JPH1160640A - Maleimide-based copolymer and thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain thermoplastic resin compositions low in discoloration and, in addition, excellent in various properties such as processability, heat resistance and impact resistance. SOLUTION: A thermoplastic resin composition is obtained by mixing a maleimide-based copolymer containing 36-90 wt.% aromatic vinyl monomer residue, 10-50 wt.% maleimide monomer residue, more than 0-less than 4 wt.% vinyl cyanide monomer residue and 0-10 wt.% monomer residue copolymerizable with these monomers such that the total of these monomer residues is 100 wt.% with a thermoplastic resin. The thermoplastic resin composition having the above described constitution is low in discoloration and, in addition, excellent in various properties such as processability, heat resistance and impact resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for use as a thermoplastic resin composition which is less colored and which is excellent in various physical properties such as processability, heat resistance and impact resistance, and a raw material for the thermoplastic resin composition. Maleimide-based copolymer to be obtained.

[0002]

2. Description of the Related Art Conventionally, for example, in automobiles, electric / electronic devices, office machines, etc., weight reduction, energy saving,
BACKGROUND ART For the purpose of cost reduction and the like, a molded product made of metal is replaced with a molded product made of synthetic resin. Various physical properties required for these molded products include, for example, processability,
Examples include heat resistance, impact resistance, and transparency. For this reason, in order to obtain molded articles having excellent physical properties, for example, ABS (Acrylonitrile-Butadiene-Styren) resin or A
Various studies have been made on improving the heat resistance of thermoplastic resins such as S (Acrylonitrile-Styrene) resin.

As a method for improving the heat resistance of a thermoplastic resin, for example, a method of introducing an α-methylstyrene unit into a molecular chain of an AS resin or the like has been attempted. However, in this method, there is a limit to improvement in heat resistance,
Further, thermal stability at high temperatures is a problem.

Therefore, in recent years, maleimide copolymers represented by copolymers of N-phenylmaleimide and styrene have been receiving attention instead of the α-methylstyrene thermoplastic resin. The N-phenylmaleimide / styrene copolymer can improve the heat resistance of a thermoplastic resin such as an ABS resin or an AS resin because of its rigid molecular structure.

However, N-phenylmaleimide /
Styrene copolymers can improve the heat resistance of thermoplastic resins such as ABS resins and AS resins, but reduce the entanglement density of molecules, which lowers physical properties such as impact resistance. Has problems. Therefore, in order to solve such a problem, a method of combining a maleimide-based copolymer with a copolymerizable third monomer such as acrylonitrile has been proposed.

For example, JP-A-57-98536 and JP-A-63-159458 disclose 15 to 50 parts by weight of an N-phenylmaleimide residue and 85 parts by weight of a vinyl aromatic monomer residue. To 40 parts by weight, and 0 to 30 parts by weight of a vinyl monomer residue copolymerizable therewith, such that the total amount thereof is 100 parts by weight.
% To 90% by weight, and 15 to 30 parts by weight of vinyl cyan monomer residue, 85 to 65 parts by weight of vinyl aromatic monomer residue, and a vinyl monomer copolymerizable therewith. A heat-resistant resin comprising a resin composition containing 90 to 10% by weight of a copolymer containing 0 to 30 parts by weight of a residue so that the total amount thereof is 100 parts by weight. A composition is disclosed.

JP-A-3-205411 discloses that 30% by weight of an aromatic vinyl compound unit, 4 to 40% by weight of a vinyl cyanide unit, and 26% by weight of an N-substituted maleimide.
Thermoplastic copolymers comprising up to 50% by weight are disclosed.

[0008]

However, the above-mentioned conventional maleimide-based copolymer and resin composition are improved in impact resistance by copolymerizing a vinyl cyanide monomer as the third monomer, but the impact resistance is improved. Since the copolymerization ratio is high, there is a problem that coloring is strong. That is, from the conventional maleimide-based copolymer and the resin composition,
It is difficult to obtain a molded article with little yellowing and excellent transparency. For this reason, a thermoplastic resin composition which is less colored and which is excellent in various physical properties such as heat resistance and impact resistance has been eagerly desired.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a thermoplastic resin composition which is less colored and which is excellent in various physical properties such as processability, heat resistance and impact resistance. Is to provide. Another object of the present invention is to provide a maleimide-based copolymer which is preferably used as a raw material for obtaining a thermoplastic resin composition which is less colored and which is excellent in various physical properties such as processability, heat resistance and impact resistance. It is to provide coalescence.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned conventional problems, and as a result, a very small amount and a specific amount of cyanide have been added to an aromatic vinyl monomer and a maleimide monomer. By using a maleimide-based copolymer obtained by copolymerizing a vinyl monomer as a raw material, it is possible to obtain a thermoplastic resin composition having significantly improved impact resistance without increasing the degree of coloring. The inventors have found and completed the present invention.

