WO2005108438A1 - Imide resin, method for producing same, and molded body using same - Google Patents

Abstract

An imide resin having excellent transparency, excellent heat resistance, low orientational birefringence and a sufficiently small optical elasticity coefficient is disclosed which can be easily produced at low cost. Such an imide resin is obtained through a reaction between various methacrylic resins and monomethylamine (or butylamine). Also disclosed is a method for producing an imide resin which is characterized in that a (meth)acrylate polymer or a (meth)acrylate-aromatic vinyl copolymer is treated with a primary amine. The imide resin has good heat resistance, transparency and processability, and thus is useful for a polarizer-protecting film.

Description

 Specification

 Imide resin, method for producing the same, and molded article using the same

 Technical field

 The present invention relates to an imide resin, a method for producing the same, and a molded article such as a polarizer protective film using the same. More specifically, an imide resin which has excellent transparency and heat resistance, and has good molding processability and low optical distortion, a method for producing the same, and a process for producing a polarizer protective film and the like using the same. About the body.

 Background art

 [0002] In recent years, electronic devices have become increasingly smaller and have been used in a variety of applications, taking advantage of their light weight and compactness, as typified by notebook computers, mobile phones, and portable information terminals. On the other hand, in the field of flat panel displays such as liquid crystal displays and plasma displays, it is also required to suppress the increase in weight due to the increase in screen size.

 [0003] In applications requiring transparency, such as the above-mentioned electronic devices, there has been a growing trend to replace conventional glass-made members with resins having good transparency.

[0004] Various acrylic resins represented by polymethyl methacrylate have better moldability and workability than glass, are less likely to break, are lighter and cheaper, and are characterized by liquid crystal displays and optical disks. It has been studied for use in pickup lenses, etc., and some have been put into practical use.

 [0005] In accordance with the development of applications such as automotive headlamp covers and liquid crystal display components

Transparent resins are required to have heat resistance in addition to transparency. However, polymethyl methacrylate and polystyrene have good transparency and are relatively inexpensive, but their low heat resistance limits their application in such applications. . For example, the glass transition temperature of these polymethyl methacrylate, polystyrene and the like measured by a differential scanning calorimeter (DSC) is about 100 ° C.

[0006] One method for improving the heat resistance of acrylic resins is to use methyl methacrylate and cyclopentane. There is a method of copolymerizing hexylmaleimide. However, according to this method, there is a problem that the use of cyclohexylmaleimide, which is an expensive monomer, increases the cost of the obtained copolymer as the heat resistance is improved.

 [0007] As another method for improving the heat resistance of an acrylic resin, a technique of treating a primary amine with an acrylic resin is disclosed, for example, in Patent Document 1 and Patent Document 2. These relate to a stretched film comprising a dartalimide resin having a dartalimide ring structure of 20% by weight or more. Further, Patent Document 3 relates to a stretched film made of a dtaltarimide acrylic resin, and describes that a film having improved mechanical strength and excellent transparency and heat shrinkage was obtained by stretching. These publications do not mention orientation birefringence. However, according to the study of the present inventors, in the case of a composition having a large number of dartalimide ring structures as disclosed in these publications, there is a problem that orientation birefringence occurs during stretching and optical distortion is likely to occur. I understand.

[0008] As a method for improving the heat resistance of polymethyl methacrylate, an extruder is used to improve the heat resistance of poly (methyl methacrylate) (see, for example, Patent Document 6) ゃ methyl methacrylate-styrene copolymer (for example, see Patent Document 7, 8, 9, 10) to treat the primary amine to imidize the methyl ester group in methyl methacrylate to obtain an imide resin. However, such imide resins have a high glass transition temperature as measured by differential scanning calorimetry (DSC), and the resin has a high melt viscosity. One of the issues is that it is not suitable for precise molding of films and the like by injection molding or extrusion molding. According to the study by the present inventors, as a result of forming an imide resin having a melt viscosity of 20,000 Poise at 260 ° C. and 122 sec- ¹ by a melt extrusion method, die lines are conspicuous and a film having poor thickness distribution is obtained. I was terrible. Therefore, when the heating temperature was increased to 280 ° C and the melt viscosity was reduced to 122 seconds- ¹ lOOOOPoise, a film was formed in the same manner. A good film could not be obtained due to gas contamination. Such transparent and heat-resistant polyimide resins are expected to be used in a wide range of applications, but they can be used to form thin films with good thickness distribution using imide resins without causing foaming and gas contamination. It was very difficult to mold, and the problem was that the moldability was poor. [0009] As a technique for eliminating the orientation birefringence of the dartalimide acryl resin, Patent Document 5 discloses a dartalimide acryl-based resin having a positive orientation birefringence and a negative orientation birefringence. A film blended with a styrenic resin is disclosed. Such resins are characterized in that a phase difference is unlikely to be developed due to environmental changes.However, since the resin is a blend, the manufacturing process becomes complicated, and the performance of the obtained film (for example, solvent resistance, etc.) Had a problem when it fell.

 [0010] On the other hand, as another method for eliminating the orientation birefringence of a transparent resin, Non-Patent Document 1 discloses a polymer having a positive orientation birefringence and a polymer having a negative orientation birefringence in an appropriate ratio. A method of random copolymerization, a method of doping a polymer with a low molecular compound having polarizability anisotropy, and the like have been proposed. However, the random copolymerization of a polymer having a positive orientation birefringence and a polymer having a negative orientation birefringence at an appropriate ratio has been performed by a combination of benzyl methacrylate and methyl methacrylate, Often, expensive monomers are used, such as the combination of 2,2-trifluoroethyl methacrylate and methyl methacrylate. In addition, the method of doping a polymer with a low-molecular compound having polarizability anisotropy is expensive in addition to the low-molecular compound, and in addition, these low-molecular compounds often bleed out from a molded article during long-term use. There are many issues to be solved.

 [0011] Non-Patent Document 2 proposes a method of reducing the orientation birefringence of polycarbonate, such as a blend of polycarbonate and polystyrene, and a method of graft copolymerizing polystyrene with polycarbonate. However, the former lacks uniformity in optical properties, and the latter requires graft polymerization to actually complicate the process.

 [0012] Examples of the use of these transparent resins for members for liquid crystal displays include polarizing plates. The polarizing plate is a material having a function of transmitting only linearly polarized light having a specific vibration direction among light passing therethrough and blocking other linearly polarized light, and is formed by laminating a polarizer film and a polarizer protection film. The one having the above configuration is generally used.

 [0013] The polarizer film is a film having a function of transmitting only linearly polarized light having a specific vibration direction. For example, a polybutyl alcohol (hereinafter, referred to as PVA) film or the like is stretched to obtain iodine or nitro- gen. A film dyed with a color dye or the like is generally used.

[0014] The polarizer protective film is a film that holds the polarizer film and is practical for the entire polarizing plate. It has a function of imparting strength and the like, and for example, a triacetyl cellulose (hereinafter, PVAt) film is generally used.

 [0015] In the polarizer protective film, it is generally considered that a film having an unnecessary retardation (in-plane retardation and thickness-direction retardation) is not preferable. This is because even if the polarizer film has a high-precision linear polarization function, the phase difference and the deviation of the optical axis of the polarizer protective film will cause the linearly polarized light passing through the polarizer film to have elliptically polarizing properties. It is also the power to give. The aforementioned TAC film also basically has a small phase difference. However, TAC film is a film that easily generates a phase difference due to the action of external stress, and its photoelastic coefficient is not sufficiently small. Further, the film has a relatively large thickness direction retardation. For this reason, especially in a large-sized liquid crystal display device, there is a problem that the contrast in the peripheral portion is lowered.

