JPH02138321A - Maleimide copolymer and preparation thereof - Google Patents

Abstract

PURPOSE:To prepare a transparent and heat-resistant molding material with excellent chem. resistance, impact resistance, molding processability, etc., by specifying the amt. of residual maleimide in the copolymer, volatile content, the ratio of Mw/Mn in a maleimide copolymer contg. specified copolymer components. CONSTITUTION:In a maleimide copolymer constituted of 28-65wt.% maleimide monomer unit (A), 16-72wt.% monomer unit (B) selected from arom. vinyl and methacrylate monomers and 0-25wt.% other monomer unit (C) (the sum of A to C is 100wt.%), a residual maleimide monomer content in the copolymer is 0.1wt.% or less; other total volatile content is 0.5wt.% or less; a ratio of wt.-average MW (Mw) to number-average MW (Mn) of the copolymer is 3 or smaller; the yellow index is 30 or smaller; and the intrinsic viscosity is 0.3-1.5. This copolymer is prepd. by feeding continuously a specified amt. of each mono mer in a thoroughly mixing polymn. vessel so as to obtain a wt. ratio of the monomer to an org. solvent in the range of 3:2-9:1.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a novel maleimide copolymer and a copolymer having excellent heat resistance, transparency, chemical resistance, impact resistance, moldability, etc. The present invention relates to a manufacturing method thereof.

[Conventional technology]

Recently, the uses of transparent molding materials are expanding.

Examples include optical information recording carriers such as video discs and audio discs, lenses for cameras and optical pickups, and head mounts for automobiles. For these uses, there is an increasing demand for materials with high heat resistance and ITitTi properties.

Until now, polycarbonate resin has mainly been used as a transparent heat-resistant molding material. Polycarbonate resin is a transparent resin with excellent heat resistance and impact resistance. However, there are some drawbacks to the applications mentioned above.

First, it is relatively expensive and has poor chemical resistance, moldability, etc. These drawbacks limit its use.

In addition, various proposals have been made regarding maleimide monomers, other vinyl monomers, and Q copolymers as resins with excellent heat resistance (JP-A-58-162616, JP-A-61-
276807, JP-A-60-79019, etc.). However, these proposed maleimide copolymers are not satisfactory for the above uses.

In particular, there are hardly any documents that feature improvement in coloration (reduction in yellowness), which is essential for transparent molding materials. Emulsion polymerization and suspension polymerization are often used in polymerization using maleimide half-mers, but these methods are not suitable because they cause coloring due to emulsifiers and other auxiliary agents. Furthermore, in bulk polymerization or solution polymerization, if the polymerization is carried out carelessly, only a colored copolymer with poor transparency and a wide molecular weight distribution can be obtained.

[Problem to be solved by the invention]

Since the maleimide copolymer targeted by the present invention needs to have heat resistance comparable to that of polycarbonate resin, a certain amount or more of the maleimide monomer is required, but if it is too large, the resulting copolymer will have impact resistance. The properties and fluidity will be poor.

The charging composition, including other vinyl monomers, must be within a specific range.

Bulk polymerization or solution polymerization is preferable to achieve good transparency and other properties, but maleimide monomers have a very fast polymerization rate (and are easy to homopolymerize).
If the molecular weight distribution and composition distribution are wide, properties such as impact resistance are likely to be inferior. Furthermore, if unreacted maleimide monomers are present in the copolymer, the copolymer will have poor transparency and significant coloring. Therefore, sufficient consideration must be given to the polymerization method and the subsequent devolatilization of unreacted monomers and organic solvents.

As a result of intensive study of these problems, the present inventors found that when polymerizing a maleimide copolymer, a specific monomer mixing ratio and a specific organic solvent should be used in a specific method. The present invention was achieved by discovering that the desired maleimide copolymer can be obtained by performing continuous polymerization and devolatilizing unreacted monomers and organic solvents in a devolatilization device.

