JPS6060109A - Thermoplastic polymer - Google Patents

Abstract

PURPOSE:A thermoplastic polymer excellent in heat decomposition resistance, transparency, etc., and suitable as an optical material or the like, obtained by thermally decomposing a polymer containing t-butyl (meth)acrylate with a copolymerizable ethylenic monomer at a specified weight ratio. CONSTITUTION:At least 5wt% (A) tert-butyl (meth)acrylate is copolymerized with at most 95wt% (B) ethylenic monomer copolymerizable with component A (e.g., methyl methacrylate or styrene) in the presence of a polymerization catalyst (e.g., dicumly peroxide) and a polymerization degree modifier (e.g., t-dodecyl mercaptan) by emulsion polymerization, bulk polymerization, solution polymerization or a like polymerization process. The resulting polymer is thermally decomposed at a temperature of about 200-450 deg.C, preferably in an atmosphere of an inert gas to obtain the purpose thermoplastic polymer containing glutaric anhydride ring structure units and having an intrinsic viscosity of 0.01-2dl/g.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a novel thermoplastic polymer having excellent heat decomposition resistance and transparency.

[Technical background of the invention and its problems] Transparent vinyl polymerized thermoplastic resins such as polymethyl methacrylate and polystyrene are widely used in home appliances, vehicle optical parts, instrument panels, lighting window materials, etc. In recent years, it has also come to be used for special purposes such as materials for optical fibers.

However, these vinyl polymerizable thermoplastic resins have the disadvantage that they depolymerize when heated and are easily decomposed into their monomers.

For this reason, there is a strong demand for these resins to have increased thermal decomposition resistance.

As a method for improving the heat resistance of these vinyl polymerized thermoplastic resins, a method of introducing a maleic anhydride structure as described in JP-A-55-1021 (14) and JP-A-57-153008 has been proposed. There is.

This method increases heat resistance by forming a ring structure in the main chain of the polymer to impart rigidity.

The copolymerization properties of maleic anhydride are quite different from those of other divinyl monomers, and it is known that a good way to improve the copolymerization properties is to use styrene as a copolymerization monomer. . In this case, the maleic anhydride/styrene copolymer has improved heat resistance due to the formation of a five-membered ring structure of maleic anhydride in the polymer main chain. Examples of such polymers include if
There are methyl methacrylate/maleic anhydride WA/styrene ternary copolymers and quaternary copolymers obtained by copolymerizing these ternary copolymers with other hynyl monomers. However, since these polymers are multi-component copolymerized polymers, they not only are difficult to manufacture, but also have the problem that the transparency of the obtained polymers is not necessarily good.

A method for obtaining a polymer that is easy to produce and has excellent heat decomposition resistance and transparency is a method in which a glutaric anhydride ring structure obtained by thermally decomposing a polymethacrylic polymer is formed in the polymer main chain. It has been known. What is referred to here as glutaric anhydride is usually acrylic acid or methacrylic acid in a polymer (hereinafter, [acrylic acid or methacrylic acid] is simply referred to as "(meth)acrylic acid").

) Means (meth)acrylic acid anhydride obtained by dehydration reaction between units.

For such polymer side chain reactions, PH1Grant
Polymer↓125 by N. Grassie
(1!180). According to the description,
When polymethacrylic acid is thermally decomposed at 200°C, a six-membered glutaric anhydride ring structure is generated in the polymer main chain, and at the same time, a condensation reaction occurs between the polymers to obtain a crosslinkable polymer.

However, since this polymer has intermolecular crosslinks, it does not dissolve or melt in a solvent. In other words, the resins obtained by these methods do not have thermal plasticity,
The workability was poor.

As described in -1- below, in the polymer side chain reaction, reactions occur not only between segments but also between polymers, and a crosslinkable polymer is usually obtained.

In fact, heat-resistant decomposition-resistant industrial products obtained using conventional polymer side chain reactions have been limited to insoluble crosslinkable polymers.

[Object of the Invention] The object of the present invention is to provide a novel polymer that has thermoplasticity, transparency, heat resistance, and heat decomposition resistance, and is easy to produce.

