JP6570944B2 - Glutarimide resin and method for producing glutarimide resin - Google Patents

Description

  The present invention relates to a glutarimide resin having an imide ring structure in the main chain and a method for producing the same.

  In recent years, there has been a demand for image display devices to develop optical materials having advanced optical characteristics in response to a demand for improvement in image sharpness. As one of the advanced optical characteristics, low birefringence is required. In general, a polymer compound used for an optical material has birefringence because the refractive index in the main chain direction of the molecule is different from the refractive index in the direction perpendicular to the main chain direction. As a polymer material for an optical film having a small birefringence, a cellulose-based resin such as triacetyl cellulose has been proposed (for example, see Patent Document 1). However, an optical film made of a cellulose-based resin produces a phase difference with respect to obliquely incident light, and the phase difference with respect to the obliquely incident light adversely affects viewing angle characteristics in a large liquid crystal display. Have

  On the other hand, polymethyl methacrylate has been conventionally proposed as an optical material having excellent moldability, high surface hardness, high light transmittance, low birefringence, and low wavelength dependency (see, for example, Patent Document 2). . However, since polymethyl methacrylate has a low glass transition temperature (Tg) of about 100 ° C. and is inferior in heat resistance, it is difficult to use it in applications requiring heat resistance, for example, image display devices. Therefore, a glutarimide resin having an imide ring structure in the main chain has been proposed as an acrylic resin having excellent heat resistance and high optical properties.

  As disclosed in Patent Documents 3 and 4, the glutarimide resin can be produced by reacting a (meth) acrylic acid ester (co) polymer with an imidizing agent. However, since the glutarimide resin produced in this manner usually has a carboxylic acid group or an acid anhydride group, the durability under wet heat decreases due to this, or the viscosity of the glutarimide resin increases. , Molding processability is reduced. Therefore, in order to solve such problems, carboxylic acid groups and acid anhydride groups contained in glutarimide resins are esterified with an esterifying agent to reduce the acid value. For example, Patent Document 4 discloses a method of reacting a glutarimide resin with an esterifying agent in the presence of a catalyst, and a heterocyclic base catalyst such as diazabicycloundecene is used as the esterification catalyst. .

JP 2009-265174 A Japanese Patent Laid-Open No. 06-102547 International Publication No. 2005/054311 Pamphlet JP2011-225699A

  As described above, various attempts have been made to improve the properties of glutarimide resins. As described above, it is desirable that glutarimide resins have excellent durability under wet heat, and optical materials. If the use is taken into consideration, it is desired that the coloring is as little as possible. The present invention has been made in view of the above circumstances, and an object thereof is to provide a glutarimide resin which is excellent in durability under wet heat and has little coloring, and a method for producing the same.

  In order to increase the durability of the glutarimide resin under wet heat, it is preferable to esterify the carboxylic acid group or acid anhydride group contained in the glutarimide resin to reduce the acid value as much as possible. As a result of investigation, it has been clarified that when a cyclic base catalyst such as diazabicycloundecene is used as an esterification catalyst, the obtained glutarimide resin tends to exhibit a yellowish color. In order to efficiently advance the esterification reaction and reduce the coloration of the resulting glutarimide resin, it is effective to use an acyclic base catalyst having a pKa of 11 or more as the esterification catalyst. Became clear.

  That is, the method for producing a glutarimide resin according to the present invention comprises an acrylic polymer having an imide ring structure and a carboxylic acid group and / or an acid anhydride group, and the presence of an acyclic base catalyst having a pKa of 11 or more. It is characterized by having a step of reacting with an esterifying agent below. According to the method for producing a glutarimide resin of the present invention, esterification is performed by using an acyclic base catalyst having a pKa of 11 or more when esterifying a carboxylic acid group and / or an acid anhydride group with an esterifying agent. The reaction can be allowed to proceed efficiently, and coloring of the resulting glutarimide resin can be suppressed.

In the production method of the present invention, the acrylic resin preferably contains an alkali metal in the range of 4.5 × 10 ⁻³ mmol to 22 × 10 ⁻³ mmol per gram of the acrylic polymer. Since alkali metals can cause coloring of the glutarimide resin, the content of alkali metal in the acrylic polymer used for the esterification reaction should be 22 × 10 ⁻³ mmol or less per 1 g of acrylic polymer. preferable. On the other hand, since the alkali metal can contribute as a catalyst for the esterification reaction, the content of the alkali metal in the acrylic polymer is 4.5 per gram of the acrylic polymer from the viewpoint of efficiently proceeding the esterification reaction. It is preferable to set it as x10 < ^-3 > mmol or more.

  The glutarimide resin obtained by the production method of the present invention preferably has a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2).

[In the formula (1), R ¹ , R ² , R ³ and R ⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ⁵ represents a hydrogen atom, 1 to carbon atoms 18 represents an alkyl group or a group having a ring structure. ]

[In Formula (2), R ⁶ and R ⁷ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ⁸ has an alkyl group having 1 to 18 carbon atoms or a ring structure. Represents a group. ]

  The present invention contains an acyclic base catalyst having a pKa of 11 or more, an acid value of 0.5 mmol / g or less, and an absorbance at a wavelength of 390 nm when a 10 mass% THF solution is used, of 1.3 or less. A glutarimide resin is also provided. The glutarimide resin of the present invention is excellent in durability under wet heat and is less colored.

The glutarimide resin of the present invention preferably contains an alkali metal in an amount of 4.5 × 10 ⁻³ mmol to 22 × 10 ⁻³ mmol per gram of glutarimide resin. Moreover, it is preferable that the glutarimide resin of this invention has a repeating unit represented by the said Formula (1), and a repeating unit represented by the said Formula (2). In the above formula (1), R ⁵ is preferably a cycloalkyl group having 3 to 12 carbon atoms or an aryl group having 6 to 10 carbon atoms, whereby a glutarimide resin having excellent heat resistance and low birefringence. It can be.

  The present invention also includes an optical film containing the glutarimide resin of the present invention, a transparent conductive film having a transparent conductive layer on at least one surface of the optical film, the optical film, and the transparent conductive film. An image display device is also provided.

  According to the method for producing a glutarimide resin of the present invention, esterification is performed by using an acyclic base catalyst having a pKa of 11 or more when esterifying a carboxylic acid group and / or an acid anhydride group with an esterifying agent. The reaction can be allowed to proceed efficiently, and coloring of the resulting glutarimide resin can be suppressed. Further, the glutarimide resin of the present invention is excellent in durability under wet heat and has little coloring.

  First, the method for producing the glutarimide resin of the present invention will be described. In the method for producing a glutarimide resin of the present invention, an acrylic polymer having an imide ring structure and having a carboxylic acid group and / or an acid anhydride group is obtained in the presence of an acyclic base catalyst having a pKa of 11 or more. It has the process (esterification process) made to react with an esterifying agent. When glutarimide resin has many carboxylic acid groups and acid anhydride groups, durability under wet heat decreases, viscosity of glutarimide resin increases, and molding processability when filming is reduced However, by esterifying a carboxylic acid group or an acid anhydride group, durability under wet heat can be improved, and molding processability to a film or the like can be improved.

  The acrylic polymer to be reacted with the esterifying agent has an imide ring structure and has a carboxylic acid group and / or an acid anhydride group, and may be hereinafter referred to as an “imidized polymer”. The acrylic polymer is preferably obtained by polymerizing a (meth) acrylic acid compound, but is not limited thereto, and a substituent such as an alkyl group may be bonded to carbons at the α-position and the β-position. Those obtained by polymerizing an α, β-unsaturated carbonyl compound which is an acrylic acid compound can be widely used. The α, β-unsaturated carbonyl compound other than the (meth) acrylic acid compound may have a substituent other than a hydrogen atom bonded to the β-position carbon, and a substituent other than a hydrogen atom or a methyl group may be bonded to the α-position carbon. It may be bonded. In addition, as a substituent other than the hydrogen atom which may be couple | bonded with (beta) -position carbon, a C1-C8 alkyl group is mentioned, for example. Examples of the substituent other than the hydrogen atom and the methyl group that may be bonded to the α-position carbon include an alkyl group having 2 to 8 carbon atoms.

  The imidized polymer preferably has a repeating unit represented by the following formula (1) (hereinafter sometimes referred to as “glutarimide unit”) as a repeating unit having an imide ring structure.

In the glutarimide unit of the formula (1), R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, n- Examples include a hexyl group, an isohexyl group, an n-heptyl group, an isoheptyl group, an n-octyl group, and a 2-ethylhexyl group. Among these, as R ¹ , R ² , R ³ and R ⁴ , a hydrogen atom or an alkyl group having 1 to 4 carbon atoms is preferable, and this makes it easy to improve the heat resistance of the resulting glutarimide resin. When an optical film is produced by forming a resin into a film, an optical film having a small birefringence is easily obtained. From the viewpoint of ease of production of the imidized polymer, R ¹ , R ² , R ³ and R ⁴ are preferably hydrogen atoms or methyl groups, R ¹ and R ³ are hydrogen atoms, R ² and More preferably, R ⁴ is a hydrogen atom or a methyl group.

In the glutarimide unit of the formula (1), R ⁵ represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or a group having a ring structure. Examples of the alkyl group having 1 to 18 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, n- Examples include a hexyl group, an isohexyl group, an n-heptyl group, an isoheptyl group, an n-octyl group, and a 2-ethylhexyl group. Examples of the group having a ring structure include a cycloalkyl group having 3 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, and an aryl group having 6 to 10 carbon atoms. Examples of the cycloalkyl group having 3 to 12 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the aralkyl group having 7 to 12 carbon atoms include a benzyl group and a naphthylmethyl group. Examples of the aryl group having 6 to 10 carbon atoms include phenyl group, tolyl group, xylyl group, naphthyl group, and biphenyl group. Among these, R ⁵ is preferably a cycloalkyl group having 3 to 12 carbon atoms or an aryl group having 6 to 10 carbon atoms in terms of obtaining a glutarimide resin having excellent heat resistance and low birefringence, and has 6 carbon atoms. 10 to 10 aryl groups are more preferred.

  The imidized polymer may contain only 1 type of the glutarimide unit of Formula (1), and may contain 2 or more types.

  The carboxylic acid group and / or acid anhydride group of the imidized polymer may be directly bonded to the main chain of the resin or may be bonded to a side chain. The imidized polymer to be subjected to the esterification step is derived from the production raw materials and production intermediates, and carboxylic acid groups and acid anhydride groups can remain in the imidized polymer. The imidized polymer is represented by the repeating unit represented by the following formula (3) (hereinafter sometimes referred to as “α, β-unsaturated carboxylic acid unit”) and / or the following formula (4). It is preferable that it contains a repeating unit (hereinafter sometimes referred to as “glutaric anhydride unit”).

