JP5132950B2 - Manufacturing method of optical film - Google Patents

Description

  The present invention relates to organic fine particles, a resin composition, an optical film, and a method for producing an optical film. More specifically, the present invention relates to a resin composition containing organic fine particles and a thermoplastic resin, as well as optical properties and flexibility. The present invention relates to an excellent optical film and a method for producing the optical film.

  An acrylic resin represented by PMMA has excellent optical performance, and has been adapted to various optical materials as an optical isotropic material having high light transmittance, low birefringence, and low retardation. However, in recent years, with the progress of flat displays such as liquid crystal display devices, plasma displays, organic EL display devices, infrared sensors, optical waveguides, etc., optical materials not only have excellent transparency and heat resistance, but also have high optical isotropy. A so-called low birefringent material having the following has been required.

As a thermoplastic resin having transparency and heat resistance, for example, a lactone ring-containing polymer obtained by subjecting a polymer having a hydroxyl group and an ester group in a molecular chain to a lactone cyclocondensation reaction is known ( For example, see Patent Documents 1 and 2).
JP 2000-230016 (released on August 12, 2000) JP 2000-302815 (released on October 31, 2000)

  However, the above-described conventional configuration has a problem that it is difficult to obtain an optical material having good moldability and few foreign matters in the film.

  Specifically, the acrylic resin, particularly the lactone ring-containing polymer is brittle and has a problem in film moldability and bending resistance (flexibility).

  By adding cross-linked elastic fine particles having a multilayer structure, the film moldability and the bending resistance can be improved. However, since the crosslinked elastic fine particles aggregate and clog the filter, it was difficult to perform filtration.

  In particular, in the case of the resin having heat resistance as described above, since the molding is performed at a high temperature, the number of foreign matters due to the deterioration of the resin also increases. Furthermore, when the filter is clogged, the filtration time is delayed, and foreign substances due to deterioration of the resin are likely to increase.

  The present invention has been made in view of the above-mentioned problems, and its purpose is to improve the moldability and bending resistance when it is contained in a film, and it is an organic material having good dispersibility in the film. An object of the present invention is to realize a fine particle, a resin composition containing the organic fine particle, an optical film excellent in film moldability and bending resistance, and having few foreign matters, and a method for producing the optical film.

The resin composition according to the present invention is a resin composition comprising a thermoplastic resin as a main component and organic fine particles having an average particle diameter of 0.01 μm or more and 1 μm or less in a range of 5 wt% or more and 50 wt% or less. In the case of a film, the number of foreign matters having a particle diameter of 20 μm or more is 1000 / m ² or less.

  According to the above configuration, since the organic fine particles are contained, for example, by using organic fine particles having elasticity, a resin composition capable of providing an optical film excellent in film moldability and bending resistance is obtained. Can do. Furthermore, since there are few foreign matters despite containing organic fine particles, an effect that it is possible to provide a resin composition that is excellent in film moldability and bending resistance and can provide an optical film with few foreign matters. Play.

In order to solve the above problems, the optical film according to the present invention is composed of a thermoplastic resin as a main component, and organic fine particles having an average particle diameter in the range of 0.01 μm to 1 μm in an amount of 5 wt% to 50 wt%. In this optical film, the number of foreign matters having a particle diameter of 20 μm or more is 1000 / m ² or less.

  According to the above configuration, since the organic fine particles are contained, for example, by using organic fine particles having elasticity, an optical film excellent in film formability and bending resistance can be obtained. Furthermore, since there are few foreign matters despite containing organic fine particles, there is an effect that it is possible to provide an optical film that is excellent in film moldability and bending resistance and has few foreign matters.

  In the optical film according to the present invention, the thermoplastic resin preferably includes an acrylic resin in a range of 50 wt% to 100 wt%.

  According to the said structure, there exists the further effect that the optical film excellent in optical characteristics, such as a light transmittance and a low birefringence, can be provided.

  Moreover, in the optical film which concerns on this invention, it is preferable that a glass transition temperature exists in the range of 110 to 200 degreeC.

  According to the said structure, there exists the further effect that it can provide the optical film which is excellent also in heat resistance in addition to being excellent in film moldability and bending resistance, and there being few foreign materials.

  In the optical film according to the present invention, the acrylic resin preferably has a lactone ring structure.

  According to the said structure, there exists the further effect that heat resistance can be improved, without deteriorating an optical characteristic.

  In the optical film according to the present invention, the acrylic resin has the following general formula (1).

(In the formula, R ¹ , R ² and R ³ each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom.)
It preferably has a structure represented by

  In the optical film according to the present invention, the organic fine particles preferably have a crosslinked structure.

  According to the said structure, since the said organic fine particle shows bridge | crosslinking elasticity, the optical film excellent in bending resistance can be provided.

  In the optical film according to the present invention, when the thickness is 100 μm, it is preferable that cracks do not occur when bent at 180 ° with a bending radius of 1 mm in an atmosphere of 25 ° C. and 65% RH.

  According to the said structure, the optical film excellent in bending resistance can be provided.

  In the optical film according to the present invention, the haze is preferably 5% or less.

  In the optical film according to the present invention, the organic fine particles are preferably organic fine particles according to the present invention.

  According to the said structure, it is excellent in a film moldability and bending resistance, and can provide the optical film with few foreign materials.

  In order to solve the above-described problems, an optical film manufacturing method according to the present invention is a method for manufacturing an optical film containing a thermoplastic resin as a main component and containing organic fine particles, wherein the organic fine particles are contained in a thermoplastic resin. The method includes a step of dispersing within a range of from 50% by weight to 50% by weight and a step of filtering the thermoplastic resin in which the organic fine particles are dispersed with a polymer filter.

  According to the above method, since the thermoplastic resin in which the organic fine particles are dispersed is filtered through the polymer filter, there are few foreign matters even though the organic fine particles are included to impart characteristics such as bending resistance. An optical film can be realized. That is, an effect is obtained that it is possible to produce an optical film that is excellent in bending resistance and has few foreign matters.

  In the method for producing an optical film according to the present invention, the thermoplastic resin preferably contains an acrylic resin in a range of 50 wt% to 100 wt%.

  In the method for producing an optical film according to the present invention, the polymer filter is preferably a leaf disk type polymer filter having a filtration accuracy within a range of 1 μm to 20 μm.

As described above, the resin composition according to the present invention contains a thermoplastic resin as a main component, and organic fine particles having an average particle diameter of 0.01 μm or more and 1 μm or less in a range of 5 wt% or more and 50 wt% or less. When the resin composition is contained in a film, the number of foreign matters having a particle diameter of 20 μm or more is 1000 / m ² or less.

  Thereby, it is effective in the ability to provide the resin composition which can provide the optical film which is excellent in film moldability and bending resistance, and there are few foreign materials.

As described above, the optical film according to the present invention contains a thermoplastic resin as a main component, and organic fine particles having an average particle diameter of 0.01 μm or more and 1 μm or less within a range of 5% by weight or more and 50% by weight or less. The foreign film having a particle diameter of 20 μm or more is 1000 / m ² or less.

  Thereby, there is an effect that it is possible to provide an optical film which is excellent in film moldability and bending resistance and has few foreign matters.

  A method for producing an optical film according to the present invention is a method for producing an optical film comprising a thermoplastic resin as a main component and containing organic fine particles, wherein the organic fine particles are contained in a thermoplastic resin in an amount of 5% by weight to 50% by weight. The method includes a step of dispersing within a range and a step of filtering the thermoplastic resin in which organic fine particles are dispersed with a polymer filter.

  Thereby, there exists an effect that it is excellent in film moldability and bending resistance, and an optical film with few foreign materials can be manufactured.

  Hereinafter, the present invention will be described in detail. However, the scope of the present invention is not limited to these descriptions, and modifications other than the following examples can be made as appropriate without departing from the spirit of the present invention.

The optical film according to the present embodiment is an optical film containing a thermoplastic resin as a main component and organic fine particles having an average particle diameter of 0.01 μm or more and 1 μm or less in a range of 5 wt% or more and 50 wt% or less. It is a film, Comprising: The foreign material whose particle diameter is 20 micrometers or more is 1000 pieces / m < ² > or less.

  In the specification, the term “foreign matter” refers to contaminants mixed in all steps from the raw material to obtaining a film molded product, by-products such as gel generated during the polymerization reaction, aggregates of organic fine particles, and It means all substances that have properties that are not compatible with thermoplastic resins, including by-products resulting from resin degradation during film molding.

  Further, “weight” is treated as a synonym for “mass”, and “weight%” is treated as a synonym for “mass%”. In addition, “A to B” indicating a range indicates that the range is A or more and B or less.

  Further, “main component” is treated as meaning that it contains 50% by weight or more. That is, the thermoplastic resin is contained in the optical film within a range of 50 wt% or more and (100 wt% −% by weight of organic fine particles in the optical film).

The number of foreign matters is preferably 1000 / m ² or less regardless of the thickness of the optical film, but the number of foreign matters is 1000 when the thickness of the optical film is 100 μm. More preferably, the number is not more than pieces / m ² .

(I) Thermoplastic resin The thermoplastic resin is not particularly limited as long as it has transparency suitable for an optical film, softens by heating, exhibits plasticity, and solidifies when cooled. For example, examples of the thermoplastic resin include acrylic resin, polycarbonate resin, cycloolefin polymer (olefin resin), polyethersulfone, polyvinyl alcohol, polyimide, polyester, and polyethersulfone. Of these, acrylic resins are preferred. These thermoplastic resins may be used alone or in combination of two or more.

  The thermoplastic resin preferably has a glass transition temperature of 110 ° C. or higher and 200 ° C. or lower, more preferably 120 ° C. or higher, and still more preferably 130 ° C. or higher.

  The acrylic resin is a resin obtained by polymerizing acrylic acid, methacrylic acid and derivatives thereof, and is not particularly limited as long as the effects of the present invention are not impaired, and a known acrylic resin is used. be able to. For example, it can manufacture by polymerizing the monomer composition which contains (meth) acrylic acid ester as a main component.

  Examples of the derivatives of acrylic acid and methacrylic acid include, for example, the general formula (2)

(In the formula, R ⁴ and R ⁵ each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)
A compound (monomer) having a structure represented by: (meth) acrylic acid methyl, (meth) acrylic acid ethyl, (meth) acrylic acid n-propyl, (meth) acrylic acid n-butyl, (meth) acrylic acid Isobutyl, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2,3,4,5,6-pentahydroxyhexyl (meth) acrylate, and 2,3, (meth) acrylic acid 4,5-tetrahydroxypentyl and the like are preferable. These may be used alone or in combination of two or more. Among these, a compound having a structure represented by the above general formula (2) and methyl methacrylate are more preferable because of excellent heat resistance and transparency.

