Methacrylic acid ester polymer

Abstract

To provide a highly stereoselective methacrylic acid ester polymer having a low molecular weight and a wide molecular weight distribution with a smaller amount of catalyst used than before by improving initiator efficiency in the production of a methacrylic acid ester polymer by polymerization.SOLUTION: Provided is a methacrylic acid ester polymer, which is a methacrylic acid ester polymer (C) containing methacrylic acid ester units (A) by 95 to 99.99 mol % and acrylic acid ester units (B) by 0.01 to 5 mol %, and in which, characterized, (a) the syndiotacticity (rr) of the triad representation is 65 to 85%, (b) the number average molecular weight (Mn) is 20,000 to 180,000, and (c) the molecular weight distribution (Mw / Mn) is 1.2 to 3.0.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to methacrylic acid ester polymers. [Background technology]

[0002] (Meth)acrylic resin is used in a variety of fields, including vehicle parts, optical materials, lighting materials, and building materials, due to its excellent transparency and weather resistance.

[0003] In recent years, molded (meth)acrylic resins have been required to perform even better as parts become thinner and more detailed. One of the performance aspects is heat resistance. In particular, in applications such as vehicle parts such as taillights and headlights, vehicle parts are exposed to high-temperature environments, so there is a demand for (meth)acrylic resins with superior heat resistance. One known method for improving the heat resistance of (meth)acrylic resins is to increase the stereoregularity (syndiotacticity) of the (meth)acrylic resin.

[0004] For example, Patent Document 1 discloses a catalyst system that combines a specific organoaluminum compound with at least one compound selected from an organic nitrogen compound (B1) that does not have a hydrogen atom directly bonded to a nitrogen atom and an organic phosphorus compound (B2) that does not have a hydrogen atom directly bonded to a phosphorus atom, and an acrylic acid ester anionic polymerization at a low temperature of -20°C.

[0005] Patent Document 2 discloses a technique for polymerizing methacrylic acid esters using a solvent with a catalyst system that combines specific organoaluminum compounds, phenols, and bisoxazoline compounds. Patent Document 3 shows that by using specific organoaluminum compounds and organophosphorus compounds as polymerization catalysts, methacrylic acid ester polymers with high stereoselectivity and high glass transition temperatures can be obtained. Here, the organophosphorus compound functions as an initiator, and the combination of the organoaluminum compound and the organophosphorus compound functions as a polymerization catalyst.

[0006] Patent Document 4 shows that a methacrylic acid ester polymer having high stereoselectivity and a high glass transition temperature can be obtained by so-called anionic polymerization using an alkyllithium as a polymerization initiator.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, in the technology disclosed in Patent Document 1, it is necessary to carry out the polymerization reaction at a low temperature, which is difficult to implement on an industrial scale. Further, when applied to methacrylic acid esters, the polymerization efficiency was insufficient. Furthermore, for acrylic acid esters, an excessive amount of solvent is required, resulting in problems with reaction efficiency and productivity.

[0009] In the technology disclosed in Patent Document 2, the synthesis is not necessarily easy, and it is necessary to use a very expensive bisoxazoline compound, which is difficult to implement on an industrial scale. Further, the oxazoline compound disclosed in the examples does not have a substituent on the crosslinking group, so it is unstable at room temperature. Furthermore, for acrylic acid esters, an excessive amount of solvent is required, resulting in problems with reaction efficiency and productivity.

[0010] In the technology disclosed in Patent Document 3, the initiator efficiency is insufficient, resulting in the production of high molecular weight polymers, which tends to worsen moldability. Furthermore, obtaining low molecular weight polymers required the use of large amounts of catalyst. Increased catalyst usage not only leads to increased manufacturing costs but also causes problems such as yellowing of the resin due to catalyst residue.

[0011] In the technology disclosed in Patent Document 4, the molecular weight distribution of the resulting methacrylic acid ester polymer is very narrow, at 1.1 or less, resulting in poor moldability. Therefore, it becomes necessary to ensure moldability by mixing multiple methacrylic resins. [Means for solving the problem]

[0012] In view of the above problems, the present inventors conducted diligent studies and found that, in accordance with the description in Patent Document 3, when polymerizing methacrylic acid esters using an organoaluminum compound and an organophosphorus compound as polymerization catalysts, copolymerizing the organophosphorus compound as an initiator with an equimolar or greater amount of acrylic acid ester improves initiator efficiency, resulting in the acquisition of a low molecular weight, highly stereoselective methacrylic acid ester polymer with a smaller catalyst amount than conventional methods. Furthermore, it was confirmed that the molecular weight distribution of the resulting polymer is 1.2 or higher, and that it exhibits excellent moldability. In other words, the present invention lies as follows.

[0013] [1] A methacrylic acid ester polymer (C) comprising 95 to 99.99 mol% of methacrylic acid ester units (A) and 0.01 to 5 mol% of acrylic acid ester units (B), (a) The syndiotacticity (rr) of the triple display is 65-85%, (b) The number-average molecular weight (Mn) is between 20,000 and 180,000. (c) The molecular weight distribution (Mw / Mn) is 1.2 to 3.0. A methacrylic acid ester polymer characterized by the following features. [2] The methacrylate ester polymer (C) of [1] above is further mixed with phosphorus at a rate of 10 to 5000 p A methacrylic acid ester polymer characterized by containing pm. [3] The methacrylate ester polymer (C) of [1] or [2] above has a phosphorus atom at its terminus. A methacrylic acid ester polymer characterized by the following. [Effects of the Invention]

