JP7147234B2 - Method for producing methacrylic acid ester polymer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polymerization catalyst for producing a methacrylic acid ester polymer and a method for producing a methacrylic acid ester polymer.
More specifically, the present invention relates to a new polymerization catalyst and a method for producing a methacrylic acid ester polymer that can stably produce a methacrylic acid ester polymer having a high degree of stereoregularity at a high yield. .

(Meth)acrylic resins are used in various fields such as vehicle parts, optical materials, lighting materials, and building materials, due to their excellent transparency and weatherability.
In recent years, (meth)acrylic resin moldings are required to have higher performance as parts become thinner and finer. One of its properties is heat resistance. In particular, in applications for vehicle parts such as tail lamps and head lamps, there is a demand for (meth)acrylic resins with higher heat resistance because vehicle parts are exposed to high temperature environments. As a technique for improving the heat resistance of a (meth)acrylic resin, a method of increasing the stereoregularity (syndiotacticity) of the (meth)acrylic resin is known.

For example, Patent Document 1 discloses a specific organoaluminum compound, an organic nitrogen compound (B1) having no hydrogen atoms directly bonded to nitrogen atoms, and an organophosphorus compound (B2) having no hydrogen atoms directly bonded to phosphorus atoms. A technique for anionically polymerizing an acrylic acid ester at a low temperature of -20°C using a catalyst system in which at least one compound selected from is combined is disclosed.
Patent Document 2 discloses a technique of polymerizing a methacrylic acid ester using a solvent in a catalyst system combining a specific organoaluminum compound, a phenol, and a bisoxazoline compound. discloses a technique for polymerizing a methacrylic acid ester at an extremely low temperature of -60 to -95°C using a catalyst system in which a tertiary phosphine and a specific aluminum phenoxide are combined.

JP-A-2002-327007 JP-A-10-139822

Proceedings of the Society of Polymer Science, Vol. 44, No. 2 (1995), p. 153

However, in the technique disclosed in Patent Document 1, the polymerization reaction needs to proceed at a low temperature, making it difficult to implement on an industrial scale. Moreover, when applied to methacrylic acid ester, the polymerization efficiency was insufficient. Furthermore, since an excessive amount of solvent is required with respect to acrylic acid ester, there are problems in reaction efficiency and productivity.
The technique disclosed in Patent Document 2 requires the use of a very expensive bisoxazoline compound, which is not necessarily easy to synthesize, and is difficult to implement on an industrial scale. In addition, since the oxazoline compounds disclosed in Examples do not have a substituent on the cross-linking group, they are unstable at room temperature. There were problems with reaction efficiency and productivity.
In the technique disclosed in Patent Document 3, the polymerization reaction needs to proceed at extremely low temperatures, making it difficult to implement on an industrial scale.

Moreover, when the polymerization reaction is carried out at a temperature below room temperature, it tends to be difficult to control the temperature in the reaction system due to the heat generated by the polymerization reaction.

An object of the present invention is to solve these problems. That is, the present invention provides a polymerization catalyst for stably producing a methacrylic acid ester polymer having high stereoregularity at a temperature higher than room temperature without requiring an excessive solvent, and a high stereoregularity An object of the present invention is to provide a method for producing a methacrylic acid ester polymer having properties.

A first gist of the present invention is to convert methacrylic acid ester to methacrylic acid, which contains an organoaluminum compound (A) represented by the following formula (1) and an organophosphorus compound (B) represented by the following formula (2). It is a polymerization catalyst for producing an ester polymer.
R1Al( ^OAr1 )( ^OAr2 ) ( ¹ )
[In Formula (1), Al represents an aluminum atom, and O represents an oxygen atom. R ¹ represents a hydrocarbon group having 2 to 10 carbon atoms. Ar ¹ and Ar ² are each independently an aromatic hydrocarbon group having 6 to 20 carbon atoms which may contain a heteroatom. ]
^{PR2R3R4 ( 2} )
[In Formula (2), P represents a phosphorus atom. R ² , R ³ and R ⁴ are each independently a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom or an aromatic hydrocarbon having 6 to 20 carbon atoms which may contain a heteroatom is any of the ]
A second gist of the present invention is a method for producing a methacrylic acid ester polymer, comprising polymerizing a methacrylic acid ester in the presence of the polymerization catalyst.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a polymerization catalyst for stably producing a methacrylic acid ester polymer having high stereoregularity at a temperature higher than room temperature without requiring an excessive solvent.
Furthermore, the present invention can provide a method for producing a methacrylic acid ester polymer having high stereoregularity.
The methacrylic acid ester polymer produced using the polymerization catalyst and production method of the present invention has excellent transparency and high stereoregularity, and thus has excellent heat resistance. Such a methacrylate ester polymer is suitable for applications such as vehicle parts such as tail lamps and head lamps.

1 is a ¹ H-NMR spectrum of a methacrylic acid ester polymer obtained in Example 1 of the present invention.

The present invention will be described in detail below.