[0016] Therefore, attempts have been made to use a film material having a smaller photoelastic coefficient than a TAC film as a polarizer protective film. As an example (for example, Patent Document 4), when the moisture permeability at 80 ° C and 90% RH is 20 g'mmZm ² '24 hr or less, and the photoelastic coefficient is 1 X 10- ^U cm ² / N or less. Certain protective films have been disclosed. However, also in this case, there was a problem that the price was high because the synthesis required a complicated route.

 By the way, in recent years, as a transparent resin, a homopolymer of cyclic olefin (or a hydrogenated carohydrate thereof), a cyclic olefin copolymer obtained by copolymerizing cyclic olefin with other olefins (or hydrogenated product thereof) ) Etc. have been proposed. These polymers have characteristics such as low birefringence, low moisture absorption, and heat resistance, and are being developed as optical materials. It has been reported that these polymers have a relatively small photoelastic coefficient, so that their optical characteristics are hardly changed even when the environment changes. However, such a cyclic olefin polymer generally requires a complicated route for synthesis, and thus has a problem that the price is high. Further, such a cyclic olefin polymer has a problem of low solubility in a solvent.

 Patent Document 1: JP 06-240017 A

 Patent Document 2: Japanese Patent Application Laid-Open No. 06-297558

Patent Document 3: Japanese Patent Application Laid-Open No. 06-256537 Patent Document 4: Japanese Patent Application Laid-Open No. 07-77608

 Patent Document 5: WO01Z37007

 Patent Document 6: U.S. Patent No. 4,246,374

 Patent Document 7: U.S. Patent No. 4,727,117

 Patent Document 8: U.S. Patent No. 4,954,574

 Patent Document 9: U.S. Patent No. 5,004,777

 Patent Document 10: U.S. Patent No. 5,264,483

 Non-Patent Document 1: Forming Process, Vol. 15, No. 3, page 194

 Non-Patent Document 2: Nikkei-U Material September 26, 1988, 56 pages

 Disclosure of the invention

 Problems to be solved by the invention

[0018] The present invention has been made in view of the above-mentioned problems of the prior art, and is easy to manufacture, excellent in transparency and heat resistance, and optically even under stress during molding and use. An object of the present invention is to provide an imide resin excellent in molding processability, which hardly causes distortion (birefringence), and a molded article such as an optical resin composition and a polarizer protective film using the imide resin.

 Means for solving the problem

In order to solve the above problems, the present inventors have conducted intensive studies and as a result, have obtained a method for treating an acrylic resin with a primary amine, which has a specific imidization reaction rate or a melt viscosity. The present inventors have found that fat is easy to produce, inexpensive, excellent in transparency and heat resistance, excellent in moldability with low orientation birefringence, and sufficiently small in photoelastic coefficient.

That is, the present invention relates to an imide resin containing a repeating unit represented by the following general formulas (1) and (2). [0021] [Formula 1]

(Wherein, R and R each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ³ represents an alkyl group having 1 to 18 carbon atoms and cycloalkyl having 3 to 12 carbon atoms. Group or aryl group having 6 to 10 carbon atoms.)

 [0023]

(Here, R ⁴ and R ⁵ each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁶ represents hydrogen or an alkyl group having 1 to 18 carbon atoms, It represents 12 cycloalkyl groups or aryl groups having 6 to 10 carbon atoms.)

 The imide resin of the present invention preferably has an orientation birefringence of 0.0001 or less, and more preferably has an orientation birefringence of 0.0001 or less.

The imide resin of the present invention preferably has a melt viscosity at 260 ° C. and 122 seconds- ¹ of 14000 Poise or less.

[0026] The imide resin of the present invention preferably contains a repeating unit represented by the following general formula (3). [0027] [Formula 3]

(Here, R ⁷ represents hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁸ represents an aryl group having 6 to 10 carbon atoms.)

 In addition, the imide resin of the present invention is preferably produced using a (meth) acrylate polymer, and the (meth) acrylate polymer is a methyl methacrylate polymer. Is more preferred,.

The imide resin of the present invention is preferably produced using a (meth) acrylate-aromatic vinyl copolymer. Aromatic Bull copolymer power Methyl methacrylate-styrene copolymer is more preferable.

The melt viscosity of the (meth) acrylate polymer and the (meth) acrylate aromatic vinyl copolymer at 260 ° C. for 122 seconds- ¹ is preferably 7000 Poise or less.

 The imide resin of the present invention is preferably produced by a method of treating a primary amine with an acrylic resin in the absence or presence of a solvent.

The imide resin of the present invention preferably has a glass transition temperature of 110 ° C. or higher.

Further, the present invention is characterized in that a (meth) acrylate polymer or a (meth) acrylate-aromatic vinyl copolymer is treated with a primary amine in the absence of a solvent. The present invention relates to a method for producing an imide resin.

[0034] The present invention also relates to an optical resin composition containing the imide resin as a main component.

[0035] The present invention also relates to a molded article comprising the resin composition for optical use.

[0036] The present invention also relates to a polarizer protective film comprising the resin composition for optical use.

Further, the present invention provides a polarizer protective film comprising the imide resin, wherein an in-plane retardation of the film is 10 nm or less and a thickness direction retardation is 20 nm or less. About.

 [0038] The polarizer protective film of the present invention is preferably stretched.

 [0039] The polarizer protective film of the present invention comprises 1 to 5 mol of the repeating unit represented by the general formula (1).

% Of the imide resin contained.

The polarizer protective film of the [0040] present invention, it is preferable photoelastic coefficient of the imide榭脂is less than 10 X 10- ¹² m Seo N.

 [0041] In the polarizer protective film of the present invention, the glass transition temperature of the imide resin is preferably 100 ° C or higher.

 [0042] The present invention also relates to a polarizing plate using the polarizer protective film.

 The invention's effect

 According to the present invention described above, it is possible to provide an imide resin which is easy to manufacture, inexpensive, has excellent transparency and heat resistance, has low orientation birefringence, and has a sufficiently small photoelastic coefficient. Therefore, a molded article having excellent moldability and having no optical distortion even when stress is generated during molding or use can be obtained. By using the imide resin of the present invention, it can be applied to a molded product requiring transparency, heat resistance and light weight, and can be used as a substitute for glass. In addition, it is possible to provide a polarizer protective film having small optical anisotropy. Further, by using the polarizer protective film of the present invention, even in a large-sized liquid crystal display device, it is possible to suppress a decrease in contrast in a peripheral portion and realize a good display. Best form

[0044] The present invention relates to an imide resin characterized by containing a repeating unit represented by the following general formulas (1) and (2). [0045]

(Wherein, R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ³ represents an alkyl group having 1 to 18 carbon atoms and 3 to 12 carbon atoms. It represents a cycloalkyl group or an aryl group having 6 to 10 carbon atoms.)

 [0047]

(Here, R ⁴ and R ⁵ each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁶ represents hydrogen or an alkyl group having 1 to 18 carbon atoms, It represents 12 cycloalkyl groups or aryl groups having 6 to 10 carbon atoms.)

