JPH0461007B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing thermoplastic polymers containing structural units of glutarimide groups in the polymer backbone. Transparent resins such as polymethyl methacrylate and polystyrene are used as melt-forming materials for home appliances, vehicle optical parts, instrument panels, lighting window materials, and, in recent years, as materials for optical fibers. I'm getting used to it. As the development of these uses becomes more sophisticated, there is also a demand for more sophisticated performance in the plastics used for these uses, and in recent years there has been a strong demand for improved heat resistance in particular. As a method for improving the heat resistance of these vinyl polymerizable thermoplastic polymers, there is a method of introducing a maleic anhydride structure, as described in JP-A-55-102614 and JP-A-57-153008. Proposed. Maleic anhydride has copolymerizability properties that are quite different from other vinyl monomers, and it is known that a good way to improve its copolymerizability is to use styrene as a copolymerizable monomer. The polymer is a multicomponent copolymer, such as a methyl methacrylate/maleic anhydride/styrene ternary copolymer or a quaternary copolymer obtained by copolymerizing these ternary copolymers with other vinyl monomers, and its production is difficult. Not only is this difficult, but the transparency of the obtained polymer is not necessarily good. As described above, proposals have been made to increase heat resistance by forming a ring structure in the polymer main chain and imparting rigidity to the ring structure. That is, the heat resistance of the maleic anhydride-styrene copolymer is improved by forming a five-membered ring structure with maleic anhydride in the polymer main chain. On the other hand, there is a method in which a glutarimide ring structure obtained by thermally decomposing a methacrylamide polymer is formed in the polymer main chain. The term glutarimide ring as used herein refers to an imide ring produced as a result of a deammoniation reaction by condensation between amides of methacrylamide or acrylamide units in a polymer. Conventionally, regarding such polymer side chain reactions, K.Crauwels, G.
Smets, Bull, Soc, Chim, Belgium 59 182
(1950), a polymer containing a glutarimide ring in the main chain is obtained by thermal decomposition condensation reaction of polymethacrylamide polymer, but this condensation reaction is not only an intramolecular reaction, but also a condensation reaction between polymers. A reaction occurs and only a crosslinked polymer is obtained. The polymer actually obtained by repeating the method described in the above-mentioned literature was an insoluble crosslinked black colored polymer. Also, Tokko Akira
44-8743 discloses that glutarimide is produced by polymerizing a mixture of methacrylic acid and methacrylonitrile or a mixture of methacrylic acid, methacrylonitrile, and methacrylamide in the presence of urea or N-N'-dimethylurea, and then thermally decomposing it. A polymer having a ring in the main chain has been obtained, and it has been reported that a heat-resistant foam material with a crosslinked structure in which the imide group-forming reaction of this polymer also occurs intermolecularly is obtained. As mentioned above, in the modification of polymers that utilizes the condensation reaction of amide groups in polymer side chains, which has been studied in the past, reactions occur not only between intramolecular segments but also between molecules, resulting in only crosslinked polymers. The current situation is that we are not getting it. Therefore, the present inventors conducted intensive studies to obtain good heat resistance and shaping processability with a polymer that has an imide ring structure in the polymer main chain and is substantially thermoplastic, and as a result, they arrived at the present invention. did. That is, the gist of the present invention is that 5 to 100% by weight of N-mono-substituted (meth)acrylamide units substituted with a group selected from an alkyl group having 1 to 6 carbon atoms and a cycloalkyl group; ) Polymer consisting of 95 to 0% by weight of acrylic ester units or 5 to 30% by weight of (meth)acrylamide units
and (meth)acrylic acid ester units 95-70% by weight
A polymer selected from copolymers consisting of (In the formula, R ₁ and R ₂ are groups selected from the same or different hydrogen atoms or alkyl groups having 1 to 4 carbon atoms, and R ₃ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a cycloalkyl group. The polymer contains 5% by weight or more of a structural unit represented by (representing a group selected from group or phenyl group) and has an intrinsic viscosity of 0.01 to 2.
dl/g. The thermoplastic polymer of the present invention containing 5% by weight or more of the structural unit represented by the above general formula [] includes: (1) 5 to 100% by weight of N-mono-substituted (meth)acrylamide units and (meth)acrylic acid ester A polymer consisting of 95 to 0% by weight of units, or (2) 5 to 30% by weight of (meth)acrylamide units and 95 to 70% by weight of (meth)acrylic acid ester units.