In the α, β-unsaturated carboxylic acid unit of the formula (3), R ⁹ and R ¹⁰ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms include the alkyl groups exemplified as the alkyl group for R ^{1 to} R ⁴ . Among them, R ⁹ and R ¹⁰ are preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom or a methyl group, R ⁹ is a hydrogen atom, and R ¹⁰ is a hydrogen atom or More preferably, it is a methyl group. In the glutaric anhydride unit of the formula (4), R ^{1 to} R ⁴ represent the same meaning as described above.

  The imidized polymer may contain only one type of α, β-unsaturated carboxylic acid unit of the formula (3), or may contain two or more types, and the glutaric anhydride unit of the formula (4). 1 type may be included and 2 or more types may be included.

  The imidized polymer to be reacted with the esterifying agent has a repeating unit derived from an α, β-unsaturated carboxylic acid ester (hereinafter sometimes referred to as “α, β-unsaturated carboxylic acid ester unit”). For example, it preferably has a repeating unit represented by the following formula (5).

In the α, β-unsaturated carboxylic acid ester unit of the formula (5), R ¹¹ and R ¹² each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms include the alkyl groups exemplified as the alkyl group for R ^{1 to} R ⁴ . Among them, R ¹¹ and R ¹² are preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom or a methyl group, R ¹¹ is a hydrogen atom, and R ¹² is a hydrogen atom or More preferably, it is a methyl group.

In the α, β-unsaturated carboxylic acid ester unit of the formula (5), R ¹³ represents a group having an alkyl group having 1 to 18 carbon atoms. Examples of the alkyl group having 1 to 18 carbon atoms include the alkyl groups exemplified as the alkyl group for R ⁵ . Among these, as R < ¹³ >, a C1-C12 alkyl group is preferable, a C1-C8 alkyl group is more preferable, a C1-C4 alkyl group is further more preferable, a methyl group, an ethyl group, or An n-butyl group is particularly preferred. Thereby, it becomes easy to improve the heat resistance of the obtained glutarimide resin, and when an optical film is produced by forming the glutarimide resin into a film, an optical film having a small birefringence is easily obtained.

  The imidized polymer may contain only one type of α, β-unsaturated carboxylic acid ester unit of the formula (5), or may contain two or more types.

  The imidized polymer may contain a repeating unit other than the above. The imidized polymer has a total content of 70% by mass or more of the glutarimide unit, the α, β-unsaturated carboxylic acid unit, the glutaric anhydride unit, and the α, β-unsaturated carboxylic acid ester unit. It is preferably 80% by mass or more, more preferably 90% by mass or more. The imidized polymer may have, for example, a unit derived from styrene as a repeating unit, but it is preferable that a large number of units derived from styrene are not contained. Accordingly, the content of styrene-derived units in the imidized polymer is preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 2% by mass or less, and particularly preferably 1% by mass or less.

  The weight average molecular weight of the imidized polymer is not particularly limited, but is preferably 10,000 or more from the viewpoint of increasing mechanical strength when a glutarimide resin obtained by esterification is formed into a film or the like. The above is more preferable. In addition, the weight average molecular weight of the imidized polymer is preferably 500,000 or less, and more preferably 300,000 or less, from the viewpoint of improving the moldability of a glutarimide resin to a film or the like.

  The glass transition temperature of the imidized polymer is, for example, preferably 130 ° C. or higher, more preferably 140 ° C. or higher, and more preferably 150 ° C. or higher, from the viewpoint of increasing the heat resistance of the glutarimide resin obtained by esterification. More preferably, 160 ° C. or higher is particularly preferable, and from the viewpoint of improving the moldability of a glutarimide resin film or the like, 250 ° C. or lower is preferable, 230 ° C. or lower is more preferable, 210 ° C. or lower is further preferable, and 200 ° C. or lower is preferable. Is particularly preferred.

  The imidized polymer can be obtained by polymerizing an α, β-unsaturated carbonyl compound as a monomer component and reacting with an imidizing agent. In the step of polymerizing the α, β-unsaturated carbonyl compound (polymerization step), the α, β-unsaturated carboxylic acid ester is homo- or copolymerized, or the α, β-unsaturated carboxylic acid ester and the α, β-unsaturated ester are copolymerized. It is preferable to copolymerize with a saturated carboxylic acid, and the obtained homopolymer or copolymer can react with the imidizing agent as it is or after activation as necessary. Hereinafter, the acrylic polymer obtained in the polymerization step may be referred to as “uncyclized polymer”.

As the α, β-unsaturated carboxylic acid ester, a compound represented by the following formula (6) is preferably used, and as the α, β-unsaturated carboxylic acid, a compound represented by the following formula (7) is preferable. Used. In the following formulas (6) and (7), R ^{9 to} R ¹³ represent the same meaning as described above. Among these, the α, β-unsaturated carboxylic acid ester represented by the formula (6) is preferably a (meth) acrylic acid ester in which R ¹¹ is a hydrogen atom and R ¹² is a hydrogen atom or a methyl group. As the α, β-unsaturated carboxylic acid represented by the formula (7), (meth) acrylic acid in which R ⁹ is a hydrogen atom and R ¹⁰ is a hydrogen atom or a methyl group is preferable.

  When α, β-unsaturated carboxylic acid ester and α, β-unsaturated carboxylic acid are copolymerized, the total amount of α, β-unsaturated carboxylic acid ester and α, β-unsaturated carboxylic acid is 100% by mass. On the other hand, the α, β-unsaturated carboxylic acid is preferably contained at a content of 45% by mass or less, more preferably 40% by mass or less. In the polymerization step, it is preferable to copolymerize an α, β-unsaturated carboxylic acid ester and an α, β-unsaturated carboxylic acid, whereby a repeating unit containing an ester group and a repeating unit containing a carboxylic acid group are formed. The uncyclized polymer is obtained, and the reaction with the imidizing agent is facilitated.

  In the polymerization step, for example, a polymerization method such as a bulk polymerization method, a solution polymerization method, an emulsion polymerization method, or a suspension polymerization method can be used, but a solution polymerization method that is a polymerization method using a solvent is preferably used. If the solution polymerization method is used, it is possible to suppress the entry of minute foreign matters into the obtained polymer, and it is easy to use it suitably for optical material applications and the like.

  As the polymerization solvent, an organic solvent used in a normal radical polymerization reaction can be used. Specifically, aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and anisole; acetic acid Esters such as ethyl, butyl acetate, propylene glycol monomethyl ether acetate, 3-methoxybutyl acetate; alcohols such as methanol, ethanol, isopropanol, n-butanol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether; acetonitrile, propionitrile , Nitriles such as butyronitrile, benzonitrile; chloroform; dimethylsulfoxy Etc. The. These solvents may use only 1 type and may use 2 or more types together.

  What is necessary is just to set suitably the density | concentration of the monomer component in a polymerization solvent according to polymerization conditions, the molecular weight desired of the polymer obtained, etc. The concentration of the monomer component in the polymerization solvent is, for example, preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and preferably 300 parts by mass or less, and 200 parts by mass with respect to 100 parts by mass of the solvent. The following is more preferable.

  The temperature of the polymerization reaction may be appropriately adjusted according to the type of solvent and the degree of progress of the polymerization reaction. For example, 50 ° C or higher is preferable, 55 ° C or higher is more preferable, 160 ° C or lower is preferable, and 145 ° C or lower is preferable. Is more preferable. The polymerization reaction time may be appropriately adjusted according to the degree of progress of the polymerization reaction. For example, the polymerization reaction time may be 1 to 48 hours (preferably 3 to 24 hours).

  In the polymerization, a known polymerization initiator may be used. Examples of the polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, dimethyl-2,2′-azobis (2-methylpropyl). Azo compounds such as 4,4′-azobis (4-cyanopentanoic acid); persulfates such as potassium persulfate; cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, Peroxides such as lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate, t-amylperoxy-2-ethylhexanoate, t-amylperoxyoctoate, t-amylperoxyisononanoate Etc. can be used. These may use only 1 type and may use 2 or more types together. It is preferable that the usage-amount of a polymerization initiator shall be 0.01-1 mass part with respect to 100 mass parts of monomer components, for example. In the polymerization, a chain transfer agent or the like may be used as necessary.

  The homo- or copolymer obtained as described above may be reacted with an imidizing agent as it is, or may be reacted after being activated. The glutaric anhydride unit described above is one of the activation units. In order to obtain an acrylic polymer having this glutaric anhydride unit, in the polymerization step, an α, β-unsaturated carboxylic acid ester and an α, β-unsaturated carboxylic acid are copolymerized to form an uncyclized polymer. Is obtained, and the obtained α-β-unsaturated carboxylic acid unit and the α-β-unsaturated carboxylic acid ester unit are dealcoholized, or the un-cyclized polymer has It is preferable to perform a cyclization step in which dehydration is performed from two adjacent α, β-unsaturated carboxylic acid units. In the cyclization step, the cyclization condensation reaction proceeds by dealcoholization or dehydration, and a glutaric anhydride structure is formed in the main chain of the acrylic polymer. Hereinafter, the acrylic polymer obtained in the cyclization step may be referred to as a “cyclization polymer”.

  If the acrylic polymer to be reacted with the imidizing agent has a glutaric anhydride unit (that is, a glutaric anhydride structure), the reactivity with the imidizing agent can be increased. When the above-mentioned uncyclized polymer is reacted with an imidizing agent to imidize, depending on the type of imidizing agent, the nucleophilicity is low, and the reaction with the carboxylic acid group or derivative thereof possessed by the uncyclized polymer May decrease. However, if a cyclized polymer having a glutaric anhydride structure (an acid anhydride group) is used, an imidization reaction can be facilitated even with an imidizing agent having low nucleophilicity. That is, in order to obtain a glutarimide resin having a high imidization rate, it is preferable to use a cyclized polymer having a glutaric anhydride unit. This method is particularly effective when an arylamine such as aniline having a low nucleophilicity is used.

  The cyclization reaction to a glutaric anhydride structure is preferably carried out by heating the uncyclized polymer under reduced pressure to cause cyclization condensation. As a method for carrying out the reaction under such conditions, a method using an extruder equipped with a vent as described later is effective.