[Means to solve the problem]

That is, the gist of the present invention is that the maleimide monomer unit (a) is selected from the group consisting of more than 28 weight units and 65 weight units or less, aromatic vinyl yarn monomers and methacrylic acid ester monomers. at least one monomer unit (b)
A maleimide system consisting of 16 weight class to less than 72 weight class and other vinyl monomer units (c) 0 to 25 weight 4 (however, the total amount of unit components (a) to (c) is 100 weight 4) A copolymer, wherein: (1) the content of residual maleimide monomer in the copolymer is 0.1 wt'1fc4 or less, and the total volatile content other than the maleimide monomer is 0.5 Heavy! 1% or less, (2) the ratio of weight average molecular weight Mw to number average molecular weight Mn in the copolymer is Mw/Mn of 3 or less; (3)
A first maleimide copolymer characterized in that the copolymer has a yellow index of 30 or less, and (4) an intrinsic viscosity of 03 to 1.5.
and maleimide monomer unit (a) exceeding 28 weight units and 65 weight units or less, at least one monomer selected from the group consisting of aromatic vinyl monomers and methacrylic acid ester monomers. (b) 16 to 72 weight units and other vinyl monomer units (c) 0 to 25 weight units! 4 (however, the total amount of unit components (a) to (c) is 100% by weight 4), maleimide monomer, aromatic vinyl monomer, and methacrylic acid. At least one monomer selected from the group consisting of ester monomers and optionally other vinyl yarn monomers, an organic solvent, and optionally a polymerization initiator, in a weight ratio of the monomer to the organic solvent. The copolymerization reaction is continued by continuously supplying dropwise to the complete mixing polymerization reactor so that the ratio is in the range of 5:2 to 9:1, and the polymerization conversion rate of all the monomers charged in the reaction system is 30. The polymerization reactants containing unreacted monomers and organic solvents are completely removed so that the monomer composition and concentration of the polymerization reactants and, if desired, the concentration of the polymerization initiator are kept constant within the range of ~70% ff4. Continuous polymerization under steady state is continued by continuously taking out the mixed polymerization reactor, and then at least unreacted maleimide monomer is polymerized in a second polymerization reactor provided as required. After that, the resulting polymerization reaction product is transferred to a devolatilization device, and unreacted monomers and organic solvents are devolatilized under reduced pressure conditions to remove residual maleimide in the resulting maleimide-based copolymer. The content of monomers is 0.1% by weight or less, and the total volatile content other than maleimide monomers is 0.54% or less,
The ratio of weight average molecular weight Mw to number average molecular weight Mn is Mw
/'Mn is 6 or less and yellow index is 30
The second invention is a method for producing a maleimide copolymer having the following properties and an intrinsic viscosity of 0.3 to 1.5.

The maleimide monomer (a) in the present invention is represented by the following formula (1
), HC=CH (wherein, R represents hydrogen, an alkyl/L' group having 1 to 4 carbon atoms, a cyclohexy μ group, an aryl group, or a substituted ary-μ group). Maleimide, N-methylmaleimide, N-ethylmaleimide, N-proylmaleimide, N-isopropylmaleimide, N-cyclohexVμmaleimide, N-phenylmaleimide, N-triVimaleimide, N-xylyμmaleimide, N- Naphthylmaleimide, N-t
-butylmaleimide, N-orthochlorophenylmaleimide, N-orthomethoxyphenylmaleimide, and the like. Among these, N-cyclohexVfi/MaVimide, N-phenylmaleimide, N-orthochlorophenylmaleimide, and N-orthomethoxyphenylmaleimide are preferred, and especially KN-cyclohexV/L/maleimide and N-phenymumaleimide are preferred. This is preferable. These maleimide monomers can be used alone or in combination of two or more.

The content of the maleimide monomer unit (a) in the maleimide copolymer of the present invention is in the range of more than 28% by weight and 65% by weight or less, preferably in the range of more than 28% by weight and not more than 55% by weight. It is necessary. If the content is less than 28% by weight, the heat resistance of the maleimide copolymer will be low and will be inferior to that of polycarbonate resin, which is not preferable. Further, if the content exceeds 65% by weight, the maleimide copolymer will have poor impact resistance and fluidity, which is not preferable.