In the present invention, "(meth)acrylic acid" means at least one selected from "acrylic acid" and "methacrylic acid".
In the present invention, "monomer" means an unpolymerized compound, and "repeating unit" means a unit derived from the monomer formed by polymerization of the monomer. The repeating unit may be a unit directly formed by a polymerization reaction, or may be a unit in which some of the units are converted to another structure by treating the polymer.
In the present invention, "% by mass" indicates the content of a specific component contained in 100% by mass of the total amount.
Unless otherwise specified, the numerical range represented by using "to" in this specification means a range including the numerical values described before and after "to" as lower and upper limits, and "A to B" means greater than or equal to A and less than or equal to B.

The present invention has the features as described above, and the embodiments thereof will be described below.
<Polymerization catalyst>
The polymerization catalyst of the present invention is a polymerization catalyst for producing a methacrylic acid ester polymer from a methacrylic acid ester containing an organoaluminum compound (A) described below and an organophosphorus compound (B) described below.

<Organoaluminum compound (A)>
The organoaluminum compound (A) is one of the constituent components of the polymerization catalyst of the present invention.
The organoaluminum compound (A) is represented by the following formula (1).
R1Al( ^OAr1 )( ^OAr2 ) ( ¹ )
[In Formula (1), Al represents an aluminum atom, and O represents an oxygen atom. R ¹ represents a hydrocarbon group having 2 to 10 carbon atoms. Ar ¹ and Ar ² are each independently an aromatic hydrocarbon group having 6 to 20 carbon atoms which may contain a heteroatom. ]

In the present invention, R ¹ in formula (1) represents a hydrocarbon group having 2 to 10 carbon atoms. It is believed that R ¹ exerts steric interactions with new monomers, greatly affecting stereoselectivity and polymerization activity. Therefore, if the number of carbon atoms in R ¹ is too small, the stereoselectivity tends to be low. Also, if the number of carbon atoms in R ¹ is excessively large, the penetration of the monomer tends to be inhibited. Therefore, R ¹ preferably has 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms.

Specific examples of R ¹ include ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, n-hexyl group, n-octyl group and n-decyl group. Among them, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, n-hexyl group and n-octyl group are preferable, and further ethyl group, n-propyl group, n-butyl group and isobutyl group. , n-hexyl groups are preferred.

In the present invention, in formula (1), Ar ¹ and Ar ² each independently represent an aromatic hydrocarbon group having 6 to 20 carbon atoms which may contain a heteroatom.
Ar ¹ and Ar ² are in the vicinity of aluminum Al and interact with Al sterically and/or electronically. In order to exert such an effect, Ar ¹ and Ar ² preferably contain bulky substituents. The bulky substituents are each independently an optionally heteroatom-containing hydrocarbon group having 3 to 6 carbon atoms or an optionally heteroatom-containing aromatic hydrocarbon group having 6 to 7 carbon atoms.

Heteroatoms included in heteroatom-containing groups include oxygen, nitrogen, phosphorus, sulfur, and silicon. Among these heteroatoms, oxygen, nitrogen and silicon are preferred. In addition, examples of heteroatom-containing groups containing these heteroatoms include oxygen-containing groups such as alkoxy groups and aryloxy groups, and nitrogen-containing groups such as dialkylamino groups and diarylamino groups, and phosphorus-containing substituents. Examples include dialkylphosphino groups and diarylphosphino groups. Examples of sulfur-containing groups include thioalkoxy groups and thioaryloxy groups. Examples of silicon-containing groups include trialkylsilyl groups, dialkylarylsilyl groups, An alkyldiarylsilyl group is mentioned. Among these heteroatom-containing groups, most preferred are alkoxy groups, aryloxy groups and trialkylsilyl groups.

Specific examples of bulky substituents include hydrocarbon groups such as isopropyl, isobutyl, tert-butyl (t-butyl), neopentyl, and cyclohexyl groups; aromatic hydrocarbon groups such as phenyl; Alkoxy groups such as propoxy group, isobutyroxy group, t-butoxy group, neopentyloxy group and cyclohexyloxy group; aryloxy groups such as phenoxy group; and trialkylsilyl groups such as trimethylsilyl group and triethylsilyl group.
Specific examples of the core of aromatic hydrocarbon groups containing bulky substituents include phenyl, 4-methylphenyl, 4-methoxyphenyl, 1-naphthyl and 2-naphthyl groups. (However, the carbon position at the base of the Al—O—Ar bond is set to 1). Among these, a phenyl group, a 4-methylphenyl group and a 4-methoxyphenyl group are preferred.

Whilst it does not matter where the bulky substituents are on the scaffold of the aromatic hydrocarbon group, positions where they interact sterically and/or electronically with Al are preferred.
Specific positions include positions 2, 6, 2 and 6, 2 and 4 and 6. Of these, positions 2 and 6, positions 2 and 4 and 6 are preferred.