[0014] The methacrylic acid ester polymer of the present invention can be produced by copolymerizing an organoaluminum compound and an organophosphorus compound as polymerization catalysts with an acrylic acid ester in equimolar or greater quantities, thereby improving initiator efficiency and enabling the production of a highly stereoselective methacrylic acid ester polymer with lower molecular weight and higher heat resistance than conventional polymers, using a smaller amount of catalyst. The methacrylic acid ester polymer obtained in this way has a relatively broad molecular weight distribution and excellent moldability. [Brief explanation of the drawing]

[0015] [Figure 1] This chart shows the 31P-NMR measurement results of PMMA obtained in Example 1. [Figure 2] This chart shows the 31P-NMR measurement results of PMMA obtained in Example 2. [Figure 3] This chart shows the 31P-NMR measurement results of PMMA obtained in Example 3. [Figure 4] This chart shows the 31P-NMR measurement results of PMMA obtained in Example 4. [Figure 5] This chart shows the 31P-NMR measurement results of PMMA obtained in Example 5. [Figure 6] This chart shows the 31P-NMR measurement results of PMMA obtained in Comparative Example 1. [Modes for carrying out the invention]

[0016] The embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is just one example of an embodiment of the present invention, and the present invention is not limited to these contents, and can be implemented in various ways within the scope of its gist.

[0017] 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 "unit" means a unit derived from the monomer formed by the polymerization of the monomer. The "unit" may be a unit directly formed by a polymerization reaction, or it may be a unit in which a part of the unit is converted to a different structure by processing the polymer. In this invention, "mass%" indicates the content of a specific component in 100% by mass of the total amount. "Mole%" indicates the amount of substance of a specific component in 100% by mole of the total amount. Unless otherwise specified, numerical ranges expressed using "~" in this specification mean a range that includes the numbers written before and after "~" as the lower and upper limits, and "A~B" means A or greater and B or less.

[0018] [Methacrylic acid ester polymer] The methacrylic acid ester polymer of the present invention is a methacrylic acid ester polymer (C) in which 95 to 99.99 mol% of methacrylic acid ester units (A) and 0.01 to 5 mol% of acrylic acid ester units (B) are contained in 100 mol% of the total constituent units of the methacrylic acid ester polymer (hereinafter, the content (mol%) of methacrylic acid ester units (A) and acrylic acid ester units (B) indicates the content in 100 mol% of the total constituent units of the methacrylic acid ester polymer), (a) The syndiotacticity (rr) of the triple display is 65-85%, (b) The number-average molecular weight (Mn) is between 20,000 and 180,000. (c) The molecular weight distribution (Mw / Mn) is 1.2 to 3.0. It is characterized by the following:

[0019] <Methacrylic acid ester unit (A)> The methacrylic acid ester constituting the methacrylic acid ester unit (A) according to the present invention is a methacrylic acid ester having a functional group derived from various alcohols or hydroxy compounds of the aliphatic, alicyclic, aromatic, aromaticaliphatic, or heterocyclic class in its side chain.

[0020] Specific examples include, but are not limited to, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, vinyl methacrylate, allyl methacrylate, phenyl methacrylate, benzyl methacrylate, naphthyl methacrylate, 2-methoxyethyl methacrylate, and dimethylaminoethyl methacrylate. These methacrylate esters may be used individually or in combination of two or more. good.

[0021] The content of methacrylic acid ester units (A) in the methacrylic acid ester polymer (C) of the present invention is 95 to 99.99 mol%, preferably 97 to 99.99 mol%.

[0022] The methacrylic acid ester used in the present invention preferably contains 80% by mass or more of methyl methacrylate (MMA) units per 100% by mass of methacrylic acid ester units (A), because the resulting methacrylic acid ester polymer has good heat resistance, transparency, weather resistance, and mechanical properties. Specifically, examples include 100% by mass of methyl methacrylate (MMA) units alone, or a mixture containing 80% by mass or more but less than 100% by mass of MMA units and other monomer units exceeding 0% by mass and 20% by mass or less.

[0023] The aforementioned other monomers are not particularly limited as long as they are methacrylate esters copolymerizable with MMA, and examples include ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, heptyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, n-nonyl methacrylate, isononyl methacrylate, decyl methacrylate, undecyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, lauryl methacrylate, benzyl methacrylate, phenyl methacrylate, cyclohexyl methacrylate, methoxyethyl methacrylate, ethoxyethyl methacrylate, 2-naphthyl methacrylate, and phenoxymethyl methacrylate, which are methacrylate ester compounds other than MMA.

[0024] These other monomers may be used individually or in combination of two or more.

[0025] <Acrylate ester unit (B)> The acrylic acid ester constituting the acrylic acid ester unit (B) according to the present invention is not particularly limited as long as it is copolymerizable with methacrylate esters. Examples include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, heptyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-nonyl acrylate, isononyl acrylate, decyl acrylate, undecyl acrylate, n-amyl acrylate, isoamyl acrylate, lauryl acrylate, benzyl acrylate, phenyl acrylate, cyclohexyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, 2-naphthyl acrylate, and phenoxymethyl acrylate. These acrylic acid esters may be used individually or in combination of two or more.

[0026] Because it is less likely to impair the inherent properties of the methacrylic resin and the resulting molded article tends to have excellent thermal decomposition resistance, the acrylic acid ester of the acrylic acid ester unit (B) is preferably an alkyl acrylate with 1 to 8 carbon atoms in the alkyl group portion, more preferably methyl acrylate, ethyl acrylate, and n-butyl acrylate, and even more preferably methyl acrylate and ethyl acrylate.