Aromatic vinyl monomers (1+1) in the present invention include styrene, a-methylstyrene, paramethylstyrene, t-butyp-styrene, black μ-styrene, vinyltoluene, etc. Methylstyrene is preferred.

Furthermore, the methacrylic acid ester monomer (
bl is methi methacrylate, methi methacrylate μ
, propyl methacrylate, butyμ methacrylate, feniμ methacrylate, isopolyte methacrylate, benziμ methacrylate, trifluoroethyl methacrylate μ, etc., with methiμ methacrylate being preferred.

In the present invention, at least one monomer selected from the group consisting of the above-mentioned aromatic vinyl monomers and methacrylic acid ester monomers is used as component +b), and in the maleimide copolymer of the present invention, The content of such aromatic vinyl monomers and methacrylic acid ester monomers (the content of one type of monomer unit (b) is in the range of 16 to 72 weight units, preferably 29 weight units) It is necessary that the content is in the range of 72% by weight or more and less than 72% by weight.If the content is less than 16% by weight, the molding processability of the maleimide copolymer will be low.If the content is 72% by weight or more, the maleimide copolymer will have poor moldability. This is not preferable because the content of mer units decreases and the resulting maleimide copolymer has low heat resistance.

Furthermore, other vinyl monomers (0) used as optional components in the present invention include vinyl cyanide monomers,
Examples include acrylic acid ester monomers, unsaturated dicarboxylic acid anhydrides, and vinyl acid monomers. Examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile, and fumaronitrile, with acrylonitrile being preferred. In addition, examples of acrylic ester monomers include methyl acrylate, ethyl acrylate, propy acrylate μ, buty acrylate μ, and acrylic μ
Examples include acid cyclohexyμ. Furthermore, examples of the unsaturated dicarboxylic anhydride include anhydrides such as maleic acid, methaconic acid, and citraconic acid, with maleic acid anhydride being preferred. Furthermore, examples of vinyl carboxylic acid monomers include acrylic acid and methacrylic acid. Acrylonitrile μ, maleic anhydride and methacrylic acid are preferably used. These other vinyl monomers (C)
can be used alone or in combination of two or more types, but it is not necessary to use them.

The content of units (C) based on other vinyl monomers in the maleimide copolymer of the present invention is in the range of 0 to 25 weight range, preferably 0 to 19 weight range, more preferably 0.
~16 weight range. If the content exceeds 25% by weight, the properties of the resulting maleimide copolymer will be undesirable and will deviate from the purpose of the present invention.

The maleimide copolymer of the present invention comprises at least one maleimide monomer unit (a), an aromatic vinyl monomer, and a methacrylic acid ester monomer.
Species monomer units (bl and other vinyl monomer units (c)
) is adjusted so that the total content of (a) unit component ( 1)) The composition ratio (weight 4) of the unit component and (c) unit component is (a)/(b) shown in the triangular coordinates in Figure 1.
) / (c) = 28 / 64 / 8 at point cA
), (a) / ('b) / (c) =65 /
16/19 of the fish), (a) / (b) /
(c) = 2 a/7210 points (01 and (a
) / (b) / (c) = 65/3510 points (A), (B), (cl and ω)
The range surrounded by a quadrilateral with vertices is (a) / (b) / (cl = 3) shown in the triangular coordinates in Figure 1.
A point that is 0/69/9 (80, (a) / (b) /
(c) Point where =55/29/16 (B points, ra)
/ (b) / (cl = 30/7 points (C and (a) / fb) / (c) = 55/4
510 points (D four points (A, (B).

A range surrounded by a quadrilateral with (C and (D) as vertices is particularly preferable because the maleimide copolymer can have excellent heat resistance, transparency, fluidity, etc.).

Furthermore, the maleimide copolymer of the present invention has a content of residual maleimide monomers in the copolymer of Q, which is less than 1% by weight, preferably less than 105% by weight, and contains no residual maleimide monomers other than maleimide monomers. The total volatile content should be less than 0.5 parts by weight, preferably less than 0.4 parts by weight. If the content of the residual maleimide monomer exceeds the α1 weight range, the coloring of the copolymer is often markedly inferior in transparency, and disadvantages such as poor weather resistance and easy thermal coloring occur, which is not preferable. . Furthermore, it is also undesirable that bleed-out occurs during molding using the copolymer, making it impossible to obtain a good molded product.

