JP5086727B2 - Acrylic polymer and method for producing optical film - Google Patents

Description

  The present invention relates to a method for producing an acrylic polymer, and a method for producing an optical film for film-forming the acrylic polymer.

  A lactone ring-containing polymer has been proposed as a transparent heat-resistant resin having both transparency and heat resistance, and further having various properties such as mechanical strength and moldability.

  Lactone ring-containing polymers are expected to be applied to various films, sheets and the like because they are excellent in surface gloss and surface hardness. However, conventional lactone ring-containing polymers have extremely poor molding processability such as filming and sheeting, and the film or sheet obtained by molding may be cracked or have a poor surface condition, resulting in mechanical strength. It was also inferior.

  In order to improve the molding processability of the lactone ring-containing polymer, it is conceivable to increase the molecular weight of the lactone ring-containing polymer. For this purpose, a hydroxyl group and an ester group are added in the molecular chain as a precursor. It is necessary to increase the molecular weight of the polymer.

  However, in the conventional production method of a polymer having a hydroxyl group and an ester group in the molecular chain, gelation of the polymerization solution occurs, so that there is a limit to increase the molecular weight (for example, see Patent Documents 1 and 2). .

Recently, for the purpose of solving the above problem, a method for producing a higher molecular weight lactone ring-containing polymer has been disclosed (for example, see Patent Document 3).
JP 10-17623 A (published January 20, 1998) JP 2004-18836 A (published January 22, 2004) Japanese Patent Laying-Open No. 2005-146084 (released on June 9, 2005)

  However, although the method of Patent Document 3 can obtain a high molecular weight polymer, since the viscosity of the polymer solution becomes high and the production becomes difficult as the polymerization proceeds, it is necessary to dilute the polymer solution with a solvent. The problem that there is.

  Specifically, the viscosity of the polymer solution in the method of Patent Document 3 is not a problem in production on a laboratory scale, but is a problem in production on an actual machine scale. For this reason, it is necessary to dilute a polymer solution with a solvent, the amount of the polymer which can be manufactured at once reduces, and the problem that production efficiency cannot be raised arises.

  Moreover, the molecular weight distribution (Mw / Mn) of the polymer obtained by the method of Patent Document 3 is widened, and the mechanical strength, particularly flexibility when formed into a film, is not satisfactory. Furthermore, the method of Patent Document 3 has a problem that the solvent that can be used is limited to a ketone or an ether.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an acrylic that can suppress the increase in viscosity of a polymer solution and can produce a high molecular weight acrylic polymer having a narrow molecular weight distribution. An object of the present invention is to realize a method for producing a polymer, and a method for producing an optical film using the acrylic polymer.

  In order to solve the above-mentioned problems, the present inventor has intensively studied the cause of the increase in the viscosity of the polymer solution of the acrylic polymer having a hydroxyl group and an ester group in the molecular chain and the cause of the broadening of the molecular weight distribution. It was. As a result, it was concluded that the increase in the viscosity of the polymerization solution and the broadening of the molecular weight distribution were caused by an esterification reaction between molecules and intermolecular crosslinking. And it discovered that an intermolecular esterification reaction could be suppressed by adding alcohol which does not have a polymeric group in a polymerization solution, and came to complete this invention.

  That is, the method for producing an acrylic polymer according to the present invention provides an acrylic polymer for solution polymerization of a monomer composition containing a hydroxyl group-containing monomer and a (meth) acrylic acid ester in order to solve the above problems. A method for producing a coalescence, comprising a step of polymerizing under a condition where the concentration of the monomer composition in the polymerization solution is 45% by mass or more, wherein in the step, an alcohol having no polymerizable group is added. It is characterized by containing the polymerization solution.

  According to the above method, since the polymerization is performed in the presence of an alcohol having no polymerizable group, the intermolecular crosslinking reaction of the polymer can be suppressed. Specifically, since a polymer has an ester group and a hydroxyl group, it is considered that an intermolecular crosslinking reaction occurs when these substituents cause an ester exchange reaction during polymerization. If there is an alcohol that does not exist, the alcohol will shift the equilibrium of the ester exchange reaction (intermolecular crosslinking) between the ester group and the hydroxyl group between the polymer molecules to the reaction system, in other words, it will cause a decrosslinking reaction. It is done. For this reason, it is thought that the said intermolecular crosslinking reaction by the ester bond between polymers can be suppressed.

  Therefore, according to the said method, since an intermolecular crosslinking reaction is suppressed, the raise of the viscosity of a polymer solution can be suppressed. For this reason, even if it is an actual machine scale, it can superpose | polymerize by raising a monomer density | concentration and can obtain a high molecular weight polymer.

  Therefore, according to the said method, there exists an effect that the high molecular weight acrylic polymer with narrow molecular weight distribution can be manufactured by suppressing the viscosity increase of a polymer solution.

  In the method for producing an acrylic polymer according to the present invention, the alcohol having no polymerizable group is preferably a saturated alcohol.

  In the method for producing an acrylic polymer according to the present invention, the hydroxyl group-containing monomer is represented by the following general formula (1).

(Wherein, ^{R 1} and ^{R 2} each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)
It preferably has a structure represented by

  According to the said method, there exists the further effect that the acrylic polymer excellent in heat resistance can be manufactured.

  In the method for producing an acrylic polymer according to the present invention, the (meth) acrylic acid ester is preferably methyl methacrylate.

  According to the said method, there exists the further effect that the acrylic polymer which is excellent in heat resistance and transparency can be manufactured.

  Moreover, the manufacturing method of the acryl-type polymer which concerns on this invention is 1 mass part or more and 122 mass parts or less of the said alcohol which does not have a polymeric group with respect to 100 mass parts of said monomer compositions at the said process. It is preferable that the polymerization solution contains within the range.

  In the method for producing an acrylic polymer according to the present invention, it is preferable that a lactone ring structure is formed in the molecule by further subjecting the polymer obtained by the above polymerization to an intramolecular dealcoholization reaction.

  According to the said method, there exists the further effect that the acrylic polymer excellent in heat resistance can be manufactured.

  Furthermore, in the method for producing an acrylic polymer according to the present invention, the lactone ring structure has the following general formula (2).

(In formula, R < ³ >, R < ⁴ >, R < ⁵ > represents a hydrogen atom or a C1-C20 organic residue each independently. In addition, the organic residue may contain the oxygen atom.)
It is preferable that it is a structure represented by these.

  According to the said method, there exists the further effect that the acrylic polymer excellent in heat resistance, transparency, solvent resistance, high surface hardness, and thermal stability can be manufactured.

  In order to solve the above problems, a method for producing an optical film according to the present invention includes a step of producing an acrylic polymer by the production method of the present invention, a step of filtering the acrylic polymer with a polymer filter, And a step of forming the acrylic polymer into a film after the filtering step.

  According to the said method, there exists an effect that the optical film excellent in mechanical strength, impact resistance, and flexibility can be manufactured.

  The optical film according to the present invention is characterized by being obtained by the method for producing an optical film in order to solve the above-described problems.

  According to the said structure, there exists an effect that the optical film excellent in mechanical strength, impact resistance, and flexibility can be provided.

  As described above, the method for producing an acrylic polymer according to the present invention is a method for producing an acrylic polymer in which a monomer composition containing a hydroxyl group-containing monomer and a (meth) acrylic acid ester is solution-polymerized. And a step of polymerizing under the condition that the concentration of the monomer composition in the polymerization solution is 45% by mass or more, and in the step, the polymerization solution contains an alcohol having no polymerizable group. It is characterized by that.

  For this reason, the increase in the viscosity of the polymer solution is suppressed, and an effect is obtained that a high molecular weight acrylic polymer having a narrow molecular weight distribution can be produced.

  Moreover, the manufacturing method of the optical film which concerns on this invention is the process of manufacturing an acrylic polymer with the manufacturing method of the said invention as mentioned above, the process of filtering the said acrylic polymer with a polymer filter, and the said And a step of forming the acrylic polymer into a film after the step of filtering.

  For this reason, there exists an effect that the optical film excellent in mechanical strength, impact resistance, and flexibility can be manufactured.

  Moreover, the optical film which concerns on this invention is obtained by the manufacturing method of the said optical film as mentioned above.

  For this reason, there exists an effect that the optical film excellent in mechanical strength, impact resistance, and flexibility can be provided.

  The present invention will be described in detail below. In this specification, “weight” is treated as a synonym for “mass”, “wt%” is treated as a synonym for “mass%”, and “ppm” is a value calculated in terms of mass unless otherwise specified. For example, 10,000 ppm means 1% by mass. Further, “A to B” indicating a range means that the range is A or more and B or less.

  In the present specification, “(meth) acrylic acid” means acrylic acid or methacrylic acid, and “acrylic polymer” means (meth) acrylic acid or (meth) acrylic acid ester or the like (meth) acrylic acid ester. It means a polymer obtained by polymerizing a monomer component containing an acrylic acid derivative as a main component, and “main component” means containing 50% by mass or more.

(I) Acrylic polymer The method for producing an acrylic polymer according to the present embodiment is an acrylic polymer in which a monomer composition containing a hydroxyl group-containing monomer and a (meth) acrylic acid ester is solution-polymerized. And the step of polymerizing under the condition that the concentration of the monomer composition in the polymerization solution is 45% by mass or more, and in the above step, the alcohol having no polymerizable group is This is a method containing a polymerization solution.

  The hydroxyl group-containing monomer is not particularly limited as long as it is a monomer containing a hydroxyl group.