The first structural unit that constitutes the imide resin of the present invention is represented by the following general formula (1), and is often referred to as a daltalimide unit (hereinafter, the general formula (1) It may be abbreviated as glutarimide unit.) O [0049]

(Here, R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ³ represents an alkyl group having 1 to 18 carbon atoms and 3 to 12 carbon atoms. It represents a cycloalkyl group or an aryl group having 6 to 10 carbon atoms.)

Preferred dartalimide units are those in which R ² is hydrogen or a methyl group, and R ³ is hydrogen, a methyl group, an n-butyl group, a cyclohexyl group, a benzyl group, from the viewpoint of availability of raw materials, cost, heat resistance, and the like. Group. It is particularly preferable that R ¹ is a methyl group, R ² is hydrogen, and R ³ is a methyl group, an n-butyl group, or a cyclohexyl group.

The dartalimide unit contained in the imide resin of the present invention may be of a single type, and the imide resin may contain a plurality of types of dartartimide units having different R ¹ R ² and R ³ .

[0052] The second structural unit constituting the imide resin of the present invention is represented by the following general formula (2) and is a (meth) acrylic ester or (meth) acrylic acid unit. Is often referred to as a (meth) acrylic ester unit (here, (meth) acrylic ester means acrylic ester, Z or methacrylic ester. Hereinafter, the general formula (2) It may be abbreviated as (meth) acrylate unit.) [0053] [Formula 7]

(Here, R ⁴ and R ⁵ each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁶ represents hydrogen or an alkyl group having 1 to 18 carbon atoms, and 3 to 5 carbon atoms. It represents 12 cycloalkyl groups or aryl groups having 6 to 10 carbon atoms.)

From the viewpoints of the availability of the (meth) acrylic acid ester or the raw material and the cost, as the (meth) acrylic acid unit, R ⁴ and R ⁵ are hydrogen or a methyl group, R ⁶ is a hydrogen or methyl group, n-butyl group, cyclohexyl group and benzyl group. R ¹ is a methyl group, R ² is methylcarbamoyl group, force when it is R ³ forces a methyl group are especially preferred.

[0055] These second structural units may be of a single type.

R ⁵ and R ⁶ may include a plurality of different types.

 [0056] The imide resin of the present invention preferably has an orientation birefringence of 0.0001 or less. Such an imide resin has substantially no orientation birefringence. The value of the orientation birefringence is more preferably 0.0001 or less. By setting the orientation birefringence to 0.0001 or less, substantially no birefringence occurs even when a stress is generated during molding and use, and a molded article without optical distortion can be obtained. .

Here, the orientation birefringence is a birefringence that occurs when the film is uniaxially stretched at a predetermined temperature and a predetermined stretching ratio, and includes an intrinsic birefringence derived from a polymer structure and an orientation distribution derived from a molecular alignment state. This is the product of the functions. In this specification, it is defined as the difference between the refractive index (nx) in the direction of maximum refractive index (nx) and the refractive index (ny) in the axial direction orthogonal thereto, and the phase difference Re (nm) measured by a phase difference meter is referred to as the difference. It is the value divided by the thickness d (μm) of the test piece at the time of phase difference measurement, and is expressed by the following equation. Orientation birefringence Δη = nx-ny = Re / d

 or

 In the present specification, unless otherwise specified, it refers to the birefringence that appears when the film is stretched 100% at a temperature 5 ° C higher than the glass transition temperature of the imide resin (drawing magnification is 2 times). And

[0058] The content of the daltarimide unit represented by the general formula (1) in the imide resin of the present invention depends on, for example, the structure of R ³ and the content of the general formula (3). 3-95% by weight is preferred. When the aromatic vinyl unit represented by the general formula (3) is not contained, particularly when a imide resin having substantially no orientation birefringence is obtained, the dartalimide unit represented by the general formula (1) is used. Is preferably from 1 to 40% by weight, particularly preferably from 3 to 30% by weight, particularly preferably from 5 to 20% by weight. On the other hand, when an aromatic vinyl unit represented by the general formula (3) is contained, a imide resin having substantially no orientation birefringence is obtained when the daltarimide unit represented by the general formula (1) is contained. The amount is preferably increased in accordance with the amount of the aromatic unit represented by the general formula (3), particularly preferably at least 20% by weight, more preferably at least 40% by weight, particularly preferably at least 50% by weight. preferable. If the proportion of dartalimide units is less than this range, the resulting polyimide resin may have insufficient heat resistance or may have poor transparency. Exceeding this range may unnecessarily increase the heat resistance and melt viscosity, deteriorating the moldability, and may also cause the mechanical strength of the obtained molded article to become extremely brittle and impair the transparency. is there.

[0059] The imide resin of the present invention preferably has a melt viscosity at 260 ° C and 122 seconds- ¹ of 14000 Poise or less. The melt viscosity in the present invention is a flow characteristic when a thermoplastic resin (imide resin) is melted by heat, and refers to a ratio between a shear stress and a shear rate. The unit is represented by Poise. By setting the melt viscosity at 260 ° C and 122 seconds- ¹ to 14000 Poise or less, the moldability of the obtained imide resin is improved, and a precise molded product can be obtained.

[0060] In the present invention, the moldability of the imide resin is good! , Means, when imide resin is processed into various molded products by various plastic processing methods such as injection molding, melt extrusion film molding, inflation molding, blow molding, compression molding, and spin molding. Defects such as poor transfer, silver, fisheye, die line, thickness unevenness, foaming, etc. are hardly generated, and it is a characteristic that precise molding is easy. [0061] The third structural unit to be contained in the imide resin of the present invention as necessary is represented by the following general formula (3), and is often often referred to as an aromatic vinyl unit. (Hereinafter, the general formula (3) may be abbreviated as an aromatic vinyl unit.)

 [0062] [Formula 8]

(Here, R ⁷ represents hydrogen or an alkyl group having 1 to 8 carbon atoms, and R. represents an aryl group having 6 to 10 carbon atoms.)

 Preferred aromatic vinyl units include styrene, -methylstyrene and the like. Of these, styrene is particularly preferred from the viewpoints of availability of raw materials and cost.

[0064] These third structural units may be of a single type.

R ⁸ may include a plurality of different types.

 [0065] The content of the aromatic vinyl unit represented by the general formula (3) in the imide resin is preferably 10% by weight or more based on the total repeating units of the imide resin. The preferred content of aromatic vinyl units is 10% by weight 40% by weight, more preferably 15 to 30% by weight, and even more preferably 15 to 25% by weight. When the aromatic unit power is larger than this range, the heat resistance of the obtained imide resin may be insufficient.

 [0066] By adjusting the proportions of the general formulas (1), (2) and (3), it is possible to adjust to various required physical properties. For example, when the imide resin of the present invention is formed by first polymerizing a (meth) acrylate-aromatic vinyl copolymer such as a methyl methacrylate-styrene copolymer and then imidizing it, for example, ) The ratio of the general formula (3) is determined by adjusting the polymerization ratio of the acrylate ester and the aromatic vinyl (the ratio of the general formula (3) can be set to 0). The proportion of the general formulas (1) and (2) can be further adjusted by adjusting the addition ratio of the amine.