In addition, the total volatile matter other than the maleimide monomer includes the constituent monomers and organic solvents, and the amount thereof is 15
If the maleimide copolymer is present in an amount exceeding the weight ratio, the heat resistance of the maleimide copolymer will be poor, and when the copolymer is molded at high temperatures, silper streaks will occur, making it difficult to obtain a good molded product. (I don't like it.

Furthermore, the weight average molecular weight M of the maleimide copolymer of the present invention
The ratio of w to number average molecular weight Mn Mw/'li! n is 3 or less, preferably 2.8 or less, more preferably 2.
It must be 5 or less. Mw/'Mn.

The ratio is widely used as a measure of the spread of molecular weight distribution υ, but if this value is larger than 3, the impact resistance and transparency of the maleimide copolymer will be poor, so it is preferable. do not have. Weight average molecular weight Mw in the present invention
and the number average molecule JIMn can be determined by converting the elution curve determined by gel permeation chromatography (GPO) to standard polystyrene.

Furthermore, the yellow index (yellowness, Y-factor) of the maleimide copolymer of the present invention is 30 or less, preferably 2.
It must be 5 or less. This yellow index refers to the value measured as a value of a molded plate molded using the maleimide copolymer obtained, and it indicates the amount of residual maleimide monomer in the maleimide copolymer and other values. When a vinyl cyanide monomer is used as the vinyl monomer, there is a close relationship with the amount of residual monomer. If the yellow index exceeds 60, the maleimide copolymer has a wide composition distribution and contains structural factors that tend to cause thermal coloring during molding, resulting in poor transparency and impact resistance, which is not preferred.

Furthermore, the intrinsic viscosity of the maleimide copolymer of the present invention is α3
-1.5, preferably 0.5-1.2. The intrinsic viscosity of the maleimide copolymer is N,
This is the value obtained by dissolving in N-dimethymu-formamide and using an Ubbelohde viscometer at 25°C. [Maleimide copolymers with an intrinsic viscosity of less than 1L3 have low impact resistance, and
Although a maleimide copolymer having an intrinsic viscosity of more than 5 has high impact resistance, it is difficult to mold due to poor fluidity and is not practical.

The maleimide copolymer of the present invention must satisfy all of the above-mentioned conditions for residual maleimide monomer content, total volatile content other than maleimide monomer, Mw/Mn ratio, yellow index, and intrinsic viscosity. is necessary.

The method for producing the maleimide copolymer of the present invention is basically bulk polymerization, but it requires the addition of an organic solvent into the reaction system. That is, first, at least one monomer selected from the group consisting of maleimide monomers, aromatic vinyl monomers, and methacrylic acid ester monomers, and optionally other vinyl monomers, and an organic solvent. and, if desired, a multiple polymerization initiator, at a weight ratio of monomer to organic solvent of 3.
It is necessary to continue the copolymerization reaction by continuously dropping the mixture into the complete mixing polymerization reactor so that the ratio is in the range of :2 to 9:1, preferably 3:2 to 8:2. If the amount of organic solvent is smaller than the amount of monomer within this weight ratio range of monomer and organic solvent, the viscosity of the reaction system increases during polymerization, making it difficult to stir the reaction. This is not preferred because it also becomes difficult to remove the polymerization reaction product from the system. In addition, when the viscosity increases, heat transfer becomes poor, causing temperature non-uniformity within the reaction system and widening the molecular weight distribution and composition distribution. On the other hand, in a region where the amount of organic solvent is greater than the amount of monomer, the polymerization rate becomes slow, and furthermore, it becomes difficult to remove the organic solvent in the devolatilization step, resulting in poor productivity, which is not preferable.

In carrying out the present invention, the aforementioned maleimide monomers, aromatic vinyl monomers, methacrylic acid ester monomers, and other vinyl monomers can be used.

