters include norbornyl methacrylate, 2-ethylcyclohexyl methacrylate, and benzyl methacrylate; examples include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, and tert-acrylate. Butyl, cyclohexyl acrylate, norbornyl acrylate, 2-ethylhexyl acrylate, benzyl acrylate, etc. can be used. These monomers may be used alone or in combination of two or more. Among these methacrylic resins, in the method of the present invention, a methyl methacrylate homopolymer or a copolymer of 25% by weight or more of methyl methacrylate and 75% by weight or less of the other monomers mentioned above is preferred. In particular, a homopolymer of methyl methacrylate is most preferred from the viewpoint of transparency. The solvent used in the method of the present invention does not inhibit the progress of the imidization reaction, which is a polymer side chain condensation reaction of methacrylic resin, and in the case of partial imidization reaction, does not change the methyl methacrylate or methacrylate ester segment. It must be something that cannot be given. The solvent has a boiling point of 50 to 50 at normal pressure.
135℃, and the solubility parameter δ value is
Must be 10.0 to 19.5 (cal/cm ³ ) ^1/2 . Specific examples of such solvents include methanol, ethanol, propanol, isopropanol, and butanol, and among these, methanol is particularly preferred. In addition, the solubility parameter δ value in the present invention is based on Polymer Handbook, 2nd edition, G.A.
Brandrup, E.H. Inmargt,
John Wiley & Sons, New York (Polymer Handbook, Second Ed, J.
Brandrup, EHImmergut.John Wiley & Sons,
New York) (1975). If the boiling point under normal pressure of the solvent used in the method of the present invention exceeds 135°C, it is difficult to sufficiently separate and remove volatile substances mainly composed of the solvent from the reaction product obtained by the imidization reaction. becomes. If the same boiling point is less than 50℃, the imidization reaction temperature cannot be raised due to an increase in the internal pressure of the reaction system, and the imidization reaction cannot be performed sufficiently. When it is separated and removed, it volatilizes suddenly, making it difficult to control the devolatilization operation. Furthermore, if the solubility parameter δ value of the solvent used in the method of the present invention is less than 10.0 (cal/cm ³ ) ^1/2 , the imidization substance is difficult to dissolve, and the specified imidization reaction of the methacrylic resin is not carried out. Difficult to progress. Furthermore, if the δ value exceeds 19.5, the raw methacrylic resin is difficult to dissolve during the imidization reaction, making it difficult to perform a uniform imidization reaction. The amount of solvent used in the method of the present invention is preferably a small amount from the viewpoint of productivity, but if the amount is too small, the effect of the solvent will be reduced, so the amount of solvent used is 10 to 1000 parts by weight per 100 parts by weight of methacrylic resin. The range of parts by weight is good. The above-mentioned solvent used in the method of the present invention can easily diffuse the imidization substance between the methacrylic resin polymers to perform the imide reaction uniformly and quickly, and can efficiently control the temperature of the reaction system. . As a result, it becomes possible to obtain a methacrylimide-containing polymer having excellent transparency and heat resistance as a desired optical material. The reaction of the methacrylic resin and the imidized material is carried out through at least two reaction zones in the presence of a solvent. In the method of the present invention, at least two reaction zones are required, one of which is a reaction zone in which the methacrylic resin and the imidization substance are reacted to cause a condensation reaction between the polymer side chains of the methacrylic resin;
The other one following this is an aging reaction zone in which the reaction product containing the imidized methacrylic resin produced in the previous reaction zone is further heated to further promote the above-mentioned condensation reaction between polymer side chains. In the method of the present invention, the imidization reaction of the methacrylic resin can be further promoted in the two steps of the reaction zone and the aging reaction zone, and if necessary, a plurality of reaction zones and/or the aging reaction zone can be added. It can also be done by combining areas. By providing the aging reaction zone after the reaction zone in this way, the light-transmitting performance of the resulting methacrylimide-containing polymer is significantly improved, although the reason for this is not clear. The reaction of the methacrylic resin and the imidized substance in the reaction zone is carried out at 100°C to 350°C, preferably 150°C to 300°C, in the presence of a solvent. Reaction temperature is 100℃
If it is less than 350°C, the imidization reaction will be slow, and if it exceeds 350°C, the decomposition reaction of the raw material methacrylic resin will easily occur. The reaction time in the reaction zone is not particularly limited, and from the viewpoint of productivity, the shorter the better, and is in the range of 20 minutes to 5 hours. In the imidization reaction, if water is present in the reaction system, the ester moiety of the methacrylic resin will be hydrolyzed by water as a side reaction during the imidization condensation reaction process, resulting in the formation of methacrylic acid in the resulting methacrylic imide-containing polymer. As a result, it becomes difficult to obtain a methacrylimide-containing polymer having the desired amount of imidization, which is the object of the present invention. Therefore, this reaction is carried out under conditions where the reaction system does not substantially contain water, that is, where the water content is 1% by weight or less, preferably under anhydrous conditions. In addition, from the viewpoint of the colorability of the imidized polymer obtained, it is preferable to carry out the reaction in an inert gas atmosphere containing nitrogen, helium, argon gas, etc. as the atmosphere of the reaction system. 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 similar to the reaction in the reaction zone of the previous step.