That is, in order to solve the above-mentioned problems, the maleimide copolymer according to claim 1 of the present invention contains an aromatic vinyl monomer residue in a range of 36% by weight to 90% by weight.
Maleimide monomer residue in the range of 10% by weight to 50% by weight,
More than 0 and less than 4% by weight of vinyl cyanide monomer residues,
And a monomer (a) residue copolymerizable with these monomers in a range of 0% by weight to 10% by weight so that the total amount is 100% by weight. .

The maleimide-based copolymer according to claim 2 of the present invention is intended to solve the above-mentioned problems.
The maleimide copolymer described in the above, the yellowness of a 15% by weight chloroform solution of the maleimide copolymer is determined by YI.
(1) The yellowness of a 15% by weight chloroform solution of the maleimide-based copolymer after heating at 265 ° C. for 4 minutes was measured by YI (2).
Then, it is characterized that YI (2) <YI (1) × 1.5.

According to the above constitution, a maleimide-based copolymer which is preferably used as a raw material of a thermoplastic resin composition which is less colored and which is excellent in various physical properties such as processability, heat resistance and impact resistance is provided. Can be provided. That is,
According to the present invention, when the maleimide-based copolymer has a specific composition, when a thermoplastic resin composition is used, when the heat resistance is improved, transparency and impact resistance, which were conventionally contradictory physical properties, are improved. Can satisfy both sexes. Also,
The maleimide-based copolymer has a small difference in yellowness before and after heating, and can suppress coloring due to heating.

According to a third aspect of the present invention, there is provided a thermoplastic resin composition comprising the maleimide copolymer according to the first or second aspect and a thermoplastic resin. It is characterized by.

According to a fourth aspect of the present invention, there is provided a thermoplastic resin composition according to the third aspect, wherein the thermoplastic resin comprises an AS resin and / or It is characterized by being an ABS resin.

According to the above configuration, it is possible to provide a thermoplastic resin composition having improved impact resistance despite suppression of coloring. That is, according to the present invention, when improving heat resistance, it is possible to satisfy both transparency and impact resistance, which are conventionally contradictory physical properties. The thermoplastic resin composition according to the present invention has little coloring, and is excellent in various physical properties such as processability, heat resistance, and impact resistance,
For example, it can be suitably used in various application fields such as automobiles, electric / electronic devices, and office machines.

Hereinafter, the present invention will be described in detail. The maleimide-based copolymer (hereinafter, simply referred to as a copolymer) according to the present invention is obtained by copolymerizing an aromatic vinyl monomer and a maleimide monomer with a specific amount of a vinyl cyanide monomer. When obtaining the copolymer, if necessary,
A monomer (a) copolymerizable with these monomers (aromatic vinyl monomer, maleimide monomer, and vinyl cyanide monomer) can be copolymerized. Thereby, the copolymer has a specific amount of an aromatic vinyl monomer residue,
It contains a maleimide monomer residue, a vinyl cyanide monomer residue, and optionally a monomer (a) residue. In the present invention, the residue indicates a structural unit derived from each monomer.

The aromatic vinyl monomer used in the present invention is, for example, styrene,
o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, α-ethylstyrene,
α-methyl-methylstyrene, dimethylstyrene, t-
Butylstyrene, chlorostyrene, dichlorostyrene,
Bromostyrene, dibromostyrene, vinylnaphthalene and the like can be mentioned, but not particularly limited. These aromatic vinyl monomers may be used alone,
Further, two or more kinds may be used in combination. Of the compounds exemplified above, styrene and α-methylstyrene are more preferred.

The above maleimide monomers include:
Specifically, for example, maleimide; N-methylmaleimide, N-ethylmaleimide, Nn-propylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide, N- (chlorophenyl And N-substituted maleimides such as maleimide and N- (bromophenyl) maleimide, but are not particularly limited thereto. One of these maleimide monomers may be used alone, or two or more thereof may be used in combination. Of the compounds exemplified above,
N-phenylmaleimide and N-cyclohexylmaleimide are more preferred from the viewpoints of availability, economy, and the like.

Further, specific examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile and the like. One of these vinyl cyanide monomers may be used alone, or two or more thereof may be used in combination. Among the compounds exemplified above, acrylonitrile is more preferred.

Further, as the above-mentioned monomer (a) optionally used in the present invention, specifically, for example, acrylic acid, methacrylic acid; methyl acrylate, ethyl acrylate, propyl acrylate, Alkyl acrylates such as butyl acrylate and 2-ethylhexyl acrylate; alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate; benzyl acrylate and the like Aryl acrylates; aryl methacrylates such as benzyl methacrylate; and unsaturated dicarboxylic acids such as maleic anhydride; but are not particularly limited thereto. One of these monomers (a) may be used alone, or two or more thereof may be used in combination. Among the compounds exemplified above, maleic anhydride is particularly preferred from the viewpoints of compatibility and the heat resistance of the obtained copolymer and thermoplastic resin composition.

In the present invention, the copolymer contains aromatic vinyl monomer residues in the range of 36 to 90% by weight and maleimide monomer residues in the range of 10 to 50% by weight. More than 0% and less than 4% by weight of vinyl cyanide monomer residues, and 0% to 10% by weight of monomer (a) residues;
Preferably, the aromatic vinyl monomer residue is in the range of 65% to 75% by weight, the maleimide monomer residue is in the range of 25% to 40% by weight, and the vinyl cyanide monomer residue is 0.5% by weight
Within the range of ３3% by weight, the total amount is 100% by weight.