[Summary of the Invention] The present inventors have obtained a transparent polymer having an acid anhydride structure in the molecule and having no intermolecular cross-linked structure, which has good heat resistance, heat decomposition resistance, and shaping processability. After extensive research, we discovered that the disadvantageous crosslinking reaction mentioned above was suppressed, and the reactive groups in the polymer side chains reacted between the intramolecular segments.
The present invention has been completed by discovering that a thermoplastic polymer containing a six-membered glutaric anhydride ring structure in the main chain and having substantially no crosslinked structure and excellent heat decomposition resistance can be obtained.

That is, the thermoplastic polymer of the present invention has a t content of 5% by weight or more.
A polymer having an intrinsic viscosity of 0.5% obtained by thermally decomposing a polymer consisting of tert-butyl acrylate or tert-butyl methacrylate and 95% by weight or less of an ethylenic monomer copolymerizable with the same. It is a thermoplastic polymer with excellent thermal decomposition resistance of O1 to 2 dl/gr.

The tert-butyl (meth)acrylate structural unit in the raw material polymer of the thermoplastic polymer of the present invention is an essential component for generating a glutaric anhydride ring within the molecule without forming intermolecular crosslinks. be.

That is, the tert-butyl (meth)acrylate structural unit in the raw material polymer easily generates and eliminates isobutyne by heat treatment, and undergoes a condensation reaction to form a (meth)acrylic anhydride ring between intramolecular segments. do. In addition, when the adjacent group is a (meth)acrylic acid ester segment, a condensation reaction occurs between the tert-butyl (meth)acrylate structural unit and the (meth)acrylic acid ester segment, and the (meth)acrylic acid ester segment occurs in the main chain. An anhydride ring is formed.

Surprisingly, in the polymer side chain reaction that produces glutaric anhydride rings as described above, a non-crosslinked polymer is produced without a condensation reaction of the polymer rings, resulting in a solvent-soluble polymer. And a meltable polymer is obtained.

Although the reason for this result is not clear, it is thought that the intramolecular inter-segment condensation reaction proceeds efficiently and preferentially due to thermal decomposition of the tert-butyl (meth)acrylate segment in the polymer.

Another reason for using a polymer containing tert-butyl (meth)acrylate as a raw material in the present invention is that in the tert-butyl ester, the hydrogen atoms of the butyl group form a six-membered ring structure between the carbonyl oxygen atoms. , hydrogen is easily abstracted, and C-O bonds and C
Considering the free rotation of the -C bond, the probability that a hydrogen atom exists near the carbonyl oxygen is highest.

For example, like tert-butyl (meth)acrylate, there are n-butyl methacrylate, 1so-butyl methacrylate, n-propyl methacrylate, 1so-propyl methacrylate, etc., which hold a hydrogen atom near carbonyl oxygen.

However, although these esters have a hydrogen atom near the carbonyl oxygen, the probability that the hydrogen atom exists near the carboxyl oxygen is lower than in tert-butyl (meth)acrylate. Therefore, in the thermal decomposition reaction, the rate of production of methacrylic acid segment intermediates is tert-
Much slower than butyl (meth)acrylate.

Therefore, in cases other than tert-butyl (meth)acrylate, the thermal decomposition reaction time becomes longer and the thermal decomposition temperature also becomes higher.

As the tert-butyl (meth)acrylate monomer, tert-butyl methacrylate is preferred.

When a polymer containing tert-butyl methacrylate is thermally decomposed, the tert-butyl methacrylate segment very easily decomposes its side chain to generate and eliminate isobutyne, which forms methacrylic anhydride through a condensation reaction.
The novel thermoplastic polymer of the present invention, which has excellent heat resistance, can be obtained.

The content of tert-butyl (meth)acrylate monomer in the raw material polymer is 5% by weight or more. This is because if the content is less than 5% by weight, a thermoplastic polymer with excellent heat resistance cannot be obtained.

The raw material polymer of the present invention can contain an ethylenic monomer copolymerizable with tert-butyl (meth)acrylate. This ethylenic monomer may be involved in the formation of the glutaric anhydride Komama structure, or may form the remaining components of the ring structure.

Examples of ethylenic monomers include substituted styrenes such as styrene and chlorostyrene, olefins such as ethylene and propylene, and acrylonitrile, as well as (meth)acrylic acid ester monomers such as methyl (meth)acrylate and ethyl (meth)acrylate. Carbon such as acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate and fluorinated alkyl (meth)acrylate Mention may be made of alkyl (meth)acrylates containing from 1 to 18 aliphatic or aromatic functional groups.

