JP3078652B2 - Maleimide copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention, molding materials, relates to a glass high transition temperatures maleimide copolymer properties is effective as such a material for improving the blended into a thermoplastic resin such as heat resistance .

[0002]

2. Description of the Related Art A maleimide copolymer is known to be a thermoplastic resin having a high heat deformation temperature and a high thermal decomposition temperature. Generally, the heat resistance and the heat resistance of products using other thermoplastic resins are known. It is used to improve impact properties and moldability. The maleimide-based copolymer is usually produced by copolymerizing a maleimide-based monomer with another monomer copolymerizable therewith.

[0003] The properties of the maleimide-based copolymer depend on the ratio of the maleimide-based monomer units in the structure. If the ratio is low, the heat resistance is low, so that sufficient heat resistance may not be imparted to the resin composition. If the ratio is too high, the molding processability may deteriorate and the impact resistance may decrease. Copolymers having a relatively small proportion of maleimide-based monomer units are generally synthesized by an emulsion polymerization method or a suspension polymerization method. According to the emulsion polymerization method, since the maleimide-based copolymer having a high ratio of the maleimide-based monomer unit is hard to soften and is very difficult to recover from the emulsion, the ratio of the maleimide-based monomer unit is low. Copolymers have been produced. A copolymer obtained by such an emulsion polymerization method is not preferred because it has poor impact resistance due to the influence of a residual emulsifier and the like and is significantly colored during molding. In the suspension polymerization method, an aromatic vinyl monomer and a maleimide monomer are easily copolymerized alternately, and if a copolymer having a high ratio of the maleimide monomer unit is to be obtained, an inhomogeneous copolymerization may occur. Coalescence is easy to form. In the solution polymerization method and the bulk polymerization method, a copolymer in which the unreacted maleimide-based monomer is reduced by an aging reaction, or a composition distribution in each molecular weight category is narrow by a specific polymerization method, and the amount of unreacted maleimide-based monomer is small. Various studies have been made in order to obtain coalescence.

A maleimide copolymer is obtained in a solution state in solution polymerization or bulk polymerization, and in a dispersion state in emulsion polymerization or suspension polymerization. From these conditions, the solvent, unreacted monomer,
It is necessary to obtain a maleimide-based copolymer by separating volatile components such as volatile by-products or impurities. This is because if volatile components such as a solvent and unreacted monomer remain in the maleimide-based copolymer, deterioration of physical properties such as heat resistance and poor appearance of a molded product (silver streak) occur. This is because the physical properties of the product are significantly reduced.

For this reason, in the emulsion polymerization method and the suspension polymerization method,
A method of separating a polymer by coagulation, filtration, steam stripping, or the like has been adopted (Japanese Patent Application Laid-Open No. 62-1).
12612, 62-138510). On the other hand, in solution polymerization or bulk polymerization, the reaction solution after polymerization is placed in another solvent in which the solvent and unreacted monomer are dissolved but the maleimide-based copolymer to be recovered is not dissolved, and the unreacted monomer is removed. Or solvent by extraction (JP-A-58-162616).
After evaporating unreacted monomers and solvents using a flash evaporator, the polymer is extracted in a molten state (JP-A-61-276807, JP-A-3-205411).
JP-A No. 62-129334), and the like.

A method is known in which the reaction mixture after the polymerization is directly or directly heated or dried and then supplied to a vent-type extruder to pelletize the polymer while devolatilizing (Japanese Patent Laid-Open No. 59-1984). -126411, 59-580
06, 57-135814, 50-40688, 57-
49603, 50-40687, 63-147501 and JP-A-3-49925). Such a method is also used as a method for obtaining a maleimide-based copolymer (JP-A-2-51514, JP-A-63-1988).
-89806).

[0007]

The glass transition temperature is 17
Maleimide copolymers exceeding 0 ° C. generally have a high thermal decomposition temperature and excellent thermal stability, but have a remarkably high melt viscosity, so that at a higher temperature than general-purpose plastics such as polystyrene and polymethyl methacrylate. Need to be handled. In particular, in order to melt and transfer the polymer, it is necessary to lower the viscosity by heating the polymer to 300 ° C. or higher. Even if a polymer is excellent in thermal stability, it will be colored and thermally degraded if handled at a high temperature such that the viscosity becomes low.