It is produced by thermally decomposing a polymer consisting of and performing an intramolecular intersegment condensation cyclization reaction. When producing the thermoplastic polymer of the present invention by the method (1) above, the polymer obtained from N-mono-substituted (meth)acrylamide as a raw material or N
-Mono-substituted-(meth)acrylamide and (meth)
When a copolymer with an acrylic ester monomer is thermally decomposed, the N-(methyl)amide segment in the polymer is converted into an adjacent N-mono-substituted (meth)acrylamide or an adjacent (meth)acrylic ester in the molecule. It is thought that a glutarimide cyclization reaction is mainly performed through a deammonia or dealkylamine reaction with the segment, and a substantially thermoplastic polymer is obtained. Therefore, according to this method, the thermoplastic polymer of the present invention can be produced extremely efficiently. The content of N-mono-substituted (meth)acrylamide units and (meth)acrylic acid ester units in the polymer that is the starting material for this method is 5 to 100% by weight of N-mono-substituted (meth)acrylamide units. , (meta)
The content of acrylic acid ester units is in the range of 95 to 0% by weight, and if the content of N-mono-substituted (meth)acrylamide units is less than 5% by weight, a polymer with excellent heat resistance cannot be obtained. Examples of N-mono-substituted (meth)acrylamides include alkyl groups having 1 to 6 carbon atoms,
For example, N-methylmethacrylamide, N-methylacrylamide, N-ethylmethacrylamide,
N-ethylacrylamide, N-propylmethacrylamide, N-propylacrylamide, N-
Isopropyl methacrylamide, N-isopropylacrylamide, N-tert.-butyl methacrylamide, N-tert.-butyl acrylamide, N-
Examples include sec.-butyl methacrylamide, N-sec.-butyl methacrylamide, N-cyclohexyl methacrylamide, and N-cyclohexyl acrylamide. Furthermore, examples of (meth)acrylic acid esters used by copolymerizing with N-mono-substituted (meth)acrylamide include methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, propyl methacrylate, propyl acrylate, n- butyl methacrylate,
n-butyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate, lauryl methacrylate, lauryl acrylate, cyclohexyl methacrylate, cyclohexyl acrylate, benzyl methacrylate,
Examples include alkyl methacrylates or acrylates containing an aliphatic or aromatic functional group having 1 to 18 carbon atoms, such as benzyl acrylate. However, it is desirable that the obtained polymer be one that is difficult to be colored by heating and one that does not form an intermolecular crosslinked structure.