  Examples of the compound represented by the general formula (2) include methyl 2- (hydroxymethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, isopropyl 2- (hydroxymethyl) acrylate, and 2- (hydroxymethyl). ) Normal butyl acrylate, tertiary butyl 2- (hydroxymethyl) acrylate, and the like. Among these, methyl 2- (hydroxymethyl) acrylate and 2- (hydroxymethyl) ethyl acrylate are preferable, and methyl 2- (hydroxymethyl) acrylate is particularly preferable in that the effect of improving heat resistance is high. As for the compound represented by General formula (2), only 1 type may be used and 2 or more types may be used together.

  The acrylic resin according to the present embodiment may be copolymerized with an N-substituted maleimide such as phenylmaleimide, cyclohexylmaleimide, methylmaleimide, etc. from the viewpoint of heat resistance, and in the molecular chain (in the main skeleton of the polymer). Or in the main chain), a lactone ring structure, a glutaric anhydride structure, a glutarimide structure, or the like may be introduced. Among these, a structure containing no nitrogen atom is preferable in that coloring (yellowing) of the film hardly occurs. In addition, it is preferable that the main chain has a lactone ring structure because the cyclization condensation reaction rate is high, crosslinking and the like hardly occur at high temperature molding, and the resin is less deteriorated.

  The polymer before the lactone cyclization reaction can be well copolymerized with a (meth) acrylic acid ester such as methyl methacrylate. In addition, the lactone ring structure in the main chain is represented by the general formula (1) to be described later in that the polymerization yield is high and a polymer having a high content of the lactone ring structure is easily obtained with a high polymerization yield. It is preferable that it is a structure.

  The acrylic resin may have a structure other than the structure obtained by polymerizing the (meth) acrylic acid ester described above. The structure other than the structure obtained by polymerizing (meth) acrylic acid ester is not particularly limited, but a hydroxyl group-containing monomer, an unsaturated carboxylic acid, 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 —C -O-R ⁸ group is represented, Ac group represents an acetyl group, R ⁷ and R ⁸ represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)
The polymer structural unit (repeating structural unit) constructed by polymerizing at least one selected from the monomers represented by

  The hydroxyl group-containing monomer is not particularly limited as long as it is a hydroxyl group-containing monomer other than the monomer represented by the general formula (2). For example, α-hydroxymethylstyrene, α-hydroxyethylstyrene; 2 2- (hydroxyalkyl) acrylic acid such as-(hydroxyethyl) acrylic acid; and the like. These may be used alone or in combination of two or more.

  Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, crotonic acid, α-substituted acrylic acid, α-substituted methacrylic acid and the like. These may be used alone or in combination of two or more. May be. Among these, acrylic acid and methacrylic acid are preferable in that the effects of the present invention are sufficiently exhibited.

  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, and these may be used alone. Two or more kinds may be used in combination. Among these, styrene and α-methylstyrene are particularly preferable in that the effects of the present invention are sufficiently exhibited.

  When the acrylic resin is a resin obtained by polymerizing a monomer containing a compound having the structure represented by the general formula (2), the acrylic resin may have a lactone ring structure. Preferred (hereinafter, an acrylic resin having a lactone ring structure is referred to as a “lactone ring-containing polymer”). Hereinafter, the lactone ring-containing polymer will be described.

  Examples of the lactone ring structure include the following general formula (1)

(Wherein R ¹ , R ² and R ³ each independently represents a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom.)
The structure represented by is mentioned.

  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 content of the lactone ring structure in the acrylic resin is preferably in the range of 5 to 90% by weight, more preferably in the range of 10 to 70% by weight, and still more preferably in the range of 10 to 60% by weight. Especially preferably, it exists in the range of 10-50 weight%. When the content of the lactone ring structure is less than 5% by weight, 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 weight, the moldability tends to be poor, which is not preferable.

  In the lactone ring-containing polymer, the content ratio of the structure other than the lactone ring structure represented by the general formula (1) is that of a polymer structural unit (repeating structural unit) constructed by polymerizing (meth) acrylic acid ester. In this case, it is preferably in the range of 10 to 95% by weight, more preferably in the range of 10 to 90% by weight, further preferably in the range of 40 to 90% by weight, particularly preferably in the range of 50 to 90% by weight. .

  In the case of a polymer structural unit (repeating structural unit) constructed by polymerizing a hydroxyl group-containing monomer, the content ratio of the structure other than the lactone ring structure represented by the general formula (1) is preferably 0 to It is in the range of 30% by weight, more preferably in the range of 0 to 20% by weight, further preferably in the range of 0 to 15% by weight, particularly preferably in the range of 0 to 10% by weight.

  In the case of a polymer structural unit (repeating structural unit) constructed by polymerizing an unsaturated carboxylic acid, the content ratio of the structure other than the lactone ring structure represented by the general formula (1) is preferably 0 to 30. It is in the range of% by weight, more preferably in the range of 0 to 20% by weight, further preferably in the range of 0 to 15% by weight, particularly preferably in the range of 0 to 10% by weight.

  In the case of a polymer structural unit (repeating structural unit) constructed by polymerizing the monomer represented by the general formula (3), it contains a structure other than the lactone ring structure represented by the general formula (1). The proportion is preferably in the range of 0 to 30% by weight, more preferably in the range of 0 to 20% by weight, still more preferably in the range of 0 to 15% by weight, particularly preferably in the range of 0 to 10% by weight. is there.

  The method for producing the lactone ring-containing polymer is not particularly limited, but preferably, after the polymer having a hydroxyl group and an ester group in the molecular chain is obtained by the polymerization step, the obtained polymer is heat-treated. Thus, a lactone ring-containing polymer can be obtained by carrying out a lactone cyclization condensation step for introducing a lactone ring structure into the polymer.

  A polymer having a hydroxyl group and an ester group in the molecular chain is obtained by performing a polymerization reaction of the monomer composition containing the compound represented by the general formula (2).

  The content ratio of the compound represented by the general formula (2) in the monomer composition provided in the polymerization reaction (polymerization step) is preferably within the range of 5 to 90% by weight, more preferably 10 to 70% by weight. More preferably, it is in the range of 10 to 60% by weight, particularly preferably in the range of 10 to 50% by weight. When the content of the monomer represented by the general formula (2) in the monomer component provided in the polymerization step is less than 5% by weight, heat resistance, solvent resistance, and surface hardness may be insufficient. Yes, not preferred. If the content of the monomer represented by the general formula (2) in the monomer composition provided in the polymerization process is more than 90% by weight, gelation may occur during polymerization or lactone cyclization, The molding processability of the obtained polymer may be poor, which is not preferable.

  The monomer composition used in the polymerization step may contain a monomer other than the monomer represented by the general formula (2). As such a monomer, for example, the (meth) acrylic acid ester, the hydroxyl group-containing monomer, the unsaturated carboxylic acid, and the monomer represented by the general formula (3) are preferably exemplified. Only one type of monomer other than the monomer represented by formula (2) may be used, or two or more types may be used in combination.

  When (meth) acrylic acid esters other than the monomer represented by the general formula (2) are used, the content ratio in the monomer component to be subjected to the polymerization step is sufficient to exert the effect of the present invention. In the range of 10 to 95% by weight, more preferably in the range of 10 to 90% by weight, still more preferably in the range of 40 to 90% by weight, and particularly preferably in the range of 50 to 90% by weight.

  In the case of using a hydroxyl group-containing monomer other than the monomer represented by the general formula (2), the content ratio in the monomer component to be subjected to the polymerization step is sufficient to exert the effect of the present invention. Preferably it is in the range of 0 to 30% by weight, more preferably in the range of 0 to 20% by weight, still more preferably in the range of 0 to 15% by weight, and particularly preferably in the range of 0 to 10% by weight.

  In the case of using an unsaturated carboxylic acid, the content ratio in the monomer component to be subjected to the polymerization step is preferably in the range of 0 to 30% by weight, more preferably 0, in order to sufficiently exert the effects of the present invention. It is in the range of -20% by weight, more preferably in the range of 0-15% by weight, particularly preferably in the range of 0-10% by weight.

  When the monomer represented by the general formula (3) is used, the content ratio in the monomer component to be subjected to the polymerization step is preferably 0 to 30% by weight in order to sufficiently exhibit the effects of the present invention. More preferably, it is in the range of 0 to 20% by weight, more preferably in the range of 0 to 15% by weight, and particularly preferably in the range of 0 to 10% by weight.

  The form of the polymerization reaction for polymerizing the monomer composition to obtain a polymer having a hydroxyl group and an ester group in the molecular chain is preferably a polymerization form using a solvent, and solution polymerization is particularly preferred. .

  The polymerization temperature and the polymerization time vary depending on the type of monomer (monomer composition) used, the ratio of use, etc., but preferably the polymerization temperature is in the range of 0 to 150 ° C., and the polymerization time is 0.5 to The polymerization time is in the range of 20 hours, more preferably, the polymerization temperature is in the range of 80 to 140 ° C., and the polymerization time is in the range of 1 to 10 hours.

  In the case of a polymerization form using a solvent, the polymerization solvent is not particularly limited. For example, 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 Etc., and only one of these may be used, or two or more may be used in combination. Moreover, since the residual volatile matter of the lactone ring containing 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; 2,2′-azobis (isobutyronitrile), 1,1′-azobis (cyclohexanecarbonitrile), 2,2′-azobis (2, Azo compounds such as 4-dimethylvaleronitrile), and the like. These may be used alone or in combination of two or more. The amount of the polymerization initiator used is not particularly limited as long as it is appropriately set according to the combination of the monomers used and the reaction conditions.

  When performing the polymerization, it is preferable to control the concentration of the produced polymer in the polymerization reaction mixture to be 50% by weight 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 50% by weight, it is preferable that the polymerization solvent is appropriately added to the polymerization reaction mixture and controlled to be 50% by weight or less. . The concentration of the produced polymer in the polymerization reaction mixture is more preferably 45% by weight or less, still more preferably 40% by weight or less. Note that if the concentration of the polymer in the polymerization reaction mixture is too low, the productivity is lowered. Therefore, the concentration of the polymer in the polymerization reaction mixture is preferably 10% by weight or more, and more preferably 20% by weight or more. It 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. By controlling the concentration of the produced polymer in the polymerization reaction mixture in this way, the gelation of the reaction solution can be more sufficiently suppressed, and in particular, to increase the lactone ring content and improve the heat resistance. Even when the ratio of hydroxyl groups and ester groups in the molecular chain is increased, 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.