(Wherein, ^{R 1} and ^{R 2} each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)
(Hereinafter, referred to as “hydroxyl group-containing monomer A”), and more specifically, methyl 2- (hydroxymethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate Isopropyl 2- (hydroxymethyl) acrylate, n-butyl 2- (hydroxymethyl) acrylate, t-butyl 2- (hydroxymethyl) acrylate, and the like.

  Examples of the hydroxyl group-containing monomer other than the monomer represented by the general formula (1) (hereinafter referred to as “hydroxyl group-containing monomer B”) include, for example, methallyl alcohol, allyl alcohol, 2-hydroxymethyl. Examples include allyl alcohol such as -1-butene, 2- (hydroxyalkyl) acrylic acid ester such as methyl 2- (hydroxyethyl) acrylate, α-hydroxymethylstyrene, α-hydroxyethylstyrene, and the like.

  Furthermore, as other hydroxyl group-containing monomers (hereinafter referred to as “hydroxyl group-containing monomer C”), 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, (meth) Examples include 2,3,4,5,6-pentahydroxyhexyl acrylate and 2,3,4,5-tetrahydroxypentyl (meth) acrylate.

  Among the hydroxyl group-containing monomers, the hydroxyl group-containing monomers A and B are preferable because they form a lactone ring by heating or the like and the heat resistance of the resulting polymer is improved.

  Among these, the hydroxyl group-containing monomer A is more preferable in terms of heat resistance and polymerizability, and is excellent in heat resistance and solvent resistance after lactone cyclization. Among these, methyl 2- (hydroxymethyl) acrylate and 2- (hydroxymethyl) ethyl acrylate are preferable, and methyl 2- (hydroxymethyl) acrylate is particularly preferable in terms of high heat resistance improvement effect. The hydroxyl group-containing monomer A may be used alone or in combination of two or more.

  Examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, (meth Preferred are t-butyl acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, and the like. These may be used alone or in combination of two or more. Among these, methyl methacrylate is more preferable from the viewpoint of excellent heat resistance and transparency.

  The alcohol having no polymerizable group is not particularly limited as long as it is an alcohol having no substituent such as a vinyl group that is polymerized with any of the monomers. Examples of such alcohols include saturated alcohols such as primary saturated alcohols, secondary saturated alcohols, and tertiary saturated alcohols, and aromatic-containing alcohols.

  Examples of the primary saturated alcohol include methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-octanol, 1-octadecanol, 2-methylpropanol, 4,5-dimethyl. Examples include alkyl alcohols such as hexanol and cyclohexanemethanol.

  Examples of the secondary saturated alcohol include alkyl alcohols such as 2-propanol, 2-butanol, 2-hexanol, and 3-hexanol; cycloalkyl alcohols such as cyclohexyl alcohol, and the like.

  Examples of the tertiary saturated alcohol include alkyl alcohols such as t-butanol and 1,1-dimethylpropanol.

  Examples of the aromatic-containing alcohol include benzyl alcohol, 4-methylbenzyl alcohol, 4-hydroxymethylbiphenyl, 2- (hydroxymethyl) anthracene and the like.

  Only 1 type may be used for the alcohol mentioned above, and 2 or more types may be used together. As said alcohol, saturated alcohol is more preferable, C1-C20 saturated alcohol is still more preferable, C1-C12 saturated alcohol is especially preferable, C1-C6 saturated alcohol is the most preferable.

  As said saturated alcohol, alkyl alcohol is more preferable, C1-C20 alkyl alcohol is still more preferable, C1-C12 alkyl alcohol is especially preferable, C1-C6 alkyl alcohol is the most preferable. The alkyl alcohol is more preferably a primary alcohol.

  The above “saturated alcohol” means an alcohol in which all carbon-carbon bonds are single bonds.

  In the production method according to the present embodiment, from the viewpoint of increasing the molecular weight of the polymer to be obtained, a step of performing polymerization under the condition that the concentration of the monomer composition in the polymerization solution is 45% by mass or more is included. However, the concentration of the monomer composition is more preferably in the range of 45 to 70% by mass, still more preferably in the range of 45 to 65% by mass, and particularly preferably 47.5 to 65% by mass. It is in the range, and most preferably in the range of 47.5 to 60% by mass.

  Moreover, it is more preferable that the total concentration of the monomer composition and the polymer obtained from the monomer composition in the polymerization solution is maintained at 45% by mass or more in the entire polymerization step.

  In the step, the concentration of the hydroxyl group-containing monomer in the polymerization solution is preferably 3% by mass or more, more preferably in the range of 3 to 30% by mass, still more preferably 5 to 25% by mass. And particularly preferably within a range of 7 to 20% by mass, and most preferably within a range of 10 to 20% by mass.

  Moreover, in the said process, it is preferable that the density | concentration of the said (meth) acrylic acid ester in the said polymerization solution is 20 mass% or more, More preferably, it exists in the range of 20-67 mass%, More preferably, 20- It is in the range of 62% by mass, particularly preferably in the range of 25-57% by mass, and most preferably in the range of 30-50% by mass.

  In the above step, the polymerization solution preferably contains the alcohol within a range of 1 part by mass to 122 parts by mass with respect to 100 parts by mass of the monomer composition, more preferably 2 to 100 parts by mass. Within the range, more preferably within the range of 5 to 75 parts by mass, particularly preferably within the range of 10 to 50 parts by mass, and most preferably within the range of 15 to 35 parts by mass.

  The acrylic polymer may have a structure other than the structure obtained by polymerizing the (meth) acrylic acid ester and the structure obtained by polymerizing the hydroxyl group-containing monomer. The structure is not particularly limited as long as the structure does not show acidity and base, but the following general formula (3)

(Wherein R ⁶ represents a hydrogen atom or a methyl group, X represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, an —OAc group, a —CN group, a —CO—R ⁷ group, or a C— Represents an O—R ⁸ group, an Ac group represents an acetyl group, R ⁷ represents a hydrogen atom or an organic residue having 1 to 20 carbon atoms, and R ⁸ represents an organic residue having 1 to 20 carbon atoms.)
The polymer structural unit (repeating structural unit) constructed by polymerizing the monomer represented by

  (Alkyl) acrylic acid such as acrylic acid or methacrylic acid may be used as the monomer, but from the viewpoint of not acting as a catalyst for transesterification and cyclization reactions, ) The concentration of acrylic acid is preferably in the range of 0-5% by weight, more preferably in the range of 0-3% by weight, even more preferably in the range of 0-1% by weight, most preferably 0% by weight. .

  Examples of the compound represented by the general formula (3) include styrene, vinyl toluene, α-methyl styrene, acrylonitrile, methyl vinyl ketone, ethylene, propylene, and vinyl acetate. These may be used alone. Two or more kinds may be used in combination. Of these, styrene and α-methylstyrene are particularly preferable. In addition, other monomers, such as a compound represented by the said General formula (3), can be used in the range of 0-22 mass% in a polymerization solution, for example.

  The solvent used for the solution polymerization is not particularly limited, and examples thereof include aromatic hydrocarbon solvents such as toluene, xylene, and ethylbenzene; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ether solvents such as tetrahydrofuran; These may be used alone or in combination of two or more. Moreover, since the residual volatile matter of the polymer finally obtained will increase when the boiling point of the solvent to be used is too high, the thing whose boiling point is in the range of 50-200 degreeC is preferable.

  During the polymerization reaction, a polymerization initiator may be added as necessary. Although it does not specifically limit as a polymerization initiator, For example, cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate, t-amyl Organic peroxides such as peroxy-2-ethylhexanoate and t-amylperoxyisononanoate; 2,2′-azobis (isobutyronitrile), 1,1′-azobis (cyclohexanecarbonitrile), Azo compounds such as 2,2′-azobis (2,4-dimethylvaleronitrile); and the like. These may be used alone or in combination of two or more. What is necessary is just to set the usage-amount of a polymerization initiator suitably according to the combination of the monomer to be used, reaction conditions, etc., and it does not specifically limit.

  When performing the polymerization, it is more preferable to control the concentration of the produced polymer in the polymerization reaction mixture to be 70% by mass or less in order to suppress gelation of the reaction solution. Specifically, when the concentration of the produced polymer in the polymerization reaction mixture exceeds 70% by mass, it is preferable that the polymerization solvent is appropriately added to the polymerization reaction mixture so as to be controlled to 70% by mass or less. . The concentration of the produced polymer in the polymerization reaction mixture is more preferably 65% by mass or less, and still more preferably 60% by mass or less. In addition, since productivity will fall when the density | concentration of the polymer in a polymerization reaction mixture is too low, it is preferable that the density | concentration of the polymer in a polymerization reaction mixture is 40 mass% or more, and it is 45 mass% or more. Is more preferable.

  The form in which the polymerization solvent is appropriately added to the polymerization reaction mixture is not particularly limited, and the polymerization solvent may be added continuously or intermittently. Thus, by controlling the concentration of the produced polymer in the polymerization reaction mixture, the gelation of the reaction solution can be more sufficiently suppressed, and in particular, the ratio of hydroxyl groups and ester groups in the molecular chain is increased. Even in this case, gelation can be sufficiently suppressed. The polymerization solvent to be added may be the same type of solvent used during the initial charging of the polymerization reaction or may be a different type of solvent, but is the same as the solvent used during the initial charging of the polymerization reaction. It is preferable to use different types of solvents. Further, the polymerization solvent to be added may be only one type of solvent or a mixed solvent of two or more types.