From this point of view, methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, n-butyl methacrylate, n-butyl acrylate, iso-butyl methacrylate,
-butyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate,
The use of lauryl methacrylate, lauryl acrylate, etc. is preferred. Among the above, it is more preferable to use N-methylmethacrylamide as the N-mono-substituted (meth)acrylamide and methyl methacrylate as the (meth)acrylic acid ester. The reason for this is not very clear, but when a polymer containing N-methylmethacrylamide structural units is heat-treated, similar N-methylamide structural units that are adjacent segments within the molecule are As a result of preferential deammonification or demethylamine reaction between N-methylamide groups and methyl ester groups, the thermoplasticity of the present invention is mainly characterized by the formation reaction of the structural unit represented by the general formula []. It is believed that a polymer is obtained. This is N-
The hydrogen atom bonded to the nitrogen atom in the methylamide group is fixed by interaction such as hydrogen bonding with the side chain carbonyl group of the adjacent segment, and as a result, the intramolecular intersegment condensation reaction proceeds efficiently and preferentially. it is conceivable that. This method is characterized in that it is not subject to any restrictions on the amount of N-mono-substituted (meth)acrylamide copolymerized. The method for producing the thermoplastic polymer of the present invention by the method (2) above is a condensation cyclization reaction between amide groups or ester groups that are present as polymer side chains in a free state. This condensation reaction easily occurs not only between intramolecular segments but also between molecules, so (meth)acrylamide and (meth)acrylic acid ester, which are the raw materials used to produce the thermoplastic polymer of the present invention, The content of (meth)acrylamide units in the copolymer must be 30% by weight or less. When a copolymer with a (meth)acrylamide copolymerization amount exceeding 30% by weight is subjected to a condensation reaction, it is possible to obtain a substantially solvent-soluble and substantially meltable polymer, which is the object of the present invention. Can not. As the polymerization initiator used to obtain the N-mono-substituted (meth)acrylamide-containing polymer or (meth)acrylamide-containing copolymer used as a starting material in the production method of the present invention, ordinary radical polymerization Initiators can be used. Specific examples include di-tert.-butyl peroxide, dicumyl peroxide, methyl ethyl ketone peroxide, tert-butyl perphthalate, tert.-butyl perbenzoate, methyl isobutyl ketone peroxide, lauroyl peroxide, cyclohexyl peroxide,
2,5 dimethyl 2,5 di-tert.-butyl peroxyhexane, tert.-butyl peroctanoate,
Organic peroxides such as tert.-butylperisobutyrate, tert.-butylperoxyisopropyl carbonate, methyl 2-2'-azobisisobutyrate, 1,1'-azobiscyclohexanecarbonitrile, 2-phenylazo- 2,4-dimethyl-4
-Methoxyvaleronitrile, 2-carbamoyl-
Examples include azo compounds such as azobisisobutyronitrile, 2-2'-azobis(2.4 dimethylvaleronitrile), and 2,2'-azobisisobutyronitrile. Also, ammonium persulfate, potassium persulfate, etc. can be used. Also, ammonium persulfate, potassium persulfate, etc. can be used. As a chain transfer agent,
There are no particular limitations, and ordinary polymerization degree regulators can be used. Examples include alkylmercaptan, carbon tetrachloride, carbon tetrabromide, dimethylacetamide, dimethylformamide, triethylamine, and the like, among which alkylmercaptan is most preferred. In the case of free radical initiation as a polymerization method,
Examples include emulsion polymerization, suspension polymerization, bulk polymerization, and solution polymerization, but other production methods can be employed depending on the purpose. It can also be obtained using a Grignard reagent, a polymerization initiation catalyst, an alkyllithium-based ionic polymerization catalyst, etc. When thermally decomposing the N-mono-substituted (meth)acrylamide-containing polymer or (meth)acrylamide-containing copolymer to obtain the thermoplastic polymer of the present invention, the heat treatment temperature of the polymer or copolymer is 200°C or higher. ,
Preferably 200℃~450℃, more preferably 200℃
The temperature is from ℃ to 300℃, and the processing time is more than 0.5 hours. The thermoplastic polymer obtained by the method of the present invention contains at least 5% by weight of a glutarimide ring structure represented by the general formula [], is substantially soluble in a solvent, and is substantially meltable by heating. The major feature is that it is possible. Since the polymer of the present invention contains the glutarimide ring structural unit represented by the general formula [] in the polymer main chain in an amount of 5% by weight or more, preferably 10% by weight or more, its heat resistance is higher than that of conventionally developed polymers. Despite being improved by 5 to 10°C compared to comparable vinyl polymers of the same type, its transparency and moldability are good. The thermoplastic polymer of the present invention has an intrinsic viscosity of
It is necessary that it is 0.01 to 2 dl/g. A molded article with excellent mechanical strength cannot be made from a polymer having an intrinsic viscosity of less than 0.01 dl/g. Further, a polymer having an intrinsic viscosity exceeding 2 dl/g has a high viscosity, which causes problems in shaping properties such as melt molding, and also causes problems such as a decrease in solubility when made into a solution. Although the thermoplastic polymer of the present invention has an improved heat resistance temperature of 5 to 10°C or more compared to comparable vinyl polymers of the same type, its transparency
It has good heat melt fluidity and solubility in various solvents such as dimethylformamide and chloroform. Therefore, the polymer of the present invention can be used in various molding materials, coating materials, resist materials, optical materials, heat-resistant films, fibers, etc., and this polymer can be used in combination with crosslinking agents such as low molecular weight polyamines, urea, ammonia, dialkyl urea, etc. Then, a resin composition exhibiting crosslinking and curable properties can be obtained. The present invention will be explained in more detail with reference to Examples below, and the following methods were used to measure the properties of the polymer. The infrared absorption spectrum was measured by the KBr disk method using an infrared spectrophotometer (manufactured by Hitachi, Ltd., model 285). Number average molecular weight (Mn), weight average molecular weight (Mw)
and Z average molecular weight (Mz) are Gel Permeation Chromatography HLC-manufactured by Toyo Soda Co., Ltd.