[0027] The content of acrylic acid ester units (B) in the methacrylic acid ester polymer (C) of the present invention is 0.01 to 5 mol%, preferably 0.01 to 3 mol%. The reason for including acrylic acid ester units (B) in the methacrylic acid ester polymer (C) is that, during the polymerization reaction, the presence of acrylic acid ester together with the organophosphorus compound (E), described later, improves the efficiency of the organophosphorus compound (E) as an initiator, making it possible to obtain a low molecular weight methacrylic acid ester polymer (C) while reducing the amount of polymerization catalyst, especially the organophosphorus compound (E), used compared to conventional methods. Furthermore, a polymer with a broad molecular weight distribution can be obtained, resulting in a methacrylic acid ester polymer with excellent moldability.

[0028] <Syndiotacticity with Triple Display (rr)> The methacrylic acid ester polymer of the present invention is preferably produced using a polymerization catalyst described later, has high stereoregularity with an rr triad % (syndiotacticity) of 65-85%, preferably 70-85%, and has a high glass transition temperature of 125°C or higher, preferably 130°C or higher, and excellent heat resistance.

[0029] The methods for determining the syndiotacticity of the methacrylate polymer and measuring the glass transition temperature are as described in the Examples section below.

[0030] <Number average molecular weight (Mn) / molecular weight distribution (Mw / Mn)> The methacrylic acid ester polymer of the present invention exhibits good initiator efficiency during production, resulting in a relatively low number-average molecular weight (Mn) of 20,000 to 180,000, preferably 20,000 to 120,000, and more preferably 40,000 to 10,000, even with the use of a relatively small amount of catalyst, especially a small amount of initiator. Furthermore, it is a polymer that exhibits a relatively wide molecular weight distribution (Mw / Mn) of 1.2 to 3.0, preferably 1.2 to 2.5, and more preferably 1.2 to 2.0, thus exhibiting excellent moldability. The number-average molecular weight (Mn) and mass-average molecular weight (Mw) of the methacrylic acid ester polymer can be determined as monodisperse polymethyl methacrylate (PMMA) equivalent values ​​by gel permeation chromatography (GPC), and the specific measurement method is shown in the Examples section below.

[0031] <Phosphorus content> The methacrylic acid ester polymer of the present invention is produced using the organophosphorus compound (E) described below as an initiator, thereby cationizing the organophosphorus compound (E) and bonding it to the methacrylic acid ester polymer. Therefore, in this case, the methacrylic acid ester polymer of the present invention contains 10 to 5000 ppm of phosphorus, preferably 100 to 5000 ppm, and more preferably 100 to 2000 ppm. The phosphorus content can be measured by ICP emission spectrometry or the like. Furthermore, the methacrylic acid ester polymer of the present invention has a phosphorus atom at the terminal of the methacrylic acid ester polymer (C), and the presence of the terminal phosphorus atom is 31 This can be confirmed by P-NMR measurement. For example, it is present at the terminal end of the methacrylate ester polymer (C) obtained by polymerization using tricyclohexylphosphine and isobutylaluminum bis(2,6-di-t-butyl-4-methylphenoxide) as shown in the examples. The phosphorus atom was measured using deuterated chloroform as the solvent at a measurement temperature of 25°C. 31 In the P-NMR spectrum, a signal (peak) is observed at 20–40 ppm.

[0032] [Method for Producing Methacrylic Acid Ester Polymer] The methacrylic acid ester polymer (C) containing such methacrylic acid ester units (A) and acrylic acid ester units (B) is obtained by polymerizing a methacrylic acid ester and an acrylic acid ester in the presence of a polymerization catalyst containing the following organoaluminum compound (D) and organophosphorus compound (E) (hereinafter, may be referred to as "the polymerization catalyst of the present invention").

[0033] Hereinafter, the method for producing the methacrylic acid ester polymer of the present invention using the polymerization catalyst of the present invention will be described. However, the method for producing the methacrylic acid ester polymer of the present invention may be any method capable of producing the methacrylic acid ester polymer of the present invention, and is not limited to the following method at all.

[0034] [1] Polymerization Catalyst [Organoaluminum Compound (D)] The organoaluminum compound (D) which is one of the constituent components of the polymerization catalyst of the present invention is represented by the following formula (1). R 1 Al(OAr 1 )(OAr 2 ) (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 , Ar 2 are each independently an aromatic hydrocarbon group having 6 to 20 carbon atoms which may contain a hetero atom.]

[0035] In the present invention, in formula (1), R 1 represents a hydrocarbon group having 2 to 10 carbon atoms. R 1 has a steric interaction with the new monomer and is considered to greatly affect the stereoselectivity and polymerization activity. Therefore, if the carbon number of R 1 is too small, the stereoselectivity tends to be low. Also, if the carbon number of R 1 is excessively large, the intrusion of the monomer tends to be inhibited. For this reason, preferable R 1The carbon number is preferably 2 to 8, with a more preferable number being 2 to 6.

[0036] R 1 Specific examples of alkyl groups include ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, n-hexyl group, n-octyl group, and n-decyl group. Of these, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, n-hexyl group, and n-octyl group are preferred, and ethyl group, n-propyl group, n-butyl group, isobutyl group, and n-hexyl group are even more preferred.

[0037] In the present invention, in formula (1), Ar 1 and Ar 2 Each of these independently represents an aromatic hydrocarbon group having 6 to 20 carbon atoms, which may contain heteroatoms. Ar 1 and Ar 2 It is located near aluminum (Al) and interacts with Al sterically and / or electronically. In order to exert these effects, Ar 1 and Ar 2 It is preferable that the compound contains bulky substituents. Each bulky substituent is independently a C3-C6 hydrocarbon group which may contain a heteroatom, or a C6-C7 aromatic hydrocarbon group which may contain a heteroatom.