  Even when the solvent is dropped, the total concentration of the monomer composition and the polymer obtained from the monomer composition in the polymerization reaction mixture is 45 to 70 mass in the total polymerization step. % Is preferably maintained, more preferably in the range of 45-65% by mass, still more preferably in the range of 47.5-65% by mass, particularly preferably 47.5-60% by mass. Within range.

  Although it does not specifically limit about the temperature at the time of the said superposition | polymerization, For example, it can carry out within the range of 0-150 degreeC, More preferably, within the range of 80-140 degreeC.

  The polymer obtained by the above polymerization process is a polymer having a hydroxyl group and an ester group in the molecular chain. In the method according to the present embodiment, the viscosity of the acrylic polymer can be suppressed to 30,000 cps or less, more preferably 20,000 cps or less in the entire polymerization step, so that operations such as dilution are not performed. Production on a real machine scale is possible. Moreover, since the weight average molecular weight of the obtained polymer can be 100,000 or more, the polymer obtained even when a lactone ring structure described later is added can provide a film having excellent flexibility. .

  Further, in the method according to the present embodiment, the intermolecular crosslinking reaction can be suppressed, so that the molecular weight distribution (Mw / Mn) of the obtained polymer can be 2.6 or less, and the obtained polymer Is excellent in mechanical strength, especially flexibility when it is made into a film.

  More preferably, the polymer is further subjected to intramolecular dealcoholization reaction to form a lactone ring structure in the molecule.

  In the polymerization reaction mixture obtained when the above polymerization step is completed, a solvent is usually contained in addition to the obtained polymer. When the above polymer is a lactone ring-containing polymer, it is not necessary to completely remove the solvent and take out the polymer in a solid state, and the subsequent lactone cyclization condensation step is performed in a state containing the solvent. Is preferred. If necessary, after taking out in a solid state, a solvent suitable for the subsequent lactone cyclization condensation step may be added again.

  The reaction for introducing a lactone ring structure into the polymer is a reaction in which a hydroxyl group and an ester group present in the molecular chain of the polymer are cyclized and condensed to form a lactone ring structure by heating. Alcohol is produced as a by-product by condensation. By forming the lactone ring structure in the molecular chain of the polymer (in the main skeleton of the polymer), high heat resistance is imparted to the polymer. If the reaction rate of the cyclization condensation reaction leading to the lactone ring structure is insufficient, the heat resistance will not be improved sufficiently, or the condensation reaction will occur during the molding process due to the heat treatment during molding, and the resulting alcohol will be contained in the molded product. It is not preferable because it may exist as bubbles or silver streaks.

  The lactone ring-containing polymer obtained in the lactone cyclization condensation step is preferably represented by the general formula (2)

(In formula, R < ³ >, R < ⁴ >, R < ⁵ > represents a hydrogen atom or a C1-C20 organic residue each independently. In addition, the organic residue may contain the oxygen atom.)
It has the lactone ring structure represented by these.

  The organic residue in the general formulas (1), (2), and (3) is not particularly limited as long as it has a carbon number in the range of 1 to 20, but for example, a linear or branched alkyl group , A linear or branched alkylene group, an aryl group, an —OAc group, a —CN group and the like.

  The method for heat-treating the polymer is not particularly limited, and a known method can be used. For example, you may heat-process the polymerization reaction mixture containing the solvent obtained by the superposition | polymerization process as it is. Moreover, you may heat-process using a ring-closing catalyst as needed in presence of a solvent. Further, the heat treatment can be performed using a heating furnace or reaction apparatus having a vacuum apparatus or a devolatilizing apparatus for removing volatile components, an extruder having a devolatilizing apparatus, or the like.

  In carrying out the cyclization condensation reaction, other thermoplastic resins may coexist in addition to the polymer. Further, when performing the cyclization condensation reaction, if necessary, an esterification catalyst or a transesterification catalyst such as p-toluenesulfonic acid generally used as a catalyst for the cyclization condensation reaction may be used. Organic carboxylic acids such as propionic acid, benzoic acid, acrylic acid, and methacrylic acid may be used as a catalyst. As disclosed in JP-A-61-254608 and JP-A-61-261303, basic compounds, organic carboxylates, carbonates and the like may be used.

  In carrying out the cyclization condensation reaction, it is preferable to use an organic phosphorus compound as a catalyst. By using an organophosphorus compound as a catalyst, the cyclization condensation reaction rate can be improved, and coloring of the resulting lactone ring-containing polymer can be greatly reduced. Furthermore, by using an organophosphorus compound as a catalyst, it is possible to suppress a decrease in molecular weight that can occur when a devolatilization step described later is used in combination, and to impart excellent mechanical strength.

  Examples of the organic phosphorus compound that can be used as a catalyst in the cyclocondensation reaction include alkyl (aryl) phosphonous acids such as methylphosphonous acid, ethylphosphonous acid, and phenylphosphonous acid (however, Tautomers (which may be alkyl (aryl) phosphinic acid) and diesters or monoesters thereof; dimethylphosphinic acid, diethylphosphinic acid, diphenylphosphinic acid, phenylmethylphosphinic acid, phenylethylphosphinic acid, etc. Dialkyl (aryl) phosphinic acids and esters thereof; alkyl (aryl) phosphonic acids such as methyl phosphonic acid, ethyl phosphonic acid, trifluoromethyl phosphonic acid, phenyl phosphonic acid, and their diesters or monoesters; methyl phosphine Alkyl (aryl) phosphinic acids such as ethylphosphinic acid and phenylphosphinic acid and their esters; methyl phosphite, ethyl phosphite, phenyl phosphite, dimethyl phosphite, diethyl phosphite, Phosphorous acid diester or monoester or triester such as diphenyl phosphate, trimethyl phosphite, triethyl phosphite, triphenyl phosphite; methyl phosphate, ethyl phosphate, 2-ethylhexyl phosphate, isodecyl phosphate, Lauryl phosphate, stearyl phosphate, isostearyl phosphate, phenyl phosphate, dimethyl phosphate, diethyl phosphate, di-2-ethylhexyl phosphate, diisodecyl phosphate, dilauryl phosphate, distearyl phosphate, diisophosphate Stearyl, diphenyl phosphate, trimethyl phosphate, phosphorus Phosphoric diesters or monoesters or triesters such as triethyl, triisodecyl phosphate, trilauryl phosphate, tristearyl phosphate, triisostearyl phosphate, triphenyl phosphate; methylphosphine, ethylphosphine, phenylphosphine, dimethylphosphine, diethyl Mono-, di- or trialkyl (aryl) phosphine such as phosphine, diphenylphosphine, trimethylphosphine, triethylphosphine, triphenylphosphine; methyldichlorophosphine, ethyldichlorophosphine, phenyldichlorophosphine, dimethylchlorophosphine, diethylchlorophosphine, diphenylchlorophosphine Alkyl (aryl) halogen phosphines such as methyl phosphine oxide, ethyl phosphine oxide , Phenylphosphine oxide, dimethylphosphine oxide, diethylphosphine oxide, diphenylphosphine oxide, trimethylphosphine oxide, triethylphosphine oxide, triphenylphosphine oxide, mono-, di- or trialkyl (aryl) phosphines; tetramethylphosphonium chloride, tetraethyl chloride Halogenated tetraalkyl (aryl) phosphonium such as phosphonium and tetraphenylphosphonium chloride; and the like. Among these, alkyl (aryl) phosphonous acid, phosphorous acid diester or monoester, phosphoric acid diester or monoester, and alkyl (aryl) phosphonic acid are preferable because of high catalytic activity and low colorability. ) Phosphorous acid, phosphorous acid diester or monoester, phosphoric acid diester or monoester are more preferred, and alkyl (aryl) phosphonous acid, phosphoric acid diester or monoester is particularly preferred. These organic phosphorus compounds may use only 1 type and may use 2 or more types together.

  The amount of the catalyst used in the cyclization condensation reaction is not particularly limited, but is preferably in the range of 0.001 to 5% by mass, more preferably 0.01 to 2.5% by mass with respect to the polymer. %, More preferably in the range of 0.01 to 1% by weight, particularly preferably in the range of 0.05 to 0.5% by weight. When the amount of the catalyst used is less than 0.001% by mass, the reaction rate of the cyclization condensation reaction may not be sufficiently improved. On the other hand, when the amount exceeds 5% by mass, coloring may occur, It may be difficult to melt and form by cross-linking of coalesced.

  The addition timing of the catalyst is not particularly limited, and it may be added at the beginning of the reaction, during the reaction, or both.

  It is preferable to carry out the cyclization condensation reaction in the presence of a solvent and to use a devolatilization step in combination with the cyclization condensation reaction. In this case, a mode in which the devolatilization step is used throughout the cyclization condensation reaction and a mode in which the devolatilization step is not used over the entire cyclization condensation reaction but only in a part of the process. In the method using the devolatilization step in combination, the alcohol produced as a by-product in the condensation cyclization reaction is forcibly devolatilized and removed, so that the equilibrium of the reaction is advantageous for the production side.

  The devolatilization step refers to a step of removing a volatile component such as a solvent and a residual monomer and an alcohol by-produced by a cyclization condensation reaction leading to a lactone ring structure, if necessary under reduced pressure heating conditions. If this removal treatment is insufficient, the residual volatile components in the produced resin increase, resulting in problems such as coloration due to alteration during molding, and molding defects such as bubbles and silver streaks.