Since these monomers have different polymerization activities, when it is desired to obtain a copolymer having the above composition, the composition of the charged monomer mixture is appropriately selected depending on their polymerization activities. The preferred composition of the monomer mixture to be charged is 7 to 5 maleimide monomers.
0 parts by weight, 40 to 90 parts by weight of aromatic vinyl monomers and methacrylic acid ester monomers, and 0 to 30 parts by weight of other vinyl monomers added as desired (however, ra) to (
c) Total monomer [100 parts by weight].

Furthermore, the organic solvent that can be used in carrying out the present invention is one that does not polymerize itself, does not interfere with the polymerization of the above monomer, and is capable of dissolving the maleimide copolymer of the present invention. It is necessary.

Specific examples of such organic solvents include methyl ethyl ketone,
Examples include diethyl ketone, methyl isobutyl ketone, acetophenone, benzene, toluene, ethylbenzene, xylene, tetrahydrofuran, N,N-dimethyl μformamide, and the like.

Furthermore, a polymerization initiator can be added if desired during polymerization in the practice of the present invention. As the polymerization initiator, generally known organic peroxides and azo compounds can be used. Examples of organic peroxides used include ketone peroxides, peroxyketas/I/s, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxy esters, peroxydicarbonates, etc. It is preferable that the 10-hour half-life temperature is in the range of 80 to 140°C. Specific examples of organic peroxides include methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, methyl cyclohexanone peroxide, acetylacetone peroxide, 1,1-dibutylperoxy-&&5-)
Rimethymu cyclohexane, 1゜1-dibutylveroxine chlorohexane, 2.2-di-t-butylperoxybutane, 2.2.4-trimethylbenchi Jv-2-hydroperoxide, dicumyl peroxide, 2 .5-
Dimethyl m2.5-di(t-butylperoxy)hexane, t-butylcumyl peroxide, di-t-butyl peroxide, triX-(t-butylperoxy)
Triazine, di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxyazelate, t-butylperoxyacetate, t-butylperoxybenzoate, t-butylperoxylaurate,
Examples include t-butyperoxyisopropyl carbonate. In addition, as a specific example of the azide compound, 1.1'
-Azobis(cyclohexane-1-carponitri lv)
, 2-phenylazo-4-methoxy-2,4-dime thousand μ
Paleronitrium, 2,2'-azobis(2,4,4-trimethylpentane) is mentioned.

As described above, the method for producing the maleimide copolymer of the present invention involves continuing the copolymerization reaction with the weight ratio of the monomer and organic solvent within a specific range, and then continuously removing the polymerization reaction product from the reaction system. It is important to carry out so-called continuous polymerization, in which the monomer and organic solvent are continuously supplied to the reaction system. This makes it possible to produce a maleimide copolymer with a narrow composition distribution and molecular weight distribution.

That is, as mentioned above, the weight ratio of monomer and organic solvent is 5:2.
The copolymerization reaction was continued by continuously supplying dropwise to the complete mixing polymerization reactor so that the ratio was in the range of ~9:1, and the polymerization conversion rate of all the monomers charged in the reaction system was 30 to 70. The polymerization reactant containing unreacted monomers and organic solvent is mixed in a completely mixed polymerization reactor so as to keep the monomer composition and concentration of the polymerization reactant constant within a certain range, as well as the concentration of the polymerization initiator if desired. It is important to continue the continuous polymerization under steady state conditions by continuous withdrawal. If the polymerization conversion rate is less than 3, it is not preferable because it becomes difficult to remove unreacted monomers in a devolatilization device, which will be described later. Furthermore, even when the polymerization conversion rate is increased in a second polymerization reactor provided as desired, which will be described later, the molecular weight distribution and composition distribution will widen, resulting in poor impact resistance, transparency, etc., which is not preferable. On the other hand, if the polymerization is carried out to a state where the polymerization conversion rate exceeds 704, the viscosity of the reaction system increases, making it difficult to stir and to take out the polymerized reaction product. Furthermore, the molecular weight distribution and composition distribution are broadened, resulting in poor impact resistance and transparency, which is undesirable.

In the present invention, the polymerization reaction product taken out after such an operation is polymerized at least the unreacted maleimide monomer in a second polymerization reactor provided as desired, and then the resulting polymerization reaction product is devolatilized. It is necessary to transfer the monomer to a device and devolatilize unreacted monomers and organic solvents under reduced pressure conditions.