However, it is preferable that the obtained polymer be one that is difficult to be colored by heating and one that does not form an intermolecular crosslinked structure, and from this point of view, the remaining components to be introduced into the thermoplastic polymer of the present invention are Preferred are methacrylic monomers such as methyl methacrylate-1., ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, and fluorinated alkyl methacrylate, with methyl methacrylate being particularly preferred.

As described above, the polymer containing tert-butyl methacrylate undergoes a thermal decomposition reaction easily, exhibits good copolymerizability with methacrylic acid ester, and easily forms a glutaric anhydride ring structure.

As the polymerization catalyst used to obtain the raw material polymer according to the present invention, common radical polymerization initiators such as G-T
ert-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, tert-
Organic peroxides such as butyl perisobutyrate, tert-butylperoxyisopropyl carbonate I, methyl-2゜2'-ambisisobutyrate, ■, l゛ -
Azobiscyclohexanecarbonitrile, 2-phenylara-2,4-dimethyl-4-methoxyvaleronitrile, 2-cal/hemoyl-7zobisisobutyronitrile,
Examples include azo compounds such as 2,2°-azobis(2,4-dimethylvaleronitrile) and 2,2°-azobisisobutyronitrile. In addition, the chain transfer agent used to prepare the raw material polymer for the thermal R+7 plastic polymer of the present invention includes:
There are no particular limitations, and ordinary polymerization degree regulators can be used. For example, alkyl mercaptan, carbon tetrachloride, carbon tetrabromide,
Examples of polymerization methods include dimethylacetamide, dimethylformamide, triethylamine, etc. Among them, alkylmercaptan is the most preferable polymerization method includes free radical initiation, emulsion polymerization, suspension polymerization, bulk polymerization, and solution polymerization, depending on the purpose. Other manufacturing methods can be adopted.

Further, a Gourigniard reagent polymerization initiation catalyst, an alkyl lithium-based ionic polymerization catalyst, etc. can be used.

The thermal decomposition temperature of these raw polymers is 100°C or higher,
In particular, the temperature is preferably 200 to 450°C, and in order to prevent abnormal reactions from occurring, the heat treatment is preferably performed in an inert gas atmosphere such as nitrogen or argon. The polymer of the present invention obtained in this way contains a glutaric anhydride ring structural unit, and in some cases, a tert-butyl (meth)acrylate structural unit which is an unreacted raw material segment or an intermediate segment. (Meth)acrylic acid structural units may be included.

A simple method for analyzing the presence or absence of a crosslinked structure in the obtained polymer is to measure the melt fluidity of the polymer, or to check the solubility in a solvent such as dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, methyl ethyl ketone, etc. Furthermore, the presence or absence of a crosslinked structure in the polymer can be confirmed by measuring undissolved particles in the polymer solution using an optical or physical method.

As an optical method, for example, there is a light scattering method, and as a physical method, there is a method of observing changes in solution concentration using a centrifuge. It is also possible to separate the crosslinkable polymer in a gel state by centrifugation. Additionally, the polymer of the present invention has an intrinsic viscosity of 0.01 to 2 du
/gr is preferable.

If the intrinsic viscosity is less than 0.01 dl/gr, the polymer will lack mechanical strength, making it difficult to use in practical terms.

Also, 2d9. If it exceeds /gr, the viscosity becomes high, which may cause problems in shaping properties such as melt molding.

In particular, when used as a molding material, it is strongly preferred that the intrinsic viscosity of this polymer be 0.1-1 d/gr.

In this specification, the intrinsic viscosity of a polymer is determined by the flow time (ts) of a dimethylformamide solution with a sample polymer concentration of 0.5% by weight and the flow rate of dimethylformamide using a Probisch M''/Deereaz-Bischoff viscometer. Time (to) and temperature 25±0.1°C
The relative viscosity of the polymer ηr is determined from the ts/lo value.
el, 1. After that, the value is calculated from the following formula.

