JPS642603B2 - - 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 for short-distance optical communication and optical Application development is progressing in fields such as sensors. However, methyl methacrylate polymer does not have sufficient heat resistance, with a heat distortion temperature of around 100°C, which limits the development of its applications in many fields.
There is a strong demand for improved heat resistance. As a method for improving the heat resistance of methyl methacrylate polymer, there is a method of imidizing the methyl methacrylate polymer. For example, (1) acrylic acid,
A method of reacting a polymer of methacrylic acid or its ester with a primary amine, ammonia, or a compound that generates ammonia or a primary amine by heating in the presence of a solvent (US Pat. No. 2,146,209, Germany) Patent No. 1077872, same no.
1242369), (2) a method of reacting a methyl methacrylate polymer with a primary amine in the presence of water (US Pat. No. 3,284,425), and (3) a method of reacting an acrylic polymer with ammonia or a primary amine. A method of reacting in an extruder (US Pat. 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 the resulting imidized polymer is colored and reduces the transparency of the resulting polymer. 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, and therefore it has the desired heat resistance. It is difficult to obtain an imidized polymer, and it is also difficult to perform a uniform imidization reaction. Furthermore, in method (3) above, it is difficult to carry out a uniform imidization reaction because the imidization reaction involves a reaction between a highly viscous polymer and a gaseous imidization substance. It is difficult to obtain a target imidized polymer. 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 suffer from poor transparency, a substantial decrease in molecular weight, or imidization. The current situation is that it has not been put into practical use yet because it results in non-uniformity. (Problems to be Solved by the Invention) The first object of the present invention is to solve the problem in view of the above-mentioned prior art, and to improve the inherent optical properties, mechanical properties, weather resistance, and moldability of methyl methacrylate polymer. It is an object of the present invention to provide a method for producing a methacrylimide-containing polymer having the above characteristics and excellent transparency and heat resistance. A second object of the present invention is to provide a method for producing a methacrylimide-containing polymer of excellent quality and in which the imidization reaction can be easily controlled. A third object of the present invention is to provide an industrially advantageous method for producing a methacrylimide-containing polymer. (Means for Solving the Problems) The method for producing a methacrylimide-containing polymer having excellent transparency and heat resistance according to the present invention comprises a methacrylic resin and the following general formula R-NH ₂ [) (wherein R represents H, or an aliphatic, alicyclic, or aromatic hydrocarbon group having 1 to 10 carbon atoms (hereinafter referred to as "imidized substance"), with a solubility parameter δ. 8.5~15.0
(cal/cm ³ ) ^1/2 non-polymerizable solvent and the following general formula []: (In the formula, R ₁ , R ₂ , and R ₃ represent the same or different aliphatic, aromatic, or alicyclic hydrocarbon groups having 1 to 10 carbon atoms.) ℃ over 350
It consists of reacting at a temperature below .degree. C. and then separating off volatile substances from the reaction product obtained. The "methacrylimide-containing polymer" used in the method of the present invention refers to a methacrylic resin in which a methacrylimide segment is introduced into the polymer side chain. The methacrylimide segment herein refers to one represented by the following structural formula. (In the formula, R represents H or an aliphatic, alicyclic, or aromatic hydrocarbon group having 1 to 10 carbon atoms.) The "methacrylic resin" used in the method of the present invention has an intrinsic viscosity of 0.01 ~3.0 methyl methacrylate homopolymer, or methyl methacrylate and up to 75% by weight of acrylic ester or methacrylic ester (excluding methyl ester), acrylic acid, methacrylic acid, styrene, α
- Refers to a copolymer with methylstyrene, etc. Examples of acrylic esters include methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, and benzyl acrylate; examples of methacrylic esters include ethyl methacrylate, butyl methacrylate, and methacrylic acid. It is possible to use cyclohexyl, 2-ethylcyclohexyl methacrylate, benzyl methacrylate, and the like. These monomers can be used alone or in combination of two or more. The present invention can be roughly divided into two steps: reaction and volatile substance separation. The reaction step is a step in which the methacrylic resin and the imidized substance are reacted to cause a condensation reaction between the polymer side chains of the methacrylic resin. The volatile substance separation process is a process of separating and removing volatile substances mainly composed of non-polymerizable solvents from the reaction product containing the imidized methacrylic resin produced in the reaction process. In the reaction step, preferably, the methacrylic resin and the imidized substance are mixed in the coexistence of a non-polymerizable solvent and a reaction catalyst, and the imidized substance and a mixture of the methacrylic resin dissolved in the non-polymerizable solvent are mixed together in the presence of a non-polymerizable solvent and a reaction catalyst. The reaction is carried out in the coexistence of a solvent and a reaction catalyst. In the reaction process, the non-polymerizable solvent used is one that does not inhibit the imidization reaction, which is a condensation reaction between polymer side chains, and in the case of a partial imidization reaction,
