JP2016186009A - Method for producing lactone ring-containing polymer, and novel polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a lactone ring-containing polymer which, by a completely different method than before, can suppress occurrence of foaming and gelation when forming and fabricating the lactone ring-containing polymer, and offers a high degree of freedom in regulating characteristics of the obtained lactone ring-containing polymer.SOLUTION: The method for obtaining a polymer having lactone ring structures in the main chain comprises subjecting a copolymer (C) having an acrylic ester unit (A) containing a hydroxyl group protected by a protective group and a (meth)acrylic acid ester unit (B) not containing a hydroxy group as constitutional units to an elimination reaction of the protective group and a cyclization reaction between the units (A) and (B).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a lactone ring-containing polymer having a lactone ring structure in the main chain, and a novel polymer that can be used in the production method.

  The acrylic polymer has high transparency, excellent surface gloss and weather resistance, and has a high balance of mechanical strength, molding processability and surface hardness. Based on this excellent property, acrylic polymers are used in various applications in various fields. However, even if the glass transition temperature (Tg) of the acrylic polymer is high, it is around 100 ° C., and it has been difficult to use the acrylic polymer in a field where heat resistance is required. Acrylic polymer with improved heat resistance for use in areas where heat resistance is required, or to meet the demands for higher design flexibility, compactness, higher performance, etc. Is desired.

  A lactone ring-containing polymer having a lactone ring structure in the main chain is known as an acrylic polymer having a high Tg and improved heat resistance. The lactone ring-containing polymer can be formed, for example, by causing a cyclization reaction to proceed on a precursor polymer having a hydroxy group or a carboxy group and an ester group in the side chain. This cyclization reaction is a dealcoholization condensation reaction that is a kind of transesterification reaction that proceeds between a hydroxy group or a carboxyl group and an ester group in the molecular chain of the precursor polymer.

  Gelation and / or foaming may occur when forming the lactone ring-containing polymer or molding the polymer or the resin composition containing the polymer. Generation | occurrence | production of gelatinization and / or foaming can become a defect of the resin molding finally obtained. In particular, in applications in which transparency of acrylic polymers is important, for example, in optical member applications, the occurrence of gelation and foaming leads to optical defects that are serious defects.

  Patent Document 1 describes that by using a specific compound as a catalyst when the cyclization reaction proceeds in the precursor polymer, it is possible to suppress the occurrence of foaming and gelation during the molding process of the lactone ring-containing polymer. Has been. Patent Document 2 describes that the use of a specific polymerization initiator for the polymerization of a precursor polymer can suppress the occurrence of gelation during the formation of a lactone ring-containing polymer and during molding.

Japanese Patent Laid-Open No. 2001-151814 JP 2007-70607 A

  One of the objects of the present invention is to suppress the occurrence of foaming and gelation during the formation of the lactone ring-containing polymer and the molding process by a completely different method from the conventional ones. An object of the present invention is to provide a method for producing a lactone ring-containing polymer having a high degree of freedom in controlling the properties of the coalescence.

  The method for producing a lactone ring-containing polymer of the present invention comprises an acrylic ester unit (A) containing a hydroxy group protected by a protecting group and a (meth) acrylic ester unit (B) not containing a hydroxy group. The copolymer (C) having the structural unit is allowed to undergo a elimination reaction of the protective group and a cyclization reaction between the units (A) and (B) to form a lactone ring structure in the main chain. It is a method of obtaining the polymer which has.

  The copolymer (C) is novel per se. That is, the novel polymer of the present invention comprises an acrylic ester unit (A) containing a hydroxy group protected by a protecting group and a (meth) acrylic ester unit (B) not containing a hydroxy group as constituent units. Have.

  According to the present invention, it is possible to suppress the occurrence of foaming and gelation at the time of formation and molding of a lactone ring-containing polymer by a completely different method, and further, the characteristics of the obtained lactone ring-containing polymer A process for producing a lactone ring-containing polymer with a high degree of freedom in control is achieved.

It is a figure which shows the relationship of the glass transition temperature (Tg) of the lactone ring containing polymer after the cyclization reaction with respect to the content rate of the specific structural unit in the precursor polymer before the cyclization reaction evaluated in the Example.

  In the method for producing a lactone ring-containing polymer of the present invention, an acrylic ester unit (A) containing a hydroxy group protected by a protective group and a (meth) acrylic ester unit (B) not containing a hydroxy group. The copolymer (C) as a structural unit is subjected to a protective group elimination reaction and a cyclization reaction between the units (A) and (B) to produce a polymer having a lactone ring structure in the main chain. Get coalesced. The copolymer (C) is a precursor polymer in which a lactone ring-containing polymer is formed by a cyclization reaction.

  Patent Documents 1 and 2 disclose that a precursor polymer having a hydroxy group-containing acrylate unit (X) and a (meth) acrylate unit (Y) not containing a hydroxy group as constituent units is a ring. It is described that a lactone ring-containing polymer is formed by advancing a fluorination reaction. The cyclization reaction proceeds between the unit (X) and the unit (Y) adjacent to each other, but this precursor polymer is a pure random polymer, and three or more units (X) are continuous in the molecular chain. There is a part to do. Then, the units (X) other than the unit (X) located at both ends of the part remain as they are during the cyclization reaction and after the cyclization reaction, that is, the hydroxy group remains in the obtained lactone ring-containing polymer. Will do. The more hydroxy groups remain, the higher the content of the unit (X) in the precursor polymer. As a result of studies, the present inventors have found that this residual hydroxy group is one of the causes of gelation and foaming during the formation of the lactone ring-containing polymer and during the molding process. This is because the residual hydroxy group induces crosslinking between molecular chains of the polymer, typically crosslinking between molecular chains from which alcohol is eliminated. Cross-linking causes gelation and detached alcohol causes foaming.

  On the other hand, in the present invention, a copolymer having as constituent units an acrylic ester unit (A) containing a hydroxy group protected by a protecting group and a (meth) acrylic ester unit (B) not containing a hydroxy group. A cyclization reaction is allowed to proceed with respect to (C) to form a lactone ring-containing polymer. Copolymer (C) is, for example, a monomer group comprising an acrylic acid ester monomer containing a hydroxy group protected by a protecting group and a (meth) acrylic acid monomer not containing a hydroxy group. At this time, the homopolymerizability of the former monomer is lowered due to the presence of the protecting group, and therefore the number and frequency of consecutive units (A) in the copolymer (C) are determined as units. Compared with the conventional precursor polymer comprised from (X) and unit (Y), it falls. For this reason, the number of hydroxy groups remaining in the copolymer (C) when the cyclization reaction proceeds and the number of hydroxy groups remaining in the lactone ring-containing polymer obtained through the reaction is reduced. The occurrence of gelation and foaming during the formation of the ring-containing polymer and during the molding process is suppressed.