  In the case of using the devolatilization step throughout the cyclization condensation reaction, the apparatus to be used is not particularly limited, but in order to perform this reaction more effectively, devolatilization consisting of a heat exchanger and a devolatilization tank. It is preferable to use an apparatus, an extruder with a vent, or an apparatus in which the devolatilizer and the extruder are arranged in series, and a devolatilizer comprising a heat exchanger and a devolatilizer or an extruder with a vent is used. It is more preferable.

  The reaction treatment temperature in the case of using a devolatilizer comprising the heat exchanger and the devolatilizer is preferably in the range of 150 to 350 ° C, more preferably in the range of 200 to 300 ° C. If the reaction treatment temperature is lower than 150 ° C., the cyclization condensation reaction may be insufficient and the residual volatile matter may increase, and if it is higher than 350 ° C., coloring or decomposition may occur.

  When using the devolatilizer comprising the heat exchanger and the devolatilizer, the pressure during the reaction treatment is preferably within the range of 931 to 1.33 hPa (700 to 1 mmHg), and 798 to 66.5 hPa (600 to More preferably within the range of 50 mmHg). When the said pressure is higher than 931 hPa, there exists a problem that the volatile matter including alcohol will remain easily, and when it is lower than 1.33 hPa, there exists a problem that industrial implementation will become difficult.

  When using the extruder with a vent, one or a plurality of vents may be used, but it is preferable to have a plurality of vents.

  In the case of using the vented extruder, the reaction treatment temperature is preferably in the range of 150 to 350 ° C, more preferably in the range of 200 to 300 ° C. If the temperature is lower than 150 ° C., the cyclization condensation reaction may be insufficient and the residual volatile content may increase. If the temperature is higher than 350 ° C., coloring or decomposition may occur.

  In the case of using the extruder with a vent, the pressure during the reaction treatment is preferably within a range of 931 to 1.33 hPa (700 to 1 mmHg), and more preferably within a range of 798 to 13.3 hPa (600 to 10 mmHg). When the pressure is higher than 931 hPa, there is a problem that volatile components including alcohol easily remain, and when the pressure is lower than 1.33 hPa, there is a problem that industrial implementation becomes difficult.

  In addition, in the case of using the devolatilization step throughout the cyclization condensation reaction, as described later, the physical properties of the lactone ring-containing polymer obtained may be deteriorated under severe heat treatment conditions. It is preferable to use a catalyst for a dealcoholization reaction and under a mild condition as much as possible using an extruder with a vent.

  In the case of using a devolatilization step throughout the cyclization condensation reaction, preferably, the polymer obtained in the polymerization step is introduced into the cyclization condensation reactor system together with a solvent. Then, it may be passed once again through the reactor system such as an extruder with a vent.

  You may perform the form used together only in a part of process, without using a devolatilization process over the whole process of cyclization condensation reaction. For example, the apparatus for producing the polymer is further heated, and if necessary, a part of the devolatilization step is used together to advance the cyclization condensation reaction to some extent in advance, and then the devolatilization step is used at the same time. In this mode, the cyclization condensation reaction is performed to complete the reaction.

  In the embodiment in which the devolatilization step is used throughout the cyclization condensation reaction described above, for example, when the polymer is heat-treated at a high temperature close to 250 ° C. or higher using a twin screw extruder, Depending on the difference, partial decomposition or the like may occur before the cyclization condensation reaction occurs, and the physical properties of the resulting lactone ring-containing polymer may be deteriorated. Therefore, if the cyclization condensation reaction is allowed to proceed to some extent before the cyclization condensation reaction using the devolatilization step at the same time, the latter reaction conditions can be relaxed and the physical properties of the resulting lactone ring-containing polymer deteriorated. Is preferable. As a particularly preferred form, the devolatilization step is started after a lapse of time from the start of the cyclization condensation reaction, i.e., the hydroxyl group and ester group present in the molecular chain of the polymer obtained in the polymerization step are previously cyclized. There is a mode in which the cyclization condensation reaction rate is increased to some extent by carrying out the cyclization condensation reaction, and then the cyclization condensation reaction is carried out simultaneously with the devolatilization step. Specifically, for example, a cyclization condensation reaction is allowed to proceed to a certain reaction rate in the presence of a solvent in advance using a kettle reactor, and then a reactor equipped with a devolatilizer, for example, a heat Preferred is a mode in which the cyclization condensation reaction is completed with a devolatilizer comprising an exchanger and a devolatilization tank, an extruder with a vent, or the like. Particularly in this form, it is more preferable that a catalyst for the cyclization condensation reaction is present.

  As described above, the hydroxyl group and ester group present in the molecular chain of the polymer obtained in the polymerization step are subjected to a cyclization condensation reaction in advance to increase the cyclization condensation reaction rate to some extent. The method of carrying out the cyclization condensation reaction simultaneously used is a preferred form for obtaining a lactone ring-containing polymer. With this configuration, a lactone ring-containing polymer having a higher cyclization condensation reaction rate, a higher glass transition temperature, and excellent heat resistance can be obtained. In this case, as a measure of the cyclization condensation reaction rate, the weight loss rate between 150 and 300 ° C. in the dynamic TG measurement is preferably 2% or less, more preferably 1.5% or less. Preferably it is 1% or less.

  The reactor that can be employed in the cyclization condensation reaction that is performed in advance before the cyclization condensation reaction using the devolatilization process at the same time is not particularly limited, but preferably an autoclave, a kettle reactor, a heat exchanger, and a devolatilization tank A vented extruder suitable for a cyclocondensation reaction using a devolatilization step at the same time can also be used. More preferred are autoclaves and kettle reactors. However, even when using a reactor such as an extruder with a vent, by adjusting the temperature condition, barrel condition, screw shape, screw operating condition, etc. It is possible to carry out the cyclization condensation reaction in the same state as the reaction state in the kettle reactor.

  In the case of the cyclization condensation reaction performed in advance before the cyclization condensation reaction using the devolatilization step at the same time, preferably, a mixture containing the polymer and the solvent obtained in the polymerization step is added (i) a catalyst. And (ii) a method of performing a heat reaction without a catalyst, and a method of performing the above (i) or (ii) under pressure.

  The “mixture containing a polymer and a solvent” to be introduced into the cyclization condensation reaction in the lactone cyclization condensation step may be the polymerization reaction mixture obtained in the polymerization step as it is, or once the solvent is removed. This means that a solvent suitable for the cyclization condensation reaction may be added again.

  The solvent that can be re-added in the cyclization condensation reaction that is carried out in advance before the cyclization condensation reaction simultaneously used in the devolatilization step is not particularly limited, for example, aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; Ketones such as methyl ethyl ketone and methyl isobutyl ketone; chloroform, DMSO, tetrahydrofuran and the like may be used, but the same solvent as that used in the polymerization step is preferable.

  Examples of the catalyst to be added in the above method (i) include commonly used esterification catalysts such as p-toluenesulfonic acid or transesterification catalysts, basic compounds, organic carboxylates, and carbonates. In the form, it is preferable to use the organophosphorus compound described above.

  The addition timing of the catalyst is not particularly limited, and it may be added at the beginning of the reaction, during the reaction, or both. The amount of the catalyst to be added is not particularly limited, but is preferably in the range of 0.001 to 5 mass%, more preferably in the range of 0.01 to 2.5 mass%, still more preferably based on the weight of the polymer. It is in the range of 0.01 to 0.1% by mass, particularly preferably in the range of 0.05 to 0.5% by mass. The heating temperature and heating time in method (i) are not particularly limited, but the heating temperature is preferably room temperature or higher, more preferably 50 ° C. or higher, and the heating time is preferably in the range of 1 to 20 hours. More preferably, it is in the range of 2 to 10 hours. If the heating temperature is low or the heating time is short, the cyclization condensation reaction rate is lowered, which is not preferable. Further, if the heating time is too long, the resin may be colored or decomposed, which is not preferable.

  Examples of the method (ii) include a method of heating the polymerization reaction mixture obtained in the polymerization step as it is using a pressure-resistant kettle or the like. The heating temperature is preferably 100 ° C. or higher, more preferably 150 ° C. or higher. The heating time is preferably in the range of 1 to 20 hours, more preferably in the range of 2 to 10 hours. If the heating temperature is low or the heating time is short, the cyclization condensation reaction rate is lowered, which is not preferable. Further, if the heating time is too long, the resin may be colored or decomposed, which is not preferable.

  Both the above methods (i) and (ii) have no problem even under pressure depending on conditions. Moreover, in the case of the cyclization condensation reaction performed beforehand before the cyclization condensation reaction which used the devolatilization process simultaneously, even if a part of the solvent volatilizes naturally during the reaction, there is no problem.

  The weight loss rate between 150 and 300 ° C. in the dynamic TG measurement at the end of the cyclization condensation reaction performed in advance before the cyclization condensation reaction simultaneously using the devolatilization step, that is, immediately before the start of the devolatilization step It is preferably 2% or less, more preferably 1.5% or less, and still more preferably 1% or less. When the weight reduction rate is higher than 2%, the cyclization condensation reaction rate does not rise to a sufficiently high level even if the cyclization condensation reaction is performed simultaneously with the devolatilization step, and the physical properties of the resulting lactone ring-containing polymer. May decrease. In addition, when performing said cyclization condensation reaction, in addition to a polymer, you may coexist other thermoplastic resins.