Specific examples of Ar ¹ and Ar ² include 2,6-diisopropylphenyl group, 2,6-diisopropyl-4-methylphenyl group, 2,6-diisopropyl-4-methoxyphenyl group, 2,6-diisobutyl phenyl group, 2,6-diisobutyl-4-methylphenyl group, 2,6-diisobutyl-4-methoxyphenyl group, 2,6-di-t-butylphenyl group, 2,6-di-t-butyl-4 -methylphenyl group, 2,6-di-t-butyl-4-methoxyphenyl group, 2,6-dineopentylphenyl group, 2,6-dineopentyl-4-methylphenyl group, 2,6-dineopentyl-4 -methoxyphenyl group, 2,6-dicyclohexylphenyl group, 2,6-dicyclohexyl-4-methylphenyl group, 2,6-dicyclohexyl-4-methoxyphenyl group, 2,6-diphenylphenyl group, 2,6-diphenyl -4-methylphenyl group, 2,6-diphenyl-4-methoxyphenyl group, 2,6-diisopropoxyphenyl group, 2,6-diisopropoxy-4-methylphenyl group, 2,6-diisopropoxy -4-methoxyphenyl group, 2,6-diisobutoxyphenyl group, 2,6-diisobutoxy-4-methylphenyl group, 2,6-diisobutoxy-4-methoxyphenyl group, 2,6-di-t-butoxyphenyl group, 2,6-di-t-butoxy-4-methylphenyl group, 2,6-di-t-butoxy-4-methoxyphenyl group, 2,6-dineopentyloxyphenyl group, 2,6-di neopentyloxy-4-methylphenyl group, 2,6-dineopentyloxy-4-methoxyphenyl group, 2,6-dicyclohexyloxyphenyl group, 2,6-dicyclohexyloxy-4-methylphenyl group, 2 ,6-dicyclohexyloxy-4-methoxyphenyl group, 2,6-diphenoxyphenyl group, 2,6-diphenoxy-4-methylphenyl group, 2,6-diphenoxy-4-methoxyphenyl group, 2,6- bis(trimethylsilyl)phenyl group, 2,6-bis(trimethylsilyl)-4-methylphenyl group, 2,6-bis(trimethylsilyl)-4-methoxyphenyl group, 2,6-bis(triethylsilyl)phenyl group, 2 ,6-bis(triethylsilyl)-4-methylphenyl group, 2,6-bis(triethylsilyl)-4-methoxyphenyl group, 2,4,6-triisopropylphenyl group, 2,4,6-tri- t-butylphenyl groups are listed. can be lifted.

Among these, 2,6-diisopropylphenyl group, 2,6-diisopropyl-4-methylphenyl group, 2,6-diisopropyl-4-methoxyphenyl group, 2,6-di-t-butylphenyl group, 2, 6-di-t-butyl-4-methylphenyl group, 2,6-di-t-butyl-4-methoxyphenyl group, 2,6-dineopentylphenyl group, 2,6-dineopentyl-4-methylphenyl group, 2,6-dineopentyl-4-methoxyphenyl group, 2,6-dicyclohexylphenyl group, 2,6-dicyclohexyl-4-methylphenyl group, 2,6-dicyclohexyl-4-methoxyphenyl group, 2,6- diphenylphenyl group, 2,6-diphenyl-4-methylphenyl group, 2,6-diphenyl-4-methoxyphenyl group, 2,6-diisopropoxyphenyl group, 2,6-diisopropoxy-4-methylphenyl group, 2,6-diisopropoxy-4-methoxyphenyl group, 2,6-dicyclohexyloxyphenyl group, 2,6-dicyclohexyloxy-4-methylphenyl group, 2,6-dicyclohexyloxy-4- methoxyphenyl group, 2,6-diphenoxyphenyl group, 2,6-diphenoxy-4-methylphenyl group, 2,6-diphenoxy-4-methoxyphenyl group, 2,6-bis(trimethylsilyl)phenyl group, 2, 6-bis(trimethylsilyl)-4-methylphenyl group, 2,6-bis(trimethylsilyl)-4-methoxyphenyl group, 2,6-bis(triethylsilyl)phenyl group, 2,6-bis(triethylsilyl)- A 4-methylphenyl group, a 2,6-bis(triethylsilyl)-4-methoxyphenyl group, a 2,4,6-triisopropylphenyl group and a 2,4,6-tri-t-butylphenyl group are preferred.

Among these, 2,6-di-t-butylphenyl group, 2,6-di-t-butyl-4-methylphenyl group, 2,6-di-t-butyl-4-methoxyphenyl group, 2, 6-dicyclohexylphenyl group, 2,6-dicyclohexyl-4-methylphenyl group, 2,6-dicyclohexyl-4-methoxyphenyl group, 2,6-diphenylphenyl group, 2,6-diphenyl-4-methylphenyl group, 2,6-diphenyl-4-methoxyphenyl group, 2,6-bis(trimethylsilyl)phenyl group, 2,6-bis(trimethylsilyl)-4-methylphenyl group, 2,6-bis(trimethylsilyl)-4-methoxy phenyl group, 2,6-bis(triethylsilyl)phenyl group, 2,6-bis(triethylsilyl)-4-methylphenyl group, 2,6-bis(triethylsilyl)-4-methoxyphenyl group, 2,4 ,6-tri-t-butylphenyl group is more preferred.