  Depending on the kind of the protecting group, the homopolymerizability of the acrylate monomer protected by the group is lost. At this time, the continuity of the unit (A) in the copolymer (C) is most suppressed, and the occurrence of gelation and foaming is most suppressed during the formation of the lactone ring-containing polymer and during the molding process.

  The effect of using the copolymer (C) for the formation of the lactone ring-containing polymer is not necessarily limited to the direct effect of suppressing the occurrence of gelation and foaming. The fact that the number and frequency of continuous units (A) in the copolymer (C) is lower than in the past means that the content of the unit (A) in the copolymer (C) as the precursor polymer can be made larger than in the past. Means. This is because even when the content rate is increased, the occurrence of gelation and foaming during the formation of the lactone ring-containing polymer and during the molding process can be suppressed. And being able to enlarge the content rate of the unit (A) in a copolymer (C) brings about the improvement of the freedom degree of control of the characteristic which the formed lactone ring containing polymer shows. The characteristics are, for example, thermal characteristics and optical characteristics. The thermal property is, for example, Tg of a lactone ring-containing polymer. As a more specific example, it is possible to form a lactone ring-containing polymer having a higher Tg while suppressing the occurrence of gelation and foaming during formation and molding. By improving the degree of freedom of control of such characteristics, it is possible to meet further demands in conventional applications such as optical applications, and for example, application of lactone ring-containing polymers to applications that require further heat resistance. Expansion is expected.

  The unit (A) is not limited as long as it is an acrylate unit containing a hydroxy group protected by a protecting group. The unit (A) is, for example, a unit represented by the following formula (1).

R ¹ and R ^{2 in} formula (1) are each independently a hydrogen atom or an organic residue having 1 to 20 carbon atoms, and the organic residue may contain oxygen. R ³ is a protecting group.

  The organic residue is, for example, an alkyl group having 1 to 20 carbon atoms such as a methyl group, an ethyl group, or a propyl group; an unsaturated aliphatic carbonization having 1 to 20 carbon atoms such as an ethenyl group or a propenyl group. A hydrogen group; an aromatic hydrocarbon group having 1 to 20 carbon atoms such as a phenyl group or a naphthyl group; in the alkyl group, the unsaturated aliphatic hydrocarbon group, and the aromatic hydrocarbon group, One or more is a group substituted by at least one group selected from a carboxyl group, an ether group and an ester group.

R ¹ is preferably a hydrogen atom; an alkyl group having 1 to 4 carbon atoms such as a methyl group or an ethyl group, and more preferably a hydrogen atom or a methyl group. R ² is preferably a C 1-4 alkyl group such as a hydrogen atom, a methyl group or an ethyl group, more preferably a hydrogen atom or a methyl group.

The structural unit represented by the formula (1) is a structural unit formed by polymerization of a monomer represented by the following formula (2). R ¹ to R ³ of formula (2) is the same as R ¹ to R ³ of formula (1).

The monomer represented by the formula (2) is a hydrogen atom in which the hydroxy group of 2-hydroxymethyl acrylate is protected by a protecting group R ^{3 and} bonded to the carbon atom to which the hydroxy group is bonded. A 2-hydroxymethyl acrylate derivative in which the atom is substituted by an R ² group. That is, the structural unit shown in Formula (1) can also be expressed as a 2-hydroxymethyl acrylate derivative unit.

The derivative in the state before the hydroxy group is protected by the protective group R ³ is, for example, 2-hydroxymethylacrylic acid, 2- (1-hydroxyethyl) acrylic acid, 2- (1-hydroxybutyl) acrylic acid, 2- (1-hydroxy-2-ethylhexyl) acrylic acid (R ¹ is a hydrogen atom), methyl 2-hydroxymethyl acrylate, methyl 2- (1-hydroxyethyl) acrylate, 2- (1-hydroxybutyl ) Methyl acrylate, 2- (1-hydroxy-2-ethylhexyl) methyl acrylate, 2-hydroxymethyl ethyl acrylate, 2- (1-hydroxyethyl) ethyl acrylate, 2- (1-hydroxybutyl) acrylic acid Ethyl, 2- (1-hydroxy-2-ethylhexyl) acrylate, 2-hydroxymethyl N-propyl acrylate, n-propyl 2- (1-hydroxyethyl) acrylate, n-propyl 2- (1-hydroxybutyl) acrylate, n-propyl 2- (1-hydroxy-2-ethylhexyl) acrylate Isopropyl 2-hydroxymethyl acrylate, isopropyl 2- (1-hydroxyethyl) acrylate, isopropyl 2- (1-hydroxybutyl) acrylate, isopropyl 2- (1-hydroxy-2-ethylhexyl) acrylate, 2- N-butyl hydroxymethyl acrylate, isobutyl 2-hydroxymethyl acrylate, t-butyl 2-hydroxymethyl acrylate, n-octyl 2-hydroxymethyl acrylate, isooctyl 2-hydroxymethyl acrylate, 2-hydroxymethyl acrylic acid 2-ethyl hex , Stearyl 2-hydroxymethyl acrylate, cyclopentyl 2-hydroxymethyl acrylate, cyclopentyl 2- (1-hydroxyethyl) acrylate, cyclopentyl 2- (1-hydroxybutyl) acrylate, 2- (1-hydroxy-2 -Ethylhexyl) cyclopentyl acrylate, cyclohexyl 2-hydroxymethyl acrylate, phenyl 2-hydroxymethyl acrylate, phenyl 2- (1-hydroxyethyl) acrylate, phenyl 2- (1-hydroxybutyl) acrylate, 2- ( 1-hydroxy-2-ethylhexyl) phenyl acrylate, 2-hydroxymethyl acrylate o-methoxyphenyl, 2-hydroxymethyl acrylate p-methoxyphenyl, 2-hydroxymethyl acrylate p-nitrophenyl 2-hydroxymethyl acrylate o- methylphenyl, 2-hydroxymethyl acrylate p- methylphenyl, 2-hydroxymethyl acrylate p-t-butylphenyl. Among these monomers, methyl 2-hydroxymethyl acrylate, ethyl 2-hydroxymethyl acrylate, n-butyl 2-hydroxymethyl acrylate, 2-ethylhexyl 2-hydroxymethyl acrylate, 2-hydroxymethyl acrylic acid 2-hydroxyethyl, 2-hydroxypropyl 2-hydroxymethyl acrylate is copolymerizable with a (meth) acrylic acid ester monomer not containing a hydroxy group, and cyclization reaction as a copolymer (C) From the viewpoint of stability, and from the viewpoint of further improving the Tg of the lactone ring-containing polymer, methyl 2-hydroxymethyl acrylate (RHMA) is preferable.