In the conventional drying method using a flash evaporator, after the flash, the thermoplastic polymer is heated and melted and discharged by a gear pump or the like. Can not. In the method of extracting and removing with a solvent, the steps of washing, filtering and drying the thermoplastic polymer after the extraction are required, and the steps are complicated because a distillation separation step for recovering a large amount of the solvent is required. Become. In the method of supplying a reaction mixture with a large amount of volatile components directly to a vent type extruder, the thermoplastic polymer is strongly foamed due to gasification of the volatile components in the vent type extruder, and the vent is blocked by the foamed polymer. Troubles, making it difficult to operate continuously for a long time, or requiring large equipment due to the large amount of volatile components, or an extruder to remove a large amount of volatile components. The residence time in the polymer becomes longer and the polymer is altered or colored.

In other methods for removing volatile components, it takes a long time to raise the temperature of the polymer, the non-volatile component after removing the volatile components is transported as a high-viscosity fluid, The residence time causes the deterioration of the polymer and the generation of side reaction products. The present invention can efficiently remove volatile components from a maleimide-based copolymer composition containing a volatile component, such as a polymerization reaction solution, and
By not heating the maleimide-based copolymer with a high melt viscosity more than necessary, without causing physical property deterioration,
Residual volatiles content less maleimide copolymer
It is an object of the present invention to provide Hisage.

[0010]

Means for Solving the Problems The inventors of the present invention have studied various methods for removing volatile components, and as a result, have found that in order to efficiently remove volatile components from a maleimide-based copolymer composition containing volatile components. Is that the process is relatively simple, there is no need to use a large amount of solvent, and there is no need to heat the copolymer to a high temperature for a long time. Research was conducted on the belief that the method of treating the coalesced composition was appropriate. As a result, when the above-described copolymer composition is treated by operating a vent-type extruder under operating conditions that have not been conventionally performed at all, foaming of the maleimide-based copolymer accompanying the gasification of volatile components as described above. Found that little or no degradation occurred and that there was no need to extend the residence time of the copolymer in the extruder to remove large amounts of volatile components .
The resulting maleimide-based copolymer has low volatile components.
Thus , the present invention was found to be excellent in thermal stability and completed the present invention.

Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a polymer obtained by solution polymerization or bulk polymerization.
A maleimide-based copolymer, wherein the maleimide-based copolymer is
Is a polymer containing a maleimide-based copolymer and volatile components.
Process the coalesced composition with a vent type screw extruder
And the treatment is performed at a screw rotation speed of 50 to 150 r.
pm, aromatic vinyl monomer unit (a)
And a maleimide-based monomer unit (b) as an essential monomer unit, and in a range of 0 to 20% by weight of all monomer units, other than the monomers (a) and (b). A vinyl monomer unit (c), wherein the monomer unit (c) is an unsaturated nitrile; a (meth) acrylate ester; a vinyl halide; a vinyl ether; (Meth) allyl esters; poly (meth) acrylates; polyarylates; glycidyl (meth) acrylate; allyl glycidyl ether;
(Meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, and a half-esterified product of these acids; at least one monomer unit selected from the group having a weight average molecular weight of 100,000 to 500,000; The glass transition temperature is 170 ° C. or higher, the molecular weight retention at 280 ° C. defined below is 90% or more, and the volatile component amount is 1000 ppm.
The present invention provides a maleimide-based copolymer characterized by the following. (However, “molecular weight retention at 280 ° C.”
Means that the copolymer is heated at 280 ° C. for 10 minutes under reduced pressure conditions (20 mmHg or less) using a differential thermobalance, and then quenched to obtain the molecular weight of the copolymer before the treatment. The ratio to the molecular weight)

In the present invention, the glass transition temperature of the maleimide-based copolymer is a value measured using a differential thermal balance. The volatile component amount is a value obtained by dissolving the maleimide copolymer in chloroform and quantifying the remaining volatile components by gas chromatography . The maleimide copolymer of the present invention comprises an aromatic vinyl monomer unit (a) and a maleimide
Containing the monomer unit (b) as an essential monomer unit
It is.