[0038] Examples of heteroatoms contained in heteroatom-containing groups include oxygen, nitrogen, phosphorus, sulfur, and silicon atoms. Of these heteroatoms, oxygen, nitrogen, and silicon atoms are preferred. Examples of heteroatom-containing groups that include these heteroatoms include alkoxy groups and allyloxy groups as oxygen atom-containing groups, dialkylamino groups and diarylamino groups as nitrogen atom-containing groups, dialkylphosphinos and diarylphosphinos as phosphorus atom-containing substituents, thioalkoxy groups (alkylthio groups) and thioaryloxy groups (arylthio groups) as sulfur atom-containing groups, and trialkylsilyl groups, dialkylarylsilyl groups, and alkyldiarylsilyl groups as silicon atom-containing groups. Of these heteroatom-containing groups, the most preferred are alkoxy groups, allyloxy groups, and trialkylsilyl groups.

[0039] Specific examples of bulky substituents include branched or cyclic hydrocarbon groups (alkyl groups) such as isopropyl, isobutyl, tert-butyl (t-butyl), neopentyl, and cyclohexyl groups; aromatic hydrocarbon groups such as phenyl groups; branched or cyclic alkoxy groups such as isopropoxy, isobutyroxy, t-butoxy, neopentyroxy, and cyclohexyloxy groups; allyloxy groups such as phenoxy; and trialkylsilyl groups such as trimethylsilyl and triethylsilyl groups.

[0040] Specific examples of aromatic hydrocarbon groups containing bulky substituents include phenyl, 4-methylphenyl, 4-methoxyphenyl, 1-naphthyl, and 2-naphthyl groups (where the carbon position at the base of the Al-O-Ar (aryl) bond is considered to be 1). Of these, phenyl, 4-methylphenyl, and 4-methoxyphenyl groups are preferred.

[0041] While the bulky substituent can be placed anywhere on the core of the aromatic hydrocarbon group, a position that exerts steric and / or electronic interactions with Al is preferred.

[0042] Specific positions include 2nd, 6th, 2nd and 6th, and 2nd, 4th and 6th. Of these, 2nd and 6th, and 2nd, 4th and 6th are preferred.

[0043] Ar 1 and Ar 2Specific examples include 2,6-diisopropylphenyl group, 2,6-diisopropyl-4-methylphenyl group, 2,6-diisopropyl-4-methoxyphenyl group, 2,6-diisobutylphenyl 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 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-dinopentyloxyphenyl group, 2,6-dinopentyloxy-4-methylphenyl group, 2,6-dinopentyloxy-4-methoxyphenyl group, 2,6-dicyclohexyloxyphenyl group, 2,6-dicyclohexyloxy-4-methylphenyl group, 2,6-dicyclohexyloxy-4-methoxyphenyl group, 2,6-diphenoxyphenyl group, Examples include 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, and 2,4,6-tri-t-butylphenyl group.

[0044] Of 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 The following groups are preferred: 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)-4-methylphenyl group, 2,6-bis(triethylsilyl)-4-methoxyphenyl group, 2,4,6-triisopropylphenyl group, and 2,4,6-tri-t-butylphenyl group.

[0045] Of 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-methoxyphenyl group, 2,6-bis(triethylsilyl)phenyl group, 2,6-bis(triethylsilyl)-4-methylphenyl group, 2,6-bis(triethylsilyl)-4-methoxyphenyl group, and 2,4,6-tri-t-butylphenyl group are more preferred.

[0046] Specific examples of organoaluminum compounds (D) include ethylaluminum bis(2,6-di-t-butylphenoxide), ethylaluminum bis(2,6-di-t-butyl-4-methylphenoxide), ethylaluminum bis(2,6-di-t-butyl-4-methoxyphenoxide), ethylaluminum bis(2,6-dicyclohexylphenoxide), ethylaluminum bis(2,6-dicyclohexyl-4-methylphenoxide), ethylaluminum bis(2,6-dicyclohexyl-4-methoxyphenoxide), and ethylaluminum bis(2,6-dicyclohexyl-4-methoxyphenoxide). Aluminum 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) n-propylaluminum bis(2,6-bis(triethylsilyl)-4-methylphenoxide), n-propylaluminum 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-dicyclohexyl-t-butyl-4-methylphenoxide), n-propylaluminum bis(2,6-di-t-butyl-4- 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-methylphenoxide), 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 Examples include nium 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), and isobutylaluminum bis(2,6-bis(triethylsilyl)-4-methoxyphenoxide).

[0047] Of 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), and isobutylaluminum bis(2,6-bis(triethylsilyl)-4-methoxyphenoxide) are preferred.

[0048] These organoaluminum compounds (D) may be used individually or in combination of two or more in any ratio.

[0049] <Organophosphorus compounds (E)> One of the components of the polymerization catalyst of the present invention, the organophosphorus compound (E), which is a polymerization initiator, is represented by the following formula (2). PR 2 R 3 R 4 (2) [In equation (2), P represents a phosphorus atom. R 2 , R 3 , R 4Each of these is independently either a hydrocarbon group having 1 to 10 carbon atoms that may contain a heteroatom, or an aromatic hydrocarbon group having 6 to 20 carbon atoms that may contain a heteroatom.

[0050] In the present invention, in formula (2), R 2 , R 3 , and R 4 Each of these independently represents a hydrocarbon group having 1 to 10 carbon atoms that may contain a heteroatom, or an aromatic hydrocarbon group having 6 to 20 carbon atoms that may contain a heteroatom.

[0051] R 2 , R 3 , and R 4 Examples of heteroatoms include oxygen, nitrogen, silicon, iodine, bromine, chlorine, and fluorine atoms. Of these heteroatoms, oxygen, nitrogen, silicon, chlorine, and fluorine atoms are preferred. Examples of heteroatom-containing groups that include these heteroatoms include alkoxyaryl and allyloxy groups as oxygen atom-containing groups, dialkylaminoaryl and diarylaminoaryl groups as nitrogen atom-containing groups, trialkylsilylaryl, dialkylarylsilylaryl and alkyldiarylsilylaryl groups as silicon atom-containing groups, aryl chlorinated groups as chlorine atom-containing groups, and aryl fluorinated groups as fluorine atom-containing groups.