  The polymer obtained in the above polymerization step is an ester group in the molecular chain (in the case where the polymer is a monomer containing a compound having a structure represented by the general formula (2), Hydroxyl group and ester group), and the weight average molecular weight of the polymer is preferably in the range of 1,000 to 2,000,000, more preferably in the range of 5,000 to 1,000,000. Of these, more preferably in the range of 10,000 to 500,000, particularly preferably in the range of 50,000 to 500,000.

  In the polymer obtained by polymerizing the monomer containing the compound having the structure represented by the general formula (2), the lactone ring structure is introduced into the polymer by heat treatment in the subsequent lactone cyclization condensation step. It can be made into a lactone ring-containing polymer.

  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 preferably has a lactone ring structure represented by the general formula (1).

  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; Alkyl (aryl) phosphinic acids such as phosphoric acid, ethylphosphinic acid, phenylphosphinic acid and their esters; methyl phosphite, ethyl phosphite, phenyl phosphite, dimethyl phosphite, phosphorous acid Phosphorous acid diester or monoester or triester such as diethyl, diphenyl phosphite, trimethyl phosphite, triethyl phosphite, triphenyl phosphite; methyl phosphate, ethyl phosphate, 2-ethylhexyl phosphate, phosphorus Isodecyl phosphate, lauryl phosphate, stearyl phosphate, isostearyl phosphate, phenyl phosphate, dimethyl phosphate, diethyl phosphate, di-2-ethylhexyl phosphate, diisodecyl phosphate, dilauryl phosphate, distearyl phosphate, phosphorus Diisostearyl acid, diphenyl phosphate, trimethyl phosphate , Phosphoric diesters or monoesters or triesters such as triethyl phosphate, triisodecyl phosphate, trilauryl phosphate, tristearyl phosphate, triisostearyl phosphate, triphenyl phosphate; methylphosphine, ethylphosphine, phenylphosphine, dimethyl Phosphine, diethylphosphine, diphenylphosphine, trimethylphosphine, triethylphosphine, triphenylphosphine, etc. mono-, di- or trialkyl (aryl) phosphine; methyldichlorophosphine, ethyldichlorophosphine, phenyldichlorophosphine, dimethylchlorophosphine, diethylchlorophosphine, Alkyl (aryl) halogen phosphines such as diphenylchlorophosphine; Sphine, phenylphosphine oxide, dimethylphosphine oxide, diethylphosphine oxide, diphenylphosphine oxide, trimethylphosphine oxide, triethylphosphine oxide, triphenylphosphine oxide, mono-, di- or trialkyl (aryl) phosphines; tetramethylphosphonium chloride, chloride And halogenated tetraalkyl (aryl) phosphonium such as tetraethylphosphonium and tetraphenylphosphonium chloride. 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 weight, more preferably 0.01 to 2.5% by weight with respect to the polymer. %, More preferably 0.01 to 1% by weight, particularly preferably 0.05 to 0.5% by weight. If the amount of the catalyst used is less than 0.001% by weight, the reaction rate of the cyclization condensation reaction may not be sufficiently improved. On the other hand, if the amount exceeds 5% by weight, coloring may occur, This is not preferable because it may be difficult to melt and form by crosslinking of the 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 volatile components such as a solvent and residual monomers and alcohol produced as a by-product by a cyclocondensation 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, or molding defects such as bubbles or silver streaks.

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

  In the case of using a devolatilizer comprising the heat exchanger and the devolatilization tank, 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 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.

  In the case of using a devolatilizer comprising the heat exchanger and the devolatilization tank, the pressure during the reaction treatment is preferably within a range of 931 to 1.33 hPa (700 to 1 mmHg), and 798 to 66.5 hPa (600 to 50 mmHg). ) Is more preferable. 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.

  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 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 of about 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. A particularly preferred form is a form in which the devolatilization step is started after a while from the start of the cyclization condensation reaction, that is, the hydroxyl group and ester group present in the molecular chain of the polymer obtained in the polymerization step are cyclized in advance. A form in which a condensation reaction is performed to increase the cyclization condensation reaction rate to some extent, and then a cyclization condensation reaction using a devolatilization step in combination is performed. 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-type 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 shown in the examples is preferably 2% or less, more preferably 1.5% or less. More 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 in which a devolatilization step is simultaneously used 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. After that, it 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 type of solvent that can be used in the polymerization step is preferable.

  Examples of the catalyst added in the above method (i) include esterification catalysts such as p-toluenesulfonic acid or transesterification catalysts, basic compounds, organic carboxylates, carbonates and the like that are generally used. Is preferably the above-described organophosphorus compound.

  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% by weight, more preferably in the range of 0.01 to 2.5% by weight, still more preferably based on the weight of the polymer. It is in the range of 0.01 to 0.1% by weight, particularly preferably in the range of 0.05 to 0.5% by weight. 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 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 is 2% or less is preferable, More preferably, it is 1.5% or less, More preferably, it is 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. Further, if necessary, other treatments such as re-adding a solvent after isolating the polymer (a polymer in which at least a part of hydroxyl groups and ester groups present in the molecular chain are subjected to 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 or the like that inhibits the physical properties of the resin composition during heat processing. When a basic substance is used as the deactivator, for example, a metal carboxylate, a metal complex, A metal 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 resin composition and causes environmental pollution at the time of disposal. For example, alkali metals such as lithium, sodium and potassium; magnesium and calcium 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 10 to 10,000 ppm (weight conversion) with respect to the acrylic resin. ), More preferably in the range of 50 to 5,000 ppm (weight conversion), and still more preferably in the range of 100 to 3,000 ppm (weight conversion).

  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 resin composition may be inhibited, for example, the molecular weight is lowered.

  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 resin, and before the obtained resin composition is thermally processed. There is no particular limitation. For example, a deactivator is added at a predetermined stage during production of an acrylic resin, or after producing an acrylic resin, the acrylic resin, the deactivator, and other components are simultaneously heated and melted and kneaded. A method of heating and melting an acrylic resin and other components and then kneading by adding a deactivator; adding a deactivator and other components after melting and melting an acrylic resin And kneading.

  Moreover, when adding a quencher, it is preferable to perform a devolatilization process after kneading a thermoplastic resin and a quencher from a viewpoint that the obtained thermoplastic resin 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 has a weight average molecular weight of preferably in the range of 1,000 to 2,000,000, more preferably in the range of 5,000 to 1,000,000, and even more preferably 10. In the range of 50,000 to 500,000, particularly preferably in the range of 50,000 to 500,000.

  The lactone ring-containing polymer preferably has a weight loss 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. It is.

  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 weight 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 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 lactone ring-containing polymer has a glass transition temperature (Tg) of preferably 115 ° C. or higher, more preferably 125 ° C. or higher, further preferably 130 ° C. or higher, more preferably 135 ° C. or higher, and most preferably 140 ° C. or higher. .

  The total amount of residual volatile components contained in the lactone ring-containing polymer is preferably 1500 ppm or less, more preferably 1000 ppm or less. If the total amount of residual volatile components is more than 1500 ppm, it may cause molding defects such as coloration, foaming, or silver streak due to alteration during molding.

  The lactone ring-containing polymer preferably has a total light transmittance of 85% or more, more preferably 88% or more, and still more preferably 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.

(II) Organic Fine Particles The optical film according to the present embodiment contains 5 wt% or more and 50 wt% of organic fine particles having the thermoplastic resin as a main component and an average particle diameter in the range of 0.01 μm to 1 μm. Includes the following:

  The organic fine particles preferably have an effect of improving the physical properties of the thermoplastic resin such as flexibility (bending resistance). In order to have the effect of improving the flexibility of the thermoplastic resin, it is more preferable that the organic fine particles have a crosslinked structure.

  The organic fine particles having a crosslinked structure can be obtained, for example, by polymerizing a monomer composition containing a polyfunctional compound having two or more nonconjugated double bonds per molecule.

  Examples of the polyfunctional compound include divinylbenzene, allyl methacrylate, allyl acrylate, dicyclopentenyl methacrylate, dicyclopentenyl acrylate, 1,4-butanediol dimethacrylate, ethylene glycol dimethacrylate, triallylsia. Nurete, triallyl isocyanurate, diallyl phthalate, diallyl maleate, divinyl adipate, divinylbenzene ethylene glycol dimethacrylate, divinylbenzene ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate -Triethylene glycol dimethacrylate, triethylene glycol diacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, Examples include lamethylol methane tetramethacrylate, tetramethylol methane tetraacrylate, dipropylene glycol dimethacrylate and dipropylene glycol diacrylate. These may be used alone. Two or more kinds may be used in combination.

  The organic fine particles may have a structure other than a structure obtained by polymerizing the polyfunctional compound (hereinafter referred to as a structure derived from the polyfunctional compound). The structure other than the structure derived from the polyfunctional compound is represented by (meth) acrylic acid ester, hydroxyl group-containing monomer, unsaturated carboxylic acid, and general formula (3) constituting the thermoplastic resin described above. It preferably has a structure of a polymer structural unit (repeating structural unit) constructed by polymerizing at least one selected from monomers.

  Since the organic fine particles have the structure of the polymer structural unit constituting the thermoplastic resin described above, the dispersibility of the organic fine particles in the thermoplastic resin is improved, and foreign matter generated by aggregation of the organic fine particles, etc. Can be further suppressed. Thereby, the filtration process at the time of optical film shaping | molding can be performed in a short time.

  The organic fine particles exhibit crosslinking elasticity when obtained by polymerizing a monomer composition containing the polyfunctional compound. Thereby, the flexibility of the molded optical film is improved, and an optical film excellent in film moldability and bending resistance can be obtained.

  The organic fine particles according to the present embodiment have a core part obtained by further polymerizing (meth) acrylate as a shell part to a particulate polymer that becomes a core part within an average particle diameter of 0.01 μm or more and 1 μm or less. Organic shell having a multilayer structure composed of a shell portion, the weight ratio of the core portion to the shell portion is in the range of 20:80 to 80:20, and the shell portion is 5% by weight or more It is preferable to include a structural unit of a monomer of 2- (hydroxymethyl) acrylate within a range of 50% by weight or less. Since the organic fine particles have a core / shell structure, they can be more uniformly dispersed in the thermoplastic resin. Further, the organic fine particles according to the present embodiment are organic fine particles having a crosslinked structure having an average particle diameter in the range of 0.01 μm to 1 μm, and in the range of 1% by weight to 100% by weight. It preferably contains a structural unit of a monomer of (hydroxymethyl) acrylate.

  As said 2- (hydroxymethyl) acrylic acid ester, the compound which has a structure represented by General formula (2) mentioned above is preferable, and 2- (hydroxymethyl) methyl acrylate is more preferable.