  The cyclization step is preferably performed under reduced pressure from the viewpoint of promoting the cyclization reaction, and the pressure (absolute pressure) in the reaction is preferably, for example, 80 kPa or less, more preferably 60 kPa or less, and 40 kPa or less. Further preferred. Although the minimum of the said pressure is not specifically limited, The equipment for implement | achieving a pressure reduction state does not become an over specification, and 1 kPa or more is preferable from the point which keeps equipment cost low.

  The reaction temperature (polymer temperature) in the cyclization step is preferably 240 ° C. or higher, more preferably 260 ° C. or higher, and further preferably 280 ° C. or higher from the viewpoint of promoting the cyclization reaction. On the other hand, the temperature is preferably 350 ° C. or lower, and more preferably 330 ° C. or lower, from the viewpoint of suppressing decomposition and coloring of the polymer.

  In the cyclization reaction to a glutaric anhydride structure, it is preferable to use a catalyst. As the cyclization catalyst for promoting the cyclization condensation reaction, at least one selected from the group consisting of acids, bases and salts thereof can be used. Kinds of acids, bases and salts thereof are not particularly limited.

  Examples of the acid include hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, phosphoric acid, phosphorous acid, phenylphosphonic acid, methyl phosphate, and the like. Examples of the base include metal hydroxide, amine, imine, metal alkoxide, ammonium hydroxide salt and the like. Examples of the acid and base salts include organic acid metal salts such as metal acetates and metal stearates; metal carbonates and the like. Among these catalysts, a compound having an alkali metal is preferable because an excellent reaction promoting effect is exhibited in a small amount. If a compound having an alkali metal is used, it not only contributes as a catalyst for the cyclization reaction, but also contributes as a catalyst for the esterification reaction described later, so that a reaction promoting effect for the esterification reaction can be expected.

  Examples of the compound having an alkali metal include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide; sodium methoxide, sodium ethoxide, sodium phenoxide, potassium methoxide, potassium ethoxide and potassium phenoxide. And alkali metal alkoxides such as organic acid alkali metal salts such as lithium acetate, sodium acetate, potassium acetate and sodium stearate. Among these compounds having an alkali metal, sodium hydroxide, sodium methoxide, lithium acetate and sodium acetate are preferable, and sodium methoxide and lithium acetate are more preferable.

  The amount of the cyclization catalyst is not particularly limited, but it is preferably used within a range that does not adversely affect the polymer such as coloring and does not lower the transparency of the polymer. The amount of the cyclization catalyst used is preferably 0.01 parts by mass or more with respect to 100 parts by mass of the monomer component used for polymerization of the uncyclized polymer to be subjected to the cyclization reaction or uncyclized polymer, for example. 0.02 parts by mass or more, more preferably 0.03 parts by mass or more, further preferably 1 part by mass or less, more preferably 0.5 parts by mass or less, further preferably 0.2 parts by mass or less, 0 More preferably, it is less than 1 part by mass.

  The weight average molecular weight of the cyclized polymer obtained as described above is preferably, for example, 10,000 or more, more preferably 30,000 or more, preferably 500,000 or less, more preferably 300,000 or less. The glass transition temperature of the cyclized polymer is preferably 115 ° C. or higher, more preferably 120 ° C. or higher, further preferably 125 ° C. or higher, more preferably 200 ° C. or lower, and more preferably 180 ° C. or lower.

  The uncyclized polymer obtained in the polymerization step or the cyclized polymer obtained in the cyclization step is then reacted with an imidizing agent (imidization step). Hereinafter, the uncyclized polymer and the cyclized polymer may be collectively referred to as “(imidized) raw material polymer”.

  By reacting the raw material polymer with an imidizing agent, the carboxylic acid group and / or acid anhydride group of the raw material polymer is imidized, and an acrylic polymer having an imide ring structure in the main chain (imidized polymer) ) Can be obtained. At this time, since it is difficult to completely imidize the carboxylic acid group and / or the acid anhydride group contained in the raw material polymer, the resulting imidized polymer has an imide ring structure, a carboxylic acid group and / or Or it has an acid anhydride group. In order to efficiently imidize, it is preferable to use a cyclized polymer having a glutaric anhydride structure. Therefore, an imidized polymer obtained by imidizing this also has at least an acid anhydride group. It is preferable that it has.

  An amine or ammonia can be used as the imidizing agent. As the amine, a primary amine is preferably used. For example, an alkylamine having an alkyl group having 1 to 18 carbon atoms: a cycloalkylamine having a cycloalkyl group having 3 to 12 carbon atoms; an aralkyl group having 7 to 12 carbon atoms Aralkylamine having an aryl group (for example, benzylamine); arylamine having an aryl group having 6 to 10 carbon atoms (for example, aniline, toluidine, trichloroaniline, etc.) can be used. These imidizing agents may be used alone or in combination of two or more. As the imidizing agent, an amine having a ring structure is preferably used from the viewpoint of obtaining a glutarimide resin having excellent heat resistance and low birefringence, and a cycloalkylamine or carbon having a cycloalkyl group having 3 to 12 carbon atoms. It is more preferable to use an arylamine having an aryl group of several 6 to 10, and an arylamine is more preferable.

  The amount of the imidizing agent may be appropriately adjusted according to the desired amount of glutarimide structure contained in the imidized polymer. The amount of the imidizing agent may be adjusted in the range of 5 to 100 parts by mass with respect to 100 parts by mass of the uncyclized polymer or cyclized polymer to be reacted with the imidizing agent. Part is more preferred.

  In the case of using a cyclized polymer having a glutaric anhydride structure introduced as a raw material polymer used in the imidization step, after isolating the cyclized polymer generated in the cyclization step, the imidization agent is used in the imidization step. By reacting with, an imidized polymer having an imide ring structure in the main chain can be produced efficiently.

  As a method for performing an imidation reaction with an imidizing agent, a known method can be used. For example, (1) a raw material polymer solution obtained by dissolving a raw material polymer in a solvent inert to imidization. A method (batch reaction method) of reacting a raw material polymer with an imidizing agent, (2) adding an imidizing agent to a raw material polymer in a molten state using an extruder, Examples thereof include a method of reacting a raw material polymer and an imidizing agent (melt kneading method).

  A batch type reaction vessel (pressure vessel) can be used for the batch type reaction method. The batch type reaction vessel (pressure vessel) preferably has a structure capable of heating and stirring a solution in which a raw material polymer is dissolved in a solvent and adding an imidizing agent. As the viscosity of the solution increases with progress, it is more preferable that the stirring efficiency is excellent. Examples of the batch type reaction tank (pressure vessel) include a Max Blend (registered trademark) stirring tank manufactured by Sumitomo Heavy Industries, Ltd.

  In the batch reaction method, examples of the solvent inert to imidization include aliphatic alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, and isobutanol; benzene, toluene, xylene, and chlorobenzene. And aromatics such as chlorotoluene; ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and anisole; These solvents may use only 1 type and may use 2 or more types together. Among these solvents, toluene or a mixed solvent of toluene and methanol is preferable.

  In the batch reaction method, the reaction temperature for reacting the raw material polymer with the imidizing agent is such that the raw material polymer is efficiently imidized with the imidizing agent, and the raw material polymer is decomposed and colored due to excessive thermal history. 160 degreeC or more is preferable from the point which suppresses etc., 180 degreeC or more is more preferable, 200 degreeC or more is more preferable, 400 degreeC or less is preferable, 350 degreeC or less is more preferable, 300 degreeC or less is more preferable.

  In the melt-kneading method, an extruder can be used. Examples of the extruder include a single screw extruder, a twin screw extruder, and a multi-screw extruder. Among these extruders, a twin-screw extruder is preferable because the raw material polymer and the imidizing agent can be efficiently mixed. One extruder may be used independently and two or more extruders may be connected in series. The extruder is preferably provided with a vent that can be depressurized below atmospheric pressure in order to remove (devolatilize) unreacted imidizing agent and by-products. The number of vents may be only one or plural.

  When using an extruder with a vent, it is preferable that the extruder has a cylinder and a screw provided in the cylinder, and includes heating means. One or more vents are provided in the cylinder. The vent is preferably provided at least on the downstream side of the raw material charging unit with respect to the transfer direction in the extruder, and may be provided on the upstream side of the raw material charging unit.

  In the melt-kneading method, imidation of the raw material polymer is performed by, for example, charging the raw material polymer from the raw material charging part of the extruder, melting the raw material polymer and filling the cylinder, and then adding the imidizing agent to the pump Can be carried out by pouring into an extruder.

  In the melt-kneading method, the temperature of the reaction zone in the extruder (polymer temperature) is preferably 150 ° C. or higher, more preferably 200 ° C. or higher, whereby the imidization reaction can be suitably advanced and obtained. Residual volatile matter in the imidized polymer can be reduced. On the other hand, the temperature is preferably 380 ° C. or less, more preferably 350 ° C. or less, and further preferably 300 ° C. or less, thereby suppressing degradation of the raw material polymer due to excessive heat history, and suppressing a decrease in molecular weight. It becomes easy to ensure the transparency of the imidized polymer. The reaction zone in the extruder means a region between the injection position of the imidizing agent and the discharge port (die part) of the imidized polymer in the cylinder of the extruder.

  In the melt-kneading method, the imidization of the raw material polymer can be promoted by increasing the reaction time of the raw material polymer and the imidizing agent in the reaction zone in the extruder. The time required for imidation of the raw material polymer in the reaction zone in the extruder is preferably 10 seconds or longer, more preferably 30 seconds or longer from the viewpoint of sufficiently imidating the raw material polymer.

  From the viewpoint of improving the solubility of the imidizing agent, at least a part of the inside of the extruder is preferably in a pressurized state (pressure zone). In this case, the pressure (absolute pressure) of the raw material polymer in the pressure zone is preferably set to atmospheric pressure or higher, and more preferably 1 MPa or higher. The pressure is preferably 50 MPa or less, more preferably 30 MPa or less, considering the pressure resistance of the extruder. When performing the imidization reaction while devolatilizing, it is preferable to perform part of the imidization reaction under reduced pressure from the viewpoint of efficiently performing devolatilization, and forming a reduced pressure zone in part of the extruder. preferable. In this case, the pressure in the decompression zone in the extruder is preferably 90 kPa or less, more preferably 80 kPa or less, and even more preferably 70 kPa or less. On the other hand, the pressure in the decompression zone is preferably 0.1 kPa or more and more preferably 1 kPa or more from the viewpoint that the equipment for realizing the decompressed state is not over-specification and the equipment cost is kept low.