The protecting group R ³ is at least one selected from, for example, a silicon group, an acetal group, a benzyl group and derivatives thereof, an acetyl group, and a benzoyl group. These groups act to reduce the homopolymerization of a monomer containing a hydroxy group protected by a protective group (for example, a 2-hydroxymethyl acrylate derivative) when forming a copolymer (C). In addition, when the lactone ring-containing polymer is formed from the copolymer (C), it is easily detached from the monomer, and the cyclization of the copolymer (C) is hardly inhibited.

  The silicon group that is a protective group is not limited, and is at least one selected from, for example, a trimethylsilyl group, a triethylsilyl group, a t-butyldimethylsilyl group, a t-butyldiphenylsilyl group, and a triisopropylsilyl group. The acetal group which is a protective group is not limited, and for example, at least selected from a methoxymethyl group, a tetrahydropyranyl group, an ethoxyethyl group, a methoxyethyl group, a methylthiomethyl group, a benzoyloxymethyl group, and a methoxyethoxymethyl group One type. The benzyl group which is a protecting group and its derivative are, for example, at least one selected from a benzyl group, a p-methylphenylbenzyl group and a p-methoxyphenylbenzyl group.

  Protecting groups are trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, t-butyldiphenylsilyl group, triisopropylsilyl group, methoxymethyl group, tetrahydropyranyl group, ethoxyethyl group, methoxyethyl group, methylthiomethyl group , A benzoyloxymethyl group, a methoxyethoxymethyl group, a benzyl group, an acetyl group, and a benzoyl group.

  The protective group is a silicon group and an acetal group from the viewpoint that the action of lowering the homopolymerizability is particularly high and elimination is more reliable when the lactone ring-containing polymer is formed from the copolymer (C). Groups are preferred.

  The unit (B) is not limited as long as it is a (meth) acrylic acid ester unit that does not contain a hydroxy group. The (meth) acrylic acid ester unit is, for example, an acrylic acid ester such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, cyclohexyl acrylate, benzyl acrylate; methacrylic acid Units formed by polymerization of monomers of methacrylic acid esters such as methyl, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate and benzyl methacrylate It is. Among them, since the lactone ring-containing polymer obtained after cyclization is excellent in cyclization reactivity with the unit (A) and has high heat resistance and optical transparency, the unit (B) is methyl methacrylate. (MMA) units are preferred.

  The copolymer (C) may have two or more types of units (A) and / or two or more types of units (B) as constituent units.

  The content rate of the unit (A) in the copolymer (C) (ratio of the unit (A) in all the structural units of the copolymer (C)) is, for example, 1 to 60 mol%. As described above, the number of consecutive units (A) in the copolymer (C) and the frequency thereof are lower than those of the conventional precursor polymer, thereby allowing gelation during the formation and molding of the lactone ring-containing polymer. And since generation | occurrence | production of foaming can be suppressed, the content rate of the unit (A) in a copolymer (C) can be enlarged.

The content rate of each structural unit which comprises a polymer can be evaluated by a well-known method, for example, < ¹ > H-nuclear magnetic resonance (NMR) method and / or infrared spectroscopy (IR) method.

  The copolymer (C) may have a structural unit other than the unit (A) and the unit (B).

The structural unit is, for example, a hydroxy group-containing acrylate unit whose hydroxy group is not protected by a protecting group. An example of such a structural unit is shown in the following formula (3). R ¹ and R ² of formula (3) is the same as R ¹ and R ² of formula (1).

The structural unit other than the unit (A) and the unit (B) is, for example, a unit formed by polymerization of an unsaturated carboxylic acid, or a unit formed by polymerization of a monomer represented by the following formula (4). R ^{4 in the} formula (4) is a hydrogen atom or a methyl group, and X is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, an —OAc group, a —CN group, —C (═O ) R ⁵ group or —C—O—R ⁶ group. Ac is an acetyl group, R ⁵ and R ⁶ are a hydrogen atom or a group exemplified as an organic residue in formula (1).

  Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, crotonic acid, α-substituted acrylic acid, and α-substituted methacrylic acid. Among these, at least one selected from acrylic acid and methacrylic acid is preferable.

  Examples of the monomer represented by the formula (4) include styrene, vinyl toluene, α-methyl styrene, acrylonitrile, methyl vinyl ketone, ethylene, propylene, and vinyl acetate. Among these, at least one selected from styrene and acrylonitrile is preferable.

  When the copolymer (C) has structural units other than the units (A) and (B), the content of the structural unit in the copolymer (C) is, for example, 0.1 to 30 mol%, The upper limit is preferably 20 mol% or less, and more preferably 15 mol% or less.

  Copolymer (C) is a novel polymer. This novel polymer can have each composition and each characteristic of copolymer (C) explained above in arbitrary combinations.

  The formation method of a copolymer (C) is not limited.

  The copolymer (C) is, for example, a monomer group including an acrylic ester monomer containing a hydroxy group protected by a protective group and a (meth) acrylic ester monomer not containing a hydroxy group. Can be formed by copolymerization. Examples of the former and latter monomers are as described above.

  The copolymerization method of the monomer group is not limited. Except for the fact that the monomer group includes an acrylate monomer containing a hydroxy group protected by a protecting group and a (meth) acrylate monomer not containing a hydroxy group, for example, Copolymerization of monomer groups can be carried out in the same manner as the polymerization step disclosed in Kai 2007-70607.

  More specifically, the copolymerization is performed, for example, by solution polymerization. When the copolymer (C) is formed by solution polymerization, the polymerization product contains the polymerization solvent used for the polymerization in addition to the copolymer (C). C) need not be taken out as a solid. Depending on the type of copolymer (C), the polymerization product may be subjected to a desorption reaction and a cyclization reaction to form a lactone ring-containing polymer from the copolymer (C) while containing a solvent. You can also. Of course, after taking out the copolymer (C) as a solid, these reactions may be carried out again in a state suitable for elimination reaction and / or cyclization reaction.

  When the copolymer (C) is formed by solution polymerization, the polymerization solvent used is, for example, aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; ketones such as methyl ethyl ketone and methyl isobutyl ketone; chloroform, dimethyl sulfoxide ( DMSO), tetrahydrofuran. Of these, aromatic hydrocarbons and ketones are preferable, and toluene and methyl isobutyl ketone are particularly preferable.

  When the copolymer (C) is polymerized, a polymerization initiator can be used as necessary. The polymerization initiator is not limited. For example, cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate, t-amyl peroxide Organic peroxides such as 2-ethylhexanoate; 2,2′-azobis (isobutyronitrile); (AIBN), 1,1′-azobis (cyclohexanecarbonitrile), 2,2′-azobis ( 2-methylisobutyronitrile) and 2,2′-azobis (2,4-dimethylvaleronitrile). Two or more polymerization initiators may be used. The usage-amount of a polymerization initiator can be suitably set according to a combination of monomers or polymerization conditions, and is not limited.