Specific examples of the organoaluminum compound (A) include ethylaluminum bis(2,6-di-t-butylphenoxide), ethylaluminum bis(2,6-di-t-butyl-4-methylphenoxide), Ethyl aluminum bis(2,6-di-t-butyl-4-methoxyphenoxide), Ethyl aluminum bis(2,6-dicyclohexylphenoxide), Ethyl aluminum bis(2,6-dicyclohexyl-4-methylphenoxide), Ethyl aluminum bis(2,6-dicyclohexyl-4-methoxyphenoxide), ethylaluminum bis(2,6-diphenylphenoxide), ethylaluminum bis(2,6-diphenyl-4-methylphenoxide), ethylaluminum bis(2,6- diphenyl-4-methoxyphenoxide), ethylaluminum bis(2,6-bis(trimethylsilyl)phenoxide), ethylaluminum bis(2,6-bis(trimethylsilyl)-4-methylphenoxide), ethylaluminum bis(2,6- bis(trimethylsilyl)-4-methoxyphenoxide), ethylaluminum bis(2,6-bis(triethylsilyl)phenoxide), ethylaluminum bis(2,6-bis(triethylsilyl)-4-methylphenoxide), ethylaluminum bis (2,6-bis(triethylsilyl)-4-methoxyphenoxide), n-propylaluminum bis(2,6-di-t-butylphenoxide), n-propylaluminum bis(2,6-di-t-butyl -4-methylphenoxide), n-propylaluminum bis(2,6-di-t-butyl-4-methoxyphenoxide), n-propylaluminum bis(2,6-dicyclohexylphenoxide), n-propylaluminum bis(2 ,6-dicyclohexyl-4-methylphenoxide), n-propylaluminum bis(2,6-dicyclohexyl-4-methoxyphenoxide), n-propylaluminum bis(2,6-diphenylphenoxide), n-propylaluminum bis(2 ,6-diphenyl-4-methylphenoxide), n-propylaluminum bis(2,6-diphenyl-4-methoxyphenoxide), n-propylaluminum bis(2,6-bis(trimethylsilyl)phenoxide), n-propylaluminum Bis(2,6-bis(trimethylsilyl)-4-methyl phenoxide), n-propylaluminum bis(2,6-bis(trimethylsilyl)-4-methoxyphenoxide), n-propylaluminum bis(2,6-bis(triethylsilyl)phenoxide), n-propylaluminum bis(2, 6-bis(triethylsilyl)-4-methylphenoxide), n-propylaluminum bis(2,6-bis(triethylsilyl)-4-methoxyphenoxide), isobutylaluminum bis(2,6-di-t-butylphenoxide) ), isobutylaluminum bis(2,6-di-t-butyl-4-methylphenoxide), isobutylaluminum bis(2,6-di-t-butyl-4-methoxyphenoxide), isobutylaluminum bis(2,6- dicyclohexylphenoxide), isobutylaluminum bis(2,6-dicyclohexyl-4-methylphenoxide), isobutylaluminum bis(2,6-dicyclohexyl-4-methoxyphenoxide), isobutylaluminum bis(2,6-diphenylphenoxide), isobutylaluminum Bis(2,6-diphenyl-4-methylphenoxide), isobutylaluminum bis(2,6-diphenyl-4-methoxyphenoxide), isobutylaluminum bis(2,6-bis(trimethylsilyl)phenoxide), isobutylaluminum bis(2 ,6-bis(trimethylsilyl)-4-methylphenoxide), isobutylaluminum bis(2,6-bis(trimethylsilyl)-4-methoxyphenoxide), isobutylaluminum bis(2,6-bis(triethylsilyl)phenoxide), isobutyl aluminum bis(2,6-bis(triethylsilyl)-4-methylphenoxide) and isobutylaluminum bis(2,6-bis(triethylsilyl)-4-methoxyphenoxide).

Among these, isobutylaluminum bis(2,6-di-t-butylphenoxide), isobutylaluminum bis(2,6-di-t-butyl-4-methylphenoxide), isobutylaluminum bis(2,6-di- t-butyl-4-methoxyphenoxide), isobutylaluminum bis(2,6-dicyclohexylphenoxide), isobutylaluminum bis(2,6-dicyclohexyl-4-methylphenoxide), isobutylaluminum bis(2,6-dicyclohexyl-4- methoxyphenoxide), isobutylaluminum bis(2,6-diphenylphenoxide), isobutylaluminum bis(2,6-diphenyl-4-methylphenoxide), isobutylaluminum bis(2,6-diphenyl-4-methoxyphenoxide), isobutylaluminum Bis(2,6-bis(trimethylsilyl)phenoxide), isobutylaluminum bis(2,6-bis(trimethylsilyl)-4-methylphenoxide), isobutylaluminum bis(2,6-bis(trimethylsilyl)-4-methoxyphenoxide) , isobutylaluminum bis(2,6-bis(triethylsilyl)phenoxide), isobutylaluminum bis(2,6-bis(triethylsilyl)-4-methylphenoxide), isobutylaluminum bis(2,6-bis(triethylsilyl) -4-methoxyphenoxide) is preferred.

<Organic phosphorus compound (B)>
The organophosphorus compound (B) is one of the constituent components of the polymerization catalyst of the present invention.
The organophosphorus compound (B) is represented by the following formula (2).
^{PR2R3R4 ( 2} )
[In Formula (2), P represents a phosphorus atom. R ² , R ³ and R ⁴ are each independently a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom or an aromatic hydrocarbon having 6 to 20 carbon atoms which may contain a heteroatom is any of the ]

In the present invention, in formula (2), R ² , R ³ and R ⁴ are each independently a hydrocarbon group optionally containing a heteroatom and having 1 to 10 carbon atoms or a heteroatom-containing It represents a good aromatic hydrocarbon group having 6 to 20 carbon atoms.