The reaction temperature is 100℃ or higher and 350℃ or lower, preferably 150℃
The temperature is above ℃ and below 300℃. The ripening time in the ripening reaction zone is required to be at least 5 minutes, and when carried out continuously, the average residence time is also required to be 5 minutes or more. The amount of imidization of the methacrylic resin in the method of the present invention is not particularly limited, but from the viewpoint of heat resistance,
The amount is 100% by weight, preferably 30 to 100% by weight, and more preferably 50 to 100% by weight. The reactor used to carry out the present invention is not particularly limited as long as it does not impede the purpose of the present invention, and includes a plug flow type reactor, a screw extrusion type reactor, a column reactor, a tubular reactor, etc. A reactor, a duct-like reactor, a tank-type reactor, etc. are used. In order to perform imidization uniformly and obtain a uniform methacrylimide-containing polymer, a tank-type reactor equipped with a stirring device with a supply port and a discharge port that has a mixing function throughout the reactor is required. preferable. Finally, most of the volatile substances are separated and removed from the reaction product containing the intermolecular condensation reaction product produced by the reaction between the methacrylic resin and the imidized substance. The content of residual volatile substances in the final polymer is 2
% by weight or less, preferably 1% by weight or less, so that the light transmission performance of the imide-containing polymer obtained is 5000 dB/Km or less, preferably 3000 dB/Km or less, more preferably 3000 dB/Km or less at a wavelength of 646 nm.
Separate and remove so that it is 1000dB/Km or less. Volatile substances can be removed using a common vent extruder, devolatizer, etc., or by other methods, such as diluting the reaction product with a solvent and precipitating and filtering it in a large amount of non-soluble medium. This can be done using a method such as drying. In the method of the present invention, additives such as antioxidants, plasticizers, lubricants, and ultraviolet absorbers may be added as necessary. The method of the invention can be carried out either continuously or batchwise. Next, a typical apparatus used in carrying out the present invention will be described with reference to FIG. The solvent is sent from the solvent storage tank 1 to the solvent supply tank 4 through the filter 41 . Additives added as needed are supplied from the storage tank 5 through line 6 to solvent supply tank 4, where they are dissolved, passed through line 2, and pumped to pump 3.
The resin is sent to the resin melting tank 10 through line 7. On the other hand, resin is supplied from the pellet storage tank 8 to the resin melting tank 10 through a line 9. Resin dissolving tank 10
is equipped with an agitator 11 and a jacket 12, into which a heat transfer medium flows through openings 13 and 14. The dissolved resin in the resin dissolution tank 10 is sent to the reaction tank 20 via the discharge line 15, pump 16, and line 17, and is then transferred to the imidized substance storage tank 18.
It reacts in the reaction tank 20 with the imidized material supplied from the wafer through the line 19 through the filter 42 . The reaction tank 20 is equipped with a spiral ribbon stirrer 21 and a jacket 22, into which a heat medium flows through openings 23 and 24. The reaction product in the reaction tank 20 is sent to an aging tank 28 via a discharge line 25, a pump 26, and a line 27.