[0052] R 2 , R 3 , and R 4Specific examples include hydrocarbon groups (alkyl groups) such as 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-heptyl group, n-octyl group, n-nonyl group, and n-decyl group; aromatic hydrocarbon groups such as phenyl group, methylphenyl group, ethylphenyl group, n-butylphenyl group, isobutylphenyl group, and t-butylphenyl group; alkoxy group-containing aryl groups such as methoxyphenyl group, ethoxyphenyl group, n-propoxyphenyl group, and isopropoxyphenyl group; aryloxy groups such as phenoxy group and methylphenoxy group; dialkylamino group-containing aryl groups such as dimethylaminophenyl group and diethylaminophenyl group; diarylamino group-containing aryl groups such as diphenylaminophenyl group; chlorinated aryl groups such as chlorophenyl group and 3,5-dichlorophenyl group; and fluorinated aryl groups such as fluorophenyl group and 3,5-difluorophenyl group. In the examples above, if the position of the substituent on the phenyl group is not specifically specified, the substituent is at position 3 or 4. For example, "methylphenyl group" refers to "3-methylphenyl group or 4-methylphenyl group."

[0053] Of these, hydrocarbon groups such as methyl, t-butyl, cyclopentyl, and cyclohexyl groups; aromatic hydrocarbon groups such as phenyl, methylphenyl, and t-butylphenyl groups; alkoxy-containing aryl groups such as methoxyphenyl groups; allyloxy groups such as phenoxy and methylphenoxy groups; chlorinated aryl groups such as chlorophenyl groups; and fluorinated aryl groups such as fluorophenyl groups are preferred. Among these, hydrocarbon groups such as methyl, t-butyl, cyclopentyl, and cyclohexyl groups; aromatic hydrocarbon groups such as phenyl, 4-methylphenyl, and 4-t-butylphenyl groups; alkoxy-containing aryl groups such as 4-methoxyphenyl groups; allyloxy groups such as phenoxy and 4-methylphenoxy groups; chlorinated aryl groups such as 4-chlorophenyl groups; and fluorinated aryl groups such as 4-fluorophenyl groups are even more preferred.

[0054] Specific examples of organophosphorus compounds (E) 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, phenyldiphenylphosphinite, dimethylphenylphosphine, di(t-butyl)phenylphosphine, dicyclohexylphenylphosphine, tri(t-butyl)phosphine, and tricyclohexylphosphine.

[0055] Of 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, phenyldiphenylphosphinite, tri(t-butyl)phosphine, and tricyclohexylphosphine are preferred.

[0056] These organophosphorus compounds (E) may be used individually or in combination of two or more in any ratio.

[0057] [Ingredient ratio and usage amount] The proportion of the constituent components of the polymerization catalyst of the present invention is not particularly limited, but the organoaluminum compound (D) and the organophosphorus compound (E) can be used in a molar ratio of (organoaluminum compound (D)):(organophosphorus compound (E)) = 1:10 to 10:1.

[0058] The polymerization catalyst of the present invention can be obtained by contacting an organoaluminum compound (D) and an organophosphorus compound (E) in the above proportions in an organic solvent such as toluene or benzene under reduced pressure to increased pressure for 1 to 86,400 seconds. However, some or all of the (meth)acrylic acid ester, which is the starting monomer, may be added before contacting the organoaluminum compound (D) and the organophosphorus compound (E), and there are no particular restrictions on the form of addition. That is, polymerization may be started by adding (meth)acrylic acid ester to the polymerization catalyst obtained as described above, or the obtained polymerization catalyst may be added to the (meth)acrylic acid ester. Alternatively, the (meth)acrylic acid ester may be mixed before contacting the organoaluminum compound (D) and the organophosphorus compound (E). For example, polymerization may be started by adding the organophosphorus compound (E) to a mixture of organoaluminum compound (D) and (meth)acrylic acid ester, or polymerization may be started by adding the organoaluminum compound (D) to a mixture of organophosphorus compound (E) and (meth)acrylic acid ester. These components may be added all at once, intermittently at a certain period, or continuously. After contact between the organoaluminum compound (D) and the organophosphorus compound (E), other components derived from (D) and (E) and the solvent components used will be present in addition to the polymerization catalyst. However, when carrying out the polymerization reaction of the present invention, these other components may or may not be removed.

[0059] There are no particular restrictions on the amount of polymerization catalyst used in the present invention, and it varies depending on the polymerization method and the molecular weight of the target methacrylic acid ester polymer (C). However, from the viewpoint of obtaining a relatively low molecular weight methacrylic acid ester polymer (C) with excellent moldability, it is preferable that the amount is 0.01 to 1 mol%, particularly 0.1 to 0.5 mol%, based on 100 mol% of the total of methacrylic acid ester and acrylic acid ester.

[0060] In particular, the methacrylic acid ester polymer of the present invention is characterized by the ability to improve the initiator efficiency of the polymerization catalyst, especially the organophosphorus compound (E), by having the acrylic acid ester coexist with the organophosphorus compound (E) in the polymerization reaction system, thereby obtaining a low molecular weight, highly stereoselective methacrylic acid ester polymer even with a small amount of polymerization catalyst. This effect can be particularly pronounced by using equimolar or greater amounts of acrylic acid ester relative to the organophosphorus compound (E). From this viewpoint, the organophosphorus compound (E) is preferably 0.01 to 1 mol%, particularly 0.1 to 0.5 mol%, relative to 100 mol% of the total amount of methacrylic acid ester and acrylic acid ester used in polymerization. Furthermore, the organoaluminum compound (D) is preferably 0.1 to 10 molar times, particularly 1 to 10 molar times, relative to the organophosphorus compound (E).