In R ² , R ³ and R ⁴ , heteroatoms include oxygen, nitrogen, silicon, iodine, bromine, chlorine and fluorine. Among these heteroatoms, oxygen, nitrogen, silicon, chlorine and fluorine are preferred. Examples of these heteroatom-containing groups containing heteroatoms include oxygen-containing groups such as alkoxyaryl groups and aryloxy groups, and nitrogen-containing groups such as dialkylaminoaryl groups and diarylaminoaryl groups. Examples of containing groups include trialkylsilylaryl groups, dialkylarylsilylaryl groups, and alkyldiarylsilylaryl groups. Examples of chlorine-containing groups include chlorinated aryl groups. Examples of fluorine-containing groups include fluorinated aryl groups. is mentioned.

Specific examples of R ² , R ³ and R ⁴ include (when the position of the substituent on the phenyl group is not specified, for example, when a methylphenyl group is described, a 3- or 4-methylphenyl group ), methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, n-pentyl group, cyclopentyl group, n-hexyl group, cyclohexyl group, n- Hydrocarbon groups such as butyl group, n-octyl group, n-nonyl group, n-decyl group, phenyl group, methylphenyl group, ethylphenyl group, n-butylphenyl group, isobutylphenyl group, t-butylphenyl group, etc. Aromatic hydrocarbon groups, methoxyphenyl groups, ethoxyphenyl groups, n-propoxyphenyl groups, alkoxy group-containing aryl groups such as isopropoxyphenyl groups, phenoxy groups, aryloxy groups such as methylphenoxy groups, dimethylaminophenyl groups, diethylamino A dialkylamino group-containing aryl group such as a phenyl group, a diarylamino group-containing aryl group such as a diphenylaminophenyl group, a chlorophenyl group, a chlorinated aryl group such as a 3,5-dichlorophenyl group, a fluorophenyl group, and 3,5-difluorophenyl and fluorinated aryl groups such as groups.
Among them, hydrocarbon groups such as methyl group, t-butyl group, cyclopentyl group and cyclohexyl group; aromatic hydrocarbon groups such as phenyl group, methylphenyl group and t-butylphenyl group; and alkoxy group-containing aryl groups such as methoxyphenyl group. phenoxy group, aryloxy group such as methylphenoxy group, chlorinated aryl group such as chlorophenyl group, and fluorinated aryl group such as fluorophenyl group.

Among these, hydrocarbon groups such as methyl group, t-butyl group, cyclopentyl group and cyclohexyl group; aromatic hydrocarbon groups such as phenyl group, 4-methylphenyl group and 4-t-butylphenyl group; More preferred are alkoxy group-containing aryl groups such as methoxyphenyl group, aryloxy groups such as phenoxy group and 4-methylphenoxy group, chlorinated aryl groups such as 4-chlorophenyl group, and fluorinated aryl groups such as 4-fluorophenyl group.

Specific examples of the organic phosphorus compound (B) include triphenylphosphine, tris(4-methylphenyl)phosphine, tris(4-t-butylphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4- chlorophenyl)phosphine, tris(4-fluorophenyl)phosphine, methyldiphenylphosphine, t-butyldiphenylphosphine, cyclopentyldiphenylphosphine, cyclohexyldiphenylphosphine, phenyldiphenylphosphine, dimethylphenylphosphine, di(t-butyl)phenylphosphine, Dicyclohexylphenylphosphine, tri(t-butyl)phosphine, tricyclohexylphosphine.

Among these, triphenylphosphine, tris(4-methylphenyl), tris(4-t-butylphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-chlorophenyl)phosphine, tris(4-fluorophenyl) ) phosphine, methyldiphenylphosphine, t-butyldiphenylphosphine, cyclopentyldiphenylphosphine, cyclohexyldiphenylphosphine, phenyldiphenylphosphine, tri(t-butyl)phosphine, tricyclohexylphosphine.

<Methacrylic acid ester>
The methacrylic acid ester used in the present invention is a functional group derived from methacrylic acid and an aliphatic group, an alicyclic group, an aromatic group, an araliphatic group, various heterocyclic alcohols, or a hydroxy compound. is a methacrylic acid ester present in
Specific examples include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, and methacryl. Examples include, but are not limited to, cyclohexyl acid, vinyl methacrylate, allyl methacrylate, phenyl methacrylate, benzyl methacrylate, naphthyl methacrylate, 2-methoxyethyl methacrylate, dimethylaminoethyl methacrylate, and the like.
Alternatively, the methacrylic acid ester used in the present invention improves the heat resistance, transparency, weather resistance, and mechanical properties of the resulting methacrylic acid ester polymer. MMA) is preferably contained in an amount of 80% by mass or more. Specifically, 100% by mass of methyl methacrylate (MMA) alone, or 80% by mass or more and less than 100% by mass of MMA and more than 0% by mass and 20% by mass or less of other monomers and monomer mixtures.