The polymerization conversion rate can be further increased in the second polymerization reactor. However, it is not preferable to increase the degree of polymerization in a main polymerization reactor in which monomers are not continuously supplied. However, before reaching the subsequent devolatilization step, the unreacted maleimide monomer in the polymerization reaction product must be polymerized. If devolatilization is performed in the presence of unreacted maleimide monomers, the resulting maleimide copolymer will be markedly colored, which is not preferred.

As the devolatilizing device, a multi-vent type devolatilizing extruder, a Fuotsunyu type devolatilizing device, a thin film type devolatilizing device, etc. are preferably used. Furthermore, a device in which a plurality of these devices are combined can also be used.

In the present invention, by going through the various processes described above, the content of residual maleimide monomer in the maleimide copolymer obtained is α1 weight or less, and the total volatile content other than the maleimide monomer is is less than 0.5 times,
Weight average molecular weight Mw and number average molecular weight MnO ratio MW/M
n is 3 or less, yellow index is 30 or less, and intrinsic viscosity is 0.3 to 1.5.

The maleimide copolymer according to the present invention can be used in the same manner as ordinary thermoplastic resins for injection molding and extrusion molding. Also, since it has better chemical properties than polycarbonate resin, it can also be used for painting. Furthermore, it is suitable for surface treatments such as plating, vapor deposition, and sputtering, so it can be used in a wider range of applications than conventional transparent heat-resistant materials.

〔Example〕

The present invention will be specifically explained below using Examples.

In addition, "part" in the following description means "part by weight." Further, various measurement methods were performed according to the following methods.

The amount of polymer in the polymerization reaction solution is determined by measuring the amount of polymerization reaction product.
It was calculated from the weight of the polymer obtained by diluting it with ketone and reprecipitating it with methanol-ρ. Using this reprecipitated polymer, composition analysis, intrinsic viscosity, GPO measurement, etc. were performed.

The amounts of unreacted monomers and residual monomers after devolatilization in the polymerization reaction solution were measured by gas chromatography.

The composition of each monomer unit of the polymer was calculated from the absorption of each characteristic group in infrared absorption spectrum μ measurement.

The intrinsic viscosity [η] of the polymer was determined by dissolving the polymer in N,N-dimethyl μformamide and using an Ubbelohde viscometer at 25°C.

Weight average molecular weight (Mw) and number average molecular weight (Mn
The ratio Mw/Mn of ) was calculated from the GPC elution curve using the ratio of Mw and Mn calculated based on a standard polystyrene polymer.

Met Flow Index (M Engineering) HajlTMD-12
38 to 230℃, load 10+? It was calculated as the discharge amount (2) for 10 minutes below.

In addition, the polymer was molded into a 1 oz injection molding machine at a cylinder temperature of 2.
Izod impact strength, Rockwell hardness, Vicat softening temperature, Yellow Index total light transmittance, and haze value were measured using the test pieces molded at 60°C by the following methods.

Izot impact strength: ASTM D-256 (V4'
(with notch) Rockwell hardness: ASTM D-78
5 (Unit: y scale/I/) Vicat softening temperature Nimu S
TM D-1525 (skg load) Yellow index (Y work): A day '1' MD-1925 (measured with a 5-thick molded plate) Total light transmittance: ASTM n-tons (l
) Haze value: Mu8TM D-1003 Examples 1 to 5 A maleimide copolymer was produced using the production apparatus shown in FIG.

First, air inside the first polymerization reactor (completely mixed polymerization reactor) 1 was removed using a vacuum pump, and then nitrogen gas was introduced into the reactor to create a nitrogen atmosphere.

This operation was repeated one more time to completely create a nitrogen atmosphere in the vessel, and then a polymerization experiment was carried out.