Using 802UR, the sample concentration was 0.1 (weight/volume)%,
Elution used dimethylformamide as a solvent, a flow rate of 1.2 ml/min, and a monodisperse polystyrene calibration curve. The heat resistance test was conducted in accordance with ASTM-D-1525, using a Vigar softening point measuring device (manufactured by Toyo Seiki Seisakusho), with a heating rate of 50 ± 5°C/Hr, and a sample size of 5 × 10 × 10
mm was used. Storage modulus (E′) and loss modulus (E″) were measured using a dynamic viscoelasticity device (manufactured by Toyo Baldwin Co., Ltd.).
Measurement was performed at 110 Hz and a heating rate of 2° C./min. The intrinsic viscosity of the thermoplastic polymer was measured as follows. A dimethylformamide solution with a polymer concentration of 0.5% by weight was used as a sample, and measured at a temperature of 25% using a Deereax-Bischoff viscometer.
Flow time of dimethylformamide at ±0.1℃: to
and the flow time of the polymer solution: ts is measured,
Determine the relative viscosity ηre of the polymer from the ts/to value,
Calculated using the following formula. ηinh=(nηre)/C [] (In the formula, C represents the number of grams of polymer per 100 ml of solvent.) In the examples, parts represent parts by weight. Example 1 50 parts of methyl methacrylate, 50 parts of N-methyl methacrylamide, 0.01 part of 2,2'-azobisisobutyronitrile and 0.1 part of tert.-dodecyl mercaptan.
The sample was melted and placed in a glass ampoule, cooled under liquid nitrogen temperature, degassed repeatedly, and sealed in a nitrogen atmosphere. Next, place this sealed ampoule in a heating bath and heat it for 70 minutes.
After heating at 120°C for 15 hours, the mixture was further heated at 120°C for 3 hours to complete polymerization. The reaction conversion rate of monomers in this polymerization was 95%. Next, the resulting polymer was dissolved in tetrahydrofuran and then poured into n-hexane for precipitation, which was repeated several times to purify the polymer. This purified polymer had the following physical properties; Number average molecular weight (Mn); 8.5×10 ⁴ Weight average molecular weight (Mw); 21.2×10 ⁴ Z average molecular weight (Mz); 33.5×10 ⁴ Mw /Mn=2.49, Mz/Mn=3.94 Intrinsic viscosity: 0.45 dl/g Further, the results of measuring the infrared absorption spectrum of this polymer are shown in FIG. At wave number 1720 cm ^-1, absorption based on stretching vibration of ester carbonyl also occurs at wave number,
Absorption based on acid amide was measured at 1620 to 1640 cm ^-1 and 1540 cm ^-1 . Next, put 30g of this polymer into a 50ml tester,
Thermal decomposition reaction was carried out in an oil bath at 230°C for 5 hours.