The proportion of aromatic vinyl monomer residues in the above copolymer, ie, aromatic vinyl monomer residues, maleimide monomer residues, vinyl cyanide monomer residues, and monomer When the proportion of the aromatic vinyl monomer residue in the total of the body (a) residues is less than 36% by weight, the mechanical strength of the obtained copolymer and the finally obtained thermoplastic resin composition Is not preferred because the mechanical strength of On the other hand, when the proportion of the aromatic vinyl monomer residue exceeds 90% by weight, the heat resistance of the obtained copolymer and thermoplastic resin composition is undesirably reduced.

If the proportion of the maleimide monomer residue in the above copolymer is less than 10% by weight, the heat resistance of the obtained copolymer and thermoplastic resin composition is undesirably reduced. On the other hand, the ratio of the maleimide monomer residue is 50
If the amount is more than 10% by weight, the fluidity of the obtained copolymer and thermoplastic resin composition is reduced, and at the same time, mechanical strength such as impact resistance and molding workability are reduced. Further, the copolymer and the thermoplastic resin composition are easily colored.

Further, when the above-mentioned copolymer contains a vinyl cyanide monomer residue, the mechanical strength such as impact resistance of the obtained copolymer and thermoplastic resin composition can be improved. . However, if the proportion of the vinyl cyanide monomer residue in the copolymer is 4% by weight or more,
The heat resistance and processability of the obtained copolymer and thermoplastic resin composition are reduced, and the coloring of the copolymer and thermoplastic resin composition is unfavorably increased. In the present invention, most notably, the proportion of the vinyl cyanide monomer residue in the copolymer is defined, that is, the copolymer exceeds the vinyl cyanide monomer residue by exceeding 0. By containing in a range of less than 4% by weight, more preferably in a range of 0.5% by weight to 3% by weight, a thermoplastic resin composition having improved impact resistance despite suppression of coloring can be obtained. Can be provided.

In the present invention, the proportion of the monomer (a) residue in the copolymer is appropriately determined according to the type of the monomer (a) to be selected. It is used within a range that does not impair the physical properties of the copolymer.
However, the proportion of the monomer (a) in the above copolymer was 10% by weight.
Exceeding the range is not preferred because mechanical strength such as impact resistance of the obtained copolymer and thermoplastic resin composition and heat resistance are reduced.

In the present invention, the above-mentioned copolymer production method, that is, the above-mentioned monomers (aromatic vinyl monomer, maleimide monomer, vinyl cyanide monomer, monomer (a)) The method of copolymerization is not particularly limited, and various conventionally known methods such as an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, and a bulk polymerization method can be employed. Among them, it is more preferable to use the solution polymerization method.

Examples of the solvent used in the solution polymerization method include, for example, saturated hydrocarbons such as hexane, heptane, octane and cyclohexane; butyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol and the like. Alcohols; ketones such as methyl ethyl ketone; ethers such as tetrahydrofuran; aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene; halogenated hydrocarbons such as carbon tetrachloride; These solvents may be used alone or as a mixture of two or more. Among the compounds exemplified above, aromatic hydrocarbons are more preferred. The amount of the solvent to be used may be appropriately set according to the combination of the monomers used, the reaction conditions, and the like, and is not particularly limited.

As the polymerization initiator used in the above copolymerization reaction, specifically, for example, cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, p-
-Menthane hydroperoxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate, 1,1-bis (t-
Organic peroxides such as butylperoxy) -3,3,5-trimethylcyclohexane; inorganic peroxides such as ammonium persulfate, potassium persulfate, sodium persulfate and hydrogen peroxide; 2,2′-azobisisobutyi Radical polymerization initiators such as azo compounds such as lonitrile; One of these polymerization initiators may be used alone, or two or more thereof may be used in combination. Furthermore, a redox initiator can also be obtained by combining the above peroxide with a reducing agent such as sulfite, bisulfite, thiosulfate, formamidine sulfinic acid, and ascorbic acid. The amount of the polymerization initiator to be used may be appropriately set according to the combination of the monomers used, the reaction conditions and the like, and is not particularly limited.

In the present invention, at the time of copolymerizing each of the above monomers, at least one of the vinyl cyanide monomers among all the monomer components is placed in a predetermined reactor equipped with a stirrer or the like. It is preferable to start the copolymerization reaction after charging the monomer component containing all or part of the monomer component. In order to further improve the uniformity of the composition of the obtained copolymer, it is preferable that Of the monomer components, at least a part of the aromatic vinyl monomer, and after charging a monomer component containing a part or all of the vinyl cyanide monomer, it is possible to start a copolymerization reaction. More preferred.