  Cyclization using a hydroxyl group and an ester group present in the molecular chain of the polymer obtained in the polymerization step in advance by a cyclization condensation reaction to increase the cyclization condensation reaction rate to a certain extent, followed by a devolatilization step at the same time. In the case of a form in which a condensation reaction is performed, a polymer obtained by a previously performed cyclization condensation reaction (a polymer in which at least a part of hydroxyl groups and ester groups in the molecular chain are subjected to a cyclization condensation reaction) and a solvent are isolated. Without carrying out, you may perform the cyclization condensation reaction which used the devolatilization process simultaneously. In addition, if necessary, other treatments such as re-adding a solvent after isolating the above polymer (a polymer in which at least a part of the hydroxyl group and ester group present in the molecular chain have undergone cyclization condensation reaction) are performed. After that, you may perform the cyclization condensation reaction which used the devolatilization process simultaneously.

  The devolatilization step is not limited to being completed at the same time as the cyclization condensation reaction, and may be completed after a lapse of time from the completion of the cyclization condensation reaction.

  In addition, even after the catalyst is added and the cyclization reaction is sufficiently performed, a small amount of unreacted reactive groups remain in the polymer. Problems such as increase and thickening due to cross-linking between polymer molecules may occur. For this reason, after adding a catalyst and fully performing a cyclization condensation reaction, it is preferable to add the deactivation agent of a cyclization condensation catalyst.

  In the cyclization condensation reaction, an acidic catalyst or a basic catalyst is often used. In that case, the deactivator deactivates the catalyst by a neutralization reaction. For this reason, when the catalyst is an acidic substance, the deactivating agent may be a basic substance. Conversely, when the catalyst is a basic substance, the deactivating agent may be an acidic substance.

  The deactivator is not particularly limited as long as it does not generate a substance that inhibits the physical properties of the polymer at the time of heat processing. However, when a basic substance is used as the deactivator, for example, metal carboxylate, metal complex, metal An oxide etc. are mentioned. Among these, metal carboxylates and metal oxides are preferable, and metal carboxylates are particularly preferable.

  The metal in the basic substance is not particularly limited as long as it does not inhibit the physical properties of the polymer and causes environmental pollution at the time of disposal. For example, alkali metals such as lithium, sodium, and potassium; magnesium, calcium, Examples include alkaline earth metals such as strontium and barium; zinc; zirconium and the like.

  The carboxylic acid constituting the metal carboxylate is not particularly limited. For example, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, lauric acid, Examples include myristic acid, palmitic acid, stearic acid, behenic acid, tridecanoic acid, pentadecanoic acid, heptadecanoic acid, lactic acid, malic acid, citric acid, oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, and adipic acid. .

  Although it does not specifically limit as an organic component in the said metal complex, Acetyl acetone etc. are mentioned. Examples of the metal oxide include zinc oxide, calcium oxide, magnesium oxide and the like, and zinc oxide is preferable.

  Moreover, when using an acidic substance for a quencher, an organic phosphoric acid compound, carboxylic acid, etc. are mentioned, for example. The quenching agent that can be used in the present embodiment may be used alone or in combination of two or more. The quenching agent may be used in any form such as a solid state such as a powder or a state dispersed in a solvent such as a suspension or an aqueous solution.

  The addition amount of the deactivator may be appropriately adjusted according to the amount of the catalyst used in the cyclization condensation reaction, and is not particularly limited, but is preferably in the range of 10 to 10,000 ppm with respect to the acrylic polymer. Of these, a range of 50 to 5,000 ppm is more preferable, and a range of 100 to 3,000 ppm is still more preferable.

  When the addition amount of the deactivator is less than 10 ppm, the function of the deactivator becomes insufficient, and thickening due to foaming or cross-linking between polymer molecules may occur during molding. On the other hand, when the addition amount of the deactivator exceeds 10,000 ppm, the deactivator is used more than necessary, and the physical properties of the polymer may be hindered such as a decrease in molecular weight.

  The timing of adding the deactivator is after the catalyst is added and the cyclization condensation reaction is sufficiently performed in the production of the acrylic polymer, and before the obtained polymer is thermally processed. There is no particular limitation. For example, a deactivator is added at a predetermined stage during production of an acrylic polymer, or after producing an acrylic polymer, the acrylic polymer, the deactivator, and other components are simultaneously heated and melted. A method of kneading by mixing; a method in which an acrylic polymer and other components are heated and melted, and then adding a deactivator; and a method in which the acrylic polymer is heated and melted and then deactivating, and other The method etc. which add and knead | mix a component etc. are mentioned.

  Moreover, when adding a quencher, it is preferable to perform a devolatilization process after kneading with a quencher from a viewpoint that the obtained acrylic polymer hardly causes foaming at the time of heat processing. As the devolatilization step, the same step as the devolatilization step performed in the production of the lactone ring-containing polymer described above can be performed.

  The obtained lactone ring-containing polymer preferably has a weight reduction rate of 150% to 300 ° C. in dynamic TG measurement of 1% or less, more preferably 0.5% or less, and still more preferably 0.3%. % Or less.

  Since the lactone ring-containing polymer has a high cyclization condensation reaction rate, it is possible to avoid the disadvantage that bubbles and silver streaks enter the molded product after molding. Furthermore, since the lactone ring structure is sufficiently introduced into the polymer due to a high cyclization condensation reaction rate, the obtained lactone ring-containing polymer has sufficiently high heat resistance.

  The lactone ring-containing polymer preferably has a coloring degree (YI) in a 15% by mass chloroform solution of 6 or less, more preferably 3 or less, still more preferably 2 or less, and most preferably 1 or less. If the coloring degree (YI) exceeds 6, transparency may be impaired due to coloring, and it may not be used for the intended purpose.

  The content ratio of the lactone ring structure of the lactone ring-containing polymer is preferably in the range of 5 to 90% by mass, more preferably in the range of 10 to 85% by mass, and still more preferably in the range of 20 to 65% by mass. Especially preferably, it exists in the range of 25-55 mass%. When the content of the lactone ring structure is less than 5% by mass, the heat resistance, solvent resistance, and surface hardness may be insufficient, which is not preferable. When the content of the lactone ring structure is more than 90% by mass, the moldability tends to be poor, which is not preferable.

  The lactone ring-containing polymer preferably has a 5% weight loss temperature in thermogravimetric analysis (TG) of 330 ° C. or higher, more preferably 350 ° C. or higher, and still more preferably 360 ° C. or higher. The 5% weight loss temperature in thermogravimetric analysis (TG) is an indicator of thermal stability, and if it is less than 330 ° C., sufficient thermal stability may not be exhibited.

  The total amount of residual volatile components contained in the lactone ring-containing polymer is preferably 1,500 ppm or less, more preferably 1,000 ppm or less. When the total amount of residual volatile components is more than 1,500 ppm, it causes molding defects such as coloring due to alteration during molding, foaming, silver streak and the like.

  The lactone ring-containing polymer has a total light transmittance of 85% or more, more preferably 88% or more, still more preferably, of a molded product obtained by injection molding, as measured by a method according to ASTM-D-1003. Is 90% or more. The total light transmittance is a measure of transparency, and if it is less than 85%, the transparency is lowered and there is a possibility that it cannot be used for the intended purpose.

  The acrylic polymer according to the present embodiment has not only excellent transparency and heat resistance, but also has desired characteristics such as low colorability, mechanical strength, and molding processability. It is useful for applications such as optical films, optical fibers, and optical disks. Among these, it is more preferable to use the optical lens, the optical prism, and the optical film.

  The acrylic polymer according to the present embodiment can be molded into various shapes depending on the application. Examples of shapes that can be formed include films, sheets, plates, disks, blocks, balls, lenses, rods, strands, cords, fibers, and the like. The molding method is not particularly limited as long as it is appropriately selected from conventionally known forming methods according to the shape.

(II) Optical film The optical film according to the present embodiment is obtained by mixing the above acrylic polymer and, if necessary, other components described later by a conventionally known mixing method, and forming into a film shape. can get. Moreover, it is good also as a stretched film by extending | stretching.

  For the mixing of the acrylic polymer and other components, for example, the acrylic polymer and other components are pre-blended with a conventionally known mixer such as an omni mixer, and then the resulting mixture is extruded and kneaded. Can be done. In this case, the mixer used for extrusion kneading is not particularly limited, and for example, a conventionally known mixer such as an extruder such as a single screw extruder or a twin screw extruder or a pressure kneader can be used. .

  Examples of the film forming method include known film forming methods such as a solution casting method (solution casting method), a melt extrusion method, a calendar method, and a compression molding method. Among these, the solution casting method (solution casting method) and the melt extrusion method are preferable.

  Solvents used in the solution casting method (solution casting method) include, for example, chlorinated solvents such as chloroform and dichloromethane; aromatic solvents such as toluene, xylene, benzene, and mixed solvents thereof; methanol, ethanol, and isopropanol And alcohol solvents such as n-butanol and 2-butanol; methyl cellosolve, ethyl cellosolve, butyl cellosolve, dimethylformamide, dimethyl sulfoxide, dioxane, cyclohexanone, tetrahydrofuran, acetone, ethyl acetate, diethyl ether, and the like. These solvents may be used alone or in combination of two or more.

  Examples of the apparatus for performing the solution casting method (solution casting method) include a drum casting machine, a band casting machine, and a spin coater.

  Examples of the melt extrusion method include a T-die method and an inflation method. In this case, the film forming temperature is preferably in the range of 200 to 350 ° C., more preferably in the range of 250 to 300 ° C., and still more preferably. Is in the range of 260-300 ° C.

  When extrusion molding is performed by the T-die method, a roll-shaped film is obtained by attaching a T-die to the tip of a known single-screw extruder or twin-screw extruder and winding up the extruded film. Can do. At this time, the temperature of the take-up roll can be adjusted as appropriate, and the uniaxial stretching step can be performed by adding stretching in the extrusion direction. Moreover, it is also possible to set it as processes, such as sequential biaxial stretching and simultaneous biaxial stretching, by adding the process of extending | stretching a film in the direction perpendicular | vertical to an extrusion direction.