  In order to form the copolymer (C) having a structural unit other than the unit (A) and the unit (B), the monomer group may further include a monomer in which the structural unit is formed by polymerization.

  The monomer group used for copolymerization includes two or more acrylate monomers containing a hydroxy group protected by a protecting group, and / or (meth) acrylate monomers not containing a hydroxy group. Two or more types may be included.

In the production method of the present invention, the elimination reaction of the protecting group R ³ and the cyclization reaction between the unit (A) and the unit (B) are allowed to proceed with respect to the copolymer (C), and the lactone is introduced into the main chain. A lactone ring-containing polymer having a ring structure is formed.

In the elimination reaction, the protecting group R ³ is eliminated from the unit (A) of the copolymer (C). As long as the protecting group can be eliminated, the specific means for proceeding with the elimination reaction is not limited. The elimination reaction can be carried out, for example, by at least one selected from application of heat to the copolymer (C), change in the environment of the copolymer (C), and use of a elimination agent. The environmental change is, for example, a change to acidic or basic, or a change to a reducing atmosphere. The release agent is, for example, a fluorine compound. These means may be arbitrarily combined. Each means to combine may be implemented simultaneously or in steps. Specific means for proceeding the elimination reaction can be selected depending on the constitution of the copolymer (C) and the kind of the protecting group.

  An example of a combination of a protecting group and a specific means is at least one selected from application of heat, change to an acidic atmosphere, and use of a leaving agent for a silicon-based protecting group. For acetal-based protecting groups, heat is applied and / or changes to an acidic atmosphere. This is a change to a reducing atmosphere for the protecting group which is a benzyl group and its derivative. For protecting groups that are acetyl and benzoyl groups, a change to a basic atmosphere and / or a change to a reducing atmosphere.

  In the elimination reaction, it is sufficient that at least a part of the protecting groups can be eliminated from the unit (A), and of course, all the protecting groups may be eliminated from the unit (A).

  When the elimination reaction proceeds by applying heat, the temperature varies depending on the type of protecting group, but for example, in the case of silicon-based and acetal-based protecting groups, it is about 100 to 300 ° C.

  When the elimination reaction proceeds by changing to an acidic atmosphere, for example, an acidic substance may be added to the atmosphere in which the copolymer (C) is placed. The acidic substance is not limited, and examples thereof include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid compounds and compounds thereof, sulfonic acids such as methanesulfonic acid and paratoluenesulfonic acid, and carboxylic acids such as formic acid and acetic acid. Along with the acidic substance, water and / or an alcohol such as methanol or ethanol may be added.

  When the elimination reaction proceeds by changing to a basic atmosphere, for example, a basic substance may be added to the atmosphere in which the copolymer (C) is placed. The basic substance is not limited, and examples thereof include alkali metals, alkaline earth metals, salts thereof, and hydroxides. Along with the basic substance, water and / or an alcohol such as methanol or ethanol may be added.

  When the elimination reaction proceeds by changing to a reducing atmosphere, for example, a reducing substance may be added to the atmosphere in which the copolymer (C) is placed. The reducing substance is not limited and is, for example, a metal hydride. Metal hydride may be generated in the above atmosphere by adding metal and hydrogen.

  When the elimination reaction is allowed to proceed by using the elimination agent, for example, the elimination agent may be added to the atmosphere in which the copolymer (C) is placed. Examples of the fluorine-based compound as a desorbing agent include hydrogen fluoride salts such as hydrogen fluoride and tetrabutylammonium fluoride, and metal fluorides such as cesium fluoride.

In the cyclization reaction, a cyclization condensation reaction proceeds between the hydroxy group of the unit (A) and the ester group of the unit (B) that are exposed when the protecting group R ³ is removed by the elimination reaction. A ring structure is formed in the main chain of the polymer. The cyclization reaction is a kind of transesterification reaction that proceeds in the molecular chain of the copolymer (C), and is a reaction in which alcohol is by-produced.

The specific means for causing the cyclization reaction to proceed is not limited. The cyclization reaction can be carried out, for example, by applying heat to the copolymer (C) from which the protecting group R ³ is eliminated and / or changing the environment of the copolymer (C). The environmental change is, for example, the change exemplified in the explanation of the elimination reaction, and a specific example is an acidic or basic atmosphere of the atmosphere in which the copolymer (C) from which the protective group R ³ is eliminated is placed. It is a change to. A cyclization catalyst that controls the cyclization reaction, typically that promotes the cyclization reaction, may be used in combination. A known catalyst can be used as the cyclization catalyst.

  When heat is applied to advance the cyclization reaction, the temperature is, for example, 100 to 300 ° C, preferably 150 to 250 ° C.

When the cyclization reaction proceeds by changing to an acidic atmosphere, for example, an acidic substance may be added to the atmosphere in which the copolymer (C) from which the protecting group R ³ is eliminated is placed. The acidic substance is not limited, and examples thereof include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid compounds and compounds thereof, sulfonic acids such as methanesulfonic acid and paratoluenesulfonic acid, and carboxylic acids such as formic acid and acetic acid.

When the cyclization reaction proceeds by changing to a basic atmosphere, for example, a basic substance may be added to the atmosphere in which the copolymer (C) from which the protecting group R ³ is eliminated is placed. The basic substance is not limited, and examples thereof include alkali metals, alkaline earth metals, salts thereof, and hydroxides.

  The cyclization reaction is a dealcoholization condensation reaction. For this reason, by reducing the atmosphere of the cyclization reaction, alcohol as a by-product may be actively removed, thereby promoting the cyclization reaction.

  In the cyclization reaction, at least the cyclization reaction between the unit (A) and the unit (B) proceeds. At this time, a further cyclization reaction may proceed between the unit (A) or the unit (B) and another structural unit constituting the copolymer (C).

  The elimination reaction and the cyclization reaction may proceed separately, or may proceed at the same time as long as the conditions for both reactions are prepared. Further, the elimination reaction, or both the elimination reaction and the cyclization reaction can be continued from the formation of the copolymer (C) if the conditions for these reactions and the polymerization conditions for the copolymer (C) are aligned. May be implemented.

The lactone ring-containing polymer (D) obtained by the production method of the present invention has a lactone ring structure in its main chain. Although the specific structure of the lactone ring structure formed is not specifically limited, For example, it is a structure shown to the following formula | equation (5). R ¹ and R ² of formula (5) is the same as R ¹ and R ² of formula (1), R ⁷ is a hydrogen atom (when the unit (B) is an acrylic ester unit) or a methyl group (unit (B) is a methacrylate unit.