The method and timing for adding the maleimide monomer in the above reaction system are not particularly limited, but it is preferable to add the maleimide monomer separately from the aromatic vinyl monomer without prior mixing. . When the maleimide monomer and the aromatic vinyl monomer are mixed in advance and added, for example, the number average molecular weight is in the range of 200 to 1,000,
The amount of low molecular weight components containing maleimide monomer residues is increased. Examples of the low molecular weight component include a Diels-Alder reaction between a maleimide monomer and an aromatic monomer and / or vinyl cyanide.
And a reactant generated by further reacting the reactant with a maleimide monomer and / or a vinyl cyanide monomer.

If these low molecular weight components are mixed in the maleimide copolymer as the final target, heat resistance and impact resistance tend to decrease, which is not preferable. Especially,
The mixture of these low molecular weight components may not be preferable depending on the use of the resin composition containing the maleimide copolymer. More specifically, it is used for specific electric and automotive parts.

Therefore, when copolymerizing each of the above monomers, it is preferable to adjust the method and timing of adding the maleimide monomer in the above reaction system so as to suppress the formation of the above low molecular weight components. . When a maleimide monomer that is solid at room temperature is added to the reaction system, the maleimide monomer may be used alone or as a monomer (a).
After mixing with (preferably maleic anhydride), the mixture is heated and dissolved, and further, the mixture is preferably dropped into the reaction system while maintaining the dissolved state by heating the dropping device, in order to more uniformly perform the copolymerization reaction. .

The solvent and the polymerization initiator may be charged in advance to the reactor in their entirety, or a part of the solvent and the polymerization initiator may be charged to the reaction solution while the copolymerization reaction is started. The remainder may be mixed with the remaining monomer components.

The reaction temperature in the above copolymerization reaction is not particularly limited, but is preferably about 70 ° C. to 180 ° C., and more preferably about 90 ° C. to 160 ° C. The reaction time may be appropriately set according to the reaction conditions such as the reaction temperature and the time required for adding the monomer component, and is not particularly limited.

In the above copolymerization reaction, if necessary, a chain transfer agent such as an alkyl mercaptan or α-methylstyrene dimer, a hindered amine or benzotriazole weathering stabilizer, and a hindered phenol oxidation Additives such as inhibitors, molecular weight regulators, plasticizers, heat stabilizers and light stabilizers may be added.

The method for removing the copolymer from the reaction solution (polymerization solution) is not particularly limited. For example, (i) the reaction solution may be so-called volatile components such as a twin-screw extruder equipped with a vent. A method of separating the copolymer from unreacted monomers and solvents by introducing (separating) the volatile components from the reaction solution by introducing into a separation and removal device; A method in which the reaction solution is poured into a solvent that does not dissolve the coalesced (poor solvent) to precipitate (precipitate) the copolymer, and then the obtained precipitate, that is, a method of filtering and drying the copolymer, and the like, Various methods can be employed. Among these methods, the method (i) is preferred because it is simple and industrially advantageous.

The above copolymer has a small difference in yellowness before and after heating. The yellowness of a 15% by weight chloroform solution of the copolymer is determined by YI (1), and the copolymer is heated at 265 ° C. for 4 minutes. Assuming that the yellowness of a 15% by weight chloroform solution of the copolymer after the reaction is YI (2), YI (2) <YI (1) × 1.5
It is. YI (1) is preferably 10 or less, more preferably 5 or less. in this way,
The above-mentioned copolymer not only has little coloring but also can suppress coloring after heating.

The proportion of the low molecular weight component containing a maleimide monomer residue in the above copolymer is preferably as small as possible. Specifically, when the weight% of the maleimide monomer residue in the copolymer is X, the ratio of the low molecular weight component is preferably (0.1 × X) or less, and (0.06 × X) More preferably,
(0.04 × X) or less is particularly preferable. When the proportion of the low molecular weight component exceeds (0.1 × X), the heat resistance and impact resistance of the copolymer tend to decrease. still,
The content (ratio) of the low molecular weight component can be measured using a known method such as GPC (gel permeation chromatography).

The thermoplastic resin composition according to the present invention can be easily obtained by mixing the above copolymer with a thermoplastic resin.

As the thermoplastic resin used in the present invention, specifically, for example, ABS (Acrylonitrile-B
utadiene-Styren) resin, AS (Acrylonitrile-Styrene)
Resin, AAS (Acrylonitrile Acrylic Styrene) resin,
Conventionally known various thermoplastic resins such as AES (Acrylonitrile-EPDM-Styren) resin can be used. One of these thermoplastic resins may be used alone, or two or more of them may be used as a mixture. Among these thermoplastic resins, an ABS resin and / or an AS resin are more preferable for obtaining the effects of the present invention.

According to the present invention, by mixing the above-mentioned copolymer with the above-mentioned thermoplastic resin, not only the heat resistance of the thermoplastic resin can be improved, but also the impact resistance can be improved while suppressing coloring. .

In the present invention, the mixing ratio of the thermoplastic resin and the copolymer is not particularly limited, but
The content of the copolymer in the thermoplastic resin composition,
It is preferable to mix so as to be in the range of 10% by weight to 50% by weight, more preferably to be in the range of 15% by weight to 45% by weight, and more preferably in the range of 20% by weight to 40% by weight. It is particularly preferable to mix so as to be inside. If the content of the copolymer is less than 10% by weight, there is a possibility that the thermoplastic resin cannot have sufficient effects of improving heat resistance, impact resistance and the like. On the other hand, the content of the copolymer is 50
If the amount is more than 10% by weight, physical properties such as processability and transparency of the obtained thermoplastic resin composition may be deteriorated.