  The organic fine particles have a structure derived from a polyfunctional compound only in the central part (core), and the part (shell) surrounding the central part is highly compatible with the thermoplastic resin constituting the optical film. It preferably has a structure. As a result, the organic fine particles can be more uniformly dispersed in the thermoplastic resin, and it is possible to further suppress the by-product of the foreign matter caused by the aggregation of the organic fine particles. Thereby, the filtration process at the time of optical film shaping can be performed in a shorter time. The organic fine particles having such a core-shell structure are, for example, the above-mentioned (meth) acrylic acid esters with the reactive functional group (double bond) left unreacted during the polymerization of the organic fine particles as a graft crossing point. , A hydroxyl group-containing monomer, an unsaturated carboxylic acid, and at least one selected from monomers represented by the general formula (3) can be obtained by graft polymerization. Hereinafter, the shell part and the core part of the core-shell structure will be described.

  The shell portion is not particularly limited as long as it has a structure with high compatibility with the thermoplastic resin constituting the optical film. Examples of the structure constituting the shell portion having a structure highly compatible with the thermoplastic resin constituting the optical film include 2- (hydroxymethyl) acrylic when the thermoplastic resin is the lactone ring-containing polymer described above. Structure (hereinafter referred to as RHMA / MMA structure) constructed by polymerizing a monomer composition consisting of methyl acid (hereinafter referred to as RHMA) and methyl methacrylate (hereinafter referred to as MMA), cyclohexyl methacrylate (Hereinafter referred to as CHMA) and a structure constructed by polymerizing a monomer composition consisting of MMA (hereinafter referred to as CHMA / MMA structure), benzyl methacrylate (hereinafter referred to as BzMA) and MMA A structure constructed by polymerizing a monomer composition (hereinafter referred to as a BzMA / MMA structure), 2-hydroxyethyl methacrylate (hereinafter referred to as a “BzMA / MMA structure”). (Hereinafter referred to as HEMA / MMA structure), acrylonitrile (hereinafter referred to as AN) and styrene (hereinafter referred to as St) constructed by polymerizing a monomer composition composed of MMA and MMA. And a structure (hereinafter referred to as AN / St structure) constructed by polymerizing a monomer composition comprising:

  When the shell part has an RHMA / MMA structure, the ratio of RHMA and MMA is preferably in the range of 5:95 to 50:50, and more preferably in the range of 10:90 to 40:60. preferable. Within the above range, the compatibility with the lactone ring-containing polymer is good, and the organic fine particles can be uniformly dispersed in the lactone ring-containing polymer. Further, in the case of the shell having the above RHMA / MMA structure, it preferably contains a lactone ring structure. The lactone ring structure can be introduced by forming a shell and then lactonizing.

  When the shell has a CHMA / MMA structure, the ratio of CHMA to MMA is preferably in the range of 5:95 to 50:50, and more preferably in the range of 10:90 to 40:60. preferable. Within the above range, the compatibility with the lactone ring-containing polymer is good, and the organic fine particles can be uniformly dispersed in the lactone ring-containing polymer.

  When the shell has a BzMA / MMA structure, the ratio of BzMA and MMA is preferably in the range of 10:90 to 60:40, and more preferably in the range of 20:80 to 50:50. preferable. Within the above range, the compatibility with the lactone ring-containing polymer is good, and the organic fine particles can be uniformly dispersed in the lactone ring-containing polymer.

  When the shell has a HEMA / MMA structure, the ratio of HEMA to MMA is preferably in the range of 2:98 to 50:50, and more preferably in the range of 5:95 to 40:60. preferable. Within the above range, the compatibility with the lactone ring-containing polymer is good, and the organic fine particles can be uniformly dispersed in the lactone ring-containing polymer.

  When the shell has an AN / St structure, the ratio of AN to St is preferably in the range of 5:95 to 50:50, and more preferably in the range of 10:90 to 40:60. preferable. Within the above range, the compatibility with the lactone ring-containing polymer is good, and the organic fine particles can be uniformly dispersed in the lactone ring-containing polymer. In addition, when the shell has an AN / St structure, not only the flexibility is improved, but also the effect of reducing the retardation of the obtained optical film is obtained.

  The core part is not particularly limited as long as it is a structure that exhibits the effect of improving the flexibility of the thermoplastic resin constituting the optical film, and examples thereof include a structure having cross-linking. Moreover, as a structure which has bridge | crosslinking, it is preferable that it is a crosslinked rubber structure.

  The cross-linked rubber structure is a rubber having elasticity by cross-linking between main chains of a polymer having a glass transition point in the range of −100 ° C. to 25 ° C. with a polyfunctional compound. Means the structure. Examples of the crosslinked rubber structure include structures of acrylic rubber, polybutadiene rubber, and olefin rubber (repeating structural unit). Among these, acrylic rubber is preferable because the average particle diameter is easily controlled to 0.3 μm or less, and optical properties such as transparency of the film are good when uniformly dispersed in the resin.

  As a structure which has the said bridge | crosslinking, the structure derived from the polyfunctional compound mentioned above is mentioned, for example. Among the polyfunctional compounds, 1,4-butanediol dimethacrylate, diethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, divinylbenzene, allyl methacrylate, allyl acrylate, and dicyclopentenyl methacrylate are more preferable.

  The amount of the polyfunctional monomer used in the production of the core part is preferably within the range of 0.01 to 15% by weight of the monomer composition used, and is within the range of 0.1 to 10% by weight. More preferably, it is within. By using a polyfunctional monomer within the above range, the resulting film exhibits good folding resistance.

  The ratio of the core part to the shell part is preferably in the range of 20:80 to 80:20, more preferably in the range of 40:60 to 60:40, as the core: shell ratio by weight. If the core portion is less than 20% by weight, the bending resistance of the film formed from the organic fine particles obtained tends to deteriorate, and if it exceeds 80% by weight, the hardness and formability of the film tend to decrease.

  The core part may or may not have a cross-linked structure. Similarly, the shell part may or may not have a cross-linked structure, but only the core part. It is more preferable that has a cross-linked structure and the shell portion does not have a cross-linked structure.

  The average particle size of the organic fine particles is preferably in the range of 0.01 to 1 μm, more preferably in the range of 0.03 to 0.5 μm, and in the range of 0.05 to 0.3 μm. It is particularly preferred. When the average particle size is less than 0.01 μm, there is a tendency that sufficient flexibility cannot be obtained when a film is formed. When the average particle size exceeds 1 μm, it is used as a filter in a filtration process during film production. There is a tendency to become clogged with organic fine particles.

  Of course, for thermoplastic resins other than acrylic resins having a lactone ring structure, the organic fine particles are uniformly dispersed in the resin, and then filtered through a polymer filter, thereby being excellent in bending resistance. An optical film with few foreign substances can be realized.

  In order to uniformly disperse the organic fine particles in the thermoplastic resin, it is preferable to introduce a component (structure) excellent in compatibility with the thermoplastic resin into the organic fine particles. For example, when organic fine particles are dispersed in an acrylic thermoplastic resin, if an acrylic polymer chain or an acrylonitrile / styrene polymer chain having good compatibility with the acrylic thermoplastic resin is introduced into the shell portion of the organic fine particle, Good. Also, introducing the same structure as the acrylic thermoplastic resin in which the organic fine particles are dispersed into the shell portion of the organic fine particles is also effective for improving the dispersibility of the organic fine particles.

  Specifically, for the acrylic thermoplastic resin copolymerized with maleimide, a maleimide structure is introduced into the shell portion of the organic fine particles, and for the acrylic thermoplastic resin having a glutaric anhydride structure or a glutarimide structure, When a glutaric anhydride structure or a glutarimide structure is introduced into the shell of the organic fine particles, the dispersibility of the organic fine particles in the thermoplastic resin is improved.

  The method for producing the organic fine particles is not particularly limited, and the above-described monomer composition can be prepared by the conventionally known emulsion polymerization method, emulsion-suspension polymerization method, suspension polymerization method, bulk polymerization method or solution polymerization method. The organic fine particles can be produced by polymerization in stages or multiple stages. Among these, the emulsion polymerization method is more preferable.

  When producing organic fine particles by emulsion polymerization, the organic fine particles are aggregated by salting out or reprecipitation of the polymer solution after emulsion polymerization, and then filtered and washed. After washing, the organic fine particles can be dried and mixed with a thermoplastic resin to produce an optical film. In addition, after washing, without drying the organic fine particles, the resulting organic fine particle cake is redispersed in an organic solvent such as MIBK (methyl isobutyl ketone), and the thermoplastic resin is dissolved or redispersed in the redispersed liquid. And a thermoplastic resin solution (solution in which a thermoplastic resin is dissolved in an organic solvent) are mixed, and then the water and / or the organic solvent is devolatilized to produce an optical film.

  As the polymerization initiator during the polymerization of the organic fine particles, conventionally known initiators such as organic peroxides, inorganic peroxides, and azo compounds can be used. Specifically, for example, t-butyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, succinic acid peroxide, peroxymaleic acid t-butyl ester, cumene hydroper Organic peroxides such as oxide and benzoyl peroxide, inorganic peroxides such as potassium persulfate and sodium persulfate, oil solubility such as azobis (2-methylpropionamidine) dihydrochloride, azobisisobutyronitrile An initiator etc. are mentioned. These may be used alone or in combination of two or more.

  The polymerization initiator is combined with a reducing agent such as sodium sulfite, sodium thiosulfate, sodium formaldehyde sulfoxylate, ascorbic acid, hydroxyacetone acid, ferrous sulfate, ferrous sulfate and disodium ethylenediaminetetraacetate. It may also be used as a normal redox type initiator.

  The organic peroxide can be added by a known addition method, such as a method of adding to a polymerization system as it is, a method of adding by mixing with a monomer, a method of adding by dispersing in an aqueous emulsifier solution, From the viewpoint of transparency, a method of adding a mixture to a monomer or a method of adding it by dispersing in an aqueous emulsifier solution is preferable.

  In addition, the organic peroxide includes an inorganic reducing agent such as a divalent iron salt and / or formaldehyde sulfoxylate soda, reducing sugar, ascorbic acid and the like from the viewpoint of polymerization stability and particle size control. It is preferable to use it as a redox initiator combined with an organic reducing agent.

  The surfactant used for the emulsion polymerization is not particularly limited, and a conventionally known surfactant for emulsion polymerization can be used. Specifically, for example, anionic surfactants such as sodium alkyl sulfonate, sodium alkyl benzene sulfonate, sodium dioctyl sulfosuccinate, sodium lauryl sulfate, sodium fatty acid, alkylphenols, aliphatic alcohols, etc. And nonionic surfactants such as reaction products of olefins with propylene oxide and ethylene oxide. These surfactants may be used alone or in combination of two or more. Furthermore, if necessary, a cationic surfactant such as an alkylamine salt may be used.