The polymer (D) comprises at least one unit selected from the unit (A) remaining unreacted during the cyclization reaction, the unit from which the protecting group R ³ is eliminated from the unit (A), and the unit (B). As a structural unit. Moreover, a polymer (D) can further have the said structural unit, when the copolymer (C) has structural units other than a unit (A) and a unit (B).

  The polymer (D) is typically a thermoplastic polymer. The polymer (D) can be, for example, an amorphous polymer.

  The unit (A) is an acrylate unit, and the unit (B) is a (meth) acrylate unit. For this reason, the lactone ring structure formed by the cyclization reaction between the unit (A) and the unit (B) is a derivative of a (meth) acrylic acid ester unit. In addition, the polymer (D) may have as constituent units a unit (A) that remains unreacted during the cyclization reaction, a unit in which a protecting group is eliminated from the unit (A), and a unit (B). These units are (meth) acrylic acid ester units. For this reason, if the sum total of the content rate of the lactone ring structure and the content rate of the (meth) acrylic acid ester unit in the polymer (D) is 50% by mass or more, the polymer (D) is an acrylic polymer. At this time, the polymer (D) has characteristics because it is an acrylic polymer, for example, high transparency, high surface gloss and weather resistance, and a high balance of mechanical strength, molding processability and surface hardness. sell.

  The content of the lactone ring structure in the polymer (D) can be made larger than that of a conventional lactone ring-containing polymer while suppressing the occurrence of gelation and foaming during the formation and molding process. Specifically, the content of the lactone ring structure in the polymer (D) can be, for example, 10 to 100% by mass.

  The polymer (D) has characteristics based on the lactone ring structure of the main chain. The characteristics are, for example, thermal characteristics and optical characteristics.

  The thermal characteristic is, for example, Tg, and the Tg of the lactone ring-containing polymer (D) is higher than that when the main chain does not have a lactone ring structure. The Tg of the lactone ring-containing polymer (D) is, for example, 100 ° C. or higher, and can be 130 ° C. or higher, 150 ° C. or higher, and further 180 ° C. or higher depending on the configuration and content of the lactone ring structure. In the lactone ring-containing polymer (D), such a high Tg is achieved while suppressing the occurrence of gelation and foaming during the formation of the polymer (D) and during the molding process.

  In addition, the lactone ring-containing polymer (D) has a higher Tg when the content of the lactone ring structure is the same as that of the lactone ring-containing polymer formed by the conventional production method. This is considered to be based on the fact that the lactone ring structure is more uniformly arranged in the molecular chain of the lactone ring-containing polymer due to the effects described above. The increase in Tg is, for example, 1 to 20 ° C.

  The optical characteristic is, for example, a birefringence characteristic. The lactone ring structure located in the main chain improves the birefringence expression (phase difference expression) of the polymer. The lactone ring structure has an effect of imparting positive intrinsic birefringence to the polymer (D). The positive or negative of the intrinsic birefringence as the polymer (D) is determined by the balance between the birefringence characteristics of the respective structural units of the polymer (D).

  Based on these characteristics, the lactone ring-containing polymer (D) can be used for various applications. The application is, for example, an optical member. The above-described thermal and optical properties of the lactone ring-containing polymer (D) can be advantageous characteristics of the optical member. Another advantage of the optical member is that the lactone ring-containing polymer (D) is excellent in transparency and heat resistance, and is less gelled and foamed during formation and molding. sell. The optical member is, for example, an optical lens, an optical prism, an optical film, an optical fiber, or an optical disk.

  The shape of the optical member is not particularly limited, and is, for example, a film (optical film). The specific use of the optical film is not particularly limited. For example, a birefringent film, a retardation film, a viewing angle compensation film, a light diffusion film, and a reflection film used in image display devices such as liquid crystal displays, plasma displays, and organic EL displays. A film, an antireflection film, an antiglare film, a brightness enhancement film, a pixel part (light emitting part) protective film, a polarizer protective film, and an ultraviolet absorbing film.

  Other uses of the lactone ring-containing polymer (D) include, for example, signboards / displays, weak electrical / industrial parts, photosensitive electronic materials, automotive parts such as automobiles, building materials / shopping, coating materials, protection for depainting. These include miscellaneous goods such as films, lighting fixtures, large water tanks, mirrors, textiles, stationery, and tableware, cosmetics, and foods.

  The lactone ring-containing polymer (D) can be molded into various shapes depending on the application. Formable shapes are, for example, films, sheets, plates, disks, blocks, balls, lenses, rods, strands, cords and fibers. The method for forming the lactone ring-containing polymer (D) into these shapes may be a known method.

  The lactone ring-containing polymer (D) may be used alone, or may be used as a resin composition (E) containing the lactone ring-containing polymer (D) and other polymers and / or additives. .

  The other polymer is not limited, but when the resin composition (E) is used for an application requiring transparency such as an optical member, the lactone ring-containing polymer (D) and the other polymer are compatible with each other. Keep in mind that you need to. Another polymer is, for example, a thermoplastic polymer. Specific examples of other polymers include olefin polymers such as polyethylene, polypropylene, ethylene-propylene copolymer, and poly (4-methyl-1-pentene); halogen-containing polymers such as vinyl chloride and chlorinated vinyl resins; Styrene polymers such as polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene block copolymer; polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate; polylactic acid, Biodegradable polyester such as polybutylene succinate; polyamide such as nylon 6, nylon 66, nylon 610; polyacetal; polycarbonate; cellulose triacetate, cellulose acetate Cellulose polymers such as lopionate and cellulose acetate butyrate; polyphenylene oxide; polyphenylene sulfide; polyether ether ketone; polyether nitrile; polysulfone; polyethersulfone; polyoxypentylene; polyamidoimide; It is a rubbery polymer such as a blended ABS resin or ASA resin.

  Additives are, for example, ultraviolet absorbers, antioxidants, lubricants, antistatic agents, plasticizers, fluidizers, colorants, dyes, flame retardants, and fillers.

  The resin composition (E) may contain two or more kinds of other polymers and / or two or more kinds of additives.

  The content rate of the lactone ring containing polymer (D) in a resin composition (E) can be freely set according to the characteristic calculated | required as a resin composition (E). The lactone ring-containing polymer (D) may be a main component of the resin composition (E). A main component means a component with the largest content rate in a resin composition. The content rate of the main component is, for example, 50% by mass or more, and may be 60% by mass or more, 70% by mass or more, 80% by mass or more, and further 90% by mass or more.