The other monomer is not particularly limited as long as it is copolymerizable with MMA, and examples thereof include the following a) to f).
a) Methyl acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-(meth)acrylate ethylhexyl, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, n-amyl (meth)acrylate, Isoamyl (meth)acrylate, Lauryl (meth)acrylate, Benzyl (meth)acrylate, Phenyl (meth)acrylate, Cyclohexyl (meth)acrylate, Methoxyethyl (meth)acrylate, Ethoxyethyl (meth)acrylate , 2-naphthyl (meth)acrylate, phenoxymethyl (meth)acrylate, and other (meth)acrylic acid ester compounds other than MMA.
b) styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, o-ethylstyrene, p-ethylstyrene, o-chlorostyrene, p-chlorostyrene, p-methoxystyrene, p-acetoxystyrene, α - Aromatic vinyl compounds such as vinylnaphthalene and 2-vinylfluorene.
c) Unsaturated nitrile compounds such as acrylonitrile, α-chloroacrylonitrile, α-methoxyacrylonitrile, methacrylonitrile, vinylidene cyanide.
d) Ethylenically unsaturated ether compounds such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, methyl allyl ether, ethyl allyl ether.
e) vinyl halide compounds such as vinyl chloride, vinylidene chloride, 1,2-dichloroethylene, vinyl bromide, vinylidene bromide, 1,2-dibromoethylene;
f) 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-neopentyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,2-dichloro-1,3-butadiene, 2,3-dichloro-1,3-butadiene, 2-bromo-1,3-butadiene, 2-cyano-1,3-butadiene, substituted linear conjugated pentadiene , aliphatic conjugated diene compounds such as linear and side chain conjugated hexadienes.

These other monomers may be used singly or in combination of two or more.
Among these other monomers, alkyl acrylate having 1 to 8 carbon atoms in the alkyl group portion is less likely to impair the original performance of the methacrylic resin and tends to be excellent in thermal decomposition resistance of the molded product. Preferred are methyl acrylate, ethyl acrylate and n-butyl acrylate, and more preferred are methyl acrylate and ethyl acrylate.

<Method for producing methacrylic acid ester polymer>
The method for producing a methacrylic acid ester polymer of the present invention includes polymerizing a methacrylic acid ester in the presence of the polymerization catalyst of the present invention.
In the production method of the present invention, the polymerization method is not particularly limited, and examples thereof include bulk polymerization, suspension polymerization, emulsion polymerization, and solution polymerization. Among these polymerization methods, it is possible to increase the polymerization conversion rate with a small amount of polymerization initiator due to the gel effect, and it is easy to control the temperature in the polymerization reaction system even when polymerization heat is generated. Bulk polymerization is preferred from the viewpoint of excellent production stability. In particular, the polymerization catalyst of the present invention can be suitably used for bulk polymerization because it sufficiently functions as a polymerization catalyst for methacrylic acid esters even at room temperature or higher. The bulk polymerization method includes a so-called bulk polymerization method using a methacrylic acid ester as a polymerization solvent, a method in which a catalyst is deactivated by reacting with the catalyst, or a monomer is reacted with to degrade it. Otherwise, the so-called solution polymerization method of polymerizing the monomers in the presence of an appropriate polymerization solvent is suitable.
The polymerization solvent for the solution polymerization method is not particularly limited as long as it is an inert solvent, and examples thereof include toluene, xylene, ethylbenzene, methylene chloride, chloroform and dichlorobenzene. These solvents may be used alone or in combination of two or more. Among these solvents, toluene, xylene, ethylbenzene, and chloroform are preferable because they are excellent in solubility, reactivity, and separability.

The lower limit of the polymerization temperature in the bulk polymerization method is not particularly limited, but the stereoregularity (rr triad %) of the resulting methacrylic acid ester polymer is increased, the heat resistance is improved, and the heat generated by the polymerization is From the viewpoint of facilitating temperature control in the polymerization reaction system even when is generated, the temperature is preferably 35° C. or higher. 40° C. or higher is more preferable, and 45° C. or higher is even more preferable. On the other hand, the upper limit of the polymerization temperature is not particularly limited, and may be a temperature equal to or higher than the boiling point of the methacrylic acid ester or the solvent used. If the polymerization temperature becomes high, the stereoregularity (rr triad %) of the obtained methacrylic acid ester polymer tends to decrease, so the polymerization temperature is preferably 120° C. or less. 110° C. or lower is more preferable, and 100° C. or lower is even more preferable.
As the bulk polymerization method, both batch type and continuous type can be adopted. A polymer can be obtained with high productivity by a method of continuously withdrawing the resulting partial polymer.

The ratio of the constituent components of the polymerization catalyst of the present invention is not particularly limited, but the organoaluminum compound (A) and the organophosphorus compound (B) are (A):(B) = 1:99 to 99:1 (molar ratio ) in an organic solvent such as toluene or benzene at 0 to 100° C. under reduced pressure to increased pressure for 1 to 86,400 seconds.
After completion of the reaction, in addition to the polymerization catalyst, other components derived from (A) and (B) and the solvent component used coexist. , may or may not be removed.
A (meth)acrylic acid ester may be added to the obtained polymerization catalyst to initiate polymerization, or the obtained polymerization catalyst may be added to the (meth)acrylic acid ester.
Also, the (meth)acrylic acid ester may be mixed before the contact. That is, the catalyst component (B) may be added to a mixed solution of the catalyst component (A) and the (meth)acrylic acid ester to initiate polymerization, or the catalyst component (B) and the (meth)acrylic acid ester Polymerization may be initiated by adding the catalyst component (A) to the mixed solution.
The addition may be made at once, or may be made at certain intervals.