  The imidized acrylic polymer used in the present invention (that is, an acrylic polymer having an imide ring structure and a carboxylic acid group and / or an acid anhydride group) can be produced as described above. . The imidized polymer thus produced varies depending on the type and amount of the monomer used, the amount of the imidizing agent used, and the like. For example, the acid value is 1.0 mmol / g or more. 2 mmol / g or more. The upper limit of the acid value of the imidized polymer is, for example, 5.0 mmol / g.

  In the production method of the present invention, an imidized polymer is reacted with an esterifying agent in the presence of an esterification catalyst (esterification step) to obtain a glutarimide resin. By the esterification step, a carboxylic acid group or an acid anhydride group contained in the imidized polymer is converted to an ester, and a glutarimide resin having a reduced acid value can be obtained. As a result, the resulting glutarimide resin becomes difficult to absorb water even under wet heat and has excellent durability under wet heat. In addition, an excessive increase in the melt viscosity of the glutarimide resin can be suppressed during molding into a film or the like, and molding processability can be improved.

  In the production method of the present invention, an acyclic base catalyst having a pKa of 11 or more is used as the esterification catalyst. By using such a catalyst, the esterification reaction can be allowed to proceed efficiently, and coloring of the resulting glutarimide resin can be suppressed. By using an acyclic base catalyst as the esterification catalyst, for example, the absorbance at a wavelength of 390 nm of the obtained resin can be suppressed lower than when a cyclic base catalyst such as diazabicycloundecene is used. it can.

  As a method of esterifying an imidized polymer with an esterifying agent, as in the case of the imidization step, for example, (1) an imidized polymer is dissolved in a solvent inert to esterification and obtained. A method of adding an esterifying agent and an esterification catalyst to the imidized polymer solution and reacting the imidized polymer with the esterifying agent (batch reaction method), (2) In a molten state using an extruder or the like A method (melt kneading method) of adding an esterifying agent and an esterification catalyst to the imidized polymer and reacting the imidized polymer with the esterifying agent can be employed.

  The acyclic base catalyst can be used without particular limitation as long as it has a pKa of 11 or more and does not have a ring structure, but a nitrogen base is preferably used. An amine can be used as the nitrogen base. However, in order to obtain an amine having a pKa of 11 or more, it is generally necessary that two or more relatively strong electron donating groups are bonded to the nitrogen atom of the amine. In this case, it is preferable to use a secondary or tertiary amine in which at least one alkyl group having 3 or more carbon atoms is bonded to the nitrogen atom of the amine. Further, the total carbon number of the amine is preferably 5 or more, and more preferably 6 or more.

  As the acyclic base catalyst, it is preferable to use a nitrogen base other than amine, and this makes it easier to suppress the amine-derived odor of the resulting glutarimide resin. As such a nitrogen base, a compound having an amidine structure is preferably used. A compound having an amidine structure has a relatively high pKa and exhibits excellent catalytic performance as an esterification catalyst. Specifically, the compound having an amidine structure is preferably a compound of the following formula (8).

In the above formula (8), R ^{14 to} R ¹⁷ are each independently a hydrogen atom, an alkyl group (the alkyl group may have an amino group as a substituent), a hydrogen atom at the N-position or An amino group to which an alkyl group is bonded is represented. When R ^{14 to} R ¹⁷ include an alkyl group, the alkyl group is linear or branched. R ^{14 to} R ¹⁶ preferably represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ¹⁷ preferably represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a hydrogen atom at the N-position or An amino group to which an alkyl group having 1 to 4 carbon atoms is bonded is represented.

  As the nitrogen base used as the acyclic base catalyst, it is also preferable to use a compound having a guanidine structure. A compound having a guanidine structure also has a relatively high pKa and exhibits excellent catalytic performance as an esterification catalyst. Specifically, the compound having a guanidine structure is preferably a compound of the following formula (9).

In the above formula (9), R ^{14 to} R ¹⁶ represent the same meaning as described above, and R ¹⁸ and R ¹⁹ each independently represent a hydrogen atom or an alkyl group (the alkyl group has an amino group as a substituent). Or an amino group having a hydrogen atom or an alkyl group bonded to the N position. When R ¹⁸ and R ¹⁹ contain an alkyl group, the alkyl group is linear or branched. R ^{14 to} R ¹⁶ and R ^{18 to} R ¹⁹ preferably represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably R ¹⁴ represents a hydrogen atom, and R ^{15 to} R ¹⁶ , R ^18. to R ¹⁹ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

  Specific examples of the acyclic base catalyst having a pKa of 11 or more include dimethylhexylamine (pKa 11.04), di-n-butylamine (pKa 11.3), diisopropylamine (pKa 11.1), guanidine, and methyl guanidine. , Ethylguanidine, tetramethylguanidine (both pKa11 or more), and the like. The acyclic base catalyst having a pKa of 11 or more may be used alone or in combination of two or more.

  The amount of the acyclic base catalyst having a pKa of 11 or more used in the esterification step is not particularly limited, but the amount of the catalyst used is preferably 100 parts by mass with respect to 100 parts by mass of the imidized polymer from the viewpoint of suitably proceeding the esterification reaction. 0.2 parts by mass or more is preferable, and 0.5 parts by mass or more is more preferable. Moreover, from the point which suppresses coloring of the obtained glutarimide resin, the usage-amount of the said catalyst is preferable 5.0 mass parts or less with respect to 100 mass parts of imidated polymers, and 4.5 mass parts or less are more preferable. 4.0 parts by mass or less is more preferable.

  Examples of the esterifying agent used in the esterification step include dimethyl carbonate, diphenyl carbonate, 2,2-dimethoxypropane, dimethyl sulfoxide, triethyl orthoformate, trimethyl orthoacetate, trimethyl orthoformate, dimethyl sulfate, methyl toluene sulfonate, Methyl trifluoromethyl sulfonate, methyl acetate, isopropenyl acetate, methanol, ethanol, methyl isocyanate, p-chlorophenyl isocyanate, dimethylcarbodiimide, dimethyl-tert-butylsilyl chloride, dimethylurea, tetramethylammonium hydroxide, dimethyldiethoxysilane, Tetra-N-butoxysilane, dimethyl (trimethylsilane) phosphite, trimethylphenol Sufaito, trimethyl phosphate, tricresyl phosphate, diazomethane, ethylene oxide, propylene oxide, cyclohexene oxide, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, benzyl glycidyl ether. These esterifying agents may be used alone or in combination of two or more.

  It is preferable to use an acyclic compound as the esterifying agent. As the esterifying agent, for example, a compound capable of introducing a linear or branched alkyl group into the carboxylic acid group or acid anhydride group of the imidized polymer by a transesterification reaction is preferable. The alkyl group preferably has 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, and still more preferably 1 to 3 carbon atoms. Further, from the viewpoint of reducing the concern about coloring of the glutarimide resin, the esterifying agent is preferably a compound composed only of carbon, oxygen and hydrogen. Among these esterifying agents, dimethyl carbonate is particularly preferable because it reduces cost and is excellent in the reactivity of the esterification reaction.

  The amount of the esterifying agent is not particularly limited, but is usually preferably 1 part by mass or more, more preferably 3 parts by mass or more, further preferably 5 parts by mass or more, and 50 parts by mass with respect to 100 parts by mass of the imidized polymer. Part or less, preferably 40 parts by weight or less, more preferably 30 parts by weight or less.

From the viewpoint of suppressing coloring of the resulting glutarimide resin, it is also preferable that the imidized polymer used for the esterification reaction has a small content of alkali metal. In producing the imidized polymer, as described above, a compound having an alkali metal may be used as a catalyst for the cyclization reaction in the cyclization step, but the compound having the alkali metal is esterified. It also contributes as a catalyst for the reaction. It is also assumed that a compound having an alkali metal is newly added as a part of the esterification catalyst in the esterification step. However, alkali metals can also cause coloring of the resulting glutarimide resin. Accordingly, the content of alkali metal imidized polymer strikes imidized polymers 1g, preferably 22 × is 10 ^-3 mmol or less, more preferably less ^{19 × 10 -3 mmol, 17 ×} 10 - ³ mmol or less is more preferable. On the other hand, the content of alkali metal in the imidized polymer is 4.5 × 10 ⁻³ mmol or more per 1 g of the imidized polymer from the viewpoint of increasing the reaction rate of the esterification reaction or the previous cyclization reaction. Is preferably 6.5 × 10 ⁻³ mmol or more, and more preferably 8.5 × 10 ⁻³ mmol or more.

  The glutarimide resin obtained as described above contains an acyclic base catalyst having a pKa of 11 or more. If such a catalyst is used to esterify a carboxylic acid group and / or an acid anhydride group, the resulting resin has a reduced acid value and a reduced color.

  The acid value of the glutarimide resin is preferably 0.5 mmol / g or less, more preferably 0.4 mmol / g or less, and further 0.3 mmol / g or less, from the viewpoint of improving durability under wet heat. preferable. The acid value of glutarimide resin is calculated | required based on the method as described in an Example.

  The glutarimide resin preferably has an absorbance at a wavelength of 390 nm of 1.3% or less, more preferably 1.0 or less, and 0.8 or less when it is made into a 10% by mass THF solution from the viewpoint of less coloring. Is more preferable, and 0.7 or less is particularly preferable. For example, when diazabicycloundecene, which is a cyclic base catalyst, is used as the esterification catalyst, an absorbance peak appears in the vicinity of a wavelength of 390 nm. Based on this, coloring of the glutarimide resin is likely to occur. According to the glutarimide resin, light absorption in the vicinity of a wavelength of 390 nm is suppressed, and the resin is hardly colored. The lower limit of the absorbance is not particularly limited, but even if some absorbance is confirmed as a measurement value, it hardly affects practically. Therefore, the absorbance may be greater than 0.3, for example, greater than 0.35. Also good. The absorbance is measured using a cell having a path length of 1 cm, and details are based on the description of the examples.

  The glutarimide resin also has a b * value of L * a * b * color system of preferably 5.00 or less, more preferably 4.00 or less, from the viewpoint of less coloring. More preferred are: For example, when diazabicycloundecene, which is a cyclic base catalyst, is used as the esterification catalyst, the b * value tends to increase and a yellowish color tends to be exhibited. However, the glutarimide resin of the present invention According to the above, such coloring is difficult to occur. In addition, b * value is a value when measuring what shape | molded the glutarimide resin in the 100-micrometer-thick unstretched film, and the measuring method is based on description of an Example.