A maleimide-based copolymer containing an aromatic vinyl-based monomer unit and a maleimide-based monomer unit as main components is excellent in heat resistance, workability, impact resistance and heat stability. By changing the constitutional ratio of each monomer unit, a copolymer having a glass transition temperature of 170 ° C. or higher, preferably 180 ° C. or higher is easily obtained, which is preferable. Polymers having a glass transition temperature of less than 170 ° C. can have their volatile components removed by conventional devolatilization methods.

The maleimide copolymer of the present invention can be obtained by copolymerizing an aromatic vinyl monomer (a) and a maleimide monomer (b), or by mixing the monomers (a), (b) and (b). It is produced by copolymerizing other copolymerizable monomers (c). The aromatic vinyl monomer (a) is represented by the following formula:

[0015]

Wherein R ² , R ³ and R ⁴ are each independently hydrogen or an alkyl group having 1 to 5 carbon atoms, R ² R ⁴ ／/ C ＝ C ／/ ³ R ³ R ^{5 5} is an aryl group or a substituted aryl group. For example, styrene; o-methylstyrene, m-methylstyrene, p-methylstyrene (o-, m-, p-methylstyrene is also referred to as vinyltoluene), 1,3-dimethyl Alkylstyrenes such as styrene, 2,4-dimethylstyrene, ethylstyrene and p-tert-butylstyrene; α-methylstyrene, α
-Ethylstyrene, α-methyl-p-methylstyrene;
Vinylnaphthalene; halogenated styrenes such as o-chlorostyrene, m-chlorostyrene, p-chlorostyrene and 2,4-dibromostyrene; halogenated alkylstyrenes such as 2-methyl-4-chlorostyrene; divinylbenzene and the like. And one or more of these can be used. From the viewpoint of the balance between productivity and physical properties, it is particularly desirable to use at least one selected from the group consisting of styrene, vinyltoluene and α-methylstyrene. When an aliphatic vinyl monomer is used without using an aromatic vinyl monomer, the reactivity of the monomer is low, the heat resistance of the obtained copolymer is low, and the hygroscopicity is low. large.

The maleimide monomer (b) has the following formula:

[0017]

## STR2 ## H-C = C-H | | O = C C = O ... \ / N | in R ¹ [wherein, R ¹ is hydrogen or a 1 to 15 carbon atoms, an alkyl group, a cycloalkyl group , A substituted alkyl group, an aryl group or a substituted aryl group. A compound represented by the formula: maleimide, N-
Methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-isobutylmaleimide, N-tert-butylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-chlorophenylmaleimide , N-methylphenylmaleimide, N-bromophenylmaleimide, N-naphthylmaleimide, N-laurylmaleimide, 2-hydroxyethylmaleimide, N
-Hydroxyphenylmaleimide, N-methoxyphenylmaleimide, N-carboxyphenylmaleimide, N
-Nitrophenylmaleimide and the like, and one or more of these can be used. In particular, it is preferable to use one or both of phenylmaleimide and cyclohexylmaleimide since a copolymer which is easily available and has excellent heat resistance can be obtained.

In the maleimide-based copolymer, if necessary, other vinyl-based monomers (c) copolymerizable with the monomers (a) and (b) can be used. .
The monomer (c) is a compound having an ethylenically unsaturated bond other than the monomer (a) and the monomer (b), and improves, for example, impact resistance, solvent resistance, and compatibility. It is used for the purpose. Monomer (c) is acrylonitrile,
Unsaturated nitriles such as methacrylonitrile, ethacrylonitrile, and phenylacrylonitrile; (meth) acrylates having an alkyl group having 1 to 18 carbon atoms, including a cycloalkyl group and a benzyl group [for example,
Methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tertiary butyl (meth) acrylate, amyl (meth) acrylate, isoamyl (meth) acrylate Octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, (meth) acrylic acid hydroxyethyl, (meth) acrylic acid hydroxypropyl, polyethylene glycol mono (meth) acrylate, etc.]; Bed Tajien, dienes and isoprene; vinyl chloride, vinylidene chloride, vinyl bromide, vinyl halides such as vinyl fluoride; Such as methyl vinyl ether and butyl vinyl ether Vinyl ethers; vinyl acetate,
Vinyl esters of saturated monocarboxylic acids such as vinyl propionate; allyl esters or methallyl esters of saturated aliphatic monocarboxylic acids such as allyl acetate and allyl propionate; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) Acrylate, diallyl phthalate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, bisphenol A ethylene oxide or propylene oxide adduct dimethacrylate, halogenated bisphenol A Di (meth) acrylate of ethylene oxide or propylene oxide adduct, tri (meth) acrylate of isocyanurate, isocyanurate Multivalent such as di- or tri (meth) acrylate of ethylene oxide or propylene oxide adduct (meth) acrylate; polyhydric arylate such as triallyl isocyanurate; glycidyl (meth) acrylate; allyl glycidyl ether; (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid Contact
And at least one selected from the half-esterified products of these acids
One type is used , and one type or two or more types are used depending on the purpose. The type and the use amount may be selected without departing from the purpose of the present invention.