  The content of the other polymer in the resin composition (E) can be freely set according to the characteristics required for the resin composition (E). The total content of other polymers in the resin composition (E) is, for example, 50% by mass or less, and may be 40% by mass or less. The content of the additive in the resin composition (E) can also be freely set according to the characteristics required for the resin composition (E). The total content of the additives in the resin composition (E) is, for example, 5 parts by mass or less with respect to 100 parts by mass of the lactone ring-containing polymer (D).

The content of each polymer contained in the resin composition can be evaluated by a known method, for example, ¹ H-NMR method and / or IR method.

  The formation method of the resin composition (E) is not limited. For example, it can be formed by mixing the lactone ring-containing polymer (D) and the other polymer and / or additive by a known mixing method. Mixing can be carried out, for example, by pre-blending with a mixer such as an omni mixer and then kneading the resulting mixture. A kneading machine is not specifically limited, For example, well-known kneading machines, such as extruders, such as a single screw extruder and a twin screw extruder, and a pressure kneader, can be used. The resin composition (E) includes a lactone ring-containing polymer (D) formed by the production method of the present invention. For this reason, also about the resin composition (E), generation | occurrence | production of the gelatinization and foaming at the time of the formation and shaping | molding process can be suppressed.

  The resin composition (E) has characteristics based on the type and content of the lactone ring-containing polymer (D), the polymer and the additive contained in the composition (E). The characteristics are, for example, the above-described thermal characteristics and optical characteristics. Resin composition (E) shows high Tg, for example. The Tg of the resin composition (E) is, for example, 100 ° C. or higher. Depending on the content of the lactone ring-containing polymer (D) contained in the composition, it is 120 ° C. or higher, 130 ° C. or higher, and further 150 ° C. It can be over. In the resin composition (E), such a high Tg is achieved while suppressing the occurrence of gelation and foaming during the formation and molding process.

  The resin composition (E) can be used for the same applications as the lactone ring-containing polymer (D).

  The lactone ring-containing polymer (D) or the resin composition (E) can be molded to form a resin molded body (F). The resin molded body (F) is composed of a lactone ring-containing polymer (D) or a resin composition (E).

  The shape of the resin molded body (F) is not limited and is, for example, a film, a sheet, a plate, a disk, a block, a ball, a lens, a rod, a strand, a cord, or a fiber.

  The resin molded body (F) has characteristics based on the characteristics of the lactone ring-containing polymer (D) or the resin composition (E) constituting the molded body.

  The use of the resin molding (F) is the same as that of the lactone ring-containing polymer (D) and the resin composition (E).

  The formation method of a resin molding (F) is not limited. The resin molded body (F) can be formed by molding the lactone ring-containing polymer (D) or the resin composition (E) by a known molding technique such as a melt extrusion method, a casting method, or a press molding method.

  The resin molded body (F) has characteristics based on the characteristics of the lactone ring-containing polymer (D) or the resin composition (E). The characteristics are, for example, the above-described thermal characteristics and optical characteristics. And in the resin molding (F), generation | occurrence | production of gelling and foaming is suppressed, and this becomes a point especially advantageous for use as an optical member of the resin molding (F). This is because gel and foam become optical defects which are serious defects as an optical member.

  The examples illustrate the invention in more detail. The present invention is not limited to the examples shown below.

  First, an evaluation method of the polymer (including the precursor polymer) produced in this example is shown.

[Rhma unit content in precursor polymer]
2-hydroxymethyl acrylate units (RHMA units in the copolymer (C) in Examples 1 to 4) in Examples 1 to 4; in the copolymer (C), the hydroxy groups are protected by tetramethylsilyl (TMS) groups. The content ratio of the RHMA derivative unit) was determined from the area ratio of the obtained ¹ H-NMR profile by performing ¹ H-NMR measurement on the precursor polymer. ^{For 1} H-NMR measurement, a nuclear magnetic resonance spectrometer (manufactured by BRUKER, AV300M) was used, and deuterated chloroform (manufactured by Wako Pure Chemical Industries) was used as a measurement solvent.

[Glass transition temperature (Tg)]
The Tg of the produced lactone ring-containing polymer was determined in accordance with JIS K7121 regulations. Specifically, using a differential scanning calorimeter (Rigaku, Thermo plus EVO DSC-8230), a sample of about 10 mg was heated from room temperature to 300 ° C. (temperature increase rate 20 ° C./min) in a nitrogen gas atmosphere. From the DSC curve obtained in this way, the starting point method was used for evaluation. Α-alumina was used as a reference.

[Weight average molecular weight]
The weight average molecular weight (Mw) of the produced lactone ring-containing polymer was determined under the following measurement conditions in terms of standard polystyrene using gel permeation chromatography (GPC).
Measurement system: “GPC system HLC-8220” manufactured by Tosoh Corporation
Developing solvent: N, N-dimethylformamide (Wako Pure Chemical Industries, special grade)
Solvent flow rate: 1 mL / min Standard sample: TSK standard polystyrene (“PS-oligomer kit” manufactured by Tosoh Corporation)
Measurement side column configuration: Guard column ("TSK guardcolumn ALPHA" manufactured by Tosoh Corporation), separation column ("TSK Gel ALPHA-5000" manufactured by Tosoh Corporation, "TSK Gel ALPHA-2500"), two in series connection

[Solubility in solvent]
The solubility of the produced lactone ring-containing polymer in a solvent was evaluated as follows. First, 10 mg of the produced lactone ring-containing polymer was put into 5 mL of DMSO and stirred at room temperature for 12 hours or more. This confirmed the presence or absence of solubility in DMSO. Next, DMSO was changed to chloroform, and the presence or absence of solubility in chloroform was similarly confirmed. In the lactone ring-containing polymer, the solubility in DMSO is usually higher than the solubility in chloroform.

(Production Example 1)
In Production Example 1, a 2-hydroxymethylacrylic acid derivative (RHMA-TMS) having a hydroxy group protected by a TMS group which is a protecting group, which becomes a unit (A) by polymerization, was produced.

  First, a dropping funnel, a condenser and a thermometer were attached to a three-necked flask having an internal volume of 300 mL, in which RHMA monomer (160 mmol, 18.6 g), triethylamine (320 mmol, 32.4 g) as a base, and dichloromethane as a solvent. 100 mL was added. Next, after putting the flask in ice water and cooling the whole, chlorotrimethylsilane (TMS-Cl; 320 mmol, 34.1 g) was added dropwise over 30 minutes via a dropping funnel. After completion of the dropwise addition, the contents in the flask were stirred overnight at room temperature. Next, the reaction solution in the flask was poured into 300 mL of water, and the organic layer was extracted with dichloromethane. The extracted organic layer was dried over sodium sulfate, and then the solvent was distilled off. The brown liquid thus obtained was isolated by silica gel chromatography to obtain 22 g (117 mmol) of RHMA-TMS monomer in a yield of 73%.