In the present invention, the method of mixing the thermoplastic resin and the copolymer is not particularly limited, and a conventionally known mixing and melting method can be employed. The thermoplastic resin composition of the present invention, for example, powder,
After mixing a bead-like or pellet-like copolymer and a thermoplastic resin at a predetermined ratio, the resulting mixture can be easily obtained by melt-kneading.

The kneader used for the above-mentioned melt kneading is not particularly limited, and examples thereof include extruders such as a single-screw extruder and a twin-screw extruder; a Banbury mixer; a pressure kneader; Can be used.

When obtaining the thermoplastic resin composition of the present invention, if necessary, an antioxidant, a weather resistance stabilizer, a flame retardant, an antistatic agent, a coloring agent, a lubricant, a release agent, etc. Or various fillers such as glass fiber. In particular, since the thermoplastic resin composition of the present invention has excellent fluidity, it is suitably used for applications in which a reinforcing agent, such as glass fiber, whose fluidity tends to decrease is blended.

The thermoplastic resin composition is formed into a target molded product by various processing methods such as an injection molding method, an extrusion molding method and a compression molding method, and has physical properties such as processability, heat resistance, impact resistance and transparency. Can be suitably used in various application fields requiring In addition, the molding method of the said thermoplastic resin composition and its use are not specifically limited.

As described above, according to the present invention, the aromatic vinyl monomer residue is in the range of 36% to 90% by weight, the maleimide monomer residue is in the range of 10% to 50% by weight, More than 0% and less than 4% by weight of vinyl cyanide monomer residues, and 0% by weight of monomer (a) residues copolymerizable with these monomers.
The present invention relates to a maleimide-based copolymer contained in an amount of 100% by weight within a range of 10% by weight. The maleimide-based copolymer has a yellowness index of 15% by weight of a chloroform solution of the maleimide-based copolymer of YI.
(1) Assuming that the yellowness of a 15% by weight chloroform solution of the maleimide-based copolymer after heating at 265 ° C. for 4 minutes is YI (2), YI (2) <YI (1) × 1.5. Further, the present invention relates to a thermoplastic resin composition containing the maleimide copolymer and a thermoplastic resin. As the thermoplastic resin, AS resin and / or AB
S resins are preferred.

According to the present invention, the above-mentioned copolymer contains the above-mentioned monomer residues, in particular, vinyl cyanide monomer residues in the above-mentioned ratio, so that the obtained molded article can be colored. For example, impact resistance can be improved while suppressing the yellowness (YI) to 30 or less. In other words, according to the present invention, when the above-mentioned copolymer has a specific composition, when the thermoplastic resin composition is used, when the heat resistance is improved, the transparency and the impact resistance, which were conventionally contradictory physical properties, are improved. And a thermoplastic resin composition having excellent processability and heat resistance. Thus, the thermoplastic resin composition according to the present invention is less colored, and furthermore, is excellent in various physical properties such as processability, heat resistance, and impact resistance. It is suitable as a part, a part of various industrial products, a molded article such as office supplies, or a food packaging material.

[0050]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto. In the Examples and Comparative Examples, “parts” indicates “parts by weight”, and “%” indicates “% by weight”. The composition of the copolymer and the physical properties of the copolymer and the thermoplastic resin composition were measured by the following methods.

Composition of Copolymer A predetermined amount of the copolymer was precisely weighed and dissolved in chloroform to form a 3% solution. Next, using this solution, a cell thickness of 0.05
Infrared spectroscopy (so-called infrared absorption method) was performed under the condition of mm.

Then, the amounts of cyano group, carbonyl group, and benzene ring contained in the copolymer are determined from the measured absorption intensity of the infrared absorption spectrum (IR), thereby obtaining the composition of the copolymer. I asked. The cyan group is derived from a vinyl cyanide monomer and has a wave number of 2237 cm.
Absorbs ^-1 infrared rays. The carbonyl group is derived from a maleimide monomer and maleic anhydride, and absorbs infrared rays having a wave number of 1712 cm ^-1 . The benzene ring is derived from an aromatic vinyl monomer and absorbs infrared rays having a wave number of 760 cm ^-1 .

Yellowness (YI) The yellowness (YI (1)) of the copolymer was measured by the following method. A predetermined amount of the copolymer was precisely weighed and dissolved in chloroform to make a 15% solution. Using this solution as a sample, a color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd .; trade name: SZ- @ 80 C)
It was determined by performing a transmission method measurement with a cell thickness of 1 cm according to JIS K 7103 using OLOR MEASURING SYSTEM. Also, the yellowness (YI) of the thermoplastic resin composition was determined by the same measurement method as described above. In addition, the same measurement as described above was performed using the obtained copolymer.
Performed after heating at 265 ° C. for 4 minutes. That is, after heating the obtained copolymer at 265 ° C. for 4 minutes, a predetermined amount of the copolymer was precisely weighed and dissolved in chloroform to form a 15% solution. This solution was used as a sample, and the degree of yellowness (YI (2)) was determined by a transmission method measurement. The yellowness of a test piece obtained by molding the thermoplastic resin composition was measured according to JIS K7.
It was determined by performing a so-called reflection method measurement in accordance with Example No. 103.