The aging tank 28 is equipped with a spiral ribbon stirrer 29 and a jacket 30, into which a heat medium flows through openings 31 and 32. The aging reaction product is discharged through a discharge line 33, a pump 34,
It is sent via line 35 to a volatile separator 36 where volatiles are removed and discharged via 37. The volatile separator 36 includes a screw 38, a belt 39,
Means 40 for heating are provided. [Effects of the Invention] According to the method of the present invention described above, it is possible to easily control the imidization reaction, to industrially advantageously produce a high-quality methacrylimide-containing polymer, and to produce the resulting polymer. The combination has excellent transparency and heat resistance. In particular, the light transmission performance of the obtained polymer is
It is excellent at 5000dB/Km or less at 646nm. Therefore, the above characteristics are required in fields such as optical fibers, optical disks, CRT filters, television filters, fluorescent tube filters, liquid crystal filters, meters, or displays such as digital display boards, and lighting. It can be used in a wide range of applications, including optical equipment, headlight covers for automobiles, lenses, electrical parts, and molding materials by blending with other resins, and its industrial significance and value are extremely high. [Example] Hereinafter, the present invention will be explained in more detail with reference to Examples. All parts and percentages used in the examples are by weight. The apparatus system shown in FIG. 1 used in the examples has the following specifications. Resin dissolution tank 500 Reaction tank 40 Volatile separation device Single screw screw vent extruder Screw; 30 mmφ x 720 mm long vent length; 60 mm In these Examples, the characteristics of the polymer were measured by the following method. (1) The infrared absorption spectrum was measured by the KBr disk method using an infrared spectrophotometer (Model 285, manufactured by Hitachi, Ltd.). (2) The intrinsic viscosity of a polymer is determined by measuring the flow time (ts) of a dimethylformamide solution with a sample polymer concentration of 0.5% by weight and the flow time (to) of dimethylformamide using a Deereax-Bischoff viscometer at a temperature of 25%. Measured at ±0.1℃,
Find the relative viscosity ηrel of the polymer from the ts/to value,
After that, it is a value calculated from the following formula. Intrinsic viscosity=(Inηrel)/c (In the formula, c represents the number of grams of polymer per 100 ml of solvent.) (3) The heat distortion temperature was measured based on ASTMD648. (4) The melt index of the polymer is
It was determined using ASTMD1238 (number of grams per 10 minutes at 230°C and a load of 3.8 kg). (5) The imidization amount (%) of the polymer is measured by elemental analysis values (measuring device CHN coder (MT-3) manufactured by Yanagimoto Seisakusho) and the nitrogen content and proton NMR.
JNM-FX-100 (JEOL) spectrometer
Measured at 100MHz. (6) The light transmission performance of the obtained polymer was measured by preparing a measurement sample using the following method. Barrel 45 with an inner diameter of 40 mmφ shown in Figure 2, outer diameter
38mmφ piston 46, inner diameter 3mmφ nozzle 4
Using a piston type extruder consisting of 7,
The barrel temperature of the extruder was adjusted to 220-250°C±1°C by heating with heater 4. Next, a sufficiently dried polymer sample 49 is put into the barrel 45 and melted, and the constant speed motor 56
The piston 46 is moved by the nozzle 47.
The molten polymer was extruded in the form of a strand, taken off by a lower nip roller 50, and shaped into a strand with a diameter of 1 mmφ. In the process of taking this shaped 1 mmφ strand, a low refractive index polymer (2,2,2 trifluoroethyl methacrylate polymer, weight average molecular weight 8×10 ⁴ , refractive index n ²⁵ _D 1.410) was mixed with ethyl acetate. A coating film having a thickness of 15 μm (dry thickness) was formed on the surface of the shaped strand by passing it through a dipping pot 51 containing a solution (polymer concentration: 35% by weight) dissolved in . The shaped strand with this coating film was passed through a dryer 54 in which air 53 heated to 150°C by a heat exchanger 52 was circulated (1 m ³ /min) to remove the ethyl acetate solvent and form a strand with a diameter of 1 mmφ. The optical transmission body was wound up by a winding machine 55. The obtained optical transmission body was used as a sample for measuring the light transmission performance. Next, using this sample, the light transmission performance (light transmission performance) was evaluated using the apparatus shown in FIG. FIG. 3 is a schematic diagram of an apparatus for measuring the light transmission performance of a sample.