  The resulting latex of organic fine particles can be separated and recovered by ordinary coagulation, washing and drying operations, or by treatment by spray drying, freeze drying or the like.

  One kind of the organic fine particles described above may be contained in the optical film, or two or more kinds thereof may be contained.

(III) Optical film The method for producing an optical film according to the present embodiment includes a step of dispersing the organic fine particles in the thermoplastic resin, and a step of filtering the thermoplastic resin in which the organic fine particles are dispersed with a polymer filter. Including.

  The content of the organic fine particles in the optical film is preferably in the range of 5 wt% to 50 wt%, more preferably in the range of 10 wt% to 30 wt%. When the content of the organic fine particles is less than 5% by weight, sufficient flexibility tends not to be obtained.

  The step of dispersing the organic fine particles in the thermoplastic resin includes, for example, pre-blending the organic fine particles and the thermoplastic resin with a conventionally known mixer such as an omni mixer and then extruding and kneading the obtained mixture. . In this case, the mixer used for extrusion kneading is not particularly limited. 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. .

  In the step of dispersing in the thermoplastic resin, in order to disperse the organic fine particles more uniformly in the thermoplastic resin, a master batch containing the organic fine particles in a high concentration in the thermoplastic resin is separately manufactured. It is more preferable to prepare an optical film by diluting with the above thermoplastic resin.

  After the step of dispersing the organic fine particles in the thermoplastic resin, it is preferable to perform a step of filtering the thermoplastic resin in which the organic fine particles are dispersed with a polymer filter. By performing the process of filtering with a polymer filter, an optical film with few foreign matters can be realized.

Specifically, the number of foreign matters in the optical film is preferably 1000 / m ² or less, more preferably 500 / m ² or less, and more preferably 200/100 or less. / M ² or less is more preferable, and ideally 0 / m ² .

  The polymer filter preferably has a filtration accuracy in the range of 1 μm to 20 μm, more preferably in the range of 1 μm to 10 μm, and still more preferably in the range of 1 μm to 5 μm. If the filtration accuracy is less than 1 μm, the filtration residence time becomes long and the production efficiency is lowered, which is not preferable. In addition, when the filtration residence time is long, the thermoplastic resin and the like are likely to be thermally deteriorated, which may increase foreign matter. If the filtration accuracy exceeds 20 μm, foreign matter is likely to be mixed, which is not preferable.

  The polymer filter is not particularly limited as long as it has a filtration accuracy within the above range, and a conventionally known polymer filter can be used. Examples of the polymer filter include a leaf disk type polymer filter, a pack disk filter, a cylindrical filter, and a candle filter. Among these, a leaf disk type polymer filter is more preferable because a filtration area is wide and pressure loss is small even when a highly viscous resin is filtered.

  When the polymer filter is a leaf disk type polymer filter, the filter is made of a material obtained by sintering a metal fiber non-woven fabric, a material made of a material obtained by sintering metal powder, or a laminate of several metal meshes. Can be mentioned. In these, what consists of the material which sintered the metal fiber nonwoven fabric is more preferable.

The filtration area with respect to the processing amount of resin (thermoplastic resin in which organic fine particles are dispersed) per time in the polymer filter is appropriately selected according to the processing amount, and is not particularly limited, for example, 0.001 to 0.00. It can be set to 15 m ² / (kg / h).

  In the filtration with the polymer filter, the temperature of the thermoplastic resin in which the organic fine particles are dispersed is preferably 260 ° C. or higher, and more preferably 270 ° C. or higher. Moreover, it is preferable that it is 310 degrees C or less, It is more preferable that it is 300 degrees C or less, It is still more preferable that it is 290 degrees C or less.

  The viscosity (when measured at a shear rate of 100 / s) of the thermoplastic resin in which organic fine particles are dispersed during filtration with the polymer filter is preferably 500 Pa · s or less, more preferably 450 Pa · s or less, and 400 Pa · s or less. S or less is more preferable.

  The residence time of the thermoplastic resin in which the organic fine particles are dispersed during filtration with the polymer filter is preferably 20 minutes or less, more preferably 10 minutes or less, and even more preferably 5 minutes or less. Moreover, the filter inlet pressure at the time of filtration with the polymer filter can be in the range of 3 to 15 MPa, for example, and the outlet pressure of the filter can be in the range of 0.3 to 10 MPa, for example. Moreover, it is preferable that the pressure loss in a filter exists in the range of 1-15 Mpa. If the pressure loss is less than 1 MPa, the resin (thermoplastic resin in which organic fine particles are dispersed) tends to be biased in the flow path through the polymer filter, and the quality of the resin after filtration (thermoplastic resin in which organic fine particles are dispersed) is degraded. Tend to happen. Conversely, when the pressure loss exceeds 15 MPa, the filter is easily damaged.

  Examples of the film forming method for the optical film include conventionally 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. Of these film forming methods, the solution casting method (solution casting method) and the melt extrusion method are particularly suitable.

  Examples of the solvent used in the solution casting method (solution casting method) include aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as cyclohexane and decalin; esters such as ethyl acetate and butyl acetate Ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; alcohols such as methanol, ethanol, isopropanol, butanol, isobutanol, methyl cellosolve, ethyl cellosolve and butyl cellosolve; ethers such as tetrahydrofuran and dioxane; dichloromethane, Halogenated hydrocarbons such as chloroform and carbon tetrachloride; dimethylformamide; dimethyl sulfoxide; 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, and the molding temperature at that time may be appropriately adjusted according to the glass transition temperature of the film raw material, and is not particularly limited. For example, it is preferably in the range of 150 to 350 ° C, more preferably in the range of 200 to 300 ° C.

  When forming a film by the T-die method, a roll-shaped film can be obtained by attaching a T-die to the tip of a known single-screw extruder or twin-screw extruder and winding the film extruded into a film. it can. At this time, it is possible to perform uniaxial stretching by appropriately adjusting the temperature of the winding roll and adding stretching in the extrusion direction. Further, simultaneous biaxial stretching, sequential biaxial stretching, and the like can be performed by stretching the film in a direction perpendicular to the extrusion direction.

  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 either a uniaxially stretched film or a biaxially stretched film. In the case of a biaxially stretched film, either a simultaneous biaxially stretched film or a sequential biaxially stretched film may be used. In the case of biaxial stretching, the mechanical strength is improved and the film performance is improved. The optical film can suppress an increase in retardation even when stretched by mixing other thermoplastic resins, and a film having optical isotropy can be obtained.

  The stretching temperature is preferably in the vicinity of the glass transition temperature of the thermoplastic resin as the film raw material, and specifically, preferably in the range of (glass transition temperature −30 ° C.) to (glass transition temperature + 100 ° C.) and more. Preferably, it is within the range of (glass transition temperature−20 ° C.) to (glass transition temperature + 80 ° C.). If the stretching temperature is less than (glass transition temperature-30 ° C.), a sufficient stretching ratio may not be obtained. On the other hand, when the stretching temperature exceeds (glass transition temperature + 100 ° C.), the polymer flows, and stable stretching may not 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 1.3 to 10 times. If the draw ratio is less than 1.1 times, the toughness accompanying the drawing may not be improved. On the other hand, when the draw ratio exceeds 25 times, the effect of increasing the draw ratio may not be recognized.

  The stretching speed is unidirectional, preferably in the range of 10 to 20,000% / min, more preferably in the range of 100 to 10,000% / min. If the stretching speed is less than 10% / min, it takes time to obtain a sufficient stretching ratio, and the production cost increases. On the other hand, when the stretching speed exceeds 20,000% / min, the stretched film may be broken.

  Note that the optical film according to the present embodiment can be subjected to a heat treatment (annealing) or the like after the stretching treatment in order to stabilize the optical isotropy and mechanical characteristics thereof. The conditions for the heat treatment may be appropriately selected similarly to the conditions for the heat treatment performed on a conventionally known stretched film, and are not particularly limited.

  The optical film according to the present embodiment preferably has a thickness in the range of 5 to 200 μm, more preferably in the range of 10 to 100 μm. When the thickness is less than 5 μm, not only the strength of the film is lowered, but also when the durability test is performed by attaching to other parts, the crimp tends to increase. On the other hand, when the thickness exceeds 200 μm, not only the transparency of the film is lowered, but also the moisture permeability becomes small, and when a water-based adhesive is used when sticking to other parts, water that is the solvent is used. The drying speed may be slow.

  The optical film according to the present embodiment preferably has a glass transition temperature of 110 ° C. or higher and 200 ° C. or lower, more preferably 120 ° C. or higher, and further preferably 130 ° C. or higher.

  The optical film according to this embodiment preferably has a haze of 5% or less, more preferably 3% or less, and even more preferably 1% or less.

  When the optical film according to the present embodiment is a film having a thickness of 100 μm, a crack occurs when it is bent 180 ° at a bending radius of 1 mm in an atmosphere of 25 ° C. and 65% RH (relative humidity). Preferably not. 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 JIS 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.

  When the optical film according to the present embodiment is a film having a thickness of 100 μm, when the film is bent at 180 ° at a bending radius of 1 mm in an atmosphere of 25 ° C. and 65% RH, the film is partially separated from the bent portion as a boundary. Or it is preferable not to isolate | separate entirely (it does not crack). 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 has a surface wet tension of preferably 40 mN / m or more, more preferably 50 mN / m or more, and further preferably 55 mN / m or more. If the surface wetting tension is at least 40 mN / m or more, the optical film can maintain a state of high adhesive strength with other components. In order to adjust the surface wetting tension, for example, corona discharge treatment, ozone spraying, ultraviolet irradiation, flame treatment, chemical treatment, and other conventionally known surface treatments can be performed.

  The optical film according to the present embodiment may contain various additives. Examples of additives include antioxidants such as hindered phenols, phosphorus, and sulfur; stabilizers such as light stabilizers, weather stabilizers, and heat stabilizers; reinforcing materials such as glass fibers and carbon fibers; phenyls UV absorbers such as salicylate, (2,2′-hydroxy-5-methylphenyl) benzotriazole, 2-hydroxybenzophenone; near infrared absorbers; tris (dibromopropyl) phosphate, triallyl phosphate, antimony oxide, etc. Flame retardants; 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; Organic fillers and inorganic fillers Agents, plasticizers, lubricants, antistatic agents, flame retardants, and the like.

  The content of the additive in the optical film 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 in the range of 0 to 0.5% by mass. .