The maleimide-based monomer (b) is a component for improving the heat resistance of the obtained copolymer, and the amount of the maleimide-based monomer (b) used depends on the amount of the aromatic vinyl-based monomer (a) and the amount of the maleimide-based monomer (b). Although it can be changed depending on the type and the ratio of the above), there is no particular problem as long as the obtained copolymer is used so that the glass transition temperature is 170 ° C. or higher. The amount of the monomer (c) used is within the range of 0 to 20% by weight, and the glass transition temperature of the obtained copolymer is 170 ° C. or higher .

In the present invention, the volatile components are those having volatility such as, for example, solvents, unreacted monomers, volatile by-products or impurities. Here, the solvent may be any solvent that can be generally used in solution polymerization or the like, and examples thereof include aromatic solvents such as toluene, xylene, and ethylbenzene; ketones such as methyl ethyl ketone and methyl isobutyl ketone; dimethyl sulfoxide; A polar solvent such as ethyl acetate;
Further, when a polymer is obtained by suspension polymerization or emulsion polymerization, water is used. The volatile by-product contained in the maleimide-based copolymer is a volatile low-molecular-weight substance generated during the reaction or a volatile impurity contained in the raw material.

The maleimide copolymer of the present invention is produced.
In this case , a vent-type single-screw or twin-screw or more screw extruder having one or more screws and one or more vents sequentially arranged along the axial direction on the side surface of the cylinder can be effectively used. . As shown in FIG. 1, the screw extruder 1 has a cylinder 10. The cylinder 10 is usually composed of a plurality of parts (barrels), and a vent port is provided on a side surface of the cylinder 10. Vent port, a rear vent 3 behind the feed section 2 of the raw material polymer composition, a plurality in the polymer outlet 4 side after the devolatilization Chi match for to the front, in 2-5 amino fore vents (FIG e.g. 3 It is preferable to provide a plurality of forevents 5a, 5b and 5c), respectively, and to gradually reduce the exhaust pressure as the devolatilization from the polymer composition progresses, since the devolatilization rate is greatly improved. If the number of forevents is one, the efficiency of removing volatile components may be significantly reduced, and even if six or more are used, the efficiency of removal may not be changed. The pressure of the rear vent 3 is 300 ~ 760mm
Hg, and the pressure at the vent port 5c near the polymer outlet 4 is preferably 600 mmHg or less, more preferably 400 mmHg or less. It is preferable to lower the pressure as the desolvation proceeds (as it approaches the outlet), because the efficiency of desolvation can be further increased. The pressure in each vent is evacuated to a predetermined pressure by using a vacuum pump. In FIG. 1, 6 is a screw drive unit, 7 is a heat exchanger, and 8 is a polymer composition storage tank.

The maleimide copolymer of the present invention is produced.
The most important point in the process is the number of revolutions of the screw when devolatilizing with a screw extruder. A polymer with little deterioration in physical properties can be obtained only by operating at a screw rotation speed of 50 to 150 rpm. Screw rotation speed is 50rp
If it is less than m, the volatile components remaining in the polymer will increase, and the appearance of the molded article will be likely to be poor, and it will be easy to vent up, so that the polymer composition cannot be stably processed. On the other hand, when the rotation speed is higher than 150 rpm, the resin temperature rises due to remarkable heat generation which is considered to be characteristic of a polymer having a high melt viscosity, and the physical properties of the polymer deteriorate due to thermal deterioration.