  The content of the acyclic base catalyst having a pKa of 11 or more in the glutarimide resin is preferably 5.0% by mass or less in 100% by mass of the glutarimide resin from the viewpoint of reducing coloring of the glutarimide resin. 4.5 mass% or less is more preferable, and 4.0 mass% or less is further more preferable. On the other hand, the content of the acyclic base catalyst having a pKa of 11 or more in the glutarimide resin is 0.1% in 100% by mass of the glutarimide resin in order to facilitate the esterification reaction in the production of the glutarimide resin. % By mass or more is preferable, and 0.5% by mass or more is more preferable.

The content of alkali metal in the glutarimide resin is preferably 22 × 10 ⁻³ mmol or less, and 19 × 10 ⁻³ mmol or less, per 1 g of glutarimide resin from the viewpoint of reducing coloring of the glutarimide resin. More preferred is 17 × 10 ⁻³ mmol or less. On the other hand, a compound having an alkali metal may be added to the glutarimide resin as a cyclization catalyst or an esterification catalyst in the production stage, and some alkali metal may be contained in the glutarimide resin. . Considering that the production of the glutarimide resin is easy, the alkali metal content in the glutarimide resin is preferably 4.5 × 10 ⁻³ mmol or more per 1 g of the glutarimide resin. 5 × 10 ⁻³ mmol or more is more preferable, and 8.5 × 10 ⁻³ mmol or more is more preferable.

The glutarimide resin preferably has a glutarimide unit represented by the following formula (1) and an α, β-unsaturated carboxylic acid ester unit represented by the following formula (2). R ^{1 to} R ⁵ in the following formula (1) are as described above.

In the above formula (2), R ⁶ and R ⁷ each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms include the alkyl groups exemplified as the alkyl group for R ^{1 to} R ⁴ . Among them, R ⁶ and R ⁷ are preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom or a methyl group, R ⁶ is a hydrogen atom, and R ⁷ is a hydrogen atom or A methyl group is preferred.

In Formula (2), R ⁸ represents an alkyl group having 1 to 18 carbon atoms or a group having a ring structure. Examples of the group having an alkyl group having 1 to 18 carbon atoms or a ring structure of R ⁸ include the groups having an alkyl group having 1 to 18 carbon atoms and the ring structure exemplified as the substituent for R ⁵ . Among them, R ^8, preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, a methyl group or an ethyl group An n-butyl group is particularly preferred. Thereby, it becomes easy to improve the heat resistance of the obtained glutarimide resin, and when an optical film is produced by forming the glutarimide resin into a film, an optical film having a small birefringence is easily obtained.

  The glutarimide resin may contain only one kind of glutarimide unit represented by the formula (1), or may contain two or more kinds, and α, β-unsaturation represented by the formula (2). Only one type of carboxylic acid ester unit may be included, or two or more types may be included.

  If the glutarimide resin has a glutarimide unit of the formula (1) and an α, β-unsaturated carboxylic acid ester unit of the formula (2), it becomes easy to improve the heat resistance and transparency of the glutarimide resin. It is easy to reduce the birefringence. That is, this glutarimide resin exhibits weak positive birefringence based on glutarimide units, weak negative birefringence based on α, β-unsaturated carboxylic acid ester units, and both birefringences cancel each other. As a whole, low birefringence is exhibited. Moreover, the moldability to a film etc. improves and it becomes easy to raise mechanical strength.

  In the glutarimide resin, the content of the glutarimide unit of the formula (1) is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, and preferably 85% by mass or less. 80 mass% or less is more preferable, and 75 mass% or less is further more preferable. When the content of the glutarimide unit of the formula (1) is 5% by mass or more, it becomes easy to improve the heat resistance and transparency of the glutarimide resin, and to easily reduce the birefringence. If the content rate of the glutarimide unit of Formula (1) is 85 mass% or less, the moldability to a film etc. will improve, it will become easy to raise mechanical strength, and it will become easy to make birefringence small.

  In the glutarimide resin, the content of the α, β-unsaturated carboxylic acid ester unit of the formula (2) is preferably 15% by mass or more, more preferably 20% by mass or more, and further preferably 25% by mass or more. Moreover, 95 mass% or less is preferable, 90 mass% or less is more preferable, and 85 mass% or less is further more preferable. When the content of the α, β-unsaturated carboxylic acid ester unit is 15% by mass or more, the moldability to a film or the like is improved, the mechanical strength is easily increased, and the birefringence can be easily reduced. Become. When the content of the α, β-unsaturated carboxylic acid ester unit is 95% by mass or less, the heat resistance and transparency of the glutarimide resin can be easily improved, and the birefringence can be easily reduced.

  The glutarimide resin may contain a repeating unit other than the repeating units represented by the formulas (1) and (2). In addition, it is preferable that glutarimide resin contains the repeating unit represented by Formula (1) and Formula (2) as a main component, Therefore, the glutarimide unit of Formula (1) and Formula (2) in glutarimide resin are preferable. The total content of the α, β-unsaturated carboxylic acid ester unit is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. The glutarimide resin may have, for example, a unit derived from styrene as a repeating unit, but it is preferable that a large number of units derived from styrene are not included. Accordingly, the content of styrene-derived units in the glutarimide resin is preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 2% by mass or less, and particularly preferably 1% by mass or less.

  The weight average molecular weight of the glutarimide resin is preferably 10,000 or more, more preferably 30,000 or more, from the viewpoint of increasing the mechanical strength when formed into a film or the like, and the viewpoint of improving the moldability to a film or the like. Therefore, 500,000 or less is preferable, and 300,000 or less is more preferable. The weight average molecular weight of glutarimide resin is calculated | required based on the method as described in an Example.

  The glutarimide resin preferably has a glass transition temperature of 130 ° C or higher, more preferably 140 ° C or higher, further preferably 150 ° C or higher, and particularly preferably 160 ° C or higher. If the glutarimide resin has such a glass transition temperature, the heat resistance of the glutarimide resin is improved, and the glutarimide resin can be applied to uses where heat resistance is required, such as an image display device. It becomes. The upper limit of the glass transition temperature of the glutarimide resin is preferably 250 ° C. or lower, more preferably 230 ° C. or lower, further preferably 210 ° C. or lower, particularly preferably 200 ° C. or lower, from the viewpoint of improving the molding processability to a film or the like. preferable. The glass transition temperature of glutarimide resin is determined based on the method described in the examples.

  The glutarimide resin has a melt flow rate measured at a temperature of 270 ° C. and a load of 98 N of preferably 4.0 g / 10 min or more, more preferably 6.0 g / 10 min or more, and even more preferably 7.5 g / 10 min or more. If the glutarimide resin has such a melt flow rate, the melt viscosity of the glutarimide resin is lowered, and the moldability can be improved. Moreover, since it is not necessary to raise the molding temperature of glutarimide resin excessively, thermal decomposition of the resin is less likely to occur, and foaming and mixing of foreign matters are less likely to occur in the obtained molded product. Prior to the molding process, when removing the foreign matter through the filter with the melt of glutarimide resin, the pressure loss of the filter can be kept low, and the productivity can be increased. On the other hand, the melt flow rate is preferably 40 g / 10 min or less, more preferably 30 g / 10 min or less, and more preferably 20 g because the melt processing may be difficult even if the melt viscosity is too low. / 10 min or less is more preferable. The melt flow rate of the glutarimide resin is determined according to JIS K 7210 (Method B).

The absolute value of the stress optical coefficient (Cr) of the glutarimide resin is 0.3 × 10 ⁻ from the viewpoint of suppressing the birefringence by suppressing the anisotropy of the refractive index of the stretched film obtained by stretching the resin. ⁹ Pa ⁻¹ or less is preferable, 0.2 × 10 ⁻⁹ Pa ⁻¹ or less is more preferable, and 0.1 × 10 ⁻⁹ Pa ⁻¹ or less is more preferable. The stress optical coefficient (Cr) of glutarimide resin can be obtained by the method described in JP-A-2015-105332.

  The glutarimide resin has a water absorption rate of preferably 3.0% or less, more preferably 2.5% or less, and even more preferably 2.0% or less, from the viewpoint of improving moldability to a film or the like. . The water absorption is determined based on the method described in the examples after forming a glutarimide resin into an unstretched film.

  The glutarimide resin may be used together with other thermoplastic resins, for example, a polymer blend or a polymer alloy. Other thermoplastic resins include, for example, olefin polymers such as polyethylene, polypropylene, ethylene-propylene copolymer, poly (4-methyl-1-pentene); polyvinyl chloride, polyvinylidene chloride, polyvinyl chloride, and the like. Vinyl halide polymer; acrylic polymer such as polymethyl methacrylate; styrene polymer such as polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene block copolymer Polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; cellulose acylates such as cellulose triacetate, cellulose acetate propionate and cellulose acetate butyrate; nylon 6, nylon Polyamide, Polyamide oxide, Polyphenylene sulfide, Polyphenylene sulfide, Polyether ether ketone, Polysulfone, Polyethersulfone, Polyoxybenzylene, Polyamideimide, ABS resin blended with polybutadiene rubber or acrylic rubber And rubbery polymers such as ASA resin.

  The glutarimide resin may contain various additives. Examples of additives include antioxidants such as hindered phenol antioxidants, phosphorus antioxidants, sulfur antioxidants; stabilization of light stabilizers, weather stabilizers, heat stabilizers, etc. Agents: Reinforcing materials such as glass fibers and carbon fibers; near infrared absorbers; ultraviolet absorbers; flame retardants such as tris (dibromopropyl) phosphate, triallyl phosphate, antimony oxide; anionic surfactants, cationic interfaces Antistatic agents such as activators and nonionic surfactants; Colorants such as inorganic pigments, organic pigments and dyes; Fillers such as organic fillers and inorganic fillers; Resin modifiers; Plasticizers; It is done.

  The glutarimide resin of the present invention can be suitably used as a raw material for optical films and the like, for example. The optical film can be manufactured by using a glutarimide resin, for example, by a melt extrusion molding method such as a T-die method or an inflation method, a cast molding method, a press molding method, or the like. When the optical film is produced by a melt extrusion molding method, for example, a single screw extruder, a twin screw extruder, or the like can be used.

  The optical film is preferably uniaxially or biaxially stretched, and more preferably biaxially stretched from the viewpoint of increasing mechanical strength or achieving a predetermined retardation. Examples of the method for biaxially stretching the optical film of the present invention include a sequential biaxial stretching method and a simultaneous biaxial stretching method.

  The stretching temperature when stretching the optical film is from the temperature lower by 20 ° C. than the glass transition temperature of the glutarimide resin, from the viewpoint of stretching the optical film without breaking and sufficiently molecular orientation. The temperature range is preferably up to 50 ° C., more preferably from 10 ° C. lower than the glass transition temperature of the glutarimide resin to 30 ° C. higher than the glass transition temperature.