It is necessary that the methyl methacrylate or methacrylate ester segment portion is not changed. Examples include alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, and butyl alcohol; aromatic hydrocarbon compounds such as benzene, toluene, and xylene; and ketones and ethers such as methyl ethyl ketone, glyme, diglyme, dioxane, and tetrahydrofuran. Compound; dimethylformamide,
Examples include dimethyl sulfoxide and dimethyl acetamide. Solubility parameter δ value of non-polymerizable solvents (Polymer Handbook, Second Ed,
J.Brandrup, EHImmergut.John Wiley &
Sons, New York. 1975) is 8.5 to 15.0 (cal/
cm ³ ) is in the range of ^1/2 . If it is less than 8.5 or more than 15.0, the solubility is insufficient. The non-polymerizable solvent used in the present invention allows the imidization substance to easily diffuse between the polymer chains of the methacrylic resin, allowing a uniform imidization reaction to occur quickly, and controlling heat generation and heat removal during the reaction. Effect: It has the effect of dissolving imidized substances and adjusting the viscosity of methacrylic resin. The amount of non-polymerizable solvent used in the method of the present invention should be small from the viewpoint of productivity, but if it is too small, the effect of the above-mentioned non-polymerizable solvent will be reduced, so A range of ~80% by weight is preferable. The imidized substance represented by the general formula [] used in the method of the present invention includes primary amines such as methylamine, ethylamine, and propylamine;
1,3-dimethylurea, 1,3-diethylurea,
Examples include compounds that generate primary amines upon heating such as 1,3-dipropylurea, ammonia, urea, and the like. The amount of these compounds to be used cannot be absolutely limited depending on the amount to be imidized, but is in the range of 10% by weight or more based on the methacrylic resin. Ten
If the amount is less than % by weight, no obvious improvement in heat resistance can be expected. The reaction between the methacrylic resin and the imidizing agent in the reactor is carried out at a temperature of 100°C or higher and lower than 350°C, preferably 150°C or higher and lower than 300°C. If the reaction temperature is less than 100°C, the imidization reaction will be slow, and if it exceeds 350°C, the decomposition reaction of the raw material methacrylic resin will occur. The reaction time is not particularly limited. In the reaction, if a large amount of water is present, the ester moiety, which is the methyl methacrylate segment, undergoes hydrolysis with water as a side reaction during the imidization condensation reaction process, resulting in the production of methacrylic acid, which is the desired object of the present invention. It becomes difficult to obtain a methacrylimide-containing polymer having an imidization amount of . Therefore, in this reaction, the conditions are substantially water-free, that is, the water content is 1% by weight or less,
Preferably, it is carried out under anhydrous conditions. The amount of imidization of the methacrylic resin in the present invention can be determined arbitrarily, but from the viewpoint of heat resistance,
It is preferably 10% or more. As a reaction catalyst, the following general formula (In the formula, R ₁ , R ₂ , and R ₃ represent the same or different C 1 to 10 fatty acids, aromatic, or alicyclic hydrocarbon groups) are used. Examples include trimethylamine, triethylamine, tributylamine, N,N-dimethylaniline, N,N-diethylaniline, dimethyl-p-
Examples include toluidine, lutidine, picoline, and quinoline. The amount of reaction catalyst used varies depending on the amount of imidized material, but in general it is
It is 20% by weight or less, preferably 10% by weight or less. In the reaction step of the present invention, it is thought that a reaction route is followed in which amidation first occurs through the reaction of the side chain ester moiety and the primary amine, and then imidization occurs. The above-mentioned reaction catalyst shows a surprising effect of accelerating the reaction of converting amide into imide. In particular, when the purpose is a partial imidization reaction, it exhibits the effect of promoting imidization of segments existing as amide intermediates. Thus, it is possible to shorten the imidization reaction time and perform the imidization reaction at a low temperature only by using a combination of the non-polymerizable solvent and the reaction catalyst. The reaction apparatus used to carry out the present invention is not particularly limited as long as it does not impede the purpose of the present invention, such as a plug flow type reaction apparatus,
Screw extrusion type reactor, tower reactor,
Examples include a tube type, duct type reaction device, and tank type reaction device. In particular, in order to uniformly perform imidization and obtain a uniform methacrylimide-containing polymer,
A tank-type reactor equipped with a stirring device having a supply port and a discharge port and having a mixing function throughout the inside of the reactor is preferred. In the volatile substance removal step, most of the volatile substances are separated and removed from the reaction product containing the intermolecular condensation reaction product by the reaction between the methacrylic resin and the imidized substance. The content of residual volatile substances in the final polymer is less than 1% by weight, preferably less than 0.1% by weight. Removal of volatile substances can be carried out using a general pent extruder, devolatizer, etc., or by other methods, for example, by diluting the reaction product with a solvent and precipitating and filtering it in a large amount of insoluble medium. This can be done using a method such as drying. In the method of the present invention, it is preferable to add a small amount of an antioxidant in order to prevent a decrease in molecular weight due to radical depolymerization of the raw material methacrylic resin under high temperature reaction. Antioxidants include phosphite-based antioxidants such as tricresyl phosphite, cresyl phenyl phosphite, tributyl phosphite, and tributoxyethyl phosphite; hindered hydroquinone, cresol, and phenol derivatives. Specific examples include phenolic antioxidants; amine antioxidants such as naphthylamine, phenylenediamine, and hydroquinoline derivatives; and alkyl merbutane and dialkyl disulfide derivatives. In addition, due to product performance requirements, plasticizers, lubricants,