Since the barrel temperature of the screw extruder varies depending on the barrel position, it cannot be determined unconditionally, but it can be operated in the range of 100 to 300 ° C. In particular, in a barrel near the extruder outlet where devolatilization from the maleimide-based copolymer has progressed, the resin temperature tends to increase due to shear heat generated by the maleimide-based copolymer, so the screw rotation speed is an important factor.

When a maleimide-based copolymer having a glass transition temperature of 170 ° C. or higher is produced by a bulk polymerization method or a solution polymerization method, the maleimide-based copolymer composition (here, a reaction mixture) contains the maleimide-based copolymer. If an attempt is made to increase the amount, the viscosity of the polymer composition increases, and special equipment is also required for removing heat generated during the polymerization, and it is difficult to transfer the extruder to the extruder. A polymer composition containing a volatile component is preferred. If the content of the volatile component of the polymer composition is below this range, the viscosity of the composition becomes too high, and handling may be difficult, and if it exceeds, the volatile component becomes too large and remains after desolvation, and remains. Volatile components may increase.

In order to devolatilize such a maleimide-based copolymer composition having a large amount of volatile components, as shown in FIG. It is transported and supplied by a gear pump or the like to a vent type screw extruder 1 maintained at atmospheric pressure or reduced pressure, and volatile components are removed through a vent port 3 located behind a supply port 2. Multiple vents 5 located in front
Preferably, the remaining volatile components are separated via a, 5b, 5c.

The heat exchanger 7 may be a screw extruder,
Further, a double tube type or a static mixer type heat exchanger may be used. The polymer composition heated to 150 to 300 ° C. by the heat exchanger 7 is subjected to
After the pressure is adjusted to 5 to 30 atm, a decrease in devolatilization efficiency due to lack of heat or the like is suppressed by being supplied to the screw extruder, and gas generated from volatile components generated in large quantities is supplied to the rear of the supply port. By removing through the vent hole located, vent-up at the fore vent and entrainment of the polymer are less likely to occur. The processing time in the vented screw extruder is preferably 0.5 to 30 minutes. Below this range, devolatilization will be insufficient, and the remaining volatile components may increase. Above this range, the resin may be easily deteriorated or deteriorated.

In the barrel preceding one or more of the forevent portions, steam or an inert liquid such as water or alcohol (a liquid that does not react with the resin) is injected into inlets 9a, 9b and 9
After press-fitting into the cylinder through c and mixing with the polymer composition by rotation of the screw, the remaining volatile components can be further reduced by vacuum separation at the vent. The amount of the inert liquid used is 0.5 to the polymer.
~ 3% by weight is preferred. Since the heat resistance of the resin tends to be remarkably reduced due to the remaining volatile components, it is preferable to reduce the residual volatile components in a maleimide copolymer having a glass transition temperature of 170 ° C. or higher, which is characterized by heat resistance. The devolatilization is performed when the amount of the volatile component remaining in the polymer is 100%.
0 ppm or less , preferably 500 pp
m or less. If the amount of the remaining volatile component is larger than that, heat resistance is inferior, and the appearance of the molded article is poor, and the physical properties of the molded article may be reduced. Thus, the maleimide monomer unit and the aromatic vinyl monomer unit are essential components (or main components), the weight average molecular weight after devolatilization is 100,000 to 500,000, and the glass transition temperature is 17
And at 0 ℃ or more, a retention of molecular weight when heated for 10 minutes was carried out at 280 ° C. is 90% or more, maleimide copolymer volatile component content and an excellent thermal stability is 1000ppm or less obtained Can be

[0028] Thermal deterioration is caused by a decrease in the degree of polymerization of the polymer, coloring,
It can be evaluated by a decrease in impact resistance. Up
The production method described above is characterized in that a maleimide-based copolymer having excellent heat resistance is treated and heated and devolatilized while operating a vent-type screw extruder within a specific screw rotation range. Among the deteriorations, it is particularly effective in suppressing a decrease in the molecular weight of the polymer.

After devolatilization, a maleimide-based copolymer having a weight-average molecular weight of less than 100,000 significantly deteriorates impact resistance and is not preferable in physical properties. A maleimide copolymer having a weight-average molecular weight higher than 500,000 has a melt viscosity that is too high. On the contrary, the amount of residual volatile components tends to increase due to a decrease in devolatilization efficiency. If the screw rotation speed is increased or the barrel temperature is increased, thermal deterioration proceeds, causing coloration or a decrease in molecular weight, which tends to be undesirable in physical properties.