3, the light is made into parallel light by an interference filter 64, and then made monochromatic by an interference filter 64. A lens 65 having a numerical aperture equal to that of the strand-shaped light transmitting body sample 60 is formed.
focus on. At this focal point, the incident end surface 6 of the light transmitting body sample 60
Adjust the transmitter sample 60 so that
Let light enter. The light incident from the input end face 66 is attenuated and output from the output face 67. This emitted light is converted into a current by a photodiode 68 having a sufficiently large area, amplified by a current-voltage conversion type amplifier 69, and read as a voltage value by a voltmeter 70. Measurement of optical transmission performance shall be performed using the following procedure. First, both end faces of the optical transmission body 60 are cut at right angles to the strand axis so that the length is l ₀ , and the surface is smoothed. Attach it so that it does not move inside. Place in a dark room and read the reading on the voltmeter. Let this voltage value be _I1 . Next, the indoor furnace is turned on, the emission end face 67 is removed from the apparatus, and the light transmitting body 60 is cut off from this end face at a point 71 having a length l. Then, the end face of the optical transmission body installed in the device is finished to be a surface perpendicular to the strand axis in the same way as the first one, and this is installed in the device as a new output end face. During these operations, care must be taken not to move the incident end surface 66 in order to keep the amount of incident light constant. Return to the dark room, read the reading on the voltmeter, and call this value _I2 . Optical transmission loss (α)
is calculated using the following formula. α=10/llog(I ₂ /I ₁ )(dB/Km) where, l: Length of optical transmission body (Km) I ₁ , I ₂ : Light amount (voltmeter reading value) The measurement conditions are as follows. Interference filter (dominant wavelength) 646nm l ₀ (Total length of optical transmission body) 2m (or 5m) l (Cutting length of optical transmission body) 1.5m (or 4.5m) D (Bobbin diameter) 190mm Here, bobbin is the device is used to make it compact, the distance between the input end face 66 and the output end face 67 is about 30 cm, and the remaining optical transmission body is wound around a bobbin (not shown). The interference filter can change the dominant wavelength from 400nm to 1200nm. The numerical aperture of the optical transmission body was measured using the measuring device shown in FIG. In the figure, 81 is a parallel light source containing a halogen lamp. After the output light from the light source is passed through an interference filter 82 with a center wavelength of 650 nm and a half width of 3 nm to make it monochromatic, parallel light rays are focused by a lens 83 whose numerical aperture is larger than that of the light transmitter 84. The light is made incident on one end surface 85. The end face 85 is cut perpendicularly to the strand axis of the optical transmission body, finished smooth, and fixed with a fixture 86 so that the strand axis and the optical axis 87 are aligned. After the incident light passes through the optical transmission body having a total length l, it exits from the other end face 88. The end face 88, which has been finished into a smooth surface and is perpendicular to the strand axis, is fixed to the fixed shaft 89 using a fixture 90 so that the central axis coincides with the central axis and the strand axis and the central axis are perpendicular to each other.