  The extruder used for the production of the optical film according to the present embodiment can be either a single-screw extruder or a multi-screw extruder, but in order to obtain a sufficiently plasticized and kneaded state of the polymer , L / D (L represents the cylinder length of the extruder, D represents the cylinder inner diameter) is preferably in the range of 10 to 100, more preferably in the range of 20 to 50, and 25 to 40. It is most preferable to be within the range. When L / D is less than 10, it is difficult to obtain a sufficiently plasticized and kneaded state of the polymer, and when it exceeds 100, excessive shearing heat generation is applied to the polymer, and the polymer may be decomposed.

  The set temperature of the cylinder is preferably in the range of 200 to 300 ° C, more preferably in the range of 250 to 300 ° C, and still more preferably in the range of 260 to 300 ° C. If it is less than 200 ° C., the melt viscosity of the polymer becomes high, so that higher power than necessary and L / D necessary for plasticization are required, which hinders productivity. If it exceeds 300 ° C, the polymer may be decomposed.

  In the method for producing an optical film according to the present embodiment, the shape of the extruder is not particularly limited, but the extruder has one or more open vent parts, and is configured to suck the decomposition gas generated in a reduced pressure state. If it exists, since the increase in residual volatile matter can be suppressed, it is more preferable.

  When making an open vent part into a pressure reduction state, the pressure reduction degree has the preferable inside of the range of 931-1.3 hPa (700-1 mmHg), and the inside of the range of 798-13.3 hPa (600-10 mmHg) is more preferable. When the pressure is higher than 931 hPa, residual volatile components in the molten resin, monomer components generated by resin decomposition, and the like are likely to remain. Moreover, when lower than 1.3 hPa, there exists a problem that industrial implementation will become difficult.

  The optical film according to the present embodiment is preferably molded after removing foreign substances in the polymer with a polymer filter in order to prevent foreign substances from affecting the appearance after molding. When the polymer filter is used, the polymer deteriorates when the polymer melted at a high temperature passes through the polymer filter, and many foreign substances such as carbides may be observed when continuously molded. Therefore, from the viewpoint of reducing the melt viscosity of the polymer and shortening the residence time in the polymer filter as much as possible, the molding temperature is preferably in the range of 250 to 300 ° C, particularly preferably in the range of 260 to 300 ° C.

The optical film has a foreign matter content of 500 pieces / m ² or less, more preferably 100 pieces / m ² or less, more preferably 30 pieces / m ² or less, and most preferably 10 pieces / m ² or less, depending on the application. Ideally, 0 / m ² is preferable. Examples of the foreign matter include carbides (so-called “burnt foreign matter”) generated when the acrylic polymer is partially heated and deteriorated during melting and kneading of the raw material in the optical film manufacturing process, and the polymer manufacturing process. Examples thereof include gels generated therein, contaminants (environmental foreign matter) mixed in each process, and the like.

By reducing the content of foreign matter in the optical film to 500 pieces / m ² or less, the optical film can be made excellent in appearance.

  As the polymer filter, a polymer filter in which a plurality of leaf disk filters are arranged in a housing is used. The filter material of the leaf disk type filter may be any of a type in which a metal fiber nonwoven fabric is sintered, a type in which metal powder is sintered, a type in which several metal meshes are laminated, a hybrid type in which these are combined, and the like. A type in which a metal fiber nonwoven fabric is sintered is most preferable.

  Further, the filtration accuracy is preferably 15 μm or less, more preferably 10 μm or less, and most preferably 5 μm or less. Moreover, since the filtration residence time becomes long when the filtration accuracy is 1 μm or less, the filtration accuracy is preferably larger than 1 μm from the viewpoint of thermal degradation of the resin and productivity. On the other hand, if the filtration accuracy exceeds 15 μm, foreign matters are likely to be mixed.

The filtration area with respect to the resin treatment amount per hour of the polymer filter is not particularly limited, and is appropriately set according to the treatment amount, for example, within a range of 0.001 to 0.15 m ² / (kg / h). be able to.

  The shape of the center pole in the polymer filter is not particularly limited. For example, an inner flow type having a plurality of resin flow ports and a resin flow path in the center pole, and a leaf disk filter inner peripheral surface having a plurality of vertices or faces. And an external flow type having a resin flow path on the outer surface of the center pole. Among these, an external flow type with a few staying places in the resin flow path is more preferable.

  Although there is no restriction | limiting in particular in the residence time at the time of filtration with the said polymer filter, Preferably it is 20 minutes or less, More preferably, it is 10 minutes or less, Most preferably, it is 5 minutes or less. Further, the filter inlet pressure and the filter outlet pressure during filtration are, for example, in the range of 3 to 15 MPa and 0.3 to 10 MPa, respectively, and the pressure loss (pressure difference between the inlet pressure and the outlet pressure of the filter) is It is preferable to be within the range of 1-15 MPa. If the pressure loss is less than 1 MPa, the flow path through which the polymer passes through the filter tends to be biased, and the quality of the resulting film tends to deteriorate. Conversely, if the pressure exceeds 15 MPa, the filter is easily damaged.

  The resin temperature of the resin composition containing the acrylic polymer introduced into the filter is appropriately set according to the viscosity, preferably in the range of 200 to 350 ° C, more preferably in the range of 250 to 300 ° C, Most preferably, it is set within the range of 260 ° C to 300 ° C.

  In addition, as a method of obtaining a film with less foreign matter and coloring matter by filtration treatment with a polymer filter, (1) a method of performing filtration treatment in a clean environment at the time of polymer production and subsequently molding in a clean environment; 2) A method in which a polymer having foreign matters and colored substances is filtered in a clean environment and subsequently molded in a clean environment. (3) A polymer having foreign substances and colored matters is filtered in a clean environment. And a method of performing molding simultaneously with the treatment. In addition, you may perform the filtration process by a polymer filter in multiple times.

  Regardless of the type of extruder used, such as single-screw extruder, twin-screw extruder, and multi-screw extruder, a gear pump can be installed between the extruder and the filter to stabilize the resin pressure in the filter. More preferred.

  The optical film according to the present embodiment may be an unstretched film or a stretched film. When it is a stretched film, it may be a uniaxially stretched film or a biaxially stretched film. In the case of a biaxially stretched film, it may be biaxially stretched simultaneously or sequentially biaxially stretched. In the case of biaxial stretching, the mechanical strength is improved and the film performance is improved.

  Examples of the stretching apparatus include a roll stretching machine, a tenter-type stretching machine, and a small experimental stretching apparatus such as a tensile testing machine, a uniaxial stretching machine, a sequential biaxial stretching machine, and a simultaneous biaxial stretching machine. Any of these apparatuses may be used.

  The stretching temperature is preferably around the glass transition temperature of the film raw material polymer. Specifically, it is preferably performed within the range of (glass transition temperature −30) ° C. to (glass transition temperature +100) ° C., and more preferably (glass transition temperature −20) ° C. to (glass transition temperature +50) ° C. Within the range, more preferably within the range of (glass transition temperature−10) ° C. to (glass transition temperature + 30) ° C. When it is lower than (glass transition temperature-30) ° C., a sufficient draw ratio cannot be obtained, which is not preferable. When the temperature is higher than (glass transition temperature + 100) ° C., resin flow occurs and stable stretching cannot be performed.

  The draw ratio defined by the area ratio is preferably in the range of 1.1 to 25 times, more preferably in the range of 1.2 to 10 times, and still more preferably in the range of 1.3 to 5 times. If it is smaller than 1.1 times, it is not preferable because it does not lead to the development of retardation performance accompanying to stretching and the improvement of toughness. When it is larger than 25 times, the effect on the increase in the draw ratio becomes small.

  When stretching in a certain direction, the stretching ratio for the one direction is preferably within a range of 1.05 to 10 times, more preferably within a range of 1.1 to 5 times, and even more preferably 1.2 to 3 times. Done within range. If it is smaller than 1.05 times, a desired phase difference value may not be obtained, which is not preferable. When the ratio is larger than 10 times, the effect on the increase in the stretching ratio is reduced, and the film may be broken during stretching.

  The stretching speed (one direction) is preferably in the range of 10 to 20,000% / min, more preferably in the range of 100 to 10,000% / min. If it is slower than 10% / min, it takes time to obtain a sufficient draw ratio, and the production cost is increased, which is not preferable. If it is faster than 20,000% / min, the stretched film may be broken, which is not preferable.

  The optical film according to the present embodiment may be in the form of a sheet. The film thickness of the optical film is not particularly limited, but is preferably in the range of 1 μm to 10 mm, more preferably in the range of 1 to 350 μm, and in the range of 5 to 200 μm. More preferably, it is most preferable that it exists in the range of 10-150 micrometers. An optical film having a film thickness within the above range hardly breaks when stretched, has high strength, and is excellent in moldability.

  The optical film according to the present embodiment preferably has a glass transition temperature in the range of 110 ° C to 200 ° C. More preferably, it is in the range of 120 ° C to 200 ° C, particularly preferably in the range of 125 ° C to 190 ° C, and most preferably in the range of 130 ° C to 180 ° C. When the temperature is less than 110 ° C., the heat resistance is insufficient for a severe use environment, and the film may be deformed to easily cause retardation unevenness. Moreover, when it exceeds 200 degreeC, it will become an ultra-high heat-resistant film, but since the moldability for obtaining this film is bad or the flexibility of a film may fall large, it is unpreferable.