[0067] In the imide resin of the present invention, the type containing the general formula (3) is methyl methacrylate-styrene. By adjusting the amount of each constituent unit and the content of dartalimide units in the ren copolymer, the melt viscosity of the imide resin at 260 ° C and 122 seconds- ¹ is 14000 Poise or less, and substantially It is also possible to provide a feature having no orientation birefringence. In order to obtain an imide resin having a melt viscosity at 260 ° C and 122 sec- ¹ of 14000 Poise or less and having substantially no orientation birefringence, it is necessary to use (meth) methacrylate such as methyl methacrylate-styrene copolymer. ) Atharyl acid ester It is necessary to adjust the amount of each structural unit in the aromatic vinyl copolymer, and further to adjust the degree of imididani. The repeating unit represented by the general formula (1) and the repeating unit represented by the general formula (3) It is preferably in the range of 2.0: 1.0 to 4.0: 1.0 in weight ratio, and 2.5: 1.0 to 4.0: 1.0 in weight ratio. Force S is more preferable, and force S in the range of 3.0: 1.0 to 3.5: 1.0 is more preferable.

 [0068] In the imide resin of the present invention, if necessary, even if the fourth structural unit is copolymerized, it does not matter. As a fourth structural unit, a copolymer of a tolyl monomer such as acrylonitrile / methacrylo-tolyl, and a maleimide monomer such as maleimide, N-methylmaleimide, N-phenylmaleimide, or N-cyclohexylmaleimide. Can be used. These may be directly copolymerized into the imide resin or by graft copolymerization.

[0069] imide榭脂of the present invention, it is favorable preferable having 1 X 10 ⁴ to weight average molecular weight of 5 X 10 ^5. When the weight average molecular weight is less than 1 × 10 ⁴ , the mechanical strength of the film is insufficient, and when the weight average molecular weight exceeds 5 × 10 ⁵ , the viscosity at the time of melting is high and the productivity of the film is reduced. Sometimes. In order to lower the melt viscosity of the imide resin, it is useful to use a branched methacrylic resin having a small molecular weight between branch points as a raw material. The molecular weight between branch points means an average molecular weight from a branch to the next branch point in a polymer having a branched structure, and is defined using a Z-average molecular weight. Also, increasing the ratio (dispersion degree) between the weight average molecular weight and the number average molecular weight of the methacrylic resin used as the raw material is also useful for lowering the melt viscosity. The weight average molecule is preferably at least 2.1 times the number average molecular weight, more preferably at least 2.5 times. If it is less than the above value, the resulting imide resin may have a high melt viscosity, and may cause poor kneading during molding.

[0070] The glass transition temperature of the imide resin of the present invention is preferably 100 ° C or higher, more preferably 110 ° C or lower. More preferably, it is more preferably 120 ° C. or more. If the glass transition temperature is lower than SlOO ° C, the application range is limited in applications requiring heat resistance.

[0071] If necessary, other thermoplastic resins can be added to the imide resin of the present invention.

 [0072] The imide resin of the present invention has properties such as high tensile strength and bending strength, solvent resistance, thermal stability, good optical properties, and weather resistance.

 [0073] The imide resin of the present invention can be produced by various known methods. For example, as described in US Pat. No. 4,246,374, in the absence of a solvent, an extruder is used to melt a molten acrylic resin ((meth) acrylate-aromatic vinyl copolymer). An imide resin can be obtained by adding a polymer imidizing agent. Further, for example, as described in Japanese Patent No. 2505970, an acrylic resin (such as a (meth) acrylic acid ester-aromatic vinyl copolymer) can be dissolved in the presence of a solvent to prevent the imidani reaction. It can also be obtained by adding an imidizing agent to a solution-based acrylic resin (such as a (meth) acrylate-aromatic vinyl copolymer) using a non-reactive solvent.

 [0074] The acrylic resin used in the present invention is not particularly limited as long as it can react with an imidizing agent and become a darthalimide unit. For example, methyl (meth) acrylate, ethyl (meth) acrylate, (Meth) acrylates such as butyl (meth) acrylate, (meth) acrylic acid such as acrylic acid and methacrylic acid, maleic acid, itaconic acid, crotonic acid, fumaric acid, α, β ethylenic acid such as citraconic acid Acid anhydrides such as unsaturated carboxylic acids and maleic anhydride, or half esters of these with straight-chain or branched alcohols having 1 to 20 carbon atoms, etc., can be imidized. Or a copolymer composed of other copolymer components. Among them, polymethyl methacrylate cost, physical properties and the like are also preferable.

 When the imide resin of the present invention is produced in the absence of a solvent, an extruder may be used, or a batch-type reaction vessel (pressure vessel) may be used!

When using an extruder for producing the imide resin of the present invention, various types of extruders such as a single-screw extruder, a twin-screw extruder and a multi-screw extruder can be used. A twin-screw extruder is preferred as an extruder capable of promoting the mixing of the imidizing agent with the polymer. Biaxial Extruders include non-mating, co-rotating, mating, co-rotating, non-mating, counter-rotating, and mating, counter-rotating. Among the twin-screw extruders, the co-rotating and co-rotating type is preferable because high-speed rotation is possible and mixing of the imidizing agent with the raw material polymer can be promoted. These extruders may be used alone or connected in series. In addition, it is preferable to equip the extruder with a vent capable of reducing the pressure below atmospheric pressure in order to remove unreacted imidizing agent and by-products.

[0077] Instead of an extruder, a high-viscosity reaction device such as a horizontal twin-screw reaction device such as Sumitomo Heavy Industries Co., Ltd. Biporak or a vertical twin-screw stirring tank such as Super Blend is also preferable. Can be used appropriately.

 [0078] The batch type reaction vessel (pressure vessel) used for producing the imide resin of the present invention is particularly limited as long as it can heat and stir a solution in which the raw material polymer is dissolved and can add an imidizing agent. However, since the viscosity of the polymer solution may increase due to the progress of the reaction, those having good stirring efficiency are preferred. For example, a stirred tank max blend manufactured by Sumitomo Heavy Industries, Ltd. can be exemplified.

 [0079] When the imide resin of the present invention is produced in the presence of a solvent, the imide resin can dissolve the acryl resin. It can be obtained by adding a dashi.

 [0080] Examples of the non-reactive solvent for the imidization reaction include aliphatic alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, and isobutynol alcohol, benzene, toluene, xylene, benzene, and chlorotoluene. And ketones such as methylethylketone, tetrahydrofuran and dioxane, and ether compounds. These may be used alone or as a mixture of at least two types. Among them, toluene and a mixed solvent of toluene and methyl alcohol are preferred!

 [0081] The concentration of the acrylic resin with respect to the non-reactive solvent is small, and from the viewpoint of production cost, the preferred solid content concentration is 10 to 80%, particularly preferably 20 to 70%.

[0082] The imidizing agent used in the present invention is not particularly limited as long as it can imidize an acrylic resin. Examples thereof include methinoleamine, ethynoleamine, n-propynoleamine, and i-propynylamine. Amines containing aliphatic hydrocarbon groups such as luminamine, n-butylamine, i-butylamine, tert-butylamine, n-hexylamine, and aromatic hydrocarbon groups such as aromatic phosphorus, toluidine, and trichloroaline; An alicyclic hydrocarbon group-containing amine such as hexylamine is exemplified. Further, urea-based compounds which generate these amines by heating such as urea, 1,3-dimethylurea, 1,3-diethylurea, and 1,3-dipropylurea can also be used. Of these imidizing agents, methylamine is preferred in view of cost and physical properties.