[0061] [2] Polymerization method The polymerization method is not particularly limited and examples include bulk polymerization, suspension polymerization, emulsion polymerization, and solution polymerization. Among these polymerization methods, bulk polymerization or solution polymerization is preferred because it is easy to increase the polymerization conversion rate, the temperature in the polymerization reaction system can be easily controlled even when polymerization exothermic occurs, and the manufacturing stability of methacrylate ester polymers is excellent.

[0062] The polymerization solvent for solution polymerization is not particularly limited as long as it does not deactivate the catalyst or react with and alter the monomer. Examples include hexane, heptane, toluene, xylene, ethylbenzene, methylene chloride, chloroform, and dichlorobenzene. These solvents may be used individually or in combination of two or more. Among these solvents, toluene, xylene, ethylbenzene, and chloroform are preferred due to their excellent solubility, reactivity, and separation properties.

[0063] The lower limit of the polymerization temperature is not particularly limited. Generally, it is preferable to have a temperature of 0°C or higher from the viewpoint of increasing the polymerization conversion rate. On the other hand, the upper limit of the polymerization temperature is not particularly limited and can be set to a temperature above the boiling point of the methacrylic acid ester or the solvent used. As the polymerization temperature increases, the stereoregularity (rr triad%) of the resulting methacrylic acid ester polymer tends to decrease, and the catalyst tends to become inactive, leading to a decrease in the polymerization conversion rate, so a temperature of 120°C or lower is preferable. 110°C or lower is more preferable, and 100°C or lower is even more preferable. In this invention, the presence of an acrylic acid ester for introducing acrylic acid ester units (B) together with an organophosphorus compound (E) in the reaction system improves the efficiency of the organophosphorus compound (E) as an initiator. Therefore, polymerization is possible over a wide temperature range. The polymerization temperature for obtaining the methacrylic acid ester polymer of this invention is preferably 0 to 100°C, and more preferably 20 to 80°C.

[0064] Both batch and continuous polymerization methods can be employed. For example, polymers can be obtained with high productivity by continuously supplying monomer components and polymerization initiators into a reaction vessel and continuously withdrawing the resulting partial polymer after it has been retained in the vessel for a predetermined time.

[0065] As described above, polymerization may be initiated by adding (meth)acrylic acid ester to the polymerization catalyst obtained by contacting organoaluminum compound (D) and organophosphorus compound (E), or the obtained polymerization catalyst may be added to the (meth)acrylic acid ester. Alternatively, the (meth)acrylic acid ester may be mixed before this contact. That is, polymerization may be initiated by adding organophosphorus compound (E) to a mixture of organoaluminum compound (D) and (meth)acrylic acid ester, or polymerization may be initiated by adding organoaluminum compound (D) to a mixture of organophosphorus compound (E) and (meth)acrylic acid ester. The addition may be done all at once, or it may be done at a certain periodic interval.

[0066] After the reaction, the volatile components in the partial polymer can be deflated using a known volatile component removal device to obtain a methacrylic acid ester polymer. A defoliation extruder, such as a single-screw extruder or twin-screw extruder, is preferred as the volatile component removal device due to its excellent defoliation efficiency. The defoliation temperature and reduced pressure during defoliation can be appropriately set by those skilled in the art based on well-known techniques.

[0067] [Application] The methacrylic acid ester polymer of the present invention can be used, for example, as a molding material. Methods for obtaining a molded article from the methacrylic acid ester polymer include, for example, known molding methods such as injection molding, extrusion molding, and pressure molding. In that case, if necessary, additives such as lubricants (including higher alcohols and higher fatty acid esters), mold release agents, ultraviolet absorbers, antioxidants, heat stabilizers, colorants, antistatic agents, and flame retardants may be included to the extent that they do not impair the effects of the present invention. [Examples]

[0068] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention.

[0069] [Measurement and Evaluation Methods] <Quantitative determination of syndiotacticity of polymers (rr triad %)> 1 The stereoselectivity of polymers was measured using a 1H-NMR spectrometer (Bruker "AVANCE400") following the procedure below. The polymer was dissolved in chloroform-d1 solvent to a concentration of approximately 5% by mass, and measurements were performed under the conditions of 32 cumulative measurements at a measurement temperature of 30°C. The chemical shift was based on chloroform (7.26 ppm). 1 The rr triad percentage (hereinafter abbreviated as "rr%") was calculated from the integral ratio of the chemical shifts of the H-NMR spectrum, and this was used as the syndiotacticity value of the polymer.

[0070] <Glass transition temperature (Tg)> The glass transition temperature (Tg) was measured using a differential scanning calorimetry (DSC) (DiamondDSC, manufactured by PerkinElmer) following the procedure below. Approximately 10 mg of polymer was placed in a sample container and held at 20°C for 1 minute. Next, the temperature was increased from 20°C to 180°C at a rate of 10°C / min and held at 180°C for 4 minutes. Then, the temperature was cooled from 180°C to 0°C at a rate of 10°C / min and held at 0°C for 4 minutes. Finally, the temperature was increased from 0°C to 180°C at a rate of 10°C / min, and the glass transition temperature (Tg) (in °C) at this time was determined.