(IV) Resin Composition The resin composition according to the present embodiment comprises a thermoplastic resin as a main component, and organic fine particles having an average particle diameter in the range of 0.01 μm to 1 μm in an amount of 5 wt% to 50 wt%. When the resin composition is contained within the following range and has a film thickness of 100 μm, the number of foreign matters having a particle diameter of 20 μm or more is 1000 / m ² or less.

  The resin composition according to the present embodiment includes the above-described thermoplastic resin and the above-described organic fine particles.

  The thermoplastic resin content in the resin composition is preferably in the range of 50 wt% to 95 wt%, and more preferably in the range of 65 wt% to 95 wt%. When the content of the thermoplastic resin is less than 50% by weight, the heat resistance and the optical properties when used as a film tend to deteriorate.

  The content of the organic fine particles in the resin composition is preferably in the range of 5% by weight to 50% by weight, and more preferably in the range of 10% by weight to 30% by weight. When the content of the organic fine particles is less than 5% by weight, there is a tendency that sufficient flexibility cannot be obtained when a film is formed.

  The resin composition according to the present embodiment may contain various additives. Examples of additives include antioxidants such as hindered phenols, phosphorus, and sulfur; stabilizers such as light stabilizers, weather stabilizers, and heat stabilizers; reinforcing materials such as glass fibers and carbon fibers; phenyls UV absorbers such as salicylate, (2,2′-hydroxy-5-methylphenyl) benzotriazole, 2-hydroxybenzophenone; near infrared absorbers; tris (dibromopropyl) phosphate, triallyl phosphate, antimony oxide, etc. Flame retardants; 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; Organic fillers and inorganic fillers Agents, plasticizers, lubricants, antistatic agents, flame retardants, and the like.

  The content of the additive in the resin composition is preferably in the range of 0 to 5% by weight, more preferably in the range of 0 to 2% by weight, and still more preferably in the range of 0 to 0.5% by weight. is there.

  The organic fine particles can be dispersed (mixed) in the thermoplastic resin under the same conditions as those for the optical film described above.

  In addition, after mixing the organic fine particles and the thermoplastic resin, it is preferable to filter the thermoplastic resin in which the organic fine particles are dispersed with a polymer filter. By filtering with a polymer filter, a resin composition with few foreign substances can be obtained. In addition, a polymer filter can be performed on the conditions similar to the conditions in the optical film mentioned above.

  In addition, the preferable range of various physical properties, such as the glass transition temperature of a resin composition, the number of foreign materials, flexibility, and a haze, is the same range as the optical film mentioned above.

  The resin composition 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 moldability, and has particularly high optical isotropy. Since it is a low birefringent material, it is useful for applications such as optical lenses, optical prisms, optical films, optical fibers, and optical disks. Among these, an optical lens, an optical prism, and an optical film are particularly preferable.

  The resin composition 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.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  Hereinafter, although an example and a comparative example explain the present invention still in detail, the present invention is not limited to these examples. In the following description, for convenience, “parts by weight” may be simply referred to as “parts”.

For convenience, the following abbreviations are used in the examples.
SFS: sodium formaldehyde sulfoxylate EDTA: disodium ethylenediaminetetraacetate MMA: methyl methacrylate RHMA: 2- (hydroxymethyl) methyl acrylate CHMA: cyclohexyl methacrylate BzMA: benzyl methacrylate HEMA: 2-hydroxyethyl methacrylate BA : N-butyl acrylate St: styrene AN: acrylonitrile BD: butadiene BDMA: 1,4-butanediol dimethacrylate AMA: allyl methacrylate PBH: t-butyl hydroperoxide CHP: cumene hydroperoxide TDM: terlead decyl Mercaptan <weight average molecular weight>
The weight average molecular weight of the thermoplastic resin was determined by GPC (GPC system manufactured by Tosoh Corporation, polystyrene conversion, developing solvent: chloroform).

<Glass transition temperature>
Thermal analysis of the thermoplastic resin was performed using 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. . The glass transition temperature (Tg) was determined by the midpoint method according to ASTM-D-3418.

<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. Volatile components and the like were removed by conducting the reaction for 3 hours or more, and the obtained white solid resin was 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)
<Average particle size>
The average particle diameter of the organic fine particles was measured using a particle size distribution measuring device (Submicron Particle Sizer NICOMP380) manufactured by NICOMP.

<Number of foreign objects>
The number of foreign matters having a particle diameter of 20 μm or more was averaged by visually observing 5 optical films having a thickness of 5 cm × 20 cm and a thickness of 100 μm. The particle size of the foreign matter was measured using an optical microscope.

<Flexibility>
When the optical film having a thickness of 100 μm is bent 180 ° at a bending radius of 1 mm in an atmosphere of 25 ° C. and 65% RH, the state where the crack does not occur is “◯”, and the state where the optical film is generated is “ “×” was evaluated.

<Cutter cutting property>
The cutter cutability of the optical film is “○” when the optical film having a thickness of 100 μm is cut with a cutter knife in an atmosphere of 25 ° C. and 65% RH and the cut portion is not cracked. Evaluated as “x”.

<Haze>
The haze was measured using a NDH-1001DP manufactured by Nippon Denshoku Industries Co., Ltd. for a film having a thickness of 100 μm.

<Dispersibility>
After the slices of the film were packed in an epoxy resin, the epoxy resin was cured and thinly cut with a microtome to prepare a sample for observation. The obtained sample was measured with a scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, FE-SEM S-4800 type), and the dispersibility of the organic fine particles with respect to the thermoplastic resin from the transmission electron image of the obtained film cross section. Was observed.

<Content of lactone ring structural unit>
The content ratio of the lactone ring structural unit was determined as follows.

  First, based on the weight loss that occurs when all hydroxyl groups are dealcoholated as methanol from the polymer composition obtained by polymerization, the decomposition of the polymer begins at 150 ° C. before the weight loss starts in dynamic TG measurement. The dealcoholization reaction rate was determined from the weight loss due to the dealcoholization reaction up to 300 ° C.

  Here, in the dynamic TG measurement of the polymer having a lactone ring structure, the weight reduction rate between 150 ° C. and 300 ° C. is measured, and the obtained actual weight reduction rate is defined as (X). On the other hand, the theoretical weight reduction amount when assuming that all hydroxyl groups are dealcoholated from the composition of the weight body (that is, the weight reduction calculated assuming that a possible dealcoholization reaction has occurred in the polymer composition 100%. Amount) is defined as (Y).

  The theoretical weight reduction amount (Y) is more specifically the molar ratio of raw material monomers having a structure (hydroxyl group) involved in the dealcoholization reaction in the polymer, that is, the raw material unit in the polymer composition. It can be calculated from the content of the monomer.

And the following formula Dealcoholization reaction rate = (1− (actually measured weight decrease rate (X) / theoretical weight decrease amount (Y))
From this, the dealcoholization reaction rate can be determined.

  As an example, the ratio which the lactone ring structure of acrylic resin (A-1) obtained by manufacture example 1 mentioned later accounts is calculated. The theoretical weight loss (Y) of the acrylic resin (A-1) is that the molecular weight of methanol is 32, the molecular weight of methyl 2- (hydroxymethyl) acrylate is 116, and 2- (hydroxymethyl) acrylic acid Since the content (weight ratio) of methyl in the polymer is 20% by weight in terms of composition, (32/116) × 20≈5.52% by weight.

On the other hand, the actual weight loss rate (X) of the acrylic resin (A-1) by dynamic TG measurement was 0.18% by weight. When these values are applied to the above-mentioned formula for the dealcoholization reaction rate,
(1- (0.18 / 5.52)) ≈0.967
And the dealcoholization reaction rate is 96.7%.

Then, assuming that the lactone cyclization reaction was performed by the amount corresponding to the dealcoholization reaction rate, the content ratio (wt%) of the following formula lactone ring = B × A × M _R / M _m
(Wherein, B is the weight proportion in the monomer composition used in the copolymerization raw monomer having a structure (hydroxyl group) responsible for the lactonization, M _R lactone ring structure to generate The unit formula weight, M _m is the molecular weight of the raw material monomer having a structure (hydroxyl group) involved in lactone cyclization, and A is the dealcoholization reaction rate)
Thus, the lactone ring content ratio can be calculated.

  For example, in Production Example 1, the content of 2- (hydroxymethyl) methyl acrylate in the acrylic resin (A-1) is 20.0% by weight, the calculated dealcoholization reaction rate is 96.7%, and the molecular weight is Since the formula amount of the lactone ring structural unit produced when the 116-methyl 2- (hydroxymethyl) acrylate is condensed with methyl methacrylate is 170, the content of the lactone ring in the acrylic resin (A-1) Is 28.3 (= 20.0 × 0.967 × 170/116) wt%.

<Production Example 1> (Production 1 of thermoplastic resin)
RHMA (10 parts), MMA (40 parts) and toluene (50 parts) were charged into a 30 L reaction kettle equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction pipe, and the temperature was raised while performing a nitrogen pass. At 105 ° C., 0.05 part of tertiary butyl peroxyisopropyl carbonate was added as an initiator, and at the same time, a solution comprising 0.1 part of tertiary butyl peroxyisopropyl carbonate and 0.9 part of toluene was added dropwise over 2 hours. The solution polymerization was performed under reflux (100 to 115 ° C.). After completion of the dropwise addition, the mixture was further aged for 4 hours under reflux (100 to 115 ° C.) to obtain a polymer solution.

  To 100 parts of the above polymer solution, 0.05 part of stearyl phosphate / distearyl phosphate mixture (manufactured by Sakai Chemical) was added, and the reaction mixture was refluxed (95-100 ° C.) for 5 hours while performing a nitrogen pass. A polycondensation reaction was performed. Next, a vent type screw twin screw extruder (diameter = 29.75 mm, L / D = 30) having a barrel temperature of 250 ° C., a rotation speed of 100 rpm, a degree of vacuum of 13.3 to 400 hPa, a rear vent number of 1 and a fore vent number of 4 The polymer solution after the cyclization condensation reaction is introduced at a processing rate of 2.0 kg / hour in terms of the amount of resin, and further cyclization condensation reaction and devolatilization are carried out in the extruder and extruded from the extruder. Thus, a pellet of a transparent thermoplastic resin (A-1) was obtained. The weight average molecular weight of the thermoplastic resin (A-1) was 139,000, and the glass transition temperature was 135 ° C.