 [0083] When imidizing an acrylic resin with an imidizing agent, the reaction temperature is set to 150 to 400 ° C in order to promote the imidizing and to suppress the decomposition and coloring of the resin due to excessive heat history. Perform within the range. It is preferably 180 to 320 ° C, and more preferably 200 to 280 ° C.

 [0084] When imidizing an acrylic resin with an imidizing agent, generally used catalysts, antioxidants, heat stabilizers, plasticizers, lubricants, ultraviolet absorbers, antistatic agents, coloring agents, An anti-shrinkage agent and the like may be added as long as the object of the present invention is not impaired.

[0085] In producing the imide resin of the present invention, a (meth) acrylate polymer such as a methyl methacrylate polymer having a melt viscosity of 7000 Poise or less at 260 ° C and 122 seconds- ¹ ; It is preferable to use a (meth) acrylate-aromatic vinyl copolymer such as methyl methacrylate-styrene copolymer in that the imide resin of the present invention can be easily produced.

[0086] In producing the imide resin of the present invention, first, a (meth) acrylate polymer or

 When a (meth) acrylic acid ester-aromatic vinyl copolymer is polymerized and then imidized to form, specifically, a raw material that gives a (meth) acrylic acid ester unit as a residue is not particularly limited. Although not required, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, benzyl (meth) ataly And cyclohexyl (meth) acrylate. Of these, methyl methacrylate is particularly preferred.

 [0087] It is further preferable that these copolymers are treated with a primary amine in the absence of a solvent to form the imide resin of the present invention.

In producing the imide resin of the present invention, first, a (meth) acrylate-aromatic vinyl copolymer such as a methyl methacrylate-styrene copolymer or a methyl methacrylate polymer (Meth) acrylic acid ester-aromatic vinyl copolymer, (meth) acrylic acid polymer which can be used when polymerizing (meth) acrylic acid ester polymer such as The coalesce may be a linear (linear) polymer as long as an imidization reaction is possible, or may be a block polymer, a core-shell polymer, a branched polymer, a ladder polymer, or a cross-linked polymer. The block polymer may be A-B type, A-B-C type, A-B-A type, or any other type of block polymer. The core shell polymer may have only one core and only one shell, or may have a multilayer structure.

 [0089] The imide resin of the present invention (which may be used alone or in a blend with another thermoplastic polymer) may be used in injection molding, melt extrusion film molding, inflation molding, blow molding, compression molding, spinning molding and the like. Various molded products can be produced by various plastic kamitsu methods. Alternatively, the imide resin of the present invention may be dissolved in a solvent such as methylene chloride or the like, and molded by a casting method or a spin coating method using a polymer solution obtained.

 [0090] At the time of molding, commonly used antioxidants, heat stabilizers, plasticizers, lubricants, ultraviolet absorbers, antistatic agents, coloring agents, anti-shrinkage agents, etc., impair the object of the present invention. It may be added in a range that is not within the range.

[0091] The molded article obtained from the imide resin of the present invention may be, for example, a camera, a VTR, an image field such as a photographic lens or finder for a projector, a filter, a prism, a Fresnel lens, a CD player, a DVD player, or an MD player. Lens field such as pick-up lens for optical discs, optical recording field for optical discs such as CD players, DVD players and MD players, light guide plate for liquid crystal, film for liquid crystal display such as polarizer protective film and retardation film, surface Information devices such as protective films, optical communication such as optical fins, optical switches, and optical connectors; vehicle fields such as automotive headlights, tail lamps, inner lenses, instrument covers, and sunroofs; and glasses, contact lenses, and endoscopes Environmental lenses, medical supplies that require sterilization Medical equipment field, road translucent plate, double-glazing lens, daylighting window and carport, lighting lens and lighting cover, building material sizing and other construction materials, microwave oven containers (tableware), home appliances It can be used for housings, toys, sunglasses, stationery, etc. [0092] The polarizer protective film of the present invention comprises the imide resin of the present invention, that is, the imide resin characterized by containing the repeating units represented by the following general formulas (1) and (2). It is characterized by that.

 [0093] [Formula 9]

(Where R and R each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ³ represents an alkyl group having 1 to 18 carbon atoms and a cycloalkyl having 3 to 12 carbon atoms. Group or aryl group having 6 to 10 carbon atoms.)

 [0095] [Formula 10]

(Wherein, R ⁴ and R ⁵ each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁶ represents an alkyl group having 1 to 18 carbon atoms and 3 to 12 carbon atoms. It represents a cycloalkyl group or an aryl group having 6 to 10 carbon atoms.)

The imide resin used in the polarizer protective film of the present invention may be any of the various forms described above as long as it is an imide resin of the present invention containing the repeating units represented by the general formulas (1) and (2). Those can be used, and it is a matter of course that the present invention is not particularly limited. For example, A repeating unit represented by the following general formula (3) may be contained in addition to the repeating units represented by the general formulas (1) and (2).

[0097] [Formula 11]

[0098] The polarizer protective film of the present invention is characterized by having small optical anisotropy. In some cases, the polarizer protective film is required to have not only small optical anisotropy in the thickness direction but also small optical anisotropy in the in-plane direction (length direction, width direction) of the film. In other words, the direction in which the in-plane refractive index becomes the maximum is the X axis, the direction perpendicular to the X axis is the Y axis, the thickness direction of the film is the Z axis, and the refractive indices in each axial direction are nx, ny, nz, and the film Is the thickness of d, the in-plane retardation Re = (nx—ny) X d and the thickness direction retardation Rth = | (nx + ny) / 2 -nz IX d (II represents the absolute value) It means that it is small. (In an ideal film that is perfectly optically isotropic in the three-dimensional direction, both the in-plane retardation Re and the thickness direction retardation Rth are 0.) o

 [0099] In the polarizer protective film of the present invention, the in-plane retardation of the film is preferably lOnm or less, and the thickness direction retardation is preferably 20 nm or less. The in-plane retardation of the film is more preferably 5 nm or less. The thickness direction retardation is more preferably lOnm or less. When the in-plane retardation of the film exceeds lOnm, or when a polarizer protective film with a thickness direction retardation of more than 20 nm is used as a polarizing plate, problems such as reduced contrast in liquid crystal display devices occur. There is.

 [0100] In order to obtain the polarizer protective film having a small optical anisotropy of the present invention, it is necessary to adjust the amount of each structural unit in the imide resin. The repeating unit power represented by the general formula (1) is preferably 1 to 10 mol% of the S imide resin, particularly preferably 1 to 5 mol%, and more preferably 3 to 4 mol%. Outside of this range, it is difficult to obtain a film having a small optical anisotropy.

[0101] The imide resin used in the polarizer protective film of the present invention preferably has a small photoelastic coefficient. Good. Photoelastic coefficient of the imide榭脂used in the present ^{invention, 20 X 10_ 12 m 2 /} N we are preferably less tool 10 X 10- ¹² m ² / and more preferably N or less tool 5 X more preferably not more than 10- ¹² m ² / N. If the absolute value of the photoelastic coefficient is larger than 20 X 10- ¹² m ² / N, the optical distortion is caused by stress, light leakage is likely to occur. This tendency is particularly remarkable under high temperature and high humidity environments.