Other additives such as UV absorbers, colorants, pigments, etc. can also be added. 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 non-polymerizable solvent containing the reaction catalyst passes through line 2 from solvent storage tank 1 to solvent supply tank 4 by pump 3.
The antioxidant, which is added as necessary, is supplied from the antioxidant storage tank 5 to the solvent supply tank 4 via the line 6, dissolved therein, and sent to the resin dissolution tank 10. On the other hand, resin is supplied from a pellet storage tank 8 to a resin melting tank 10 through a line 9. The resin melting tank 10 is equipped with an agitator 11 and a jacket 12, into which a heat 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 reacted with the imidized substance supplied from the imidized substance storage tank 18 in the reaction tank 20. The reaction tank 20 has a spiral ribbon type stirrer 21
and a jacket 22, in the jacket,
A ripening medium flows through the apertures 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 has a spiral ribbon type stirrer 29
and a jacket 30, through which a heat medium flows through holes 31 and 32. The aged reaction product is sent via discharge line 33, pump 34 and line 35 to volatile separator 36 where volatiles are removed and discharged through 37. The volatile separator 36 is equipped with a screw 38, a vent 39 and means 40 for heating. (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 device system shown in FIG. 1 has the following specifications. Resin dissolution tank 500 Reaction tank 40 Aging tank 20 Volatile separator Single screw vent extruder Screw: 30 mmφ x 720 mm length Vent length: 60 mm In these Examples, the following method was used to measure the properties of the polymer. (1) The infrared absorption spectrum was measured by the KBr disk method using an infrared spectrophotometer (Hitachi, Ltd. model 285). (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=(Inηfel)/c (where 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 total light transmittance (%) and haze value (%) of the molded product were measured according to ASTM D1003. (6) The imidization amount (%) of the polymer was determined from the nitrogen content determined by elemental analysis (measurement device CHN coder (MT-3) manufactured by Yanagimoto Seisakusho). (7) The amount of amide (%) in a polymer can be measured using protons.
Determined by NMR measurement (FX-90 JEOL). Example 1 100 parts of sufficiently dried methyl methacrylate polymer (manufactured by Mitsubishi Rayon Co., Ltd., Acrypet (trademark) VH, intrinsic viscosity = 0.51), 90 parts of dehydrated and dried toluene
10 parts of dehydrated and dried methanol, 0.01 part of an antioxidant (manufactured by Kawaguchi Chemical Co., Ltd., ANTAGE (trademark) BHT, chemical name: tert.-butyl-P-cresol), and 0.1 part of triethylamine. 500
The polymer was placed in a dissolution tank at 200°C and dissolved under stirring. Next, this solution was continuously supplied to the reaction tank at a supply rate of 5/hour, and the temperature inside the tank was adjusted to 230° C. while sufficiently mixing the solution at a stirring rotation speed of 90 rpm.
Thereafter, dry methylamine was continuously fed into the reactor at a rate of 20 mol/hour to bring the internal pressure to 75 Kg/cm ² gauge pressure. The temperature inside the reaction vessel was maintained at 230°C during the reaction, and the average residence time was 1.0 hour. The reaction product taken out from this reaction tank is put into an aging tank using a pump, and the average residence time is 0.5 hours.
The temperature inside the aging tank was set at 230°C, and the mixture was aged with sufficient stirring. The aged reactant was continuously fed to a vented extruder to separate and remove volatile materials. 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. After cooling the strand extruded from the die with water, the strand was cut to obtain a pellet-like polymer having good transparency. On the other hand, toluene, methanol, and unreacted methylamine discharged from the vent were cooled and collected. When the infrared absorption spectrum of this obtained polymer was measured, it was found that wave numbers of 1720 cm ^-1 , 1633 cm ^-1 and
An absorption characteristic of methyl methacrylimide polymer was observed at 750 cm ^-1 , a nitrogen content of 8.3% was observed in elemental analysis, and an absorption corresponding to methyl methacrylimide was observed in NMR measurement, and the intermediate methyl No absorption corresponding to methacrylamide was observed. The amount of imidization was 100%, and it was confirmed that the polymer was almost completely a poly-N-methylmethacrylimide polymer. Further, when the physical properties of this polymer were evaluated, it had the following properties. Intrinsic viscosity: 0.48 Melt index: 1.7 Heat distortion temperature: 182°C Total light transmittance: 93.0% Haze value: 1.0% Examples 2 to 30 Implemented using methacrylic resin and imidized substance as shown in Table 1. Various methacrylimide-containing polymers were prepared using the same method as in the apparatus of Example 1. The internal pressure of the reaction tank was set to 20 to 45 Kg/cm ² ·gauge pressure. Table 1 shows the reaction conditions and the evaluation results of the obtained polymers.