A methacrylic acid ester polymer can be obtained by devolatilizing the volatile components in the partial polymer using a known volatile component removing device. A devolatilizing extruder such as a single-screw extruder or a twin-screw extruder is preferable as the volatile component removing device because of its excellent devolatilizing efficiency. A person skilled in the art can appropriately set the devolatilization temperature and the degree of pressure reduction when devolatilizing the volatile components based on well-known techniques.

<Methacrylic acid ester polymer>
The methacrylic acid ester polymer of the present invention is a polymer of the methacrylic acid ester described above, and is an MMA homopolymer, or a repeating unit derived from MMA of 80% by mass or more and less than 100% by mass and derived from the other monomer described above. It is an MMA copolymer containing more than 0% by mass and 20% by mass or less of repeating units.
The methacrylic acid ester polymer of the present invention is produced using the polymerization catalyst of the present invention. and has excellent heat resistance.
Specifically, as disclosed in the Examples, when the methacrylate polymer is an MMA homopolymer, a glass transition temperature of 130-131° C. can be obtained at an rr triad % of 75-80%. In addition, the methacrylic acid ester polymer of the present invention is not limited to such an MMA homopolymer.

The methacrylic acid ester polymer of the present invention can be used, for example, as a molding material. Examples of methods for obtaining a molded article from a methacrylic acid ester polymer include known molding methods such as known injection molding methods, extrusion molding methods, and pressure molding methods.
In that case, if necessary, lubricants such as higher alcohols and higher fatty acid esters, release agents, ultraviolet absorbers, antioxidants, heat stabilizers, colorants, antistatic agents, flame retardants, etc. may be contained within a range that does not impair the effects of the present invention.

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these.
Nitrogen used in the experiment was dehydrated using a molecular sieve (manufactured by Kishida Chemical Co., Ltd., product name "Molecular Sieve 4A") calcined at 300 ° C. in a nitrogen atmosphere, and then subjected to gas screen dry column (Nika Seiko Co., Ltd.) Purified nitrogen from which oxygen was removed using the product name "GASCLEAN GC-RX" (manufactured by the company) was used.
All the solvents and reagents used in the experiments were purified, degassed and dehydrated by known methods, and then stored under a purified nitrogen atmosphere.
A Schlenk cannula technique and a dry box filled with purified nitrogen were used when working with compounds that were readily degraded by air or moisture. Synthesis of the polymerization catalyst and polymerization of the methacrylic acid ester were carried out in a flask filled with purified nitrogen.

Each measurement/evaluation method in this example is as follows.

[Measurement/Evaluation]
<Quantitative determination of polymer syndiotacticity (rr triad %)>
Using ^{a 1} H-NMR spectrometer (manufactured by Bruker, "AVANCE400"), the stereoselectivity of the polymer was measured according to the following procedure.
The polymer was dissolved in chloroform _- d1 solvent so that the concentration was about 5% by mass, and the measurement was carried out under the conditions of 32 accumulation times and a measurement temperature of 20°C. The rr triad % (hereinafter abbreviated as "rr %") was calculated from the integral ratio of the chemical shifts of ¹ H-NMR and used as the value of the syndiotacticity of the polymer.

<Glass transition temperature (Tg)>
Using a differential scanning calorimeter (DSC) ("Diamond DSC" manufactured by PerkinElmer), the glass transition temperature (Tg) was measured according to the following procedure. About 10 mg of polymer was placed in a sample container and held at 20° C. for 1 minute. Then, the temperature was raised from 20° C. to 180° C. at a temperature elevation rate of 10° C./min, and held at 180° C. for 4 minutes. Then, it was cooled from 180°C to 0°C at a cooling rate of 10°C/min and held at 0°C for 4 minutes. After that, the temperature was raised from 0° C. to 180° C. at a heating rate of 10° C./min, and the glass transition temperature (Tg) (unit:° C.) at this time was determined.

<Melt flow index (MI)>
Using a manual/tabletop melt indexer ("L260" manufactured by Tateyama Kagaku Kogyo Co., Ltd.), the diameter is measured under the conditions of 230 ° C. and a load of 3.8 kgf (37 N) according to Japanese Industrial Standards ISO8257-1. The discharge amount (unit: g) of the polymer discharged from a nozzle having a length of 2 mm and a length of 8 mm was measured. The cutting interval of the discharged polymer is set to 10 seconds to 180 seconds according to the fluidity of the polymer, and is converted to the discharge amount per 10 minutes (unit: g/10 minutes), which is the melt flow index of the polymer. (MI).

(raw materials)
The abbreviations of the compounds used in Examples and Comparative Examples are as follows.
MMA: methyl methacrylate PCy ₃ : tricyclohexylphosphine Organoaluminum compound (A-1): isobutylaluminum bis(2,6-di-t-butyl-4-methylphenoxide), chemical formula: iBuAl(BHT) ₂ , "J .App. Poly. Sci.
Organoaluminum compound (A-2): methylaluminum bis(2,6-di-t-butyl-4-methylphenoxide), chemical formula: MeAl(BHT) ₂ , manufactured by Tokyo Chemical Industry Co., Ltd.