[0102] The photoelastic coefficient is such that when an external force is applied to an isotropic solid to cause stress (AF), the solid temporarily exhibits optical anisotropy and exhibits birefringence (An). The ratio between the stress and the birefringence is called the photoelastic coefficient (c).

 c = An / AF

 Indicated by

 [0103] As a method of forming the imide resin into the form of the polarizer protective film of the present invention, any conventionally known method can be used. For example, a solution casting method, a melt extrusion method and the like can be mentioned. Any of them can be adopted. The solution casting method is suitable for producing a film having a good surface property with less deterioration of resin, and the melt molding method can obtain a film with high productivity. As a solvent for the solution casting method, methylene chloride or the like can be suitably used. Examples of the melt molding method include a melt extrusion method, an inflation method, and the like.

[0104] The thickness of the polarizer protective film of the present invention is preferably from 20 Pm to 300 Pm, and more preferably from 30 Pm to 200 Pm. More preferably, the force is from 50 μm to 100 μm. The thickness unevenness of the film is preferably 10% or less of the average thickness, more preferably 5% or less.

 [0105] The light transmittance of the polarizer protective film of the present invention is preferably 85% or more, more preferably 88% or more, and further preferably 90% or more. The turbidity of the film is preferably 2% or less, more preferably 1% or less, and further preferably 0.5% or less.

 [0106] In the present specification, for the sake of convenience of description, a film after the imide resin is formed into a film shape and before stretching is sometimes referred to as a "raw material film".

[0107] The raw material film can be directly used as a polarizer protective film without being stretched. In the production of the polarizer protective film of the present invention, after the film is formed by the above-described method, Preferably, a film having a predetermined thickness is produced by uniaxial stretching or biaxial stretching. Stretching further improves the mechanical properties of the film. To give an example of the embodiment,

After a raw material film having a thickness of 150 m is produced by such melt extrusion molding, a film having a thickness of 40 μm can be produced by biaxial stretching.

 [0108] Stretching of the film may be performed continuously immediately after forming the raw material film. Here, there is a case where the state of the “raw material film” exists only momentarily. In the case where the film exists only momentarily, the state from the moment the film is formed to the time it is stretched is called a raw material film. In addition, the raw material film does not need to be in a perfect film state if it is formed into a film enough to be stretched thereafter, and of course, has the performance as a finished film. You don't have to. If necessary, after forming the raw material film, the film may be stored or moved, and then the film may be stretched. As a method for stretching the raw material film, any conventionally known stretching method can be adopted. Specifically, there are, for example, longitudinal stretching using a roll or a hot blast stove, transverse stretching using a tenter, and sequential biaxial stretching in which these are sequentially combined. Further, a simultaneous biaxial stretching method in which the film is stretched simultaneously in the machine and transverse directions can also be employed. After the longitudinal stretching of the roll, a transverse stretching by a tenter may be adopted.

 [0109] The polarizer protective film of the present invention can be used as a final product in the state of a uniaxially stretched film. Furthermore, a biaxially stretched film may be formed by performing a stretching process in combination. In the case of biaxial stretching, if necessary, the film can maintain its mechanical anisotropy even if the stretching conditions such as the temperature and magnification for longitudinal stretching and transverse stretching are the same. May be given.

[0110] The stretching temperature and the stretching ratio of the film can be appropriately adjusted using the mechanical strength, surface properties, and thickness accuracy of the obtained film as indices. The range of the stretching temperature is preferably (Tg−30 ° C.) to (Tg + 30 ° C.), where Tg is the glass transition temperature of the film determined by the DSC method. More preferably, it is in the range of (Tg-20 ° C) to (Tg + 20 ° C). More preferably, it is in the range of (in Tg) to (Tg + 20 ° C.). If the stretching temperature is too high, the thickness unevenness of the obtained film tends to increase, and the mechanical properties such as elongation, tear propagation strength, and fatigue resistance to massaging tend to be insufficient. Also, if the film is low The problem of sticking to the file is likely to occur. Conversely, if the stretching temperature is too low, the turbidity of the stretched film increases, and in extreme cases, problems such as tearing and breaking of the film are likely to occur. The preferred stretching ratio depends on the stretching temperature, but is selected in the range of 1.1 to 3 times. More preferably, it is 1.3 to 2.5 times. More preferably, it is 1.5 to 2.3 times.

[0111] Further, at the time of film formation, a processability improver such as a heat stabilizer, an ultraviolet absorber, a lubricant, or a known additive such as a filler, or another polymer is contained as necessary. It doesn't matter. In particular, a filler may be included for the purpose of improving the slipperiness of the film. As the filler, inorganic or organic fine particles can be used. Examples of the inorganic fine particles include metal oxide fine particles such as silicon dioxide, titanium dioxide, aluminum oxide and zirconium oxide, calcined calcium silicate, calcium silicate hydrate, aluminum silicate, magnesium silicate and the like. Fine particles of silicate, calcium carbonate, talc, clay, calcined phosphorus, calcium phosphate and the like can be used. As the organic fine particles, fine resin particles such as a silicon resin, a fluorine resin, an acrylic resin, and a crosslinked styrene resin can be used.

 [0112] By adding an ultraviolet absorber to the polarizer protective film of the present invention, the weather resistance of the polarizer protective film of the present invention is improved, and the durability of a liquid crystal display device using the polarizer protective film of the present invention is improved. It is also practically preferable because the property can be improved. Examples of UV absorbers include benzotriazole UV absorbers such as 2- (2H-benzotriazono-1-yne) p-creso-nore, 2-benzotriazono-2-yl-4,6-di-t-butylphenol , 2- (4,6-diphenyl-1,3,5-triazine-2-yl) -5-[(hexyl) oxy] -triol UV absorber such as phenol, octabenzone Examples include benzophenone ultraviolet absorbers, and benzoate light stabilizers such as 2,4-di-tert-butylphenyl 3,5 di-tert-butyl-4-hydroxybenzoate and bis (2,2,6,6- Light stabilizers such as hindered amine light stabilizers such as tetramethyl-4-piperidyl) sebacate can also be used.

[0113] The polarizer protective film of the present invention can be subjected to a surface treatment, if necessary, to improve the adhesion to other materials. As a method of surface treatment, any conventionally known arbitrary A method is possible. For example, electrical treatment such as corona discharge treatment or spark treatment, plasma treatment at low or normal pressure, ultraviolet irradiation treatment in the presence or absence of ozone, acid treatment with chromic acid, etc., alkali saponification treatment, and flame treatment Treatment, and silane-based primer treatment or titanium-based primer treatment. By these methods, the surface tension of the film surface can be increased to 50dyneZcm or more.

[0114] In order to improve the affinity with an adhesive or a pressure-sensitive adhesive, an easy-adhesion layer can be provided on one side or both sides of the film. Preferred adhesive layers include copolymerized polyesters, urethane-modified polyesters thereof, copolymerized polyesters having a carboxyl group and a sulfonic acid group, and a solution or aqueous dispersion of polyvinyl alcohol or the like. Cloth dried layers can be used. Alternatively, a method in which a cellulose ester resin or the like is provided as an easy-adhesion layer and this is subjected to an alkali saponification treatment to improve the affinity can be used.

 [0115] The polarizer protective film of the present invention can be subjected to a coating treatment such as a hard coat, an anti-glare coat, an anti-reflection coat, and other functional coats, if necessary.

 Example

 [0116] The present invention will be described in more detail based on examples, but the present invention is not limited to these examples. In addition, each measuring method of the physical property measured in the following Examples and Comparative Examples is as follows.