<Production Example 2> (Production 1 of organic fine particles)
In a polymerization vessel equipped with a cooler and a stirrer, 710 parts of deionized water and 1.5 parts of sodium lauryl sulfate were added and dissolved, and the internal temperature was raised to 70 ° C. Then, a mixed solution of 0.93 part of SFS, 0.001 part of ferrous sulfate, 0.003 part of EDTA, and 20 parts of deionized water was charged all at once into the polymerization vessel, and the inside of the polymerization vessel was sufficiently replaced with nitrogen gas.

  Monomer mixture (M-1) (BA 7.10 parts, St 2.86 parts, BDMA 0.02 parts, AMA 0.02 parts) and a polymerization initiator solution (PBH 0.13 parts, deionized water 10.0 parts). The polymerization vessel was added all at once and the polymerization reaction was carried out for 60 minutes.

  Subsequently, the monomer mixture (M-2) (BA 63.90 parts, St 25.74 parts, BDMA 0.18 parts, AMA 0.18 parts) and a polymerization initiator solution (PBH 0.246 parts, deionized water 20.0 parts) ) Was separately dropped over 90 minutes separately. Polymerization was continued for another 60 minutes after the completion of the dropping. As a result, a core part of the core / shell structure of the organic fine particles was obtained.

  Subsequently, the monomer mixed solution (M-3) (RHMA 20.0 parts, MMA 80.0 parts) and the polymerization initiator solution (PBH 0.27 parts, deionized water 20.0 parts) were continuously separated over 100 minutes. Polymerization was performed while dropping, and after completion of the dropping, the internal temperature was raised to 80 ° C. and polymerization was continued for 120 minutes. Next, after cooling to an internal temperature of 40 ° C., the mixture was passed through a 300 mesh wire net to obtain an emulsion polymerization liquid of organic fine particles.

  The obtained emulsion polymerization solution of organic fine particles was salted out with calcium chloride, coagulated, washed with water and dried to obtain powdery organic fine particles (B-1, average particle size 0.086 μm).

<Production Example 3> (Production of organic fine particles 2)
Except for changing RHMA in the monomer mixture (M-3) to CHMA, polymerization is performed in the same manner as in Production Example 2, solidified, washed with water, and dried to form powdered organic fine particles (B-2, average particles) 0.094 μm in diameter) was obtained.

<Production Example 4> (Production of organic fine particles 3)
The composition of the monomer mixture (M-1) is BA 7.10 parts, St 1.86 parts, BD 1.00 parts, BDMA 0.02 parts, AMA 0.02 parts, and the composition of the monomer mixture (M-2) is Polymerization was carried out in the same manner as in Production Example 2 except that the composition was changed to BA 63.90 parts, St 16.74 parts, BD 9.00 parts, BDMA 0.18 parts, and AMA 0.18 parts. Solid organic fine particles (B-3, average particle diameter of 0.103 μm) were obtained.

<Production Example 5> (Production of Organic Fine Particles 4)
In a polymerization vessel equipped with a cooler and a stirrer, 630 parts of deionized water, 250 parts of Superflex 410 (carbonate urethane emulsion, solid content 40.1%, average particle size 0.2 μm, manufactured by Daiichi Kogyo Seiyaku), Sodium dioctyl sulfosuccinate (0.1 part) was added, and the internal temperature was raised to 60 ° C. Then, a mixed solution of 0.93 part of SFS, 0.001 part of ferrous sulfate, 0.003 part of EDTA, and 20 parts of deionized water was charged all at once into the polymerization vessel, and the inside of the polymerization vessel was sufficiently replaced with nitrogen gas.

  Polymerization while continuously dropping a mixture of monomer and polymerization initiator (RHMA 20.0 parts, MMA 80.0 parts, cumene hydroperoxide (trade name: Park Mill H, manufactured by NOF Corporation) 0.27 parts) over 5 hours After completion of the dropping, the polymerization was continued for 2 hours at an internal temperature of 60 ° C. Next, after cooling to an internal temperature of 40 ° C., the mixture was passed through a 300 mesh wire net to obtain an emulsion polymerization liquid of organic fine particles.

  The obtained emulsion polymerization liquid of organic fine particles was salted out with calcium chloride, coagulated, washed with water and dried to obtain powdered organic fine particles (B-4, average particle size 0.220 μm).

<Production Example 6> (Production 2 of thermoplastic resin)
A 30-liter reaction kettle equipped with a stirrer, temperature sensor, cooling pipe, and nitrogen introduction pipe was charged with 9,000 g of methyl methacrylate, 1,000 g of N-phenylmaleimide, 10,000 g of toluene, and 105 ° C. while performing a nitrogen pass. The temperature was raised to. After refluxing, 12 g of tertiary amyl peroxyisononate (trade name: Lupazole 570, manufactured by Atofina Yoshitomi) was added as an initiator, and at the same time, 24 g of tertiary amyl peroxyisononate and 136 g of toluene were formed. Solution polymerization was performed under reflux (about 105 to 120 ° C.) while dropping the solution over 2 hours. After completion of the dropwise addition, the mixture was further aged for 4 hours to obtain a polymer solution.

  The obtained polymer solution was converted into a vent type screw twin screw extruder (diameter: barrel temperature 240 ° C., rotation speed 120 rpm, degree of vacuum 13.3 to 400 hPa (10 to 300 mmHg), one rear vent and four forevents. = 29.75 mm, L / D = 30), the polymer solution after the cyclocondensation reaction was introduced at a treatment rate of 2.0 kg / hour in terms of resin amount, and a further cyclocondensation reaction was carried out in the extruder. Volatilization was performed and extrusion from an extruder gave a transparent thermoplastic resin (A-2) pellet. The weight average molecular weight of the thermoplastic resin (A-2) was 158,000, and the glass transition temperature was 131 ° C.

<Production Example 7> ( Production of organic fine particles 5 )
In a polymerization vessel equipped with a cooler and a stirrer, 710 parts of deionized water and 1.5 parts of sodium lauryl sulfate were added and dissolved, and the internal temperature was raised to 70 ° C. Then, a mixed solution of 0.93 part of SFS, 0.001 part of ferrous sulfate, 0.003 part of EDTA, and 20 parts of deionized water was charged all at once into the polymerization vessel, and the inside of the polymerization vessel was sufficiently replaced with nitrogen gas.

  Monomer mixture (M-1) (BA 7.10 parts, St 2.80 parts, AMA 0.1 part) and polymerization initiator solution (PBH 0.13 parts, deionized water 10.0 parts) in the polymerization vessel The polymerization reaction was carried out for 60 minutes.

  Subsequently, the monomer mixture (M-2) (BA 63.90 parts, St 25.20 parts, AMA 0.9 parts) and the polymerization initiator solution (PBH 0.246 parts, deionized water 20.0 parts) were separately prepared. Polymerization was performed while continuously dropping over 90 minutes. Polymerization was continued for another 60 minutes after the completion of the dropping.

  Subsequently, the monomer mixed solution (M-3) (St 73.0 parts, AN 27.0 parts) and the polymerization initiator solution (PBH 0.27 parts, deionized water 20.0 parts) were continuously separated over 100 minutes. Polymerization was carried out while dropping. After completion of the dropwise addition, the internal temperature was raised to 80 ° C. and polymerization was continued for 120 minutes.

  Next, after cooling to an internal temperature of 40 ° C., the mixture was passed through a 300-mesh wire mesh to obtain an emulsion polymerization liquid (average particle size 0.105 μm) of organic fine particles.

  The obtained emulsion polymerization liquid of organic fine particles was salted out with calcium chloride, solidified, washed with water and dried to obtain powdery organic fine particles (B-5).

<Production Example 8> ( Production of organic fine particles 6 )
In a polymerization vessel equipped with a cooler and a stirrer, 550 parts of deionized water and 37.5 parts of a 2 wt% sodium dioctylsulfosuccinate aqueous solution were added and dissolved, and the internal temperature was raised to 61 ° C. The inside was sufficiently replaced with nitrogen gas.

  Then, a mixed solution of 0.45 part of SFS, 0.00075 part of ferrous sulfate, 0.003 part of EDTA, and 12 parts of deionized water was charged all at once into the polymerization vessel, and the inside of the polymerization vessel was sufficiently replaced with nitrogen gas again. .

  Monomer mixture (M-1) (132 parts of BA, 14.7 parts of MMA, 2.93 parts of AMA, 0.293 parts of CHP) was added dropwise at 60 ° C. over 5 hours, and polymerization was continued for another 30 minutes after the completion of the addition.

  Subsequently, after adding 7.5 parts of 2 wt% sodium dioctyl sulfosuccinate aqueous solution and 5 parts of deionized water, monomer mixture (M-2) (MMA 120.0 parts, St 30.0 parts, TDM 0.45 parts) , CHP0.45 part) was added dropwise over 5 hours. After completion of the dropwise addition, the polymerization was continued for 2 hours.

  Next, after cooling to an internal temperature of 25 ° C., the mixture was passed through a 300-mesh wire mesh to obtain an emulsion polymerization liquid (average particle size 0.119 μm) of organic fine particles.

  The obtained emulsion polymerization liquid of organic fine particles was salted out with calcium chloride, coagulated, washed with water and dried to obtain powdered organic fine particles (B-6).

[Example 1]
The thermoplastic resin (A-1) obtained in Production Example 1 and the organic fine particles (B-1) obtained in Production Example 2 are thermoplastic resin (A-1) / organic fine particles (B-1) = While feeding using a feeder at a weight ratio of 80/20, kneading at a temperature of 280 ° C. using a twin-screw extruder (cylinder diameter: 20 mm), a leaf disk polymer filter (manufactured by Nagase Sangyo, filtration accuracy 5 μm) To obtain a pellet. Further, melt extrusion was carried out from a coat hanger type T die (width 150 mm) at 260 ° C. using a single screw extruder to produce an optical film (unstretched film) (C-1) having a thickness of 100 μm. Table 1 shows various measurement results of the optical film.

[Example 2]
The thermoplastic resin (A-1) obtained in Production Example 1 and the organic fine particles (B-2) obtained in Production Example 3 are thermoplastic resin (A-1) / organic fine particles (B-2) = 80. Kneaded at a temperature of 280 ° C. using a twin screw extruder (cylinder diameter: 20 mm) while feeding with a feeder at a weight ratio of / 20, and a leaf disk type polymer filter (manufactured by Nagase Sangyo, filtration accuracy 5 μm) To obtain a pellet. Furthermore, melt extrusion was carried out from a coat hanger type T die (width 150 mm) at 260 ° C. using a single screw extruder to produce an optical film (unstretched film) (C-2) having a thickness of 100 μm. Table 1 shows various measurement results of the optical film.