η 1nh= (Inη rel)/C (In the formula, C represents the number of grams of polymer per 100 ml of solvent.) [Effects of the invention] The thermoplastic polymer of the present invention Although the heat resistance temperature has been improved by 5 to 10°C compared to the coalescence, and the heat decomposition resistance has been improved,
Its transparency, hot melt fluidity and solubility in various solvents are good. Therefore, the polymer of the present invention can be used as various molding materials, coating materials, resist materials, optical materials, heat-resistant films, m-string materials, and the like. When this polymer is used in combination with a crosslinking agent such as a low molecular weight polyamine, it can be made into a resin composition exhibiting crosslinking and curable properties.

Furthermore, a polymer having a glutarimide ring structure can be obtained by subjecting the thermoplastic polymer of the present invention to a heat reaction with ammonia or a reagent capable of generating ammonia. Note that examples of reagents having ammonia generating ability include R element, substituted urea, formamide, and ammonia aqueous solution. Further, by reacting with a primary amine such as methylamine, ethylamine, or aniline, a polymer having an N-alkyl-substituted geltarimide ring structure can be obtained.

[Examples of the Invention] Hereinafter, the thermoplastic polymer of the present invention will be explained in more detail with reference to Examples.

In these Examples, the following method was used to measure the properties of the polymer.

The infrared absorption spectrum was measured by the KBr disk method using an infrared spectrophotometer (Model 285 manufactured by 11 Ritsu Seisakusho).

Thousands of equal parts -11 (Mn), weight average molecular weight (My) and Z'1 equal molecular weight Wk (Kz) are measured using Toyo Soda Paving Gel Permeation Chromatography) ILc-802UR, and the sample c degree is 0.1. (double star/volume)%, the elution solvent was dimethylformamide, and the flow rate was 1°21 parts.

A monodisperse polystyrene calibration curve was used as the calibration curve.

The heat resistance test was conducted according to ASTM-D-1525 using a Hikanto softening point measuring machine (newly manufactured by Toyo Seiki Co., Ltd.) at a heating rate of 50.
Soil: The temperature was set at 5°C/hr, and the sample piece used was 5X IOX 10cm.

Storage elastic modulus (Eo) and loss elastic modulus (E”) were measured at 110 Hz using a dynamic bone resistance measuring device (manufactured by Toyo Baldwin ■).
Measurement was performed at a heating rate of 2°C/min.

A differential scanning calorimeter (PERKI) is used to measure the glass transition temperature.
N-ELMER DSC-2C type) was used.

Degradability can be measured using thermogravimetric analysis (TGA) (PERKI
N-ELMER TGS-1 type).

A simple method for the solubility test was to visually test the solubility in a specific solvent. At the same time, centrifugation method (Kubota Seisakusho ■%
After centrifugation for 80 minutes at 15,000 rpm using a KH-180 centrifuge, solubility was evaluated based on the presence or absence of gel fraction.

In addition, "r part" described below shall represent a weight part.

50 parts of methyl methacrylate, 1-50 parts of tert-butyl methacrylate, 0.01 part of 2,2'-7 zobisisobutyronitrile and 0.1 part of tert-dodecyl mercaptan were dissolved. It was placed in a glass ampoule, cooled under liquid nitrogen temperature, and then degassed repeatedly and sealed in a nitrogen atmosphere. Next, put this sealed ampoule in a heating bath. After heating at Q'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.

The purified polymer had the following physical properties.

Number average molecular weight (Mn); 8.81 x 104 weight average molecular weight (Mw); 20.8 x 10'Z average molecular weight (Mz); 32. OX 104Mw/Mn
= 2.44, Mz/ Mn = 3.72 intrinsic viscosity;
0.35 parts/gr Further, the results of measuring the infrared absorption spectrum of this polymer are shown in FIG. The absorption power was measured at a wave number of 1720 cm-' based on the stretching vibration of L-ester carbonyl. Next, this polymer was placed in glass V& and subjected to a thermal decomposition reaction at 230° C. for 15 hours in an oil bath under a honey atmosphere. In this reaction, isobutyne was produced as a volatile organic gas, and methanol and water were also produced. After the reaction was completed, volatile components were removed under reduced pressure of 1.0 mmHg for 1 hour, and the foamed white resin body was obtained as f4). Next, this resin body was crushed. This pulverized polymer has the following physical properties of 1/X.