A rotary arm 91 rotates around the central axis of the fixed shaft 89, and the rotation angle θ can be read. 9
Reference numeral 2 denotes a photomultiplier tube for detecting light, which is installed inside the case 93 and measures the amount of light passing through the hole 94 as a current. The hole 94 has a diameter of
It is 1.5mm and located 125mm from the center axis. Using the apparatus configured as shown in FIG. 3, the distribution of emitted light is measured based on the relationship between the rotation angle .theta. of the rotary arm and the current of the photomultiplier tube, and an example is shown in FIG. 5. Letting the maximum current be _Inax , the numerical aperture (N _A ) can be determined from the angle width 2θw at which _Inax is reduced to 1/2 and the following formula. N _A =sinθw (7) The residual volatile content was calculated by the following formula after measuring the heating loss value of the polymer in a vacuum heating dryer at 200°C and 3 mmHg. w ₀ −w/w ₀ ×100 (%) w ₀ is the initial weight of the polymer. w is the weight after drying. Example 1 Sufficiently dried methyl methacrylate-methyl acrylate copolymer (weight ratio = 99/1, intrinsic viscosity
0.51) and 100 parts of methanol passed through a 0.1 μm fluoropore (manufactured by Sumitomo Electric Industries, Ltd.) after dehydration and drying.The raw materials were placed in a dissolution tank, and after being sufficiently replaced with nitrogen, the mixture was stirred at 200℃ to form a polymer. was dissolved. Then,
This solution was continuously fed to the reaction tank at a feed rate of 5 kg/hour, and the stirring speed was adjusted to 90 rpm and the temperature to 230°C. Thereafter, the dried methylamine was passed through a 0.1 μm fluoropore and continuously fed into the reaction tank at a rate of 20 mol/hour, and the internal pressure was adjusted to 65 Kg/cm ² ·G. The temperature in the reaction tank was maintained at 230°C, and the average residence time in the reaction tank was 2 hours. The reaction product taken out from the reaction tank was sent to the aging tank by a pump, and was aged with sufficient stirring for an average residence time of 1.0 hours, at a tank internal temperature of 230° C. and a stirring rotation speed of 30 rpm. The reactants were continuously fed into a vented extruder to separate and remove volatile substances, mainly solvent. The temperature of the vent extruder was 230°C in the vent part, 230°C in the extrusion part, and the degree of vacuum in the vent part was 9 mmHg·Abs. The strand extruded from the die was cooled with water and then cut to obtain a pellet-like polymer having good transparency. On the other hand, volatile substances mainly composed of solvent discharged from the vent section were cooled and collected. When the infrared absorption spectrum of the obtained polymer was measured, the wave numbers were 1720 cm ^-1 , 1663 cm ^-1 and 750 cm ^-1
Absorption characteristic of methacrylimide-containing polymers was observed. In addition, nuclear magnetic resonance spectra showed signals indicating this structure. As a result of elemental analysis, the nitrogen content was 8.3%, and it was confirmed that it was a methacrylimide polymer that was almost completely N-methylated. When the physical properties of this polymer were evaluated,
It showed the following characteristics. Melt index: 1.45 g/10 minutes Heat distortion temperature: 182°C Residual volatile content was 0.2%. A light transmission body was prepared using the above polymer pellet as a sample for measuring light transmission performance using the apparatus and method shown in FIG. 2 (cylinder temperature: 250°C). The light transmission performance of the obtained optical transmission body was measured using the apparatus shown in FIGS. 3 and 4, and was found to be 545 dB/Km. Further, the numerical aperture of this optical transmission body was 0.57. This numerical aperture is a theoretical value calculated assuming that the refractive index of N-methyl methacrylimide polymer is 1.530 and the refractive index of 2,2,2-trifluoroethyl methacrylate polymer is 1.410 (N _A = √ ₁ ² − ₂ ² = 0.59). Examples 2 to 35 Various methacrylimide-containing polymers were obtained in the same manner as in Example 1, except that the methacrylic resin, solvent, imidizing agent, and reaction conditions shown in Table 1 were used. The internal pressure of the reaction tank was 20 to 80 Kg/cm ² G. The properties of the obtained polymer are shown in Table 1.

【table】

【table】

[Table] Comparative Examples 1 to 5 Various polymers were produced by repeating the method of Example 1 under the conditions shown in Table 2, and evaluated. The results obtained are shown in Table 2. In Comparative Example 1, biphenyl was used as a solvent, but the amount of residual volatile matter was large, the uniform imidization reaction did not proceed, and the molecular weight of the methacrylimide-containing polymer was low. Translucent performance was extremely poor. In Comparative Examples 2 and 3, diethylene glycol and ethylene glycol were used as solvents, respectively, but both had a large amount of volatile matter and were inferior in light transmitting performance. In Comparative Example 4, xylene was used as a solvent, but the homogeneous imidization reaction did not proceed and the degree of polymerization of the product was low. The amount of volatile matter was also large, and the light transmission performance could not be said to be good. In Comparative Example 5, toluene was used as a solvent, but the homogeneous imidization reaction did not proceed and the degree of polymerization of the product was low.