Impact Resistance The impact resistance (kg / cm.cm) is defined as the so-called 1/4 '' notched Izod impact strength of a test piece obtained by molding a thermoplastic resin composition in accordance with JIS K 7110. It was evaluated by measuring. That is, a test piece having a V-shaped notch (notch) in the center was supported at one end, hit with a hammer from the same side as the notch, and the amount of energy absorbed by the damage was determined.

Heat Resistance Heat resistance was evaluated by measuring HDT (deflection temperature under load; ° C.) of a test piece obtained by molding a thermoplastic resin composition. In other words, a load corresponding to a stress of 18.5 kgf / cm ² was applied to the center of the test piece (12.5 mm x 6 mm), and 2 ° C / min.
The temperature at which a deflection of 0.26 mm occurred in the test piece was defined as the deflection temperature under load. Note that the measurement of the heat resistance was performed based on JIS K 7207.

Processability Processability was evaluated by measuring the fluidity of the obtained thermoplastic resin composition. That is, the obtained thermoplastic resin composition was extruded from a predetermined test apparatus under the conditions of a temperature of 220 ° C. and a load of 10 kg, and the extruded amount per 10 minutes (M
FR; g / 10 min). still,
The measurement of the fluidity was performed based on JIS K7210.

Example 1 Styrene as an aromatic vinyl monomer was placed in a stainless steel container equipped with a thermometer, a nitrogen gas inlet tube, two dropping devices, a reflux condenser, and a stirrer.
15 parts, acrylonitrile as vinyl cyanide monomer
0.5 part and 24.2 parts of toluene as a solvent were charged. In addition, styrene 2 was added to one dropping device (dropping system 1).
A mixture (A ₁ ) consisting of 6.8 parts and 0.1 part of t-butyl peroxyisopropyl carbonate as a polymerization initiator was charged. Further, the other dropping device (dropping system 2) was charged with N-phenylmaleimide 19.1 as a maleimide monomer.
A mixture (B ₁ ) consisting of 0.8 parts of maleic anhydride as monomer (a), 0.3 part of acrylonitrile, and 13.3 parts of toluene was dissolved at 70 ° C. and charged.
It was kept at 70 ° C.

Next, the temperature of the toluene solution in the stainless steel container was raised to 115 ° C. while stirring under a nitrogen atmosphere, and 0.05 parts of t-butylperoxyisopropyl carbonate was further added to the toluene solution. Then, the copolymerization reaction was started (initial preparation). After the start of the copolymerization reaction, the mixture (A ₁ ) was continuously dropped into the reaction solution over 3.5 hours, and the mixture (B ₁ ) kept at 70 ° C. was added to the reaction solution for 3.5 hours.
It was dropped continuously over time.

When five hours have passed since the start of the copolymerization reaction, the copolymerization reaction was terminated. Thereafter, the obtained reaction solution (polymerization liquid) was introduced into a vented twin-screw extruder. Then, the pressure was reduced to a predetermined pressure, and the solvent was removed by heating to 250 ° C. to obtain 60 parts of a pellet-shaped copolymer.
The weight average molecular weight (Mw) of the copolymer measured by gel permeation chromatography (GPC) was 1
It was 00,000. When the composition of the copolymer was determined, the copolymer contained 65.3% of styrene residues, 32% of N-phenylmaleimide residues, and 1.4% of maleic anhydride residues.
% Of acrylonitrile residues. Further, a low molecular weight component containing a maleimide monomer residue (the number average molecular weight by GPC is 20%) contained in the above-mentioned copolymer.
The content of the components in the range of 0 to 1,000; hereinafter simply referred to as low molecular weight components) was measured, and the content of the low molecular weight components was 0.7%. In addition, various physical properties of the copolymer were evaluated by the methods described above, and the appearance was visually evaluated. The results are shown in Table 1 together with the main reaction conditions.

Next, this copolymer and ABS resin (manufactured by Nippon Synthetic Rubber Co., Ltd .; trade name: ABS-10) were fed to a twin screw extruder at a ratio of 65 parts of ABS resin to 35 parts of copolymer. To obtain a thermoplastic resin composition according to the present invention.
Thereafter, the thermoplastic resin composition was injection-molded under predetermined conditions to obtain a molded article composed of the thermoplastic resin composition. Various physical properties of the obtained thermoplastic resin composition and its molded product were evaluated by the above-described methods, and the appearance of the molded product was visually evaluated. Table 2 shows the results together.