Number average molecular weight (Mn); 8.22 x 104 Weight average molecular weight (niw); 17. B X 10'IZ average molecular weight (Hz); 28 X 104Mw/Mn
= 2.34, Mz/ Mn = 3.51 Intrinsic viscosity
, 9.32 parts/gr Dimethylformamide 10 (weight/volume) of this polymer
When dissolved as a % solution, it was visually determined that it was uniformly dissolved. This solution was centrifuged at 15,000 times/min to confirm the presence or absence of gel components in the V part of the sediment, and it was found that the solution was homogeneous and no gel components were present. Further, this polymer was heated and pressure-molded at 250° C.1150 kg/cm2 to prepare a film having a thickness of 150 parts m, and its dynamic viscoelasticity was measured. The dispersion peak of loss modulus (E”) is 1
It was 46°C.

A 5 mm (thickness) flat plate of IOX IOX was prepared in the same manner and the Hikant softening point was measured, and the value was 151°C.

The glass transition temperature determined using a differential scanning calorimeter was between 123 and 154°C.

Furthermore, the infrared absorption spectrum of the two-legged 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-', the wave number of 1756 c'',
Absorption of acid anhydride carbonyl stretching vibration was confirmed at 1802 cm - 1 due to generation of glugulic acid anhydride group.

Next, this polymer was extruded using a melt indexer (Toyo Seiki Seisakusho Co., Ltd.) at 230° C. under a load of 1 l0 kg, and a good strand-shaped resin body was obtained, showing an MI value of 5.8 gr/10 min.

The molecular weight and molecular weight distribution of the starting material, tert-butyl methacrylate/methyl methacrylate copolymer, and the molecular weight and molecular weight distribution of the polymer of the present invention obtained by heat-treating this raw material polymer were determined by gel permeation. When measured by chromatography (CPC) and compared, it was found that the polymer of the present invention has a lower apparent molecular weight due to deolefination, dehydration, dealcoholization accompanying thermal decomposition, and slight decomposition of polymer buttons at the initial stage of thermal decomposition. A decrease was observed. However, no increase in molecular weight due to intermolecular cross-linking reaction, no expansion of molecular weight distribution, no significant decrease in molecular weight due to J-breakage of the main chain, and no significant change in molecular weight distribution were observed.

This polymer was extruded using a 25φ vent type 4! ! After extrusion molding, pelletization was performed using a machine (manufactured by Daiichi Jitsugyo ■, Goose temperature 230°C, adapter temperature 230°C, screw barrel temperature 200-230'C!, full flight screw L/D = 24). Using this pelletized polymer, a flat plate (80 x 80
×21! III+) was obtained.

For approved resin molded plates, ASTM D-100
When the optical properties were measured according to 3, the total light transmittance was 9.
0%, and the haze value was 4.5.

Table 1 shows the main physical properties obtained.

14 Refreshing: ":jrj1 As shown in Table 1, a raw material polymer was prepared by repeating the same operation as in Example 1 using the intermediate composition, and this was heat-treated to obtain the polymer of the present invention. Obtained. Table 1 shows the results of measuring the physical properties.

[Minkan J 2] 50 parts of methyl methacrylate, 50 parts of tert-butyl methacrylate, 0.01 part of 2,2°-ambisisobutyronitrile, and 0.0 parts of tert-dodecyl mercaptan.
11-iB was dissolved and placed in a glass ampoule to prepare a polymer in the same manner as in Example 1, and the purified Togopolymer was prepared as follows. This polymer was placed in an oil bath in the same manner as in Example 1.
A thermal decomposition reaction was carried out at 230°C for 30 minutes.

The reaction conversion rate of this thermally decomposed product was confirmed to be 30% based on the absorption amount of acid anhydride carbonyl in the infrared absorption spectrum. Further, thermal decomposition treatment was performed, and the physical properties of the resulting polymer were measured at the heat treatment times shown in Table 1. The results are shown in Table 1.

[Breathe] 80 parts of tert-butyl methacrylate, 20 parts of methyl methacrylate, 0.001 part of 2,2'-ambisisobutyronitrile and 0.1 part of tart-dodecyl mercaptan were dissolved and placed in a glass ampoule. ,
After carrying out a thermal decomposition reaction in an oil bath in the same manner as in Example 1, its physical properties were measured. The results are shown in Table 1.