Example 1
First, the RHMA-TMS monomer produced in Production Example 1 and the methyl methacrylate (MMA) monomer are copolymerized to form the unit (A), the RHMA-TMS unit and the unit (B). A copolymer (C) having MMA units as constituent units was produced.

Specifically, the RHMA-TMS monomer (1.4 mmol, 2.64 g) prepared in Production Example 1 and the MMA (1.4 mmol, 1.40 g) monomer were placed in a pressure-resistant tube having an internal volume of 100 mL. Then, 8 mg of AIBN as an initiator and 2.4 g of toluene as a solvent were further added. Next, after bubbling nitrogen inside the tube for 2 minutes, the tube was sealed and immersed in an oil bath at 65 ° C. for 8 hours. Next, the contents of the tube were dissolved in chloroform and reprecipitated with hexane, and then the solvent was removed. Thus, the copolymerization of the RHMA-TMS monomer and the MMA monomer was advanced to obtain a white solid copolymer (C-1) which is an RHMA-TMS / MMA copolymer. When the content of the RHMA-TMS unit in the copolymer (C-1) was evaluated by ¹ H-NMR, it was 49 mol%.

  Next, elimination reaction and cyclization reaction of the protecting group were allowed to proceed on the copolymer (C-1) thus obtained.

  Specifically, a dropping funnel, a condenser tube and a thermometer were attached to a three-necked flask having an internal volume of 100 mL, and then 2 g of the produced copolymer (C-1) was dissolved in 18 mL of tetrahydrofuran (THF) in the flask. Next, 4 mL of HCl having a concentration of 6N was dropped into the flask from the dropping funnel, and then the contents in the flask were stirred at room temperature for 2 hours. After stirring, the reaction product in the flask was diluted with water, and the precipitated white solid was filtered and washed with hexane. The solid thus obtained was dissolved in dimethylacetamide (DMAc) and reprecipitated with 2-propanol. Next, the solvent was dried from the re-precipitate and further subjected to heat treatment at 240 ° C. for 1 hour to obtain a lactone ring-containing polymer (D-1) having a lactone ring structure in the main chain. The Tg of the polymer (D-1) was 188 ° C. Moreover, although the polymer (D-1) was press-molded at 240 ° C. with a press molding machine to produce a film, foaming did not occur in the obtained film.

(Example 2)
The amount of the monomer charged into the pressure tube when forming the copolymer (C) was 1.06 mmol (2 g) for the RHMA-TMS monomer and 2 mmol (2 g) for the MMA monomer. Produced a white solid copolymer (C-2) as an RHMA-TMS / MMA copolymer in the same manner as in Example 1. When the content of the RHMA-TMS unit in the copolymer (C-2) was evaluated by ¹ H-NMR, it was 36 mol%.

  Next, the copolymer (C-2) thus obtained was subjected to a protective group elimination reaction and a cyclization reaction in the same manner as in Example 1 to obtain a lactone ring-containing polymer (D-2). ) The Tg of the polymer (D-2) was 158 ° C. Moreover, although the polymer (D-2) was press-molded at 240 ° C. with a press molding machine to produce a film, foaming did not occur in the obtained film.

Example 3
The amount of the monomer charged into the pressure-resistant tube when forming the copolymer (C) was 1 mmol (1.88 g) for the RHMA-TMS monomer and 2 mmol (2 g) for the MMA monomer. Produced a white solid copolymer (C-3) as an RHMA-TMS / MMA copolymer in the same manner as in Example 1. When the content of the RHMA-TMS unit in the copolymer (C-3) was evaluated by ¹ H-NMR, it was 32 mol%.

  Next, the copolymer (C-3) thus obtained was subjected to a protecting group elimination reaction and a cyclization reaction in the same manner as in Example 1 to produce a lactone ring-containing polymer (D-3). ) Tg of the polymer (D-3) was 151 ° C. Moreover, although the polymer (D-3) was press-molded at 240 ° C. with a press molding machine to produce a film, foaming did not occur in the obtained film.

Example 4
The monomer charge into the pressure-resistant tube when forming the copolymer (C) was 0.6 mmol (1.13 g) for the RHMA-TMS monomer and 2.7 mmol (2 for the MMA monomer). A white solid copolymer (C-4), which is a RHMA-TMS / MMA copolymer, was obtained in the same manner as in Example 1 except that the amount was changed to 0.7 g). When the content of the RHMA-TMS unit in the copolymer (C-4) was evaluated by ¹ H-NMR, it was 20 mol%.

  Next, the copolymer (C-4) thus obtained was subjected to a protecting group elimination reaction and a cyclization reaction in the same manner as in Example 1 to produce a lactone ring-containing polymer (D-4). ) Tg of the polymer (D-4) was 137 ° C. Moreover, although the polymer (D-4) was press-molded at 240 ° C. by a press molding machine to produce a film, foaming did not occur in the obtained film.

(Comparative Example 1)
First, an RHMA monomer and an MMA monomer were copolymerized to prepare a precursor polymer (G) having RHMA units and MMA units as constituent units.

Specifically, RHMA monomer (1.38 mmol, 1.6 g) and MMA monomer (2.4 mmol, 2.40 g) were charged into a pressure-resistant tube having an internal volume of 100 mL, and then used as an initiator. An additional 8 mg of AIBN and 2.4 g of toluene as solvent were added. Next, after bubbling nitrogen inside the tube for 2 minutes, the tube was sealed and immersed in an oil bath at 65 ° C. for 8 hours. Next, the contents of the tube were dissolved in chloroform and reprecipitated with hexane, and then the solvent was removed. Thus, the copolymerization of the RHMA monomer and the MMA monomer was advanced to obtain a white solid copolymer (G-1) as an RHMA / MMA copolymer. When the content of the RHMA unit in the copolymer (G-1) was evaluated by ¹ H-NMR, it was 36 mol%.

  Next, the cyclization reaction was advanced with respect to the copolymer (G-1) obtained in this way.

  Specifically, a dropping funnel, a condenser tube and a thermometer were attached to a three-necked flask having an internal volume of 100 mL, and then 2 g of the produced copolymer (G-1) was dissolved in 18 mL of THF in the flask. Next, 4 mL of 6N HCl was dropped into the flask from the dropping funnel, and the contents in the flask were stirred at room temperature for 4 hours. After stirring, the reaction product in the flask was diluted with water, and the precipitated white solid was filtered and washed with THF. The solid thus obtained was dissolved in DMAc and reprecipitated with 2-propanol. Next, the solvent was dried from the reprecipitate, and further subjected to a heat treatment at 240 ° C. for 1 hour to obtain a lactone ring-containing polymer (H-1) having a lactone ring structure in the main chain. In the polymer (H-1), gelation has progressed partially, and an attempt was made to dissolve the polymer (H-1) in DMSO, but insoluble components remained. The Tg of the polymer (H-1) was 152 ° C. Moreover, when the polymer (H-1) was press-molded at 240 ° C. with a press molding machine to produce a film, foaming occurred in the obtained film.