  The optical film according to the present embodiment preferably has a total light transmittance of 85% or more. More preferably, it is 90% or more, More preferably, it is 91%. The total light transmittance is a measure of transparency, and if it is less than 85%, the transparency is lowered and it is not suitable as an optical film.

  The optical film according to the present embodiment preferably has a haze of 5% or less. More preferably, it is 3% or less, More preferably, it is 1% or less. When the haze exceeds 5%, the transparency is lowered and it is not suitable as an optical film.

  The optical film according to the present embodiment has flexibility. More preferably, the film has flexibility in any two orthogonal directions in the film plane. Specifically, in an atmosphere of 25 ° C. and 65% RH (relative humidity), the bending radius is 1 mm. When bent 180 ° in a direction parallel to the slow axis in the film plane and in a direction perpendicular to the slow axis in the film plane, it is preferable that no cracks occur in either direction. Here, the bending radius means the distance from the center of bending of the film to the end of the bent portion. A film that does not cause cracks when bent 180 ° at a bending radius of 1 mm is very easy to handle and industrially useful. When bent 180 ° at a bending radius of 1 mm in an atmosphere of 65% RH at 25 ° C., a film that cracks is insufficiently flexible and difficult to handle. In addition, what is necessary is just to perform a bending test based on JIS. For example, it is preferable to carry out in accordance with K5600-5-1 (1999). The shape of the crack is not particularly limited, and means, for example, a crack having a length of 1 mm or more.

  In addition, the optical film according to the present embodiment is in the direction parallel to the slow axis in the film plane and in the slow plane in the film plane at a bending radius of 1 mm in an atmosphere of 25 ° C. and 65% RH (relative humidity). When the film is bent 180 ° in the direction perpendicular to the phase axis, it is preferable that the film does not separate (not crack) partially or entirely with the bent portion as a boundary in either direction. In this case, micro cracks may be generated to such an extent that the film does not separate at the folded portion as a boundary, but it is more preferable that such micro cracks do not occur.

  The optical film according to the present embodiment includes various optical disk (VD (video disk), CD (compact disc), DVD (Digital Versatile Disc), MD (magnetic disk), LD (Laser Disc), etc.) substrate protective films, Optical protective films such as polarizer protective films used for polarizing plates for liquid crystal display devices, retardation films, viewing angle compensation films, light diffusion films, reflective films, antireflection films, antiglare films, brightness enhancement films, touch panels It can be used as a conductive film or the like.

  Further, the optical film according to the present embodiment is suitably used as an optical compensation member for a liquid crystal display device. Specifically, for example, retardation films for LCD such as STN type LCD, TFT-TN type LCD, OCB type LCD, VA type LCD, IPS type LCD, etc .; 1/2 wavelength plate; 1/4 wavelength plate; reverse wavelength Dispersion characteristic film; optical compensation film such as polarizing plate optical compensation film.

  The optical film according to the present embodiment includes an acrylic polymer molded into a film, an antistatic layer, an adhesive layer, an adhesive layer, an easy-adhesion layer, an antiglare (non-glare) layer, a photocatalyst, depending on the purpose. A film obtained by laminating and coating various functional coating layers such as an antifouling layer such as a layer, an antireflection layer, a hard coat layer, an ultraviolet ray shielding layer, a heat ray shielding layer, an electromagnetic wave shielding layer, and a gas barrier layer may be used. Moreover, the film which laminated | stacked the member by which the said various functional coating layer was apply | coated to the acrylic polymer shape | molded into the film through the adhesive or the adhesive agent may be sufficient. In addition, the stacking order of each layer is not particularly limited, and the stacking method is not particularly limited.

  The optical film according to the present embodiment can further control optical characteristics by being laminated with the same kind of optical material and / or different kind of optical material in addition to the use alone. Although it does not specifically limit as an optical material laminated | stacked in this case, For example, a polarizing plate, the stretched orientation film made from a polycarbonate, the stretched orientation film made from cyclic polyolefin, etc. are mentioned. In addition, the use which applied the optical film which concerns on this Embodiment is not restrict | limited to these.

(III) Containing components other than acrylic polymer The optical film according to the present embodiment may contain a polymer other than the acrylic polymer.

  Examples of the polymer other than the acrylic polymer include elastic organic fine particles, and other polymers such as olefins such as polyethylene, polypropylene, ethylene-propylene copolymer, and poly (4-methyl-1-pentene). Polymers; halogen-containing polymers such as vinyl chloride and chlorinated vinyl resins; styrene polymers such as polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene block copolymer; polyethylene Polyesters such as terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamides such as nylon 6, nylon 66, and nylon 610; polyacetals; polycarbonates; polyphenylene oxides; Polyethersulfone; Polysulfone; Polysulfone; Polyoxybenzylene; Polyamideimide; Polybutadiene rubber, acrylic polymers such as polymethyl methacrylate other than those described above, ABS resin or ASA (acrylic rubber) blended with acrylic rubber -Rubber polymer such as (styrene-acrylonitrile) resin. The rubbery polymer preferably has a graft portion having a composition compatible with the lactone ring-containing polymer according to the present embodiment on the surface. Further, the average particle diameter of the rubbery polymer is preferably 300 nm or less, and more preferably 150 nm or less, from the viewpoint of improving the transparency when formed into an extruded film.

  In particular, when the acrylic polymer is the above-described lactone ring-containing polymer, the optical film exhibits positive birefringence (positive phase difference), and therefore has positive birefringence (positive phase difference). In terms of increasing, it is preferable to contain a polymer exhibiting positive birefringence (positive retardation) such as vinyl chloride, polycarbonate, and other polymers containing an aromatic ring in the main chain.

  Also, thermoplastic resins that are thermodynamically compatible with lactone ring-containing polymers include structures derived from vinyl cyanide monomers such as acrylonitrile-styrene copolymers and aromatic vinyl monomers. And a polymer containing 50% by mass or more of a structure derived from the above structure, a polyvinyl chloride resin, and a structure derived from methacrylic acid esters. Among these, acrylonitrile-styrene copolymer is compatible with lactone ring-containing polymers in a wide range of copolymer compositions, and also has positive birefringence (positive retardation) of lactone ring and acrylonitrile-styrene copolymer. A combination with the negative birefringence (negative phase difference) of the copolymer is preferable because the phase difference can be controlled low.

  The content ratio of the other polymer in the optical film according to the present embodiment is preferably in the range of 0 to 50% by mass, more preferably in the range of 0 to 40% by mass, and still more preferably 0 to 30% by mass. And particularly preferably within the range of 0 to 20% by mass.

  Moreover, the optical film according to the present embodiment may contain other additives. Examples of other additives include hindered phenol-based, phosphorus-based and sulfur-based antioxidants; light-resistant stabilizers, weather-resistant stabilizers, heat-stabilizers, and other stabilizers; reinforcing materials such as glass fibers and carbon fibers. UV absorbers such as phenyl salicylate, (2,2′-hydroxy-5-methylphenyl) benzotriazole, 2-hydroxybenzophenone; near infrared absorbers; tris (dibromopropyl) phosphate, triallyl phosphate, antimony oxide Flame retardants such as: antistatic agents such as anionic, cationic and nonionic surfactants; colorants such as inorganic pigments, organic pigments and dyes; organic fillers and inorganic fillers; resin modifiers; Inorganic fillers; plasticizers; lubricants; antistatic agents; flame retardants;

  The content of other additives in the optical film according to the present embodiment is preferably in the range of 0 to 5% by mass, more preferably in the range of 0 to 2% by mass, and still more preferably 0 to 0.5%. It is in the range of mass%.

  In addition, the specific method of each analysis mentioned by description of embodiment mentioned above is demonstrated below.

<Dynamic TG>
The polymer (or polymer solution or pellet) is once dissolved or diluted in tetrahydrofuran, poured into excess hexane or methanol for reprecipitation, and the taken out precipitate is vacuum dried (1 mmHg (1.33 hPa), 80 ° C. 3 hours or more), volatile components and the like are removed, and the obtained white solid resin is analyzed by the following method (dynamic TG method).

Measuring apparatus: Thermo Plus2 TG-8120 Dynamic TG (manufactured by Rigaku Corporation)
Measurement conditions: Sample amount 5 to 10 mg
Temperature increase rate: 10 ° C / min
Atmosphere: Nitrogen flow 200ml / min
Method: Step-like isothermal control method (controlled at a weight reduction rate value of 0.005% / sec or less between 60 ° C and 500 ° C)

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to a following example.

<Polymerization reaction rate, polymer composition analysis>
The reaction rate during the polymerization reaction and the content of the specific monomer unit in the polymer were determined by gas chromatography (manufactured by Shimadzu Corporation, apparatus name: GC17A) based on the amount of unreacted monomer in the obtained polymerization reaction mixture. ) And measured.

<Weight average molecular weight>
The weight average molecular weight of the polymer was determined by polystyrene conversion of GPC (GPC system manufactured by Tosoh Corporation, chloroform solvent).

<Thermal analysis of polymer and film>
Thermal analysis of polymers and films, etc., was performed using a DSC (manufactured by Rigaku Corporation, apparatus name: DSC-8230) under conditions of a sample of about 10 mg, a heating rate of 10 ° C./min, and a nitrogen flow of 50 cc / min. went. The glass transition temperature (Tg) was determined by the midpoint method according to ASTM-D-3418.