That is, various mixed liquids A and mixed liquid B in the proportions shown in Table 1 are continuously supplied dropwise from separate pipes to the first polymerization reactor 1, and copolymerized under the conditions of the polymerization temperature and residence time shown in Table 1. When the reaction is carried out and the polymerization conversion rate of the monomers supplied reaches the value shown in Table 1, an amount equal to the total amount of monomers supplied is continuously extracted from the bottom of the reactor using gear pump 2, and continuous operation is continued. I did it. The polymerization reaction liquid exiting the first polymerization reactor 1 was transferred by a gear pump 2 to a second polymerization reactor 3 of an extrusion flow type. Polymerization was further carried out in the second polymerization reactor 3 within the operating temperature range shown in Table 2 to greatly reduce the amount of residual maleimide monomer. Thereafter, the polymerization reaction product was supplied from the second polymerization reactor 3 to a devolatilizing extruder 5 through a gear bonder 4. Table 2 shows the composition of the polymerization reaction liquid at the outlet of the first polymerization reactor. The devolatilizing extruder 5 at this time is a two-vent type (v8. and Vρ twin-screw extruder in Figure 2).After removing residual monomers, organic solvents, etc. in the devolatilizing extruder 5, BeV
A transparent pellet was obtained by pelletizing using a dizer 6. Table 3 shows the operating conditions of the devolatilizing extruder 5 and the contents of residue and monomer units in the various maleimide copolymers obtained. Further, Table 4 shows various physical property values of the various maleimide copolymers obtained.

Comparative Example 1 A maleimide copolymer was produced using the same polymerization recipe and polymerization conditions as in Example 1, except that the pare μ temperature in the devolatilizing extruder 5 and the degree of vacuum in the vent section (V) were as shown in Table 3. A polymer was obtained.

The total volatile content in this maleimide copolymer showed a high value of 1.02 weight range. Table 1 shows various manufacturing conditions and physical property values.
- Shown in Table 4.

Comparative Example 2 (Production of maleimide copolymer by emulsion polymerization method) A 5 t glass reactor equipped with a stirrer was charged with the following composition.

Pure water 200
Sodium dodecylbenzene μphonate 2
Part Rongarite α5 part Ferrous sulfate (1005 parts Disodium ethylenediaminetetraacetate 101 parts The temperature of the charge was raised to 60°C, and a mixed solution having the following composition was continuously added dropwise over 3 hours while maintaining the internal temperature at 60°C. After the dropwise addition was completed, the temperature was maintained at 60° C. for 1 hour and then cooled.

Acrylonitrile lv 15 parts styrene
55 parts N-phenymaleimide 30 parts cumene hydroperoxide
α5 parts The obtained maleimide copolymer latex was coagulated with magnesium sulfate, dehydrated, and dried to obtain a white powder maleimide copolymer. The results of measuring various physical property values are shown in Tables 5 to 4.

Comparative Example 3 Without using the second polymerization reactor 3, the polymerization reactant was directly supplied from the outlet of the first polymerization reactor to the devolatilizing extruder 5 via the gear pump 2, and the pent gas in the devolatilizing extruder 5 was A maleimide copolymer was obtained using the same polymerization recipe and polymerization conditions as in Example 1, except that the degree of vacuum in part (V) was as shown in Table 3.

Various manufacturing conditions and physical property values are shown in Tables 1 to 4.

A maleimide copolymer having a large amount of residual maleimide monomer and a large total volatile content was obtained, and its heat resistance was lower than that of the maleimide copolymer obtained in Example 1. Further, during molding, a large amount of V/L/burst leak occurred than the molding percentage.

Comparative Example 4 A maleimide copolymer was produced using the same polymerization recipe and polymerization conditions as in Example 1, except that 13 parts of Tajaryde decime-captan was added to mixture A as a chain transfer agent. Obtained. Various manufacturing conditions and physical property values are shown in Tables 1 to 4.

In particular, the intrinsic viscosity value was low, and the Izot impact strength value was low.

Comparative Example 5 As shown in Table 1, a maleimide copolymer was produced using the same polymerization recipe and polymerization conditions as in Example 1, except that the ratio of methi μ ethi μ ketone was higher than in Example 1. I got it. Various manufacturing conditions and physical property values are shown in Tables 1 to 4. In the devolatilization step, methyμethyμketone was not completely removed, resulting in low heat resistance.