[Production Example 1 (Synthesis of iBuAl(BHT) ₂ )]
To a toluene solution (8.0 mL) of 2,6-di-t-butyl-4-methylphenol (7.58 g, 0.034 mol) was added a toluene solution (11 .5 mL) was added dropwise at 25° C. over 30 minutes. The mixture was stirred at the same temperature for 1 hour to synthesize isobutylaluminum bis(2,6-di-t-butyl-4-methylphenoxide), which was used as an organoaluminum compound (A-1) (hereinafter referred to as " iBuAl(BHT) ₂ ”).

[Example 1]
After degassing the inside of a 300 mL four-necked separable flask and replacing it with purified nitrogen, 23.3 g of MMA and 0.16 mL of a 0.6 M toluene solution of PCy ₃ (PCy ₃ : 0.10 mmol) were added, and purified nitrogen was added. Under the atmosphere, the mixture was stirred with a mechanical stirrer at 40° C. for 5 minutes to obtain a mixture.
To the obtained mixture, 0.33 mL of a 0.60 mol/L toluene solution of iBuAl(BHT) ₂ (0.20 mmol as the amount of iBuAl(BHT) ₂ added) was added as a polymerization catalyst. C. for 36 minutes. Then, 3 mL of methanol and 80 mL of chloroform were added and stirred at 40° C. for 30 minutes to obtain a reaction solution.
The resulting reaction solution was slowly added dropwise to a mixture (x2) of methanol (800 mL) and 1N hydrochloric acid (10 mL) to obtain a precipitate (MMA polymer). After the obtained precipitate was filtered with a Kiriyama funnel and taken out, purification by a reprecipitation method using chloroform as a good solvent and methanol as a poor solvent was repeated several times to wash the precipitate. After the washed precipitate was air-dried overnight, it was finally dried under reduced pressure at 25° C. for 4 hours to obtain 9.0 g of a methacrylic acid ester polymer. Table 1 shows the evaluation results of the obtained methacrylic acid ester polymer.

[Example 2]
A methacrylic acid ester polymer was obtained in the same manner as in Example 1 except that the polymerization temperature was 52° C. and the amount of iBuAl(BHT) ₂ added as a polymerization catalyst was 0.12 mmol. Table 1 shows the evaluation results of the obtained methacrylic acid ester polymer.

[Example 3]
A methacrylic acid ester polymer was obtained in the same manner as in Example 2 except that the polymerization temperature was changed to 71°C. Table 1 shows the evaluation results of the obtained methacrylic acid ester polymer.
[Comparative Examples 1 to 3]
0.30 mL of a 0.60 mol/L toluene solution of the organoaluminum compound (A-2) (hereinafter also referred to as “MeAl(BHT) ₂ ”) used as a polymerization catalyst (addition amount of MeAl(BHT) ₂ is 0.18 mmol; ), and the polymerization temperature shown in Table 1 was changed to obtain a methacrylic acid ester polymer in the same manner as in Example 1. Table 1 shows the evaluation results of the obtained methacrylic acid ester polymer.

In the production methods of Examples 1 to 3, since the polymerization catalyst of the present invention is used, a methacrylic acid ester polymer having excellent stereoselectivity and heat resistance can be produced at a high temperature of 43 to 71°C. did it.
On the other hand, since the methacrylic acid ester polymers obtained by the production methods of Comparative Examples 1 to 3 were not produced using the polymerization catalyst of the present invention, they were obtained in Examples 1 to 3, which were carried out at almost the same polymerization temperature. Compared with the methacrylic acid ester polymer obtained, the stereoselectivity and heat resistance were inferior.

Claims (4)

A method for producing a methacrylic acid ester polymer having an rr triad % of 75% or more, comprising polymerizing a methacrylic acid ester in the presence of a polymerization catalyst,
The polymerization catalyst contains an organoaluminum compound (A) represented by the following formula (1) and an organophosphorus compound (B) represented by the following formula (2) ,
A method for producing a methacrylic acid ester polymer , comprising polymerizing a methacrylic acid ester at a temperature of 35° C. or higher .
R1Al( ^OAr1 )( ^OAr2 ) ( ¹ )
[In Formula (1), Al represents an aluminum atom, and O represents an oxygen atom. R ¹ represents a hydrocarbon group having 2 to 10 carbon atoms. Ar ¹ and Ar ² are each independently an aromatic hydrocarbon group having 6 to 20 carbon atoms which may contain a heteroatom. ]
^{PR2R3R4 ( 2} )
[In Formula (2), P represents a phosphorus atom. R ² , R ³ and R ⁴ are each independently a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom or an aromatic hydrocarbon having 6 to 20 carbon atoms which may contain a heteroatom is any of the ] 2. The methacryl according to claim 1, wherein R ¹ in formula (1) is at least one selected from the group consisting of ethyl, n-propyl, n-butyl, isobutyl and n-hexyl. A method for producing an acid ester polymer . The method for producing a methacrylic acid ester polymer according to claim 1, wherein R1 in general formula ( ¹ ) is an isobutyl group. The method for producing a methacrylic acid ester polymer according to any one of claims 1 to 3, wherein the methacrylic acid ester contains 80% by mass or more of methyl methacrylate with respect to the total mass.

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