<Viscosity during polymerization reaction>
The maximum viscosity during the polymerization reaction was measured using a B type viscometer (B type Viscometer (Model BH), manufactured by TOKIMEC).

<Optical characteristics>
The retardation value was determined from the value of the in-plane retardation value (Re) at a wavelength of 589 nm measured using KOBRA-WR manufactured by Oji Scientific Instruments.

  The average refractive index of the film measured with an Abbe refractometer, the film thickness d, the slow axis as the tilt central axis, and the incident angle of 40 ° are input, and the in-plane retardation value (Re) and the thickness direction retardation value ( Rth), a retardation value (Re (40 °)) measured by tilting by 40 ° with the slow axis as the tilt axis, and three-dimensional refractive indexes nx, ny, and nz were obtained.

  The total light transmittance and haze were measured using NDH-1001DP manufactured by Nippon Denshoku Industries Co., Ltd. The refractive index was measured in accordance with JIS K 7142 using a refractometer (manufactured by Atago Co., Ltd., apparatus name: Digital Abbe refractometer DR-M2) with respect to a measurement wavelength of 589 nm.

<Thickness of film>
Measurement was performed using a Digimatic Micrometer (manufactured by Mitutoyo Corporation).

[Example 1]
In a reaction kettle equipped with a stirrer, temperature sensor, cooling pipe and nitrogen introduction pipe, 30 parts by mass of methyl methacrylate (MMA), 15 parts by mass of methyl 2- (hydroxymethyl) acrylate (MHMA), n-butyl methacrylate 5 parts by mass of (BMA), 40 parts by mass of toluene, and 10 parts by mass of n-butanol (BtOH) were charged, and the temperature was raised to 105 ° C. while introducing nitrogen. After the start of reflux, 0.03 parts by mass of t-amylperoxyisononanoate (trade name: Luperox 570, manufactured by Arkema Yoshitomi Corp.) was added as an initiator, and at the same time, t-amylperoxyisonononate 0.06. Solution polymerization was carried out under reflux (about 105 to 111 ° C.) while adding an initiator solution consisting of part by mass g, 2.67 parts by mass of toluene and 0.665 parts by mass of BtOH over 6 hours. After the dropwise addition of the initiator solution, aging was further performed for 2 hours.

  The weight average molecular weight of the obtained polymer (1A) was 158,000, the molecular weight distribution (Mw / Mn) was 2.2, and the reaction rate was 96.1%. Further, the content of the MHMA structural unit in the polymer is 30.0% by mass, the content of the MMA structural unit is 60.0% by mass, and the content of the BMA structural unit is 10.0% by mass. It was. The maximum viscosity during the polymerization reaction (immediately before the end of the polymerization) was 8,000 cps at 106 ° C.

[Comparative Example 1]
In a 30 L reaction kettle equipped with a stirrer, temperature sensor, cooling pipe, and nitrogen introduction pipe, 30 parts by mass of methyl methacrylate (MMA), 15 parts by mass of methyl 2- (hydroxymethyl) acrylate (MHMA), n-methacrylic acid n- 5 parts by mass of butyl (BMA) and 50 parts by mass of toluene were charged, and the temperature was raised to 105 ° C. while introducing nitrogen. After the start of reflux, 0.03 parts by mass of t-amylperoxyisononanoate (trade name: Luperox 570, manufactured by Arkema Yoshitomi Corp.) was added as an initiator, and at the same time, t-amylperoxyisonononate 0.06. Solution polymerization was carried out under reflux (about 105 to 111 ° C.) while adding an initiator solution consisting of parts by mass and 3.335 parts by mass of toluene dropwise over 6 hours. After the dropwise addition of the initiator solution, aging was further performed for 2 hours.

  The weight average molecular weight of the obtained polymer (2A) was 195,000, the molecular weight distribution (Mw / Mn) was 2.8, and the reaction rate was 96.2%. Further, the content of the MHMA structural unit in the polymer was 30.2% by mass, the content of the MMA structural unit was 59.9% by mass, and the content of the BMA structural unit was 9.9% by mass. It was. The maximum viscosity during the polymerization reaction (immediately before the end of the polymerization) was 31,000 cps at 106 ° C.

[Example 2]
To the above polymer solution obtained in Example 1, 0.1 part by mass of an octyl phosphate / dioctyl phosphate mixture (trade name: Phoslex A-8, manufactured by Sakai Chemical) was added and refluxed (about 85 to 105 ° C). ) For 2 hours (dealcoholization reaction in the polymer molecule to form a lactone ring structure in the polymer), and using a heating medium at 240 ° C. under pressure in an autoclave, The cyclization condensation reaction was carried out at 240 ° C. for 1.5 hours.

  The polymer solution obtained by the above cyclization condensation reaction is a bent type screw having a barrel temperature of 250 ° C., a rotation speed of 170 rpm, a degree of vacuum of 13.3 to 400 hPa (10 to 300 mmHg), a rear vent number of 1, and a forevent number of 4. It introduce | transduced into the twin-screw extruder ((phi) = 42mm, L / D = 42) at the processing rate of 15 kg / hour in conversion of resin amount, and the cyclization condensation reaction and devolatilization were performed in the extruder. At that time, 9.8 parts by mass of zinc octylate (18% Nikka octix zinc, manufactured by Nippon Chemical Industry Co., Ltd.) and Irganox 1010 (Ciba Specialty Chemicals) between the first and second forevents. Co., Ltd.) 0.8 part by mass, Adeka Stub AO-412S (Asahi Denka Kogyo Co., Ltd.) 0.8 part by mass, toluene 88.6 parts by mass, a solution of 0.46 kg / hour Infused at a rate. A transparent pellet (1B) was obtained by the devolatilization operation.

  The weight average molecular weight of the obtained pellet (1B) was 126,000, and the glass transition temperature was 128 ° C.

Example 3
The pellet (1B) obtained in Example 2 was charged into a single-screw extruder with a vent having a diameter of 65 mm, L / D = 32, and a unimelt screw. The temperature of the pellet (1B) was heated to 60 ° C. by blowing dehumidified air heated to the hopper. Further, nitrogen gas was introduced into the extruder with a nitrogen introduction space provided at the bottom of the hopper.

The pellet (1B) was melt-kneaded with a unimelt screw at a rate of 30 kg / hour while suctioning from the vent port at 13 hPa (10 mmHg). After melt-kneading, the pellet (1B) is passed through a leaf disk filter having a filtration area of 0.75 m ² and a filtration accuracy of 5 μm using a gear pump, and a film is formed on a cooling roll at 90 ° C. from a T-die having a width of 600 mm. did. The temperature of the cylinder, gear pump, filter and T-die was set at 265 ° C. The film thickness of the obtained optical film (1C) was 140 μm, the average number of foreign matters of 20 μm or more observed by visual observation under a microscope was 18 / m ² , and the film appearance was good.

  When a sample was cut out from the obtained unstretched film (1C) and subjected to retardation measurement, the in-plane retardation value was 5 nm. The total light transmittance was 93%, the haze was 0.3%, and the glass transition temperature was 128 ° C.

Example 4
Using an autograph (AGS-100D, manufactured by Shimadzu Corp.), the film (1C) obtained in Example 3 was uniaxially stretched at a rate of 400% / min. A stretched film (1D) having a thickness of 100 μm was obtained.

  When the retardation measurement of the obtained stretched film (1D) was performed, the in-plane retardation value was 180 nm. The total light transmittance was 93%, the haze was 0.3%, and the glass transition temperature was 128 ° C.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The method for producing an acrylic polymer of the present invention can produce a high molecular weight acrylic polymer while suppressing an increase in the viscosity of the polymer solution. For this reason, it can be applied to the production of various acrylic polymers from lab scale to plant scale.

Claims (8)

It is a method for producing an acrylic polymer by solution polymerization of a monomer composition containing a hydroxyl group-containing monomer and a (meth) acrylic acid ester,
Including a step of performing polymerization under conditions where the concentration of the monomer composition in the polymerization solution is 45% by mass or more,
In the above step, the method for producing an acrylic polymer, wherein the polymerization solution contains an alcohol having no polymerizable group.   The method for producing an acrylic polymer according to claim 1, wherein the alcohol having no polymerizable group is a saturated alcohol. The hydroxyl group-containing monomer is represented by the following general formula (1)
(Wherein, ^{R 1} and ^{R 2} each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)
The method for producing an acrylic polymer according to claim 1, wherein the acrylic polymer has a structure represented by:   The method for producing an acrylic polymer according to any one of claims 1 to 3, wherein the (meth) acrylic acid ester is methyl methacrylate.   In the step, the polymerization solution contains the alcohol having no polymerizable group in a range of 1 part by mass to 122 parts by mass with respect to 100 parts by mass of the monomer composition. The method for producing an acrylic polymer according to any one of claims 1 to 4.   The acrylic polymer according to any one of claims 1 to 5, wherein the polymer obtained by the polymerization is further subjected to intramolecular dealcoholization reaction to form a lactone ring structure in the molecule. A method for producing a polymer. The lactone ring structure is represented by the following general formula (2)
(In formula, R < ³ >, R < ⁴ >, R < ⁵ > represents a hydrogen atom or a C1-C20 organic residue each independently. In addition, the organic residue may contain the oxygen atom.)
The method for producing an acrylic polymer according to claim 6, wherein the structure is represented by the formula: A step of producing an acrylic polymer by the production method according to any one of claims 1 to 7,
Filtering the acrylic polymer with a polymer filter;
Forming the acrylic polymer into a film after the filtering step;
The manufacturing method of the optical film characterized by including.