Comparative Example 6 As shown in Table 1, a polymerization reaction was carried out under the same polymerization recipe and polymerization conditions as in Example 1, except that the ratio of methi-p-ethy-μ-ketone was lower than in Example 1. However,
As the polymerization progressed, the viscosity in the reactor increased and stirring became impossible, so the polymerization was stopped.

Comparative Example 7 As shown in Table 1, a polymerization reaction was carried out using the same recipe as in Example 1 under conditions where the amount of N-phenylmaleimide charged was small to obtain a maleimide copolymer. Various manufacturing conditions and physical property values are shown in Tables 1 to 4.

〔Effect of the invention〕

The maleimide copolymer of the present invention has the above-mentioned composition and physical properties, and has excellent heat resistance, transparency, chemical resistance, impact resistance, moldability, etc. By employing the above-mentioned special bulk polymerization method, the method for producing maleimide-based copolymers can produce maleimide-based copolymers having various excellent properties and exhibits excellent effects.

[Brief explanation of the drawing]

Figure 1 shows the triangular coordinates of the preferred composition range of the maleimide copolymer according to the present invention, and Figure 2 shows an example of the production equipment used to carry out the present invention. (completely mixed polymerization reactor), 2 and 4 are gear pumps, 5 is the second
A polymerization reactor, 5 a devolatilizing extruder, and 6 a V-tizer. Patent applicant Mitsubishi Rayon Co., Ltd./(C)

Claims (1)

[Claims] 1. Maleimide monomer unit (a) exceeding 28% by weight6
5% by weight or less, at least one selected from the group consisting of aromatic vinyl monomers and methacrylic acid ester monomers
Seed monomer unit (b) 16% to less than 72% by weight and other vinyl monomer unit (c) 0 to 25% by weight (however, the total amount of unit components (a) to (c) is 100% by weight) %), wherein (1) the content of residual maleimide monomers in the copolymer is 0.1% by weight or less, and the content of residual maleimide monomers other than maleimide monomers is the total volatile content is 0.5% by weight or less, (2) the ratio Mw/Mn of the weight average molecular weight Mw to the number average molecular weight Mn of the copolymer is 3 or less, and (3) the copolymer has a yellow color. A maleimide copolymer having an index of 30 or less and (4) an intrinsic viscosity of 0.3 to 1.5. 2. Maleimide monomer unit (a) exceeding 28% by weight6
5% by weight or less, at least one selected from the group consisting of aromatic vinyl monomers and methacrylic acid ester monomers
Seed monomer unit (b) 16% to less than 72% by weight and other vinyl monomer unit (c) 0 to 25% by weight (however, the total amount of unit components (a) to (c) is 100% by weight) %), at least one monomer selected from the group consisting of maleimide monomers, aromatic vinyl monomers, and methacrylic acid ester monomers. and, if desired, other vinyl monomers, an organic solvent, and, if desired, a polymerization initiator, in a complete mixing polymerization reaction such that the weight ratio of the monomers to the organic solvent is in the range of 3:2 to 9:1. The copolymerization reaction is continued by continuously supplying the monomers dropwise into the reactor, and the monomer composition and polymerization reaction product are kept constant so that the polymerization conversion rate of the total monomers in the reaction system is in the range of 30 to 70% by weight. Continuous polymerization under steady state conditions is achieved by continuously taking out the polymerization reactant containing unreacted monomers and organic solvent from the complete mixing polymerization reactor so as to keep the concentration of polymerization initiator and, if desired, the concentration of polymerization initiator constant. After that, at least unreacted maleimide monomers are polymerized in a second polymerization reactor provided as required, and the resulting polymerization reaction product is transferred to a devolatilization device to remove unreacted monomers. The residual maleimide monomer content in the resulting maleimide copolymer is 0.1% by weight or less, and the maleimide monomer is devolatilized under reduced pressure conditions. The total volatile content other than polymers is 0.5% by weight or less, and the weight average molecular weight Mw
and the number average molecular weight Mn, the ratio Mw/Mn is 3 or less, and the yellow index is 3.
0 or less and has an intrinsic viscosity of 0.3 to 1.5.