[0071] <Mass-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution (Mw / Mn)> An eluent was prepared by dissolving 14 g of sodium perchlorate monohydrate in 1 L of special grade tetrahydrofuran (THF). After collecting the polymer (approximately 4 mg) in a glass vial, 2 mL of the eluent was added and allowed to stand overnight to prepare a sample solution with a concentration of approximately 0.2% by mass. The obtained sample solution was filtered through a 0.45 μm pretreatment filter (GL Sciences "Chromatodisk 13N") and subjected to GPC measurement. GPC measurements were performed using two "PLgel 10μ Mixed-B (7.5×300mm, 10μm)" columns from Polymer Laboratory Inc. and a Tosoh Corporation "HLC-8420GPC" equipped with an RI detector. The measurement conditions were as follows: Sample injection volume: 100 μL Column temperature: 40℃ Elution solvent: 0.1M sodium perchlorate special grade THF solution Fluid delivery rate: 1 mL / min The converted average molecular weight was calculated as follows: Using "STANDARD M-75," a commercially available monodisperse PMMA manufactured by Shoko Science Co., Ltd., as the standard sample, a calibration curve was created relating the retention time and molecular weight of the PMMA standard sample. Based on this calibration curve, the mass average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) were calculated.

[0072] <Detection of phosphorus> 31 The detection of phosphorus in polymers was performed using a P-NMR analyzer (Bruker AVANCE500) according to the following procedure. 40 mg of the polymer was dissolved in 0.5 mL of chloroform-d1 solvent, and measurements were performed under conditions of 5000 cumulative cycles at a measurement temperature of 25°C. A 15% H3PO4D2O solution was used as the standard sample, and the chemical shift of this standard sample was set to 0 ppm for correction.

[0073] <Phosphorus concentration> The phosphorus content in PMMA was quantified using ICP emission spectroscopy according to the following procedure. 50 mg of the sample was weighed into a quartz vessel, 5 mL of nitric acid was added, and the sample was decomposed in a microwave sample preparation device (Anton Paar "Multiwave7000") at a maximum temperature of 260°C for 25 minutes. After decomposition, the sample was diluted with pure water to a final volume (50 mL). The phosphorus concentration in this sample solution was quantified using an inductively coupled plasma atomic emission spectrometer (ICP-OES) (ThermoFisher Scientific "iCAP7600Duo") based on the acid concentration matching absolute calibration curve method.

[0074] <Initial agent efficiency> The initiator efficiency was calculated as follows: Initiator efficiency = Mn (calc) / Mn×Conversion Here, Mn (calc) =([MMA]+[MA]) / [PCy3]×100, where [MMA] represents the amount of methyl methacrylate used in the reaction, [MA] represents the amount of methyl acrylate used in the reaction, and [PCy3] represents the amount of PCy3 used in the reaction. Also, Conversion represents the monomer conversion rate (%).

[0075] [raw materials] The abbreviations for the compounds used in the examples and comparative examples are as follows: MMA: Methyl methacrylate MA: Methyl acrylate PCy3: Tricyclohexylphosphine iBuAl(BHT)2: Isobutylaluminum bis(2,6-di-t-butyl-4-methylphenoxide) iBuAl(BHT)2 was synthesized according to the method described in "J.App.Poly.Sci.2016, 133, 43276" as shown in the following manufacturing example.

[0076] [Manufacturing example: 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), a toluene solution (11.5 mL) of triisobutylaluminum (2.90 g, 0.017 mol) was added dropwise at 25°C for 30 minutes. The mixture was stirred at the same temperature for 1 hour to synthesize iBuAl(BHT)2.

[0077] [Example 1] The inside of a 300 mL four-neck separable flask was degassed and replaced with purified nitrogen. Then, 21 mL of MMA, 0.080 mL of MA, and 49 mL of anhydrous toluene were added, and nitrogen bubbling was performed for more than 10 minutes (0.45 mol% of MA relative to a total of 100 mol% of MMA and MA). The solution was heated to 40°C under a purified nitrogen atmosphere while stirring with a mechanical stirrer set to 80 rpm. 0.56 mL of a 0.6 mol / L toluene solution of PCy3 (0.17 mol% of PCy3 relative to a total of 100 mol% of MMA and MA) and 1.4 mL of a 0.6 mol / L toluene solution of iBuAl(BHT)2 were added. This solution was stirred for 120 minutes. 10 mL of methanol was added as a reaction stopper, and the solution was cooled to room temperature. Purification was performed by reprecipitation using chloroform as a good solvent and methanol as a poor solvent to obtain PMMA with a monomer conversion rate of 100%. The obtained PMMA was dried under reduced pressure. Confirmation results of phosphorus detection in the obtained PMMA ( 31 The P-NMR measurement results are shown in Figure 1.

[0078] [Example 2] The inside of a 300 mL four-neck separable flask was degassed and replaced with purified nitrogen. Then, 21 mL of MMA, 0.16 mL of MA, and 49 mL of anhydrous toluene were added, and nitrogen bubbling was performed for more than 10 minutes (0.96 mol% of MA relative to a total of 100 mol% of MMA and MA). The solution was heated to 20°C under a purified nitrogen atmosphere while stirring with a mechanical stirrer set to 80 rpm. 0.56 mL of a 0.6 mol / L toluene solution of PCy3 (0.17 mol% of PCy3 relative to a total of 100 mol% of MMA and MA) was added, followed by 1.4 mL of a 0.6 mol / L toluene solution of iBuAl(BHT)2. This solution was stirred for 120 minutes. 10 mL of methanol was added as a reaction stopper, and the solution was cooled to room temperature. Purification was performed by reprecipitation using chloroform as a good solvent and methanol as a poor solvent to obtain PMMA with a monomer conversion rate of 85%. The obtained PMMA was dried under reduced pressure. Confirmation results of phosphorus detection in the obtained PMMA ( 31 The P-NMR measurement results are shown in Figure 2.