The maleimide-based copolymer obtained by the method of the present invention has excellent heat stability, and its molecular weight hardly decreases even after heating and holding at 280 ° C. for further 10 minutes. It has a retention of at least 90%, preferably at least 95%, in comparison. the above
This is because in the production method described above, an appropriate heat history can be given to the maleimide copolymer by removing volatile components of the maleimide copolymer under specific conditions. By this operation, it is possible to convert to a thermally stable maleimide-based copolymer without causing significant thermal degradation, so that the resulting maleimide copolymer no longer has such a heat-labile structure or component. Is not present and is presumed to be excellent in thermal stability. As a standard for such thermal stability,
The present inventors have introduced a new parameter of the molecular weight retention at 280 ° C.

A maleimide-based copolymer having excellent thermal stability exhibits excellent heat resistance and impact resistance even when molded alone, and when used in a blended state with another thermoplastic resin composition. Also has the characteristic that the physical properties hardly fluctuate depending on the blending temperature and kneading conditions. The maleimide-based copolymer from which volatile components have been removed by the method of the present invention, when used in such a blend, has excellent heat resistance, good moldability and particularly excellent impact resistance, and is obtained. The advantage is that the physical properties of the resulting blend are stable.

[0032] Since the Ma Reimido copolymer of the invention has become less volatile component content without causing deterioration of physical, using this polymer, the heat resistance, the physical properties represented by impact resistance It has an excellent balance and is useful for applications in which heat resistance and rigidity are improved by blending with these resins as a modifier for general-purpose plastics and engineering plastics.

[0033]

According to the present invention, a maleimide copolymer having a glass transition temperature of 170 ° C. or higher and a polymer composition containing a volatile component are supplied to a vent type screw extruder at a screw rotation speed of 50 to 150 rpm. Since the devolatilization is performed by operating the extruder, a polymer with little deterioration in physical properties can be obtained.

[0034]

EXAMPLES Specific examples and comparative examples of the present invention will be shown below, but the present invention is not limited to the following examples.
In the following, “parts” means “parts by weight”. (Production Example 1) A polymerization reaction tank equipped with a condenser, a stirrer, and two dropping funnels was charged with 7.2 parts of styrene and 36.5 parts of toluene. The inside of the reaction tank was replaced with nitrogen, and the temperature was raised to 114 ° C.

The reaction was started by adding 0.01 part of t-butylperoxyisopropyl carbonate as a polymerization initiator into the reaction vessel, and 23.3 parts of N-phenylmaleimide and 15.1. 5 parts of a dropping liquid (1), and 17.5 parts of styrene and t-
Polymerization was carried out under reflux while dropping liquids (2) each consisting of 0.02 parts of butyl peroxyisopropyl carbonate were separately dropped at a uniform rate over 3.5 hours. After completion of the dropwise addition, the reaction mixture was further heated for 1.5 hours, so that 52.0 wt% of toluene and 5.1 w of styrene were added.
Thus, a maleimide-based copolymer composition (A) consisting of t% and 42.9% by weight of the maleimide-based copolymer was obtained. N-
Phenylmaleimide was less than 0.05 wt% and could not be detected. The resulting maleimide-based copolymer was composed of 54.3 wt% of N-phenylmaleimide units and 4 of styrene units.
It consisted of 5.7% by weight and had a glass transition temperature of 206 ° C.

(Production Example 2) 21.1 parts of styrene and 31.9 parts of methyl ethyl ketone were charged into a polymerization reactor; t-butylperoxy-2-ethylhexanoate was used as a polymerization initiator in a reactor.
04 parts added; N-phenylmaleimide
A dropping solution (1) consisting of 1 part and 5.3 parts of methyl ethyl ketone was used; and 22.6 parts of styrene and t
-Butyl peroxy-2-ethylhexanoate 0.0
Using a dropping solution (2) composed of 4 parts, the polymerization temperature was set to 90 ° C., and after the dropping was completed, the same procedure as in Production Example 1 was repeated except that the temperature was set to 60 ° C. 40.3 wt% of coalesced and methyl el ketone 3
A maleimide-based copolymer composition (B) consisting of 7.2% by weight was obtained. N-phenylmaleimide is 0.05
It was less than wt% and could not be detected. The obtained copolymer was composed of 47.4% by weight of N-phenylmaleimide unit and 52.6% by weight of styrene unit, and had a glass transition temperature of 1%.
89 ° C.