LL Keizuki 100 parts of tert-butyl methacrylate, 0.01 part of 2,2°-azobylisobutyronitrile and tert-butyl methacrylate
- 0.1 part of dodecyl mercaptan was dissolved and placed in a glass ampule, cooled under liquid nitrogen temperature, and then degassed repeatedly and sealed in a nitrogen atmosphere. Next 1. This M in %
The tube ampoule was placed in a heating bath and heated at 70°C for 15 hours, and then 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 dimethylformamide for precipitation, which was repeated several times to purify the polymer. The intrinsic viscosity of this purified polymer was 0.43 db/gr.

The results of measuring the infrared absorption spectrum of this polymer were
It is shown in 1χ.

Absorption based on stretching vibration of ester carbonyl was measured at To Hk 1720 cm-'.

Next, this polymer was placed in a glass tube and subjected to a thermal decomposition reaction at 230° C. for 5 hours in an oil bath under a nitrogen atmosphere.

In this reaction, isobutyne was produced as a volatile organic residue, and the production of thin ice was also confirmed.

1 day after the completion of the reaction 1. Volatile components were removed under reduced pressure of om+aHg to obtain a foamed white resin body.

Next, this resin body was crushed. The intrinsic viscosity of this ground polymer was 0.40 dfl/gr.

Dimethylformamide 10 (weight/volume) of this polymer
When dissolved as a % solution, it was visually determined that it was uniformly dissolved. This solution was centrifuged at 15,000 times/min to confirm the presence or absence of gel components in the precipitate, and it was found to be a homogeneous solution with no gel components present.

Also, this polymer was heated at 250°C1150kg/c++12
A film having a thickness of 150 g11 was prepared by heating and pressure molding, and its dynamic tackiness was measured. The loss modulus (E”) dispersion peak was 158°C.

A flat plate of IOX IOX 5mm (thickness) was made in the same way and the Vicat softening point was measured at 165°C.
showed the value of

Further, the glass transition temperature was measured using a differential scanning calorimeter and was found to be between 155 and +81'c.

Furthermore, A11 of the infrared absorption spectrum of the above molded film
I made a determination. The results are shown in FIG. As can be seen from Figure 4, the wave numbers are 1758c+a-'' and 1802cm
-' Absorption of acid anhydride carbonyl stretching vibration due to generation of nigertal acid anhydride group was confirmed.

In addition, when the thermally decomposed polymer was extruded using a melt indexer (manufactured by Jusho Seiki Seisakusho) under a load of 230°C and 1C11o, a good strand-shaped resin body was obtained with a weight of 3.9g.
The MI value was shown as r/10 min.

Table 1 shows the main physical properties.

In addition, 100 parts of tert-butyl methacrylate, 0.01 part of 2,2°-7 sobisisobutyronitrile and tert-butyl methacrylate were added.
-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 9, and a purified polymer was obtained.

This polymer was prepared in the same manner as in Example 9 in an oil bath.
A thermal decomposition reaction was carried out at 230°C for 30 minutes. The reaction conversion rate of this thermally decomposed product was 40% based on the infrared absorption spectrum of acid anhydride absorption: 11.

Next, thermal decomposition treatment was performed for the heat treatment time shown in Table 1, and the physical properties of the obtained polymer were measured.

The results are shown in Table 1.

100 parts of dimethyl methacrylate, 0.01 part of 2.2'-azihisinbutyronitrile, and 0.1 part of tert-dodecyl mercaptan were dissolved and placed in a glass ampoule, and cooled under liquid nitrogen temperature. After that, degassing was repeated and the tube was made into a 'M' tube under a nitrogen atmosphere.

Next, this Lj tube ampoule was placed in a heating bath and heated to 151+ at 70°C. 7. After heating for a further 120'
Polymerization was completed by heating at C for 3 hours. The reaction conversion rate of monomers in this polymerization was 87%.

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 komama.

Of course average molecule -71 (Mn); 5.71X 104Φ
j, j average molecular weight (?h); 14.3 X 10'
Z average molecular weight (Mz); 20. OX 10 part Mw
/Mn = 2.68, Hz/Mn = 3.50 intrinsic viscosity, 0.30 dm/gr In addition, the infrared absorption spectrum of this polymer showed that there was an absorption based on the stretching vibration of the ester carbonyl at a wave number of 1720co+-'. Measured.