【table】

【table】

[Table] Example 31 Into 10 reactors equipped with a paddle spiral stirrer, a pressure gauge, a sample injection container, and a jacket heater, thoroughly dried methyl methacrylate polymer (Acrypet (trademark) VH, Mitsubishi Rayon Co., Ltd. ), intrinsic viscosity = 0.51), 90 parts of dry toluene, 10 parts of dehydrated and dry methanol, and an antioxidant (Chivar,
Manufactured by Geigy, Irganox (trademark) 1076)
After adding 0.01 part of the mixture and thoroughly purging with nitrogen,
The temperature was raised to 230°C and the polymer was dissolved by stirring. Next, at a temperature of 230°C, 12.4 parts of methylamine (0.4 molar ratio) and 1.01 parts of triethylamine (0.01 molar ratio) were added to dry methanol from the reagent injection container.
It was added as a 50% solution and reacted for 1.5 hours at an internal pressure of 26 kg/cm ² gauge pressure. After the reaction was completed, the methacrylimide-containing polymer solution was reprecipitated with n-hexane, filtered, and dried in a vacuum dryer at 70°C to obtain a white powdery polymer.
When the infrared absorption spectrum of this obtained polymer was measured, the wavenumbers were 1720 cm ^-1 , 1663 cm ^-1 and 750 cm -1 .
Absorption characteristic of methacrylimide was observed at cm ^-1 , confirming that it was a methacrylimide-containing polymer. Table 2 shows the evaluation results of the physical properties of this polymer. Examples 32-44, Comparative Examples 1-8 Various polymers were produced by repeating the method of Example 31 under the conditions shown in Table 2, and evaluated. The results obtained are shown in Table 2.

【table】

[Table] (Effects of the Invention) According to the method of the present invention, it is possible to easily control the imidization reaction, to industrially advantageously produce a methacrylimide-containing polymer of excellent quality, and to obtain the obtained polymer. has excellent transparency and heat resistance. Therefore, fields where such characteristics are required, e.g.
It can be used in a wide range of applications such as CRT filters, television filters, fluorescent tube filters, liquid crystal filters, meters, displays such as digital display boards, lighting optics, automobile head covers, electrical parts, etc., and has industrial significance. It is extremely valuable.

[Brief explanation of the drawing]

FIG. 1 diagrammatically shows one embodiment of the apparatus used in the practice of the invention. In the figure, 10 is a resin dissolution tank, 20 is a reaction tank, 28
36 is a ripening tank, and 36 is a volatile substance separation device.

Claims (1)

[Scope of Claims] 1 A methacrylic resin and the following general formula R-NH ₂ [) (wherein, R represents H or an aliphatic, alicyclic or aromatic hydrocarbon group having 1 to 10 carbon atoms. ) with a solubility parameter δ of 8.5.
~15.0 (cal/cm ³ ) ^1/2 non-polymerizable solvent and the following general formula []: (In the formula, R ₁ , R ₂ and R ₃ represent the same or different aliphatic, aromatic or alicyclic hydrocarbon groups having 1 to 10 carbon atoms) at 100°C in the presence of a reaction catalyst represented by More than 350℃
1. A method for producing a methacrylimide-containing polymer having excellent transparency and heat resistance, the method comprising carrying out the reaction at a temperature below 100 mL, and then separating and removing volatile substances from the obtained reaction product.