In this reaction, methylamine was produced as a volatile organic gas, and methanol was also produced. After the reaction was completed, volatile components were removed under reduced pressure of 1.0 mmHg for 1 hour to obtain a foamed white resin body. This resin body was crushed. This pulverized polymer had the following physical properties; Number average molecular weight (Mn): 7.95×10 ⁴ Weight average molecular weight (Mw): 18.5×10 ⁴ Z average molecular weight (Mz): 28.5×10 ⁴ Mw/Mn=2.32, Mz/Mn=3.58 Intrinsic viscosity: 0.40dl/g This polymer sample was heated and pressure molded at 250℃ and 150Kg/ ^cm2 to produce a film with a thickness of 150μ. Elasticity was measured. The dispersion peak of the loss modulus (E″) was at 140°C. When a flat plate of 10 mm x 10 mm x 5 mm (thickness) was similarly prepared and the Vigor softening point was measured, it was found to be 147°C.
The value of Further, the glass transition temperature was measured using a differential scanning calorimeter and was found to be between 140 and 161°C. Furthermore, the infrared absorption spectrum of the above molded film was measured. The results are shown in FIG. As can be seen from Figure 2, in addition to the absorption of the stretching vibration of ester carbonyl at a wave number of 1720 cm ^-1 , the wave number of 1756 cm ^-1 ,
Absorption due to the formation of glutarimide groups was confirmed at 1802 cm ^-1 and 742 cm ^-1 . The amount of glutarimide produced was 63% by weight from the ratio of absorption based on glutarimide and absorption based on ester carbonyl. Further, when the thermally decomposed polymer was extruded using a melt indexer (manufactured by Toyo Seiki Seisakusho) at 230°C under a load of 10 kg, a good strand-shaped resin body was obtained, showing an MI value of 5.5 g/10 min. This polymer was passed through a 25φ vented extruder (manufactured by Daiichi Jitsugyo Co., Ltd., full flight screw L/D = 24) and extruded into pellets at a barrel temperature of 200°C and a die temperature of 230°C. . A 1 ounce vertical screw type injection molding machine (manufactured by Yamashiro Seiki Seisakusho)
SAV-30A) to produce a molded plate of 60 mm x 80 mm x 2 mm. This molded plate had excellent heat resistance. The above results show the molecular weight and molecular weight distribution measured by gel permeation chromatography (GPC) of a polymer using N-methyl methacrylamide and methyl methacrylate copolymer as starting materials, and heat treatment of this raw material polymer. From the measurement of the molecular weight and molecular weight distribution of the thermoplastic polymer of the present invention obtained by the GPC method, it was found that demethylamination and demethanolization were performed by thermal decomposition, and that a small number of polymer chains were formed during the initial stage of thermal decomposition. decomposition occurred, and an apparent decrease in molecular weight was observed, but no increase in molecular weight due to intermolecular cross-linking reaction, widening of molecular weight distribution, or significant change in molecular weight due to main chain scission was observed. Examples 2 to 7 Polymers were prepared by repeating the same operations as in Example 1 using the monomer compositions shown in Table 1, and the polymers were heat-treated and their physical properties were measured. The results are shown in Table 1. Examples 8-11 50 parts of methyl methacrylate, 50 parts of N-methylmethacrylamide, 0.01 part of 2,2'-azobisisobutyronitrile and tert.-dodecylmercaptan
0.1 part was dissolved and put into a glass ampoule, and a polymer was prepared in the same manner as in Example 1, and a purified polymer was obtained. As in Example 1, 30 g of this polymer was subjected to a thermal decomposition reaction in an oil bath at 230° C. for 30 minutes. The reaction conversion rate of this thermal reaction decomposition product was confirmed to be 30% based on the absorption amount of ester carbonyl in the infrared absorption spectrum. Further, this thermal decomposition reaction was continued in an oil bath at 230° C. for the time shown in Table 1, and the resin properties of the resulting polymer were measured. The results are shown in Table 1. Example 12 100 parts of N-methylmethacrylamide, 2,2'-
0.01 part of azobisisobutyronitrile and tert.−
0.1 part of dodecyl mercaptan was dissolved and placed in a glass ampoule, and after cooling at liquid nitrogen temperature, deaeration was repeated and the tube was sealed in a nitrogen atmosphere. Next, place this sealed ampoule in a heating bath and heat it for 70 minutes.