(Production Example 3) 47.0 parts of styrene and 28.0 parts of toluene were charged into a polymerization reactor; 0.01 part of t-butylperoxyisopropyl carbonate was added as a polymerization initiator to the reactor. A dropping liquid (1) consisting of 11.9 parts of N-phenylmaleimide and 1.3 parts of toluene was used; and a dropping liquid consisting of 11.1 parts of styrene and 0.02 parts of t-butylperoxyisopropyl carbonate Using (2), 31.5 wt% of styrene, 30.0 wt% of toluene, and 38.4 wt% of a maleimide copolymer were obtained in the same manner as in Production Example 1 except that the temperature was set to 60 ° C. after completion of the dropping.
And a maleimide-based copolymer composition (C) consisting of 0.1 wt% of N-phenylmaleimide. The obtained copolymer had 30.7 wt% of N-phenylmaleimide units,
It consisted of 69.3 wt% of styrene units and had a glass transition temperature of 150 ° C.

The glass transition temperature of the above copolymer was measured using DSC-8230 manufactured by Rigaku Denki KK under a nitrogen stream.
It was determined by a midpoint method from a DSC curve measured at a heating rate of 5 ° C./min using α-alumina as a reference. (Example 1) A vent type screw extruder is a twin-screw co-engaging type extruder manufactured by Nippon Steel Works Co., Ltd., having a screw diameter (D) of 65 mm, a cylinder length (L) of 2600 mm, L
/ D = 40, number of vents 4 (rear vent 1, fore vent 3) was used. The maleimide-based copolymer composition (A) obtained in Production Example 1 was passed through a static mixer type heat exchanger circulating a 285 ° C. heat medium using a gear pump and heated to 240 ° C. 20 kg
/ Cm ^2, and then supplied to a screw extruder set to the operating conditions shown in Table 1 to obtain a maleimide-based copolymer (a-1). In addition, water was injected at a supply rate of 7 kg / h in each stage before the second and third vents.

Examples 2 and 3 and Comparative Examples 1 and 2 The same operation as in Example 1 was repeated except that the temperature of the copolymer composition or the operating conditions of the screw extruder were changed as shown in Table 1. Maleimide copolymer (a-2)
(A-3) and (a-6) to (a-7) were obtained. In addition, the supply speed was 7 kg / h each in the second stage before the third vent.
Water was injected.

(Examples 4 and 5 ) The vent type screw extruder was a twin-screw co-engaging type extruder manufactured by Japan Steel Works, Ltd., having a screw diameter (D) of 120 mm and a cylinder length (L) of 5460 mm. ,
The same operation as in Example 1 was repeated except that L / D = 45.5 and the number of vents was 4 as shown in Table 1 (rear vent 1, fore vent 3), and the maleimide-based copolymer (a
-4) and (a-5) were obtained. The water injection operation was performed at a supply rate of 60 kg / h in the same manner as in Example 1.

(Examples 6 and 7 , Comparative Examples 3 and 4 ) Screw diameter (D) 44 mm, cylinder length (L) 19
The maleimide copolymer composition was changed to (B) and (C), respectively, using a vent type screw extruder having 58 mm, L / D = 45.5, and 4 vents (1 rear vent, 3 for vents). The same operation as in Example 1 was repeated except as shown in Table 1 to obtain maleimide polymers (b-1), (b-2), (c-1), and (c-2). The water injection operation was performed at a supply speed of 4 kg / h in the same manner as in Example 1.

Example 8 The same operation as in Example 1 was repeated except that the injection of the inert liquid was not carried out, and the maleimide polymer (a-8) was obtained.
I got In Table 1, Forevents 1, 2, and 3 represent the order of forevents from the polymer composition supply port.