[Table] Comparative Example 6 After thoroughly drying the same methyl methacrylate copolymer used in Example 1, it was put into a twin screw extruder (L/D=33) with a screw diameter of 50 mmφ at 12 kg/Hr.
was supplied at the rate of This twin-screw extruder is composed of a pellet plasticization zone, an imidization agent supply zone, an imidization reaction zone, a vent zone, a metal ring extrusion zone, and a die section, and the respective temperatures are 245℃, 255℃, 275℃, and 270℃. ℃, 275℃ and 255℃
It was set at ℃. Vent zone vacuum level 5mmHg
Maintained abs. Methylamine was supplied to the imidizing agent supply zone of the twin-screw extruder through a check valve at a rate of 2.79 kg/hour. The strand obtained from the die part was cooled with water and then pelletized to form a sample. After drying this sample, it was shaped into a strand using an extrusion shaping device and evaluated for light transmission performance in the same manner as in Example 1. When the infrared absorption spectrum of the obtained polymer was measured, the wave numbers were 1720 cm ^-1 , 1663 cm ^-1 and 750 cm ^-1
Absorption characteristic of N-methyl methacrylimide polymer was observed, and it was confirmed that it was a methacrylimide polymer. The physical properties of the obtained polymer were evaluated. The results are shown below. Melt index: 8.5gr/10min Heat distortion temperature: 153℃ Transmission performance: 35000dB/Km (646nm) From the above results, the imide-containing polymer has excellent translucency even when imidization is performed in a solvent-free system. It turned out that union was not possible. The reason for this is thought to be that in the absence of a solvent in the twin-screw extruder, the highly viscous molten methacrylic polymer and methylamine are not sufficiently mixed, so that the imidization reaction does not proceed uniformly.

[Brief explanation of drawings]

FIG. 1 diagrammatically shows one embodiment of the apparatus used in the practice of the invention. FIG. 2 is a schematic diagram of an apparatus for preparing a sample for measuring the light-transmitting performance of a polymer. FIG. 3 is a schematic diagram of an apparatus for measuring the light transmission performance of a polymer sample. FIG. 4 is a schematic diagram of an apparatus for measuring the numerical aperture of a polymer sample. FIG. 5 is a diagram showing an example of the results measured by the apparatus shown in FIG. 4.

Claims (1)

[Claims] 1. A methacrylic ester homopolymer or methacrylic ester having an intrinsic viscosity of 0.01 to 3.025
A copolymer of 75% by weight or more of other copolymerizable monomers with 75% by weight or less of other monomers having the general formula R-NH ₂ () (wherein R is a hydrogen atom or an aliphatic group having 1 to 20 carbon atoms) , aromatic or alicyclic hydrocarbon group) with a boiling point of 50 to 135°C under normal pressure and a solubility parameter δ
There is a reaction zone where a condensation reaction occurs between polymer side chains in the presence of a solvent with a value of 10.0 to 19.5 (cal/cm ³ ) ^1/2 , and a reaction zone where a condensation reaction occurs between polymer side chains by heating the reaction product. The reaction is carried out at a temperature of 100°C or higher and 350°C or lower through at least two reaction zones including an aging reaction zone that further accelerates the condensation reaction, and then volatile substances are separated and removed from the resulting reaction product. The general formula (In the formula, R is as described above.) A methacrylimide-containing polymer with excellent transparency and heat resistance consisting of 2 to 100% by weight of the structural unit represented by the formula (wherein R is as described above) and 0 to 98% by weight of the ethylenic monomer structural unit. Coalescing method. 2. The method for producing a methacrylimide-containing polymer according to claim 1, wherein volatile substances are separated and removed so that the light transmission performance of the methacrylimide-containing polymer is 5000 dB/Km or less at a wavelength of 646 nm. 3. Claim 1 or 3, wherein the reaction between the homopolymer or copolymer of methacrylic acid ester and the compound represented by the general formula () is carried out in a state where the water content in the reaction system is 1% by weight or less. 2. A method for producing a methacrylimide-containing polymer according to item 2.