(Comparative Example 2)
The amount of monomer charged into the pressure-resistant tube when forming the copolymer (G) was 1.2 mmol (1.03 g) for the RHMA monomer and 2.8 mmol (2.8 g) for the MMA monomer. The white solid copolymer (G-2), which is an RHMA / MMA copolymer, was obtained in the same manner as in Comparative Example 1 except that. When the content of RHMA units in the copolymer (G-2) was evaluated by ¹ H-NMR, it was 27 mol%.

  Next, the cyclization reaction was allowed to proceed in the same manner as in Comparative Example 1 with respect to the copolymer (G-2) thus obtained to obtain a lactone ring-containing polymer (H-2). In the polymer (H-2), gelation still proceeds to a part thereof, and an attempt was made to dissolve the polymer (H-2) in DMSO, but insoluble components remained. The Tg of the polymer (H-2) was 140 ° C. Moreover, when the polymer (H-2) was press-molded at 240 ° C. with a press molding machine to produce a film, foaming occurred in the obtained film.

(Comparative Example 3)
The monomer charge to the pressure-resistant tube when forming the copolymer (G) was 0.8 mmol (0.69 g) for the RHMA monomer and 3.2 mmol (3.2 g) for the MMA monomer. The white solid copolymer (G-3), which is an RHMA / MMA copolymer, was obtained in the same manner as in Comparative Example 1 except that. When the content of RHMA units in the copolymer (G-3) was evaluated by ¹ H-NMR, it was 18 mol%.

  Next, the cyclization reaction was allowed to proceed in the same manner as in Comparative Example 1 for the copolymer (G-3) thus obtained, to obtain a lactone ring-containing polymer (H-3). The Tg of the polymer (H-3) was 127 ° C. In the polymer (H-3), no gelled portion was observed. Moreover, although the polymer (H-3) was press-molded by a press molding machine at 240 ° C. to produce a film, foaming did not occur in the obtained film.

  Table 1 below summarizes the compositions of the precursor polymers prepared in each Example and Comparative Example, and the weight average molecular weight Mw, solvent solubility, and Tg of the lactone ring-containing polymer. Further, the content of the RHMA derivative unit (Examples 1 to 4) or the RHMA unit (Comparative Examples 1 to 3) in the precursor polymer and the Tg of the lactone ring-containing polymer obtained by cyclizing the precursor polymer The relationship is shown in FIG.

  As shown in Table 1, in Examples 1 to 4, compared with Comparative Examples 1 to 3, even when the content of the RHMA derivative unit in the precursor polymer is high, gelation at the time of formation of the lactone ring-containing polymer and Foaming during molding was suppressed. More specifically, in Comparative Examples 1 to 3 using the RHMA monomer, when the content of the RHMA unit in the precursor polymer exceeds 18 mol%, gelation occurs in a part of the formed lactone ring-containing polymer. As seen, foaming occurred when the polymer was film-formed. In contrast, in Examples 1 to 4 using the RHMA-TMS monomer, a lactone ring-containing polymer was formed without gelation even when the content of the RHMA-TMS unit in the precursor polymer was higher. In addition, foaming did not occur when the polymer was formed into a film.

  Moreover, as shown in Table 1 and FIG. 1, when the content rate of the RHMA derivative unit (Examples 1-4) and RHMA unit (Comparative Examples 1-3) in a precursor polymer is equivalent, it implemented compared with a comparative example. The Tg of the lactone ring-containing polymer obtained in the example was high.

  The lactone ring-containing polymer obtained by the production method of the present invention can be used for the same applications as conventional lactone ring-containing polymers.

Claims (10)

  For the copolymer (C) having as constituent units an acrylic ester unit (A) containing a hydroxy group protected by a protective group and a (meth) acrylic ester unit (B) not containing a hydroxy group Production of a lactone ring-containing polymer by proceeding with the elimination reaction of the protective group and the cyclization reaction between the units (A) and (B) to obtain a polymer having a lactone ring structure in the main chain Method. The method for producing a lactone ring-containing polymer according to claim 1, wherein the unit (A) is a unit represented by the following formula (1).

R ¹ and R ^{2 in} formula (1) are each independently a hydrogen atom or an organic residue having 1 to 20 carbon atoms, and the organic residue may contain oxygen. R ³ is the protecting group.   The method for producing a lactone ring-containing polymer according to claim 1 or 2, wherein the protecting group is at least one selected from a silicon group, an acetal group, a benzyl group and derivatives thereof, an acetyl group, and a benzoyl group.   The protective group is trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, t-butyldiphenylsilyl group, triisopropylsilyl group, methoxymethyl group, tetrahydropyranyl group, ethoxyethyl group, methoxyethyl group, methylthiomethyl. The method for producing a lactone ring-containing polymer according to claim 1 or 2, which is at least one selected from a group, a benzoyloxymethyl group, a methoxyethoxymethyl group, a benzyl group, an acetyl group, and a benzoyl group.   The desorption reaction is caused to proceed by at least one selected from application of heat to the copolymer (C), change in the environment of the copolymer (C), and use of a desorbing agent. 5. A method for producing a lactone ring-containing polymer according to any one of 4 above.   Monomer group including the copolymer (C), an acrylate monomer containing a hydroxy group protected by the protecting group, and a (meth) acrylate monomer not containing a hydroxy group The method for producing a lactone ring-containing polymer according to any one of claims 1 to 5, wherein the lactone ring-containing polymer is formed by copolymerization.   A novel polymer having as constituent units an acrylic ester unit (A) containing a hydroxy group protected by a protective group and a (meth) acrylic ester unit (B) not containing a hydroxy group. The novel polymer according to claim 7, wherein the unit (A) is a unit represented by the following formula (1).

R ¹ and R ^{2 in} formula (1) are each independently a hydrogen atom or an organic residue having 1 to 20 carbon atoms, and the organic residue may contain oxygen. R ³ is the protecting group.   The novel polymer according to claim 7 or 8, wherein the protective group is at least one selected from a silicon group, an acetal group, a benzyl group and derivatives thereof, an acetyl group, and a benzoyl group.   The protective group is trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, t-butyldiphenylsilyl group, triisopropylsilyl group, methoxymethyl group, tetrahydropyranyl group, ethoxyethyl group, methoxyethyl group, methylthiomethyl. The novel polymer according to claim 7 or 8, which is at least one selected from a group, a benzoyloxymethyl group, a methoxyethoxymethyl group, a benzyl group, an acetyl group, and a benzoyl group.

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