[0043]

[Table 1] The obtained maleimide-based copolymers (a-1) to (a-
5), (a-7), (a-8), (b-1), (b-
Table 2 shows the analysis results of the volatile component amounts, weight average molecular weights, thermal degradation, appearance, and molecular weight retention of (2), (c-1) and (c-2). The amount of volatile components was determined by dissolving the obtained maleimide-based copolymer in chloroform, using a solvent, ST
(Styrene) and PMI (N-phenylmaleimide) were quantified by gas chromatography.

The type and ratio of the monomer units in the copolymer structure were determined by infrared absorption spectrum, 1H-NMR, and elemental analysis. The weight average molecular weight of the copolymer was represented by a value obtained by using tetrahydrofuran (THF) as an eluent and measuring the molecular weight measured by gel permeation chromatography (GPC) using standard polystyrene.

For the thermal deterioration, a test piece (thickness: 3 mm) of a maleimide copolymer obtained by injection molding with the cylinder temperature set at 280 ° C. was subjected to an Izod impact test based on JIS K7110, and the Izod impact value was measured. Indicated. The larger the value, the less the degree of thermal degradation. The appearance of the test piece was visually observed.

The molecular weight retention was measured at 280 ° C. under a reduced pressure (20 mmHg or less) using a differential thermobalance.
After heating for 1 minute, the copolymer was quenched and the molecular weight of the obtained copolymer was measured, and the ratio to the value before the treatment was determined.

[0047]

[Table 2] As shown in Tables 1 and 2, the polymer of the present invention has a small amount of volatile components, and also has a low molecular weight reduction and coloring of the polymer.
No. Also, it has a high molecular weight retention and excellent thermal stability . Polymer ratio Comparative Examples or subjected to thermal degradation, or the molecular weight of retention was achieved, or lower.

[0048]

Effects of the Invention According to the inventions, since it removes the volatile components without heating unnecessarily high melt viscosity maleimide copolymer, less maleimide copolymer heavy residual volatiles content Coalescence can be efficiently obtained without deterioration of physical properties. Further, the obtained maleimide-based copolymer has a high molecular weight retention at 280 ° C. and is excellent in thermal stability.

[Brief description of the drawings]

1 is a schematic diagram showing an example of a vent type screw extruder used to produce the maleimide copolymer of the inventions.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vent type screw extruder 2 Supply port 3 Rear vent 5a Fore vent 5b Fore vent 5c Fore vent 7 Heat exchanger

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Kazuchika Fujioka 992, Nishioki, Okihama-shi, Aboshi-ku, Himeji-shi, Hyogo Japan Nippon Shokubai Co., Ltd. Himeji Laboratory (56) References JP-A-63-77904 (JP, A) ( 58) Field surveyed (Int.Cl. ⁷ , DB name) C08F 222/40 C08F 6/10 B29C 47/76

Claims (1)

(57) [Claims] 1. A polymer obtained by solution polymerization or bulk polymerization.
A maleimide-based copolymer, wherein the maleimide-based copolymer is a maleimide-based copolymer.
A polymer composition containing volatile components is
Obtained by processing with a screw extruder. The processing is performed at a screw rotation speed of 50 to 150 rpm.
The aromatic vinyl monomer unit (a) and the maleimide monomer unit (b) as essential monomer units, and
A vinyl monomer unit (c) other than the monomers (a) and (b) in a range of 0 to 20% by weight of the total monomer units; ) Are unsaturated nitriles; (meth)
Acrylic acid esters; vinyl halides; vinyl ethers; vinyl esters; (meth) allyl esters; poly (meth) acrylates;
Glycidyl (meth) acrylate; allyl glycidyl ether; a unit of at least one monomer selected from (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, and half-esterified products of these acids; It has a molecular weight of 100,000 to 500,000, a glass transition temperature of 170 ° C. or more, a molecular weight retention at 280 ° C. defined below of 90% or more, and a volatile component amount of 1000 ppm or less. , characterized in that, maleimide copolymer. (However,
“The retention of molecular weight at 280 ° C.” refers to the fact that the copolymer is 280 under reduced pressure (20 mmHg or less) using a differential thermobalance.
After heating at 10 ° C. for 10 minutes, the ratio of the molecular weight of the copolymer obtained by rapid cooling to the molecular weight of the copolymer before the treatment is referred to).