Example 2 A stainless steel container similar to that of Example 1 was charged with 13 parts of styrene, 1.0 part of acrylonitrile, and 26.0 parts of toluene. Then, a mixture (A ₁ ) composed of 25.8 parts of styrene and 0.1 part of t-butylperoxyisopropyl carbonate was charged into _one dropping device (dropping system 1). Further, a mixture (B) comprising 19.9 parts of N-phenylmaleimide, 1.0 part of acrylonitrile, and 13.3 parts of toluene was added to the other dropping device (dropping system 2).
₂ ) was dissolved and charged at 70 ° C, and the dropping device was maintained at 70 ° C.

Thereafter, the temperature of the toluene solution in the stainless steel container, that is, the polymerization temperature, was raised from 115 ° C. to 11 ° C.
Except that the temperature was changed to 2 ° C., the same reaction and operation as in Example 1 were performed to obtain 60 parts of a pellet-shaped copolymer. The weight average molecular weight (Mw) of the copolymer measured by GPC was 10
It was 0,000. When the composition of the copolymer was determined, the copolymer contained 64.0% of styrene residues, 33% of N-phenylmaleimide residues, and 3.0% of acrylonitrile residues.
%. Further, when the content of the low molecular weight component containing the maleimide monomer residue contained in the above copolymer was measured, the content of the low molecular weight component was 0.8%. In addition, various physical properties of the copolymer were evaluated by the methods described above, and the appearance was visually evaluated. The results are shown in Table 1 together with the main reaction conditions.

Next, this copolymer and an ABS resin (manufactured by Nippon Synthetic Rubber Co., Ltd .; trade name: ABS-10) were fed to a twin screw extruder at a ratio of 35 parts of the copolymer to 65 parts of the ABS resin. To obtain a thermoplastic resin composition according to the present invention.
Thereafter, the thermoplastic resin composition was injection-molded under the same conditions as in Example 1 to obtain a molded article made of the thermoplastic resin composition. Various physical properties of the obtained thermoplastic resin composition and its molded product were evaluated by the above-described methods, and the appearance of the molded product was visually evaluated. Table 2 shows the results together.

Comparative Example 1 The same stainless steel container as in Example 1 was charged with 15 parts of styrene and 25 parts of toluene. Then, styrene is added to one of the dropping devices (dropping system 1).
A mixture (A ₁ ) consisting of 26.8 parts and 0.1 part of t-butylperoxyisopropyl carbonate was charged. Further, 19.1 parts of N-phenylmaleimide, 0.8 parts of maleic anhydride, and toluene were added to the other dropping device (dropping system 2).
A mixture (B ₃ ) consisting of 13.3 parts was dissolved and charged at 70 ° C., and the dropping device was maintained at 70 ° C.

Thereafter, the same reaction and operation as in Example 1 were performed to obtain 60 parts of a comparative copolymer in the form of pellets. GP
Weight average molecular weight (Mw) of the copolymer measured by C
Was 100,000. When the composition of the copolymer was determined, the copolymer had a styrene residue of 66.6%, an N-phenylmaleimide residue of 32%, and a maleic anhydride residue of 1.
4% and did not contain acrylonitrile monomer residues (ie, vinyl cyanide monomer residues). Further, when the content of the low molecular weight component containing the maleimide monomer residue contained in the above copolymer was measured, the content of the low molecular weight component was 0.8%. In addition, various physical properties of the copolymer were evaluated by the methods described above, and the appearance was visually evaluated. The results are shown in Table 1 together with the main reaction conditions.

Next, this copolymer and an ABS resin (manufactured by Nippon Synthetic Rubber Co., Ltd .; trade name: ABS-10) were fed to a twin-screw extruder at a ratio of 65 parts of the ABS resin to 35 parts of the copolymer. To obtain a thermoplastic resin composition for comparison. Thereafter, the thermoplastic resin composition was injection-molded under the same conditions as in Example 1 to obtain a molded article made of the thermoplastic resin composition. Various physical properties of the obtained thermoplastic resin composition and its molded product were evaluated by the above-described methods, and the appearance of the molded product was visually evaluated. Table 2 shows the results together.

Comparative Example 2 The same stainless steel container as in Example 1 was charged with 10 parts of styrene, 5 parts of acrylonitrile, and 25 parts of toluene. Then, a mixture (A ₂ ) composed of 22.8 parts of styrene and 0.1 part of t-butylperoxyisopropyl carbonate was charged into one dropping device (dropping system 1). Further, 19.1 parts of N-phenylmaleimide, 0.8 parts of maleic anhydride, 4 parts of acrylonitrile, and 13.3 parts of toluene were added to the other dropping device (dropping system 2).
A mixture (B ₄ ) consisting of 3 parts by weight at 70 ° C.
The dropping device was kept at 70 ° C.

Thereafter, the same reaction and operation as in Example 1 were carried out except that the polymerization temperature was changed from 115 ° C. to 105 ° C.
60 parts of a pellet-shaped copolymer were obtained. The weight average molecular weight (Mw) of the copolymer measured by GPC was 100,000. When the composition of the copolymer was determined, the copolymer contained 56.6% of styrene residues, 32% of N-phenylmaleimide residues, 1.4% of maleic anhydride residues, and 10% of acrylonitrile residues. %. Further, when the content of the low molecular weight component containing the maleimide monomer residue contained in the above copolymer was measured, the content of the low molecular weight component was 1.4%. Various physical properties of the copolymer were evaluated by the methods described above, and the appearance was visually evaluated. The results are shown in Table 1 together with the main reaction conditions.