 [0117] (1) Determination of imidation ratio by infrared spectrophotometer (IR)

Using the product pellet as it was, the IR spectrum was measured at room temperature using TravellR manufactured by SensIR Technologies. From the obtained spectrum, esters carbonitrile of 1720 cm ¹ - the absorption intensity assignable to Le group (Abs), the 1660 cm ¹ Imidokarubo - Le group

 ester

 From the ratio of the assigned absorption intensities (Abs), the imidani ratio (Im% (IR))

 lmiae

 I asked.

[0118] [Number 1] Im% (IR) = —— ^imide x 100

Abs _esier + Abs _imide

[0119] (2) — Determination of imidation ratio by NMR

 The product lOmg obtained using methylamine was dissolved in CDC1 lg, and Varian N

 Three

¹ H-NMR was measured at room temperature using an MR measurement device Gemini-300. From the obtained vector, the integrated intensity (CH) attributed to the methyl group in the methyl ester portion and N—

 3 (, ester) From the ratio of the integrated intensity (CH) attributed to the methyl group of the methylimide ring structure,

 3 (inude)

 According to 2, the imidani ratio (Im% (NMR)) was determined.

[0120] [Number 2]

Im% (NMR) = —— ^CH ^ → —— χ 100

H _este + H ₃ ( _imide )

[0121] Note that Im% (NMR) has not been determined for the product obtained using an amine other than methylamine, because it is difficult to make an assignment.

[0122] (3) Content of Daltarimide Unit (Im%)

With respect to the resin for which the imidation ratio by ¹ H-NMR was determined, this value was taken as the glutarimide unit content (Im%). — For the resin for which the imidation ratio was not determined by NMR, the correlation between Im% (IR) and Im% (NMR) measured for the product obtained using methylamine was determined, and the im% (IR) was determined. The value obtained by converting the measured force of the above was taken as the content (Im%) of dartalimide units.

[0123] (4) Glass transition temperature (Tg)

 Using the product lOmg, a differential scanning calorimeter (DSC, Shimadzu DSC-

(Model 50) under a nitrogen atmosphere at a heating rate of 20 ° CZmin and determined by the midpoint method.

 [0124] (5) Melt viscosity of resin

Using 40 g of fat, a capillagraph manufactured by Toyo Seiki Seisakusho and a diameter of lmm, length of 10 mm The melt viscosity at a shear rate of 122 seconds- ¹ and a temperature of 260 ° C was measured in accordance with JIS K7199 using a capillary.

 (6) Total light transmittance

 A test piece having a size of 50 mm × 50 mm was cut out from the film. Using a turbidimeter NDH 300A manufactured by Nippon Denshoku Industries Co., Ltd., at a temperature of 23 ° C ± 2 ° C and a humidity of 50% ± 5%, according to the method described in 5.5 of JIS K7105-1981. It was measured.

 [7] Turbidity (haze)

 Measure the test piece obtained in (8) using a turbidimeter NDH 300A manufactured by Nippon Denshoku Industries Co., Ltd. at a temperature of 23 ° C ± 2 ° C and a humidity of 50% ± 5% according to JIS K7136. did.

 (9) Orientation birefringence

 A sample having a width of 50 mm and a length of 150 mm was cut out from the film, and a uniaxially stretched film was prepared at a draw ratio of 2 and a temperature 5 ° C higher than the glass transition temperature. A 35 mm x 35 mm test piece was cut out from the center of the uniaxially stretched film in the TD direction. The temperature of the test piece was 23 ± 2 using an automatic birefringence meter (KOBRA-WR manufactured by Oji Scientific Instruments). At C and a humidity of 50 ± 5%, the phase difference was measured at a wavelength of 590 nm and an incident angle of 0 °. The value obtained by dividing the phase difference by the thickness of the test piece measured using a digimatic indicator (manufactured by Mitutoyo Corporation) was defined as the orientation birefringence.

 (10) In-plane retardation Re and thickness direction retardation Rth

 A 40 mm × 40 mm test piece was cut from the film. Using an automatic birefringence meter (KOBRA-WR manufactured by Oji Keisoku Co., Ltd.), the test piece was measured at a temperature of 23 ± 2 ° C and a humidity of 50 ± 5% at a wavelength of 590 nm and an incident angle of 0 °, and the in-plane phase difference Re was measured. Was measured. The thickness d of the test piece measured using a Digimatic Indicator (Mitutoyo Co., Ltd.), the refractive index n measured with an Abbe refractometer (3T manufactured by Atago Co., Ltd.), and the wavelength 590 nm measured with an automatic birefringence meter The three-dimensional refractive index nx, ny, nz is obtained from the in-plane retardation Re and the retardation value in the 40 ° tilt direction, and the thickness direction retardation Rth = | (nx + ny) / 2-nz | X d (| | Represents an absolute value).

 (11) Photoelastic coefficient

From the film, cut out a test piece into a strip of 15mm width x 60mm length and automatically birefringent Measurement was performed at a wavelength of 590 nm at a temperature of 23 ± 2 and a humidity of 50 ± 5% using a total meter (KOBRA-WR manufactured by Oji Keisoku Co., Ltd.). The birefringence was measured while one of the films was fixed and the other was loaded sequentially from no load to 1 OOOgf for each 100gf, and the amount of change in birefringence due to unit stress was calculated from the obtained results.

(12) Uneven film thickness

 A sample having a length of 300 mm in the TD direction and a length of 50 mm in the MD direction was cut out from the film, and the thickness of the entire width in the TD direction was measured using an Anritsu contact type continuous thickness gauge KB601B. From the measured thickness, the following formula was used to determine the thickness unevenness with respect to the target film thickness of 150 m.

 (Thickness unevenness) = I Maximum thickness Minimum thickness I / 2

 (13) Film appearance inspection

 Two samples of 500 mm length in the TD direction and 500 mm length in the MD direction are cut out from the film, and the light of a desk stand (SQ948H made by National, fluorescent lamp 27W) is illuminated in a dark room. The presence or absence of fish eyes was visually evaluated.

(14) ASTM No. 1 dumbbell test piece appearance inspection

 The surface of 10 dumbbell specimens was visually observed, and the flow marks, fish eyes, and the presence or absence of foaming were evaluated.

[0132] (Resin Production Example 1)

Using a methacrylic resin (SUMIPEX MH, manufactured by Sumitomo Danigaku Co., Ltd.) and monomethylamine (manufactured by Mitsubishi Gas Chemical Co., Ltd.) as an imidizing agent, an imidio dani resin was produced. The extruder used was a twin-screw twin-screw extruder with a diameter of 15 mm. Set the temperature of each temperature control zone of the extruder to 230 ° C, screw rotation speed 150rpm, supply methacrylic resin at 1.Okg / hr, and supply monomethylamine to methacrylic resin. 3 parts by weight. A hot methacrylic resin was also added, and the resin was melted and filled with a kneading block, and then monomethylamine was injected with a nozzle cap. A sealing ring was placed at the end of the reaction zone and filled with resin. The by-products after the reaction and excess methylamine were devolatilized by reducing the pressure of the reactor to 1.0 MPa. The resin that emerged as a strand from the die provided at the extruder outlet was cooled in a water tank and then pelletized with a pelletizer. (Resin Production Example 2)

 Except that the methacrylic resin was changed to Atfina HT121 made by Atofina, the same procedure was followed as in Resin Production Example 1.