Next, this polymer was placed in a glass tube and subjected to a thermal decomposition reaction at 230° C. for 15 hours in an oil bath under a nitrogen atmosphere. Volatile organic gas was generated in this reaction, but the volatile gas component was methyl methacrylate monomer, which was due to depolymerization of the polymer main chain. After the reaction, the pressure was reduced to 1.0 mmHg for 1 hour. Volatile components were removed below to obtain a transparent resin body.

Next, this resin body was crushed. This pulverized polymer had the following physical properties.

Number average molecule* (Mn); 5.20X +o4 weight average molecular weight (in favor of); 13.5
．． 8, Hz/Mn=3.42 hard 1 viscosity, 0
．． 27 dl/gr Chloroform lO(
When dissolved as a solution (polymerization/volume), it was visually determined that the solution was uniformly dissolved. This solution was centrifuged at 15,000 times/min to confirm the presence or absence of gel components in the precipitate, and it was found that the solution was homogeneous and no gel components were present.

This polymer sample was heated and pressure-molded at 250° C. and 150 kg/cm to form a film with a thickness of +50 μm, and its dynamic viscoelasticity was measured.

The dispersion peak of the loss modulus (E”) was 107°C.A flat plate of IOX IOX 5mm (thickness) was prepared in the same way and the vicanto+1ijH point was measured.9
It showed a value of 8°C. In addition, when the glass transition temperature was measured using a differential scanning calorimeter, the temperature was 78-10
It was between 9°C.

Furthermore, when the infrared absorption spectrum of the above-mentioned formed film was measured, absorption of the stretching vibration of the ester carbonyl was observed at a wave number of 1720 cm '1, but absorption at wavelengths of 1758 cm ' and 1802 cm was similar to that of the polymer before the thermal decomposition reaction.
Absorption of the carbonyl stretching vibration of the amorphous hydrate due to the formation of the glutaric anhydride group at a+-' was not observed. 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, and an MI value of +5 gr/10 min was obtained. Table 1 shows the main physical properties obtained.

[Brief explanation of drawings]

ttS Figures 1 and 2 show the infrared absorption spectra of the polymer obtained in Example 1, and Figures 3 and 4 show the infrared absorption spectra of the polymer obtained in Example 1.
The figure shows the infrared absorption spectrum of the polymer side obtained in Example 1O. Procedures Amendment Written April 5, 1980 Kazuo Wakasugi, Commissioner of the Patent Office1, Indication of the case, Patent Application No. 167519 of 19822, Title of the invention: Thermoplastic polymer3, Name of the person making the amendment Relationship with Patent applicant name (eo3) Mitsubishi Rayon Co., Ltd. 4, Agent 5, Date of amendment order Voluntary 6, Number of inventions increased by amendment None ■, Statement in the claims column of the specification Correct as shown in the attached sheet. II. The description in the Detailed Description of the Invention column of the specification is supplemented as follows. (1) Statement on page 1, line 16, page 2, line 8, page 3, line 13, page 5, line 13, and page 6, line 1 of the specification "Heat decomposition resistance" is corrected to "heat resistance." (2) [However, as stated on page 2, lines 5 to 7]
... had some shortcomings" should be deleted. (3) Claims characterized by "for this purpose" as stated in page 2, line 8 of the same claim: 1.5% by weight or more of tert-butyl acrylate or tert-butyl methacrylate, and copolymerizable with them. Intrinsic viscosity 0.01 to 2 d/
A thermoplastic polymer with excellent gr resistance of 1. 2. Ethylene monomer is acrylic ester or meta>
The thermoplastic polymer according to claim 1, which is a lyric acid ester.

Claims (1)

[Claims] Intrinsic viscosity 0.01 obtained by thermally decomposing a polymer consisting of 1.5% by weight or more of tert-butyl acrylate or tert-butyl methacrylate and 95% by weight or less of an ethylenic monomer copolymerizable with them. ~2d//
A thermoplastic polymer with excellent thermal decomposition resistance. 2. The thermoplastic polymer according to claim 1, wherein the ethylenic monomer is an acrylic ester or a methacrylic ester.