Next, this copolymer and an ABS resin (manufactured by Nippon Synthetic Rubber Co., Ltd .; trade name: ABS-10) were fed to a twin screw extruder at a ratio of 65 parts of the ABS resin to 35 parts of the copolymer. To obtain a thermoplastic resin composition for comparison. Thereafter, the thermoplastic resin composition was injection-molded under the same conditions as in Example 1 to obtain a molded article made of the thermoplastic resin composition. Various physical properties of the obtained thermoplastic resin composition and its molded product were evaluated by the above-described methods, and the appearance of the molded product was visually evaluated. Table 2 shows the results together.

[0070]

[Table 1]

[0071]

[Table 2]

From the results shown in Tables 1 and 2, according to this example, the impact resistance was improved by using a copolymer having a specific composition as a raw material, despite suppression of coloring. It can be seen that an improved thermoplastic resin composition can be obtained. Each of the thermoplastic resin compositions obtained in this example has little coloring and is excellent in various physical properties such as processability, heat resistance and impact resistance. On the other hand, when the copolymer in the thermoplastic resin composition does not contain an acrylonitrile residue (vinyl cyanide monomer residue), the coloring is small,
It turns out that it is inferior to impact resistance. Further, it is found that when the content of the acrylonitrile residue in the copolymer is large, the impact resistance is improved, but the coloring becomes strong. Further, in the present example, the content of the acrylonitrile residue in the copolymer used as a raw material of the thermoplastic resin composition was adjusted to more than 0 and less than 4% by weight. It is also found that they are excellent in impact resistance and have little coloring, and can suppress coloring by heating.

[0073]

As described above, the maleimide-based copolymer according to claim 1 of the present invention has an aromatic vinyl monomer residue of 36%.
10% by weight of maleimide monomer residue in the range of 90% by weight to 90% by weight.
In the range of from 50% by weight to 50% by weight, more than 0% and less than 4% by weight of the vinyl cyanide monomer residue, and 0% by weight of the monomer (a) residue copolymerizable with these monomers. % In the range of 10% by weight to 10% by weight.

The maleimide-based copolymer according to claim 2 of the present invention is, as described above,
The yellowness of the weight% chloroform solution was determined by YI (1) at 265 ° C.
15% by weight of the maleimide-based copolymer after heating for 4 minutes at
Assuming that the yellowness of the chloroform solution is YI (2), YI
(2) <YI (1) × 1.5

According to the above constitution, a maleimide-based copolymer which is preferably used as a raw material of a thermoplastic resin composition which is less colored and which is excellent in various physical properties such as processability, heat resistance and impact resistance is provided. Can be provided. That is,
According to the present invention, when the maleimide-based copolymer has a specific composition, when a thermoplastic resin composition is used, when the heat resistance is improved, transparency and impact resistance, which were conventionally contradictory physical properties, are improved. Can satisfy both sexes. Also,
The maleimide-based copolymer has an effect that the difference in yellowness between before and after heating is small and coloring due to heating can be suppressed.

As described above, the thermoplastic resin composition according to the third aspect of the present invention has a structure containing the maleimide-based copolymer according to the first or second aspect and a thermoplastic resin.

As described above, the thermoplastic resin composition according to the fourth aspect of the present invention has a constitution in which the thermoplastic resin is an AS resin and / or an ABS resin.

According to the above configuration, it is possible to provide a thermoplastic resin composition having improved impact resistance despite suppression of coloring. That is, according to the present invention, when improving heat resistance, it is possible to satisfy both transparency and impact resistance, which are conventionally contradictory physical properties. The thermoplastic resin composition according to the present invention has little coloring, and is excellent in various physical properties such as processability, heat resistance, and impact resistance,
For example, there is an effect that it can be suitably used in various application fields such as automobiles, electric / electronic devices, and office machines.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // (C08F 212/00 222: 40 220: 42)

Claims (4)

[Claims] 1. An aromatic vinyl monomer residue in the range of 36% to 90% by weight, a maleimide monomer residue in a range of 10% to 50% by weight, and a vinyl cyanide monomer residue. Group and more than 4% by weight, and the monomer (a) residue copolymerizable with these monomers is in the range of 0% to 10% by weight, and the total amount is 100% by weight. A maleimide-based copolymer, which is contained so as to be: 2. The yellowness of a 15% by weight chloroform solution of the maleimide-based copolymer was determined using YI (1), and the yellowness of a 15% by weight chloroform solution of the maleimide-based copolymer after heating at 265 ° C. for 4 minutes. Assuming that YI (2), YI (2) <Y
2. The maleimide-based copolymer according to claim 1, wherein I (1) × 1.5. 3. A thermoplastic resin composition comprising the maleimide copolymer according to claim 1 and a thermoplastic resin. 4. The thermoplastic resin composition according to claim 3, wherein said thermoplastic resin is an AS resin and / or an ABS resin.