  The stretching ratio of the optical film is about 1.5 to 3 times from the viewpoint of increasing the mechanical strength and adjusting the phase difference in both the longitudinal direction and the transverse direction perpendicular to the longitudinal direction. It is preferable that it is about 1.5 to 2.5 times.

  The dimensional change rate of the stretched optical film is preferably 1.0% or less from the viewpoint of improving the durability of a film subjected to secondary processing such as a transparent conductive film, for example, 0.7% The following is more preferable, 0.5% or less is more preferable, and 0.2% or less is particularly preferable. The dimensional change rate of the optical film is determined by the following method. An unstretched film obtained by melt extrusion is cut into a size of 96 mm × 96 mm, and a stretching speed of 240 mm / min at a temperature of Tg + 20 ° C. using a sequential biaxial stretching machine (X-6S, manufactured by Toyo Seiki Seisakusho Co., Ltd.). Then, biaxial stretching is sequentially performed so that the stretching ratio becomes 2 times in the order of the machine direction (MD direction) and the transverse direction (TD direction). After biaxial stretching of the unstretched film, the obtained stretched film is quickly taken out from the test apparatus and cooled to obtain a film having a thickness of 40 μm, and by cutting this, 40 mm × 40 mm Three samples of size are made. The length of each side of the sample (La1, La2, La3, La4) is measured with a digital caliper. Next, the sample is stored in a thermostatic chamber at a temperature of 85 ° C. and a relative humidity of 85%, taken out from the thermostatic chamber after 250 hours, and the lengths of the four pieces (Lb1, Lb2, Lb3, Lb4) of the sample are again measured. taking measurement. The dimensional change rate at each side of the three samples is obtained by the following formula: dimensional change rate (%) = | (Lb−La) / La | × 100 (where La is the length of one side before the test, and Lb is Represents the length of the piece after the test). The average value of the dimensional change rates of each side of the three obtained samples is obtained, and the sum of the average values of the respective sides is divided by 4 to obtain the dimensional change rate of the film.

  Since the thickness of the optical film varies depending on the application, it cannot be determined unconditionally. For example, when the optical film is used for a protective film, an antireflection film, a polarizing film or the like used in an image display device such as a liquid crystal display device or an organic EL display device, the thickness of the optical film is 1 μm or more. Is preferably 10 μm or more, more preferably 20 μm or more, further preferably 250 μm or less, more preferably 100 μm or less, and further preferably 80 μm or less. For example, when the optical film is used for applications such as a transparent conductive film used for an ITO film, a silver nanowire film, a metal mesh film, etc., the thickness of the optical film is preferably 20 μm or more, and 30 μm or more. Is more preferable, 40 μm or more is further preferable, 400 μm or less is preferable, 350 μm or less is more preferable, and 300 μm or less is more preferable.

The in-plane retardation Re of the optical film is preferably 20 nm or less, more preferably 10 nm or less, further preferably 5 nm or less, and further preferably 3 nm or less from the viewpoint of suppressing the refractive index anisotropy of the optical film and reducing the birefringence. Is particularly preferred. The absolute value of the thickness direction retardation Rth of the optical film is preferably 20 nm or less from the viewpoint of suppressing the anisotropy of the refractive index of the optical film and reducing the birefringence, as in the in-plane retardation Re. 10 nm or less is more preferable, 5 nm or less is further more preferable, and 3 nm or less is especially preferable. For example, by controlling the absolute value of the stress optical coefficient (Cr) described above to 0.3 × 10 ⁻⁹ Pa ⁻¹ or less, the absolute value of the thickness direction retardation Rth of the optical film after biaxial stretching. Can be made 20 nm or less.

  The in-plane retardation Re and the thickness direction retardation Rth of the optical film were measured under the conditions of a light having a wavelength of 590 nm and an incident angle of 40 ° using a retardation film / optical material inspection apparatus (Otsuka Electronics, RETS-100). Obtained by measuring with The in-plane retardation Re of the optical film is expressed by the formula: Re = (nx−ny) × d (where nx is the direction of the slow axis for light having a wavelength of 590 nm (the direction showing the maximum refractive index in the plane of the optical film). ), Ny is the refractive index in the fast axis direction (direction perpendicular to nx in the plane of the optical film), and d is the thickness (nm) of the optical film. The thickness direction phase difference Rth is expressed by the formula: Rth = {(nx + ny) / 2−nz} × d (where nx is the refractive index in the slow axis direction with respect to light having a wavelength of 590 nm, and ny is in the fast axis direction) Nz is a refractive index in the thickness direction of the film, and d is a thickness (nm) of the film).

The absolute value of the photoelastic coefficient of the optical film is preferably 10 × 10 ⁻¹² Pa ⁻¹ or less, preferably 6 × 10 ⁻¹² Pa ⁻¹ from the viewpoint of suppressing light leakage, particularly light leakage in a high temperature and high humidity environment. The following is more preferable. The photoelastic coefficient of the optical film is determined according to the following method. That is, the sample was cut into 20 mm × 50 mm with the extending direction of the optical film as the long side, and this sample was mounted on a photoelasticity measurement unit of an ellipsometer (manufactured by JASCO Corporation, product number: M-150). The birefringence is measured at three points while applying a stress load of 5 to 25 N in parallel with the light, and the inclination of the birefringence with respect to the stress is obtained as a photoelastic coefficient using light having a wavelength of 590 nm.

The linear expansion coefficient in the temperature range of 60 to 100 ° C. of the optical film is preferably 80 × 10 ⁻⁶ K ⁻¹ or less, and preferably 70 × 10 ⁻⁶ K ⁻¹ or less, from the viewpoint of suppressing dimensional change in a high temperature environment. More preferred. The linear expansion coefficient at 60 to 100 ° C. of the optical film was increased from 60 ° C. to 100 ° C. at a measurement load of 5 g and a heating rate of 5 ° C./min using a thermomechanical measuring device (manufactured by Shimadzu Corporation, TMA-60). Calculated as the slope when heating. The sample for measurement is prepared by cutting the optical film into a size of 5 mm × 20 mm with the stretching direction as the long side, pretreating it at 60 ° C. for 15 hours, and then cooling to room temperature.

  The optical film is provided with a coating layer on at least one surface as necessary. Examples of the coating layer include an antistatic layer, an adhesive layer, an adhesive layer, an easy-adhesion layer, an antiglare layer (non-glare) layer, a photocatalyst layer, an antifouling layer, an antireflection layer, a hard coat layer, an ultraviolet shielding layer, and a heat ray. Examples thereof include a shielding layer, an electromagnetic shielding layer, and a gas barrier layer.

  A transparent conductive layer may be provided on at least one surface of the optical film, whereby a transparent conductive film can be formed. As the material constituting the transparent conductive layer, any material conventionally used as a conductive material in the field can be used. Specifically, an organic conductive compound; an organic conductive polymer; indium oxide; Metal oxides such as tin oxide, zinc oxide, indium-tin oxide (ITO), antimony-tin oxide (ATO), zinc-aluminum oxide, indium-zinc oxide (IZO); gold, silver, copper, Examples include metals such as palladium and aluminum. Among these, those containing zinc oxide or indium oxide are preferable, and those containing indium oxide are more preferable. Among these, indium-tin oxide is preferable because it has both high transparency and conductivity.

  The transparent conductive layer is formed, for example, on a hard coat layer provided on at least one surface of the optical film. The transparent conductive layer may be provided in contact with the hard coat layer or may be provided via another layer. For example, the transparent conductive layer can be formed on the hard coat layer by thin film forming means such as sputtering, ion plating, and vacuum deposition.

  The thickness of the transparent conductive layer is preferably 0.001 μm or more, more preferably 0.005 μm or more, further preferably 0.01 μm or more from the viewpoint of ensuring conductivity, and 10 μm or less from the viewpoint of improving light transmittance. Is preferably 1 μm or less, and more preferably 0.5 μm or less.

  An optical adjustment layer may be formed on the surface of the optical film. The optical adjustment layer is a layer for appropriately adjusting the transmittance or reflectance of incident light. The optical adjustment layer can be formed by alternately laminating a low refractive index layer having a relatively low refractive index and a high refractive index layer having a relatively high refractive index.

  The optical film is, for example, a protective film for an optical disc, a polarizer protective film used for a polarizing plate of an image display device such as a liquid crystal display device, a retardation film, a viewing angle compensation film, a light diffusion film, a reflective film, an antireflection film, It is expected to be used for applications such as antiglare films, brightness enhancement films, conductive films for touch panels, diffusion plates, light guides, and prism sheets. Therefore, the optical film can be suitably used for applications such as an image display device (for example, a liquid crystal display device).

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to these examples, and all modifications made without departing from the spirit of the present invention are described in the present invention. It is included in the technical scope of the invention.

(1) Analysis method (1-1) Weight average molecular weight (Mw)
The weight average molecular weight of the polymer was determined in terms of polystyrene using gel permeation chromatography (GPC). The apparatus and measurement conditions used for the measurement are as follows.
-Measurement system: GPC system HLC-8220 manufactured by Tosoh Corporation
-Measurement column configuration:
Tosoh Corporation, TSK-GEL SuperHZM-M 6.0 × 150, 2 in series connection Tosoh Corporation, TSK-GEL SuperHZ-L 4.6 × 35, 1-reference column configuration:
Tosoh Co., Ltd., TSK-GEL SuperH-RC 6.0 × 150, 2 in series connection—Developing solvent: Tetrahydrofuran (made by Wako Pure Chemical Industries, special grade)
-Solvent flow rate: 0.6 mL / min-Standard sample: TSK standard polystyrene (manufactured by Tosoh Corporation, PS-oligomer kit)
-Column temperature: 40 ° C

(1-2) Glass transition temperature (Tg)
The glass transition temperature was determined in accordance with JIS K 7121. Specifically, using a differential scanning calorimeter (Rigaku Corporation, Thermo plus EVO DSC-8230), a sample of about 10 mg was heated from room temperature to 200 ° C. under a nitrogen gas atmosphere (heating rate 20 ° C./min). From the DSC curve obtained in this way, evaluation was made by the starting point method. Α-alumina was used as a reference.