After heating at 120°C for 15 hours, the mixture was further heated at 120°C for 3 hours to complete polymerization. The reaction conversion rate of monomers in this polymerization was 96%. The results of measuring the infrared absorption spectrum of this polymer are shown in FIG. Carbonyl absorption based on acid amide was measured at wavenumbers of 1620 to 1640 cm ^-1 . Next, put 30g of this polymer into a 50ml test tube,
Thermal decomposition reaction was carried out in an oil bath at 230°C for 5 hours.
In this reaction, methylamine was produced as a volatile organic gas. 1 hour after reaction, 1.0mm
Volatile components were removed under reduced pressure of Hg to obtain a foamed white resin body. This resin body was crushed. This polymer sample was heated and pressure-molded at 250° C. and 150 kg/cm ² to prepare a film with a thickness of 150 μm, and its dynamic viscoelasticity was measured. The dispersion peak of the loss modulus (E'') was at 165°C. When a flat plate of 10 mm x 10 mm x 5 mm (thickness) was similarly prepared and the Vigor softening point was measured, it was found to be 167°C.
The value of Further, the glass transition temperature was measured using a differential scanning calorimeter and was found to be between 162 and 188°C. Furthermore, the infrared absorption spectrum of the above molded film was measured. The results are shown in FIG. As can be seen from FIG. 4, absorption due to the formation of glutarimide groups was confirmed at wave numbers of 1720 cm ^-1 , 1660 cm ^-1 and 742 cm ^-1 . From the ratio of absorption based on glutarimide to absorption based on ester carbonyl, the amount of glutarimide produced was 95% by weight. Further, when the thermally decomposed polymer was extruded using a melt indexer (manufactured by Toyo Seiki Seisakusho) at 230°C under a load of 10 kg, a good strand-shaped resin body was obtained, showing an MI value of 2.9 g/10 min. Examples 13-16 100 parts of N-methyl methacrylamide, 2,2'-
0.01 part of azobisisobutyronitrile and tert.−
0.1 part of dodecyl mercaptan was dissolved and placed in a glass ampoule to prepare a polymer in the same manner as in Example 12, and a purified polymer was obtained. 30 g of this polymer was heated in an oil bath at 230°C for 30 g as in Example 1.
A thermal decomposition reaction was carried out for a minute. The reaction conversion rate of this thermally decomposed product was confirmed to be 40% based on the absorption amount of carbonyl and imidocarbonyl in the infrared absorption spectrum, and the thermally decomposed reaction was continued for the time shown in Table 1 in an oil bath at 230°C. The resin properties of the obtained polymer were measured. The results are shown in Table 1. Comparative Example 1 100 parts of methyl methacrylate, 0.01 part of 2,2'-azobisisobutyronitrile and 0.1 part of tert.-dodecylmercaptan were dissolved and placed in a glass ampoule, cooled at liquid nitrogen temperature, and then desorbed. The tube was sealed in a nitrogen atmosphere after repeated stirring. Next, place this sealed ampoule in a heating bath and heat it for 70 minutes.