[0079] [Example 3] The inside of a 50 mL Schlenk flask was degassed and replaced with purified nitrogen. Then, 5.3 mL of MMA, 2.0 mL of a 0.1 mol / L toluene solution of MA, and 8.7 mL of anhydrous toluene were added (0.4 mol% MA relative to a total of 100 mol% MMA and MA). Under a purified nitrogen atmosphere, the solution was heated to 20°C while stirring with a mechanical stirrer. 0.8 mL of a 0.1 mol / L toluene solution of PCy3 (0.16 mol% PCy3 relative to a total of 100 mol% MMA and MA) and 2.0 mL of a 0.1 mol / L toluene solution of iBuAl(BHT)2 were added, and the solution was stirred for 120 minutes. 2.5 mL of methanol was added as a reaction stopper. Purification was performed by reprecipitation using chloroform as a good solvent and methanol as a poor solvent to obtain PMMA with a monomer conversion rate of 100%. The obtained PMMA was dried under reduced pressure. Confirmation results of phosphorus detection in the obtained PMMA ( 31 The P-NMR measurement results are shown in Figure 3.

[0080] [Example 4] The inside of a 300 mL four-neck separable flask was degassed and replaced with purified nitrogen. Then, 21 mL of MMA, 0.080 mL of MA, and 49 mL of anhydrous toluene were added, and nitrogen bubbling was performed for more than 10 minutes (0.45 mol% of MA relative to a total of 100 mol% of MMA and MA). The solution was heated to 20°C under a purified nitrogen atmosphere while stirring with a mechanical stirrer set to 80 rpm. 1.12 mL of a 0.6 mol / L toluene solution of PCy3 (0.34 mol% of PCy3 relative to a total of 100 mol% of MMA and MA) was added, followed by 2.7 mL of a 0.6 mol / L toluene solution of iBuAl(BHT)2, and the solution was stirred for 120 minutes. 10 mL of methanol was added as a reaction stopper, and the solution was cooled to room temperature. Purification was performed by reprecipitation using chloroform as a good solvent and methanol as a poor solvent to obtain PMMA with a monomer conversion rate of 100%. The obtained PMMA was dried under reduced pressure. Confirmation results of phosphorus detection in the obtained PMMA ( 31 The P-NMR measurement results are shown in Figure 4.

[0081] [Example 5] The inside of a 300 mL four-neck separable flask was degassed and replaced with purified nitrogen. Then, 21 mL of MMA, 0.040 mL of MA, and 49 mL of anhydrous toluene were added, and nitrogen bubbling was performed for more than 10 minutes (0.22 mol% of MA relative to a total of 100 mol% of MMA and MA). The solution was cooled to 0°C under a purified nitrogen atmosphere while stirring with a mechanical stirrer set to 80 rpm. 0.56 mL of a 0.6 mol / L toluene solution of PCy3 (0.22 mol% of PCy3 relative to a total of 100 mol% of MMA and MA) was added, followed by 1.4 mL of a 0.6 mol / L toluene solution of iBuAl(BHT)2, and the solution was stirred for 120 minutes. 10 mL of methanol was added as a reaction stopper, and the solution was cooled to room temperature. Purification was performed by reprecipitation using chloroform as a good solvent and methanol as a poor solvent to obtain PMMA with a monomer conversion rate of 81%. The obtained PMMA was dried under reduced pressure. Confirmation results of phosphorus detection in the obtained PMMA ( 31 The P-NMR measurement results are shown in Figure 5.

[0082] [Comparative Example 1] The inside of a 300 mL four-neck separable flask was degassed and replaced with purified nitrogen. Then, 21 mL of MMA and 49 mL of anhydrous toluene were added, and nitrogen bubbling was performed for more than 10 minutes. Under a purified nitrogen atmosphere, the solution was stirred with a mechanical stirrer set to 80 rpm and the temperature was raised to 40°C. 0.56 mL of a 0.6 mol / L toluene solution of PCy3 (0.17 mol% PCy3 per 100 mol% MMA) and 1.4 mL of a 0.6 mol / L toluene solution of iBuAl(BHT)2 were added. This solution was stirred for 120 minutes. 10 mL of methanol was added as a reaction stopper, and the solution was cooled to room temperature. The solution was purified by reprecipitation using chloroform as a good solvent and methanol as a poor solvent to obtain PMMA. The obtained PMMA was dried under reduced pressure. Confirmation results of phosphorus detection in the obtained PMMA ( 31 The P-NMR measurement results are shown in Figure 6.

[0083] Table 1 shows the polymerization conditions (amounts of MA and PCy3 used relative to a total of 100 mol% of MMA and MA, and polymerization temperature) for Examples 1-5 and Comparative Example 1, as well as the evaluation results of the obtained PMMA.

[0084] [Table 1]

[0085] As is clear from Table 1, in Examples 1 to 5, polymers with higher initiator efficiency and lower molecular weight were obtained compared to Comparative Example 1. The polymers obtained in Examples 1 to 5 exhibit excellent stereoselectivity and heat resistance, as well as low molecular weight, a large molecular weight distribution, and excellent moldability.

Claims

1. A methacrylic acid ester polymer (C) comprising 95 to 99.99 mol% of methacrylic acid ester units (A) and 0.01 to 5 mol% of acrylic acid ester units (B), wherein the methacrylic acid ester polymer (C) has a phosphorus atom at its terminal end. (a) The syndiotacticity (rr) of the triple display is 65-85%, (b) The number-average molecular weight (Mn) is between 20,000 and 180,000. (c) The molecular weight distribution (Mw / Mn) is 1.2 to 3.

0. A methacrylic acid ester polymer characterized by the following features.

2. The methacrylic acid ester polymer according to Claim 1, characterized in that it contains phosphorus in a mass ratio of 10 to 5000 ppm relative to the methacrylic acid ester polymer (C).

Images