(1-3) Acid value 0.15 g of glutarimide resin was dissolved in 24.94 g of methylene chloride, 14.85 g of methanol was added, and the mixture was stirred for 3 hours. Thereafter, 2 drops of a 1% by weight phenolphthalein ethanol solution were added to this solution, while stirring, a 0.1N sodium hydroxide aqueous solution was added, and stirring was continued for 1 hour at room temperature. The amount of sodium aqueous solution used was A (mL). 0.1N hydrochloric acid was added dropwise to this solution, and the amount of dropwise addition B (mL) of 0.1N hydrochloric acid until the reddish purple color of the solution disappeared was measured. Next, 2 drops of a 1% by weight phenolphthalein ethanol solution were added to a mixed solution of 24.94 g of methylene chloride and 14.85 g of methanol, and a 0.1N sodium hydroxide aqueous solution was added while stirring, followed by stirring at room temperature for 1 hour. The amount of 0.1N aqueous sodium hydroxide used at this time was C (mL). 0.1N hydrochloric acid was added dropwise to this solution, and the amount of dropwise addition D (mL) of 0.1N hydrochloric acid until the reddish purple color of the solution disappeared was measured. The amount of the acid component remaining in the resin (total amount of carboxyl group and acid anhydride group), that is, the acid value was determined by the following formula:
Acid value (mmol / g) = 0.1 × {(A−B) − (C−D)} / 0.15

(1-4) Absorbance Absorbance is measured by placing a tetrahydrofuran (THF) solution of glutarimide resin (resin concentration: 10% by mass) in a cell having a thickness of 1 cm and using a spectrophotometer (Shimadzu Corporation, UV-3100). The wavelength was measured in the range of 200 nm to 800 nm, and calculated using the measured value at a wavelength of 390 nm.

(1-5) b * value Glutarimide resin was melt-extruded with an extruder to produce an unstretched film having a thickness of 100 μm. The b * value of the produced unstretched film was calculated | required based on the prescription | regulation of JISZ8730 using the spectral color difference meter (The Nippon Denshoku Industries Co., Ltd. make, Colormeter ZE6000).

(1-6) Content of Acyclic Base Catalyst The content of the acyclic base catalyst of the glutarimide resin was performed using gas chromatography (Shimadzu Corporation, GC2010). First, a calibration curve solution was prepared by dissolving acyclic base catalyst and dimethyl succinate in acetone, and a calibration curve was prepared from the peak area obtained by measuring the solution by gas chromatography under the following measurement conditions. Next, a measurement sample prepared by dissolving glutarimide resin and dimethyl succinate, which are measurement objects, in acetone was prepared, the sample was measured by gas chromatography under the following measurement conditions, and the prepared calibration curve was used. The content of the acyclic base catalyst of the glutarimide resin was determined by an internal standard method. The measurement conditions are as follows.
Column: RESTEK Rxi-624Sil MS
-Temperature: inlet temperature 250 ° C, detector temperature 315 ° C
-Carrier gas: helium (column flow rate 2.69 mL / min)
-Injection volume: 1.0 μL
-Internal standard sample: Dimethyl succinate-Diluting solvent: Acetone Specifically,
Column: RESTEK Rxi-624Sil MS 0.25mmID 30m
-Temperature: 40 ° C (5 minutes hold) + 40 ° C to 310 ° C (10 ° C / min) + 310 ° C (10 minutes hold)
-Inlet temperature: 250 ° C
-Detector temperature: 315 ° C
-Carrier gas: helium (column flow rate 1.27 mL / min)
-Injection volume: 1.0 μL
-Internal standard sample: Tridecane-Diluting solvent: Acetone

(1-7) Alkali metal content The alkali metal content of the glutarimide resin is obtained by pretreating the glutarimide resin using a microwave sample pretreatment device (ETHOS ONE, manufactured by Milestone Corporation). Was diluted with water, and measured using ICP-MS (Agilent Technology, Agilent (registered trademark) 7700S).

(1-8) Water Absorption Glutarimide resin was melt-extruded with an extruder to produce an unstretched film having a thickness of 100 μm. The obtained unstretched film was dried at 80 ° C. for 24 hours, and then its mass (X) was measured. Next, the unstretched film obtained above is absorbed in water by storing it in a thermostatic bath at 85 ° C. and a relative humidity of 85%, taken out from the thermostatic bath after 250 hours, and the mass of the unstretched film after water absorption (Y ) Was measured. The water absorption of the unstretched film was determined by the following formula: water absorption (%) = {(Y−X) / X} × 100.

(2) Production of glutarimide resin (2-1) Example 1
In a reaction kettle equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introduction pipe, 79.4 parts by mass of methyl methacrylate, 20.6 parts by mass of methacrylic acid, 90.0 parts by mass of toluene and 22.5 parts of methanol as polymerization solvents. A mixed solvent of parts by mass and 0.05 parts by mass of an antioxidant (manufactured by ADEKA, ADK STAB (registered trademark) 2112) were charged, and the temperature was raised to 73 ° C. while passing nitrogen gas into the reaction kettle. At the time when the reflux accompanying the temperature rise starts, 0.25 parts by mass of dimethyl-2,2′-azobis (2-methylpropionate) (Wako Pure Chemical Industries, V-601) is reacted as a polymerization initiator. A solution prepared by adding 0.35 parts by mass of dimethyl-2,2′-azobis (2-methylpropionate) in a mixed solvent of 7.3 parts by mass of toluene and 1.8 parts by mass of methanol while being added to the kettle Was dropped into the reaction kettle over 2 hours, and solution polymerization was performed under reflux at about 71 to 76 ° C. After completion of the dropwise addition of dimethyl-2,2′-azobis (2-methylpropionate), the mixture was further aged for 4 hours to obtain a polymer solution. The content of the repeating unit derived from methacrylic acid in the acrylic polymer (uncyclized polymer) contained in the obtained polymer solution was 20.6% by mass, and the weight average molecular weight was 110,000.

  Next, a catalyst solution in which 0.05 part by mass of sodium methoxide, which is a catalyst for the cyclization condensation reaction (cyclization catalyst), was dissolved in 9.9 parts by mass of methanol was added to a heavy solution in a reaction vessel at about 65 to 70 ° C. The solution was added dropwise to the combined solution over 20 minutes to obtain a uniform catalyst-containing polymer solution. The resulting catalyst-containing polymer solution was a vent type screw twin screw extruder having a barrel temperature of 290 ° C., a rotation speed of 70 rpm, a reduced pressure of 13.3 to 400 hPa (10 to 300 mmHg), a rear vent number of 1, and a forevent number of 2. (Pore diameter: 15 mm, L / D: 45) Introduced at a processing rate of 300 g / h in terms of resin amount, devolatilized in this extruder, and extruded with an in-shaft residence time of about 0.9 minutes A transparent pellet P of an acrylic polymer (cyclized polymer) having a glutaric anhydride structure was obtained. The obtained cyclized polymer had a weight average molecular weight of 100,000 and a glass transition temperature of 131 ° C.

Next, the obtained pellet P is a vent type screw twin screw extruder (hole diameter: 15 mm, L) having a barrel temperature of 330 ° C., a rotation speed of 300 rpm, a degree of vacuum of 13.3 to 400 hPa (10 to 300 mmHg), and a single vent. / D: 45) is introduced from the hopper at a processing rate of 480 g / h in terms of resin amount, and aniline is injected into the extruder at a feeding rate of 230 g / h by a liquid pump after the hopper, By extruding with a residence time of about 5.6 minutes, a transparent pellet Q of an acrylic polymer (imidized polymer) having an imide ring structure was obtained. The obtained imidized polymer has a repeating unit in which R ¹ and R ³ are hydrogen atoms, R ² and R ⁴ are methyl groups, and R ⁵ is a phenyl group in formula (1), and in formula (2): It has a repeating unit in which R ⁶ is a hydrogen atom, R ⁷ is a methyl group, and R ⁸ is a methyl group. The weight average molecular weight is 94,000, the glass transition temperature is 179 ° C., and the acid value is 1.27 mmol / g.

  Next, the obtained pellet Q is a vent type screw twin screw extruder (hole diameter: 15 mm, L) with a barrel temperature of 260 ° C., a rotation speed of 300 rpm, a degree of vacuum of 13.3 to 400 hPa (10 to 300 mmHg), and a single vent. / D: 45), introduced from the hopper at a processing rate of 420 g / h in terms of resin amount, and 24.0 parts by mass of dimethyl carbonate and 3.0 parts by mass with respect to 100 parts by mass of the resin after the hopper. Esterification by injecting a mixed liquid of tetramethylguanidine (TMG; acyclic base catalyst having a pKa of 11 or more) into the extruder with a liquid pump and extruding with an in-shaft residence time of about 2.2 minutes The obtained transparent pellet R of glutarimide resin was obtained. The obtained glutarimide resin had a weight average molecular weight of 80,000, a glass transition temperature of 159 ° C., an acid value of 0.26 mmol / g, and the tetramethylguanidine content in the resin was 1.8% by mass. It was.

  Next, the obtained pellet R is put into a single screw extruder (hole diameter: 20 mm, L / D: 25), the T die temperature is adjusted to 275 ° C., and melt extrusion is performed from a coat hanger type T die (width 150 mm). The unstretched film of thickness 100 micrometers was produced by performing and discharging on the cooling roll of roll temperature 145 degreeC. The absorbance of the obtained film at a wavelength of 390 nm was 0.63, and the b * value was 2.95.

(2-2) Example 2
Except for using the pellet Q obtained in Example 1, the addition amount of dimethyl carbonate was changed to 16.0 parts by mass, and the addition amount of tetramethylguanidine was changed to 1.0 part by mass. Pellet R was manufactured from pellet Q. The resulting pellet R glutarimide resin has a weight average molecular weight of 80,000, a glass transition temperature of 162 ° C. and an acid value of 0.26 mmol / g, and the tetramethylguanidine content in the resin is 0.5 mass. %Met. Further, when an unstretched film having a thickness of 100 μm was produced in the same manner as in Example 1, the absorbance at a wavelength of 390 nm of this film was 0.40, and the b * value was 1.29.

(2-3) Example 3
The pellet Q obtained in Example 1 was used, and the addition amount of dimethyl carbonate was changed to 24.0 parts by mass, and the addition amount of tetramethylguanidine was changed to 1.0 part by mass. Pellet R was manufactured from pellet Q. The resulting pellet R glutarimide resin has a weight average molecular weight of 80,000, a glass transition temperature of 161 ° C. and an acid value of 0.17 mmol / g, and the tetramethylguanidine content in the resin is 0.6 mass. %Met. Further, when an unstretched film having a thickness of 100 μm was produced in the same manner as in Example 1, the absorbance at a wavelength of 390 nm of this film was 0.42, and the b * value was 1.41.