Example 3
The thermoplastic resin (A-1) obtained in Production Example 1 and the organic fine particles (B-3) obtained in Production Example 4 are thermoplastic resin (A-1) / organic fine particles (B-3) = While feeding using a feeder at a weight ratio of 80/20, kneading at a temperature of 280 ° C. using a twin-screw extruder (cylinder diameter: 20 mm), a leaf disk polymer filter (manufactured by Nagase Sangyo, filtration accuracy 5 μm) To obtain a pellet. Further, melt extrusion was carried out from a coat hanger type T die (width 150 mm) at 260 ° C. using a single screw extruder to produce an optical film (unstretched film) (C-3) having a thickness of 100 μm. Table 1 shows various measurement results of the optical film.

Example 4
The thermoplastic resin (A-1) obtained in Production Example 1 and the organic fine particles (B-4) obtained in Production Example 5 are thermoplastic resin (A-1) / organic fine particles (B-4) = While feeding using a feeder at a weight ratio of 80/20, kneading at a temperature of 280 ° C. using a twin-screw extruder (cylinder diameter: 20 mm), a leaf disk polymer filter (manufactured by Nagase Sangyo, filtration accuracy 5 μm) To obtain a pellet. Further, melt extrusion was carried out from a coat hanger type T die (width 150 mm) at 260 ° C. using a single screw extruder to produce an optical film (unstretched film) (C-4) having a thickness of 100 μm. Table 1 shows various measurement results of the optical film.

[Comparative Example 1]
The thermoplastic resin (A-1) obtained in Production Example 1 was kneaded at a temperature of 280 ° C. using a single screw extruder (cylinder diameter: 20 mm), and a leaf disk polymer filter (manufactured by Nagase Sangyo, filtration accuracy) 5 μm) to obtain a pellet. Furthermore, it melt-extruded from the coat hanger type T die (width 150mm) at 260 degreeC using the single screw extruder, and produced the optical film (unstretched film) (C-5) with a thickness of 100 micrometers. Table 1 shows various measurement results of the optical film.

[Comparative Example 2]
The thermoplastic resin (A-1) obtained in Production Example 1 and the organic fine particles (B-2) obtained in Production Example 3 are thermoplastic resin (A-1) / organic fine particles (B-2) = 80 / While feeding using a feeder at a weight ratio of 20, the mixture was kneaded at a temperature of 280 ° C. using a twin screw extruder (cylinder diameter: 20 mm) to obtain pellets. Furthermore, it melt-extruded from the coat hanger type T die (width 150mm) at 260 degreeC using the single screw extruder, and produced the 100-micrometer-thick optical film (unstretched film) (C-6). Table 1 shows various measurement results of the optical film.

Example 5
The thermoplastic resin (A-2) obtained in Production Example 2 and the organic fine particles (B-5) obtained in Production Example 7 are thermoplastic resin (A-2) / organic fine particles (B-5) = While feeding using a feeder at a weight ratio of 70/30, the mixture was kneaded at a temperature of 260 ° C. using a twin screw extruder (cylinder diameter: 20 mm), and a leaf disk type polymer filter (manufactured by Nagase Sangyo, filtration accuracy 5 μm) To obtain a pellet. Furthermore, melt extrusion was carried out from a coat hanger type T die (width 150 mm) at 260 ° C. using a single screw extruder to produce an optical film (unstretched film) (C-7) having a thickness of 100 μm. Table 1 shows various measurement results of the optical film.

  Further, the transmission electron image of the cross section of the film (C-7) was measured with a scanning electron microscope, and the dispersibility of the organic fine particles (B-5) in the acrylic resin (A-2) was observed. Particles having a particle size of about 1 μm were uniformly dispersed, and aggregates of organic fine particles were not observed.

Example 6
The thermoplastic resin (A-1) obtained in Production Example 1, the organic fine particles (B-5) obtained in Production Example 7 and zinc acetate were combined into thermoplastic resin (A-2) / organic fine particles (B- 5) Kneading at a temperature of 260 ° C. using a twin screw extruder (cylinder diameter: 20 mm) while feeding using a feeder at a weight ratio of / zinc acetate = 80/20 / 0.032, and a leaf disk type polymer Filtration through a filter (manufactured by Nagase Sangyo Co., Ltd., filtration accuracy 5 μm) gave a pellet. Furthermore, it melt-extruded from the coat hanger type T die (width 150mm) at 260 degreeC using the single screw extruder, and produced the 100-micrometer-thick optical film (unstretched film) (C-8). Table 1 shows various measurement results of the optical film.

  Further, the transmission electron image of the cross section of the film (C-8) was measured with a scanning electron microscope, and the dispersibility of the organic fine particles (B-5) in the acrylic resin (A-1) was observed. Particles having a particle size of about 1 μm were uniformly dispersed, and aggregates of organic fine particles were not observed.

[Comparative Example 3]
The thermoplastic resin (A-1) obtained in Production Example 1 and the organic fine particles (B-6) obtained in Production Example 8 are thermoplastic resin (A-1) / organic fine particles (B-6) = While feeding using a feeder at a weight ratio of 80/20, the mixture was kneaded at a temperature of 260 ° C. using a twin screw extruder (cylinder diameter: 20 mm), and a leaf disk type polymer filter (manufactured by Nagase Sangyo, filtration accuracy 5 μm) However, since the resin pressure (inlet pressure) of the filter increased rapidly, the apparatus was stopped.

  Therefore, kneading was performed under the same conditions as in Example 1 except that filtration with a polymer filter was not performed, and the obtained pellets were formed into a film by hot pressing (240 ° C.) to produce a film having a thickness of 130 μm.

  The flexibility and cutter cutability of the obtained film were ○, but the haze was 36%.

  Moreover, when the transmission electron image of the cross section of the said film was measured with the scanning electron microscope and the dispersibility of the organic fine particle (B-6) with respect to acrylic resin (A-1) was observed, the organic fine particle was 1-3 micrometers in diameter. It was aggregated to the extent.

  As shown in Table 1, the optical film of Comparative Example 1 has a small number of foreign matters, but does not contain organic fine particles, and therefore has poor flexibility and cutter cutability. Moreover, although the optical film of Comparative Example 2 has organic fine particles but is not filtered with a polymer filter, it has excellent flexibility and cutter cutability, but has a large number of foreign matters.

  On the other hand, in the optical film of Examples 1-6, it is excellent in flexibility and cutter cut property, and there are few foreign materials.

  The optical film of the present invention is not only excellent in transparency and heat resistance, but also has desired characteristics such as low colorability, mechanical strength, and moldability, and has few foreign matters. For this reason, it can be used widely for optical applications and the like, and can be suitably used particularly in the field related to optical materials.

Claims (6)

A method for producing an optical film comprising a thermoplastic resin as a main component and containing organic fine particles,
Dispersing the organic fine particles in a thermoplastic resin within a range of 5 wt% or more and 50 wt% or less;
A thermoplastic resin which organic fine particles are dispersed saw including a step of filtering a polymer filter,
The optical film satisfies the following conditions : A method for producing an optical film :
An optical film comprising a thermoplastic resin as a main component and organic fine particles having an average particle size of 0.01 μm or more and 1 μm or less in a range of 5 wt% or more and 50 wt% or less,
Foreign matter having a particle size of 20 μm or more is 1000 / m ² or less,
The glass transition temperature is in the range of 110 ° C. or more and 200 ° C. or less,
The thermoplastic resin contains an acrylic resin in a range of 50 wt% to 100 wt%,
The acrylic resin may be copolymerized with an N-substituted maleimide, and a lactone ring structure, glutaric anhydride structure, or glutarimide structure is introduced into the molecular chain,
The organic fine particles have a core part and a shell part surrounding the core part,
The core part has a structure obtained by polymerizing a polyfunctional compound having two or more non-conjugated double bonds per molecule,
The shell part has the same structure as an acrylic polymer chain, an acrylonitrile / styrene polymer chain, or the thermoplastic resin,
The weight ratio of the core part to the shell part is in the range of 20:80 to 80:20,
The organic fine particles have a crosslinked structure. The shell part has a structure constructed by polymerizing a monomer composition comprising 2- (hydroxymethyl) methyl acrylate and methyl methacrylate, a monomer composition comprising cyclohexyl methacrylate and methyl methacrylate. A structure constructed by polymerizing a monomer, a structure constructed by polymerizing a monomer composition composed of benzyl methacrylate and methyl methacrylate, a monomer composed of 2-hydroxyethyl methacrylate and methyl methacrylate 2. The method for producing an optical film according to claim 1, wherein the optical film has a structure constructed by polymerizing the composition or a structure constructed by polymerizing a monomer composition composed of acrylonitrile and styrene . A method for producing an optical film comprising a thermoplastic resin as a main component and containing organic fine particles,
Dispersing the organic fine particles in a thermoplastic resin within a range of 5 wt% or more and 50 wt% or less;
A thermoplastic resin which organic fine particles are dispersed saw including a step of filtering a polymer filter,
The optical film satisfies the following conditions : A method for producing an optical film :
An optical film comprising a thermoplastic resin as a main component and organic fine particles having an average particle size of 0.01 μm or more and 1 μm or less in a range of 5 wt% or more and 50 wt% or less,
Foreign matter having a particle size of 20 μm or more is 1000 / m ² or less,
The glass transition temperature is in the range of 110 ° C. or more and 200 ° C. or less,
The thermoplastic resin viewed contains an acrylic resin in the range of 100 wt% to 50 wt% or less,
The acrylic resin may be copolymerized with an N-substituted maleimide, and a lactone ring structure, glutaric anhydride structure, or glutarimide structure is introduced into the molecular chain,
The organic fine particles are obtained by further polymerizing (meth) acrylic acid ester as a shell portion to a particulate polymer that becomes a core portion having an average particle diameter of 0.01 μm or more and 1 μm or less. Having a multilayer structure consisting of
The weight ratio of the core part to the shell part is in the range of 20:80 to 80:20,
The core part has a structure obtained by polymerizing a polyfunctional compound having two or more non-conjugated double bonds per molecule,
The shell portion includes a structural unit of a monomer of 2- (hydroxymethyl) acrylic acid ester within a range of 5 wt% or more and 50 wt% or less,
The organic fine particles have a crosslinked structure . The said acrylic resin has a lactone ring structure, The manufacturing method of the optical film of any one of Claims 1-3 characterized by the above-mentioned. The acrylic resin has the following general formula (1)

(In the formula, R ¹ , R ² and R ³ each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms, and the organic residue may contain an oxygen atom.)
It has the structure represented by these. The manufacturing method of the optical film of Claim 4 characterized by the above-mentioned. The method for producing an optical film according to claim 1, wherein the polymer filter is a leaf disk type polymer filter having a filtration accuracy in a range of 1 μm to 20 μm.