After heating at 120°C for 15 hours, the mixture was further heated at 120°C for 3 hours to complete polymerization. The reaction conversion rate of monomers in this polymerization was 97%. Next, the resulting polymer was dissolved in tetrahydrofuran and then poured into n-hexane for precipitation, which was repeated several times to purify the polymer. This purified polymer had the following physical properties; Number average molecular weight (Mn); 5.71×10 ⁴ Weight average molecular weight (Mw); 14.3×10 ⁴ Z average molecular weight (Mz); 20.0×10 ⁴ Mw /Mn=2.68, Mz/Mn=3.50 Intrinsic viscosity: 0.30 dl/g When the infrared absorption spectrum of this polymer was measured, absorption based on stretching vibration of ester carbonyl was measured at a wave number of 1720 cm ^-1 . Next, put 30g of this polymer into a 50ml test tube,
Thermal decomposition reaction was carried out in an oil bath at 230°C for 5 hours.
Volatile organic gas was produced in this reaction, but
The volatile component is methyl methacrylate monomer,
This is based on the depolymerization of the polymer main chain. After the reaction was completed, volatile components were removed under reduced pressure of 1.0 mmHg for 1 hour to obtain a foamed white resin body. This resin body was crushed. This pulverized polymer had the following physical properties; Number average molecular weight (Mn); 5.20×10 ⁴ Weight average molecular weight (Mw); 13.5×10 ⁴ Z average molecular weight (Mz); 17.8×10 ⁴ Mw/Mn=2.60, Mz/Mn=3.42 Intrinsic viscosity: 0.27 dl/g This polymer sample was heated and pressure molded at 250°C and 150 kg/ ^cm2 to produce a film with a thickness of 150 μ. Elasticity was measured. The dispersion peak of the loss modulus (E″) was 107°C. When a flat plate of 10 mm x 10 mm x 5 mm (thickness) was similarly prepared and the Vigor softening point was measured, it showed a value of 98°C. Furthermore, when the glass transition temperature was measured using a differential scanning calorimeter, it was found to be between 78 and 109°C.Furthermore, when the infrared absorption spectrum of the above molded film was measured, it was found that the wave number was 1720 cm ^-1 . It showed absorption of the stretching vibration of the ester carbonyl, but like the polymer before the thermal decomposition reaction, no absorption due to glutarimide was observed.The thermally decomposed polymer was also subjected to a melt indexer (manufactured by Toyo Seiki Seisakusho) at 230°C. When extruded at ℃ under a load of 10 kg, a good strand-shaped resin body was obtained, showing an MI value of 10.5 g/10 min. Comparative Example 2 100 parts of methacrylamide, 500 parts of water, 0.05 parts of potassium persulfate and tert.-dodecyl mercaptan 0.1
Mix and melt the parts and place in a glass ampoule.
Heat treatment was performed in the same manner as in Example 12. The resulting polymer was a crosslinked polymer that was yellowish brown in color and did not dissolve or melt in the solvent. Table 1 shows the main physical properties of the polymers obtained after the thermal decomposition reaction in the above Examples and Comparative Examples.

【table】

【table】 [Brief explanation of the drawing]

Figures 1 and 2 show infrared absorption spectra of the copolymer in Example 1 before and after the thermal decomposition reaction, and Figures 3 and 4 show the infrared absorption spectra of the polymer in Example 12 before and after the thermal decomposition reaction. The infrared absorption spectra after the reaction are shown.

Claims (1)

[Scope of Claims] 1 5 to 100% by weight of N-mono-substituted (meth)acrylamide units substituted with a group selected from an alkyl group having 1 to 6 carbon atoms and a cycloalkyl group and a (meth)acrylic acid ester Polymer consisting of 95 to 0% by weight of units or 5 to (meth)acrylamide units
30% by weight and (meth)acrylic acid ester units 95~
A polymer selected from copolymers consisting of 70% by weight.
After heat treatment at a temperature of 200℃ or higher, the following general formula (In the formula, R ₁ and R ₂ are groups selected from the same or different hydrogen atoms or alkyl groups having 1 to 4 carbon atoms, and R ₃ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a cycloalkyl group. The polymer contains 5% by weight or more of a structural unit represented by (representing a group selected from groups or phenyl groups), and has an inherent clay of 0.01 to 2.
1. A method for producing a thermoplastic polymer, characterized in that a polymer having a dl/g is obtained.