(2-4) Example 4
In Example 1, the pellet P was manufactured like Example 1 except having changed the addition amount of sodium methoxide which is a cyclization catalyst into 0.02 mass part. Next, in the production of the pellet Q from the pellet P, the processing speed of the pellet P introduced into the twin-screw extruder is changed to 450 g / h, the charging speed of aniline is changed to 260 g / h, and the residence time is 4. A pellet Q was produced from the pellet P in the same manner as in Example 1 except that the time was changed to about 5 minutes. The acrylic polymer (imidized polymer) having an imide ring structure of the obtained pellet Q has the following formula (1): R ¹ and R ³ are hydrogen atoms, R ² and R ⁴ are methyl groups, and R ⁵ is A repeating unit which is a phenyl group, and a repeating unit in which R ⁶ is a hydrogen atom, R ⁷ is a methyl group, and R ⁸ is a methyl group in the formula (2), and the weight average molecular weight is 92,000, The glass transition temperature was 171 ° C. and the acid value was 1.58 mmol / g.

  Next, Example 1 was used except that the addition amount of dimethyl carbonate was changed to 16.0 parts by mass and the addition amount of tetramethylguanidine was changed to 2.0 parts by mass using the pellet Q obtained above. Pellet R was produced from pellet Q under the same production conditions. The obtained pellet R glutarimide resin has a weight average molecular weight of 82,000, a glass transition temperature of 168 ° C., and an acid value of 1.16 mmol / g, and the tetramethylguanidine content in the resin is 0.00. It was 9% by mass. Further, when an unstretched film having a thickness of 100 μm was produced in the same manner as in Example 1, the absorbance at a wavelength of 390 nm of this film was 0.41, and the b * value was 1.40.

(2-5) Example 5
In Example 1, pellets P were produced in the same manner as in Example 1 except that the amount of sodium methoxide as a cyclization catalyst was changed to 0.1 parts by mass. Next, in the production of the pellet Q from the pellet P, Example 1 except that the processing speed of the pellet P introduced into the twin-screw extruder was changed to 450 g / h and the charging speed of aniline was changed to 162 g / h. In the same manner as above, pellet Q was produced from pellet P. The acrylic polymer (imidized polymer) having an imide ring structure of the obtained pellet Q has the following formula (1): R ¹ and R ³ are hydrogen atoms, R ² and R ⁴ are methyl groups, and R ⁵ is A repeating unit which is a phenyl group, and a repeating unit in which R ⁶ is a hydrogen atom, R ⁷ is a methyl group, and R ⁸ is a methyl group in the formula (2), and the weight average molecular weight is 92,000, The glass transition temperature was 161 ° C. and the acid value was 1.15 mmol / g.

  Next, Example 1 was used except that the addition amount of dimethyl carbonate was changed to 16.0 parts by mass and the addition amount of tetramethylguanidine was changed to 2.0 parts by mass using the pellet Q obtained above. Pellet R was produced from pellet Q under the same production conditions. The resulting pellet R glutarimide resin has a weight average molecular weight of 79,000, a glass transition temperature of 148 ° C. and an acid value of 0.25 mmol / g, and the tetramethylguanidine content in the resin is 0.00. It was 8 mass%. Further, when an unstretched film having a thickness of 100 μm was produced in the same manner as in Example 1, the absorbance at a wavelength of 390 nm of this film was 1.21, and the b * value was 3.20.

(2-6) Comparative Example 1
Pellet Q obtained in Example 1 was used in the same manner as in Example 1 except that 3.0 parts by mass of diazabicycloundecene (DBU; cyclic base catalyst) was used instead of tetramethylguanidine. Pellets R were produced from Q. The obtained glutarimide resin had a weight average molecular weight of 80,000, a glass transition temperature of 159 ° C., and an acid value of 0.43 mmol / g. Further, when an unstretched film having a thickness of 100 μm was produced in the same manner as in Example 1, the absorbance at a wavelength of 390 nm of this film was 1.41, and the b * value was 5.85.

(2-7) Comparative Example 2
A pellet R was produced from the pellet Q in the same manner as in Example 4 except that the pellet Q obtained in Example 4 was used and 2.0 parts by mass of diazabicycloundecene was used instead of tetramethylguanidine. The obtained glutarimide resin had a weight average molecular weight of 84,000, a glass transition temperature of 155 ° C., and an acid value of 0.77 mmol / g. Further, when an unstretched film having a thickness of 100 μm was produced in the same manner as in Example 1, the absorbance at a wavelength of 390 nm of this film was 0.80, and the b * value was 2.50.

(2-8) Comparative Example 3
Pellets R were produced from pellets Q in the same manner as in Example 5 except that 2.0 parts by mass of diazabicycloundecene was used instead of tetramethylguanidine using pellets Q obtained in Example 5. The obtained glutarimide resin had a weight average molecular weight of 76,000, a glass transition temperature of 148 ° C., and an acid value of 0.13 mmol / g. Further, when an unstretched film having a thickness of 100 μm was produced in the same manner as in Example 1, the absorbance at a wavelength of 390 nm of this film was 3.86, and the b * value was 15.90.

(2-9) Results The results of Examples 1 to 5 and Comparative Examples 1 to 3 are summarized in Table 1. As can be seen from the results in Table 1, under the same conditions of addition of sodium methoxide as the cyclization catalyst, by using tetramethylguanidine, which is an acyclic base catalyst having a pKa of 11 or more, as the esterification catalyst, A glutarimide resin having a smaller absorbance and a b * value at a wavelength of 390 nm was obtained than when diazabicycloundecene as a base catalyst was used.

  The glutarimide resin according to the present invention is used for, for example, a protective film for a substrate of an optical disk such as VD, CD, DVD, MD, and LD, and a polarizing plate provided in an image display device such as a liquid crystal display device such as an LCD. Suitable for optical film materials such as optical protective films such as polarizer protective films, antireflection films used in organic EL displays (OLED), transparent conductive films formed with transparent conductive layers such as ITO layers, etc. can do.

Claims (20)

And having an imide ring structure, an acrylic polymer having a carboxylic acid group and / or acid anhydride groups, that having a step of reacting with an esterifying agent in the presence of a pKa of 11 or more acyclic base catalyst a method of manufacturing a grayed Rutaruimido resin,
The glutarimide resin has a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2):

[In the formula (1), R ¹ , R ² , R ³ and R ⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ⁵ represents a hydrogen atom, 1 to carbon atoms 18 represents an alkyl group or a group having a ring structure. ]

[In Formula (2), R ⁶ and R ⁷ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ⁸ has an alkyl group having 1 to 18 carbon atoms or a ring structure. Represents a group. ]
A method for producing a glutarimide resin, wherein a compound having a secondary amine, a tertiary amine, or an amidine structure is used as the acyclic base catalyst . 2. The method for producing a glutarimide resin according to claim 1, wherein the alkali metal is contained in an amount of 4.5 × 10 ⁻³ mmol to 22 × 10 ⁻³ mmol per 1 g of the acrylic polymer. The method for producing a glutarimide resin according to claim 1 or 2, wherein the compound having an amidine structure is a compound having a guanidine structure. The glutarimide according to any one of claims 1 to 3, wherein dimethylhexylamine, di-n-butylamine, diisopropylamine, guanidine, methylguanidine, ethylguanidine, or tetramethylguanidine is used as the acyclic base catalyst. Manufacturing method of resin. The glutarimide resin according to any one of claims 1 to 4, wherein the acyclic base catalyst is used in an amount of 0.2 parts by mass or more and 5.0 parts by mass or less based on 100 parts by mass of the acrylic polymer. Production method. In the glutarimide resin, the content of the repeating unit represented by the formula (1) is 5% by mass or more and 85% by mass or less, and the content of the repeating unit represented by the formula (2) is 15% by mass. The method for producing a glutarimide resin according to any one of claims 1 to 5, wherein the content is 95% by mass or less. In the formula (1), R ^Five Is a C3-C12 cycloalkyl group or a C6-C10 aryl group, The manufacturing method of the glutarimide resin as described in any one of Claims 1-6. The method for producing a glutarimide resin according to any one of claims 1 to 7, wherein the glutarimide resin has an L * a * b * color system b * value of 5.00 or less. The method for producing a glutarimide resin according to any one of claims 1 to 8, wherein the esterifying agent is an acyclic compound. The method for producing a glutarimide resin according to any one of claims 1 to 9, wherein the esterifying agent is a compound composed only of carbon, oxygen, and hydrogen. A glutarimide resin containing an acyclic base catalyst having a pKa of 11 or more in a content of 5.0% by mass or less ,
The acid value is 0.5 mmol / g or less,
Absorbance at a wavelength 390nm when the 10 mass% THF solution Ri der 1.3 or less,
The glutarimide resin has a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2):

[In the formula (1), R ¹ , R ² , R ³ and R ⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ⁵ represents a hydrogen atom, 1 to carbon atoms 18 represents an alkyl group or a group having a ring structure. ]

[In Formula (2), R ⁶ and R ⁷ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ⁸ has an alkyl group having 1 to 18 carbon atoms or a ring structure. Represents a group. ]
The acyclic basic catalyst, secondary amine, tertiary amine or the compound der glutarimide resin, characterized in Rukoto having an amidine structure. The glutarimide resin according to claim 11 , wherein the alkali metal is contained in an amount of 4.5 × 10 ⁻³ mmol to 22 × 10 ⁻³ mmol per gram of glutarimide resin. The glutarimide resin according to claim 11 or 12, wherein the compound having an amidine structure is a compound having a guanidine structure. The glutarimide according to any one of claims 11 to 13, wherein the acyclic base catalyst is dimethylhexylamine, di-n-butylamine, diisopropylamine, guanidine, methylguanidine, ethylguanidine, or tetramethylguanidine. resin. The content of the repeating unit represented by the formula (1) is 5% by mass or more and 85% by mass or less, and the content of the repeating unit represented by the formula (2) is 15% by mass or more and 95% by mass or less. The glutarimide resin according to any one of claims 11 to 14. In the formula (1), R ⁵ is, glutarimide resin according to any one of claims 11 to 15 is a cycloalkyl group or an aryl group having 6 to 10 carbon atoms having 3 to 12 carbon atoms. The glutarimide resin according to any one of claims 11 to 16, wherein the b * value of the L * a * b * color system is 5.00 or less. An optical film comprising the glutarimide resin according to any one of claims 11 to 17 . A transparent conductive film comprising a transparent conductive layer on at least one surface of the optical film according to claim 18 . An image display device comprising the optical film according to claim 18 or the transparent conductive film according to claim 19 .