(Resin Production Example 3)

 Except that the methacrylic resin was Ataripet VH manufactured by Mitsubishi Rayon Co., Ltd., the supply amount of the resin was 2 kgZhr, n-butylamine was used instead of monomethylamine, and the supply amount was 20 parts by weight. Performed in the same manner as in Production Example 1.

[0135] (Resin Production Example 4)

 The methacrylic resin is Ataripet VH manufactured by Mitsubishi Rayon Co., Ltd., the supply amount of the resin is 2 kgZhr, and c-hexylamine (manufactured by Koei Chemical Co., Ltd.) is used instead of monomethylamine. The same procedure was performed as in Resin Production Example 1 except that the amount was changed to parts by weight.

[0136] (Resin manufacturing example 5)

 Dissolve 100 parts by weight of methacrylic resin (SUMIPEX LG, manufactured by Sumitomo Iridaku Co., Ltd.) in 100 parts by weight of toluene and 10 parts by weight of Z-methyl alcohol using TEM-VIOOON (200 mL pressure vessel) manufactured by Pressure-Resistant Glass Industry Co., Ltd. I let it. The reaction vessel was immersed in a mixed solution of dry ice and methanol, and after cooling, 5 parts by weight of monomethylamine was added, followed by a reaction at 230 ° C for 2.5 hours. After allowing to cool, the reaction mixture was dissolved in methylene chloride, and precipitated with methanol to recover the product.

[0137] (Resin Production Example 6)

 The same procedure as in Resin Production Example 1 was carried out except that the supply amount of the resin was 1 kgZhr and the supply amount of monomethylamine was 10 parts by weight.

(Resin Production Example 7)

 The procedure was the same as in Resin Production Example 3, except that the supply amount of the resin was 1.5 kgZhr and the supply amount of n-butylamine was 45 parts by weight.

[0139] Table 1 shows the imidization ratio, the content of dartalimide units, and the glass transition temperature of the imide resins obtained in Resin Production Examples 1 to 7.

[0140] (Example 1)

The imide resin obtained in Resin Production Example 1 was dissolved in methylene chloride (resin concentration 25 wt%), It was applied on a PET film and dried to form a cast film. From this film, a sample having a width of 50 mm and a length of 150 mm was cut out, and a uniaxially stretched film was prepared at a stretching ratio of 2 and at a temperature higher by 5 ° C than the glass transition temperature. Table 2 shows the total light transmittance, turbidity, orientation birefringence, in-plane retardation, and retardation in the thickness direction of the uniaxially stretched film. The measured photoelastic coefficient of the uniaxial axis oriented film was 3 X 10- ¹² m ² ZN.

[0141] [Table 1]

[0142] [Table 2]

(Example 2)

A cast film prepared using the same imide resin as in Example 1 was stretched by a factor of 2 (vertical and horizontal) and simultaneously biaxially stretched at a temperature 20 ° C higher than the glass transition temperature (biaxial stretching manufactured by Toyo Seiki Co., Ltd.). The device X4HD) was used to prepare a biaxially stretched film. The whole of this biaxially stretched film Table 2 shows the light transmittance, turbidity, in-plane retardation, and retardation in the thickness direction.

(Example 3)

 Total light transmittance, turbidity, orientation birefringence, in-plane retardation, thickness retardation of a uniaxially stretched film prepared in the same manner as in Example 1 using the imide resin obtained in Resin Production Example 2. Are shown in Table 2.

(Example 4)

 Table 2 shows the total light transmittance, turbidity, in-plane retardation, and retardation in the thickness direction of the biaxially stretched film prepared in the same manner as in Example 2 using the imide resin obtained in Resin Production Example 2. Shown in

(Example 5)

 Total light transmittance, turbidity, orientation birefringence, in-plane retardation, thickness retardation of a uniaxially stretched film prepared in the same manner as in Example 1 using the imide resin obtained in Resin Production Example 3. Are shown in Table 2.

(Example 6)

 Total light transmittance, turbidity, orientation birefringence, in-plane retardation, thickness retardation of a uniaxially stretched film prepared in the same manner as in Example 1 using the imide resin obtained in Resin Production Example 4. Are shown in Table 2.

(Example 7)

 Total light transmittance, turbidity, orientation birefringence, in-plane retardation, thickness retardation of a uniaxially stretched film prepared in the same manner as in Example 1 using the imide resin obtained in Resin Production Example 5 Are shown in Table 2.

(Comparative Example 1)

Table 2 shows the total light transmittance, turbidity, in-plane retardation, and thickness direction retardation of a triacetyl cellulose (TAC) film manufactured by Fuji Photo Film Co., Ltd. Measurement of the photoelastic coefficient of the film was 15 X 10- ¹² m ² ZN.

[0150] (Comparative Example 2)

The glass transition temperature of Sumipex MH used in Resin Production Example 1 was 118 ° C. Table 2 shows the total light transmittance, turbidity, orientation birefringence, in-plane retardation, and retardation in the thickness direction of a uniaxially stretched film prepared using the resin in the same manner as in Example 1. [0151] (Comparative Example 3)

 The glass transition temperature of Atgrass HT121 used in Resin Preparation Example 2 was 128 ° C. Table 2 shows the total light transmittance, turbidity, orientation birefringence, in-plane retardation, and retardation in the thickness direction of a uniaxially stretched film prepared by using this resin in the same manner as in Example 1.

 [0152] (Comparative Example 4)

 Table 1 shows the imidization ratio and glass transition temperature of the imidation dandelion obtained in Resin Production Example 6. Table 2 shows the total light transmittance, turbidity, orientation birefringence, in-plane retardation, and retardation in the thickness direction of the uniaxially stretched film prepared in the same manner as in Example 1 using this resin.

 (Comparative Example 5)

 Table 1 shows the imidation ratio and glass transition temperature of the imidation dandelion obtained in Resin Production Example 7. Table 2 shows the total light transmittance, turbidity, orientation birefringence, in-plane retardation, and retardation in the thickness direction of the uniaxially stretched film prepared in the same manner as in Example 1 using this resin.

 As described above, the imide resin of the present invention has good heat resistance and transparency, and is useful as a polarizer protective film with small optical anisotropy.

 Next, an example of production using a (meth) acrylic acid ester-aromatic butyl copolymer will be described.

 [0156] (Resin Production Example 8)

Using a polymethylstyrene methacrylate copolymer having a melt viscosity of 5100 Poise at 260 ° C. and 122 sec- ^{1 and} monomethylamine as an imidizing agent, an imido ligand was produced. The extruder used was a twin-screw twin-screw extruder with a diameter of 15 mm. Set the temperature of each temperature control zone of the extruder at 230 ° C, screw rotation speed 300 rpm, supply polymethyl methacrylate-styrene copolymer at lkgZhr, and supply monomethylamine with polymethyl methacrylate-styrene. It was 30 parts by weight based on the polymer. At this time, the hopper cap was also charged with a polymethyl methacrylate-styrene copolymer, and the resin was melted and filled with a kneading block, followed by injection of monomethylamine with a nozzle force. A seal ring and a reverse flight were placed at the end of the reaction zone to fill the resin. The by-product after the reaction and excess methylamine were devolatilized by reducing the pressure at the vent port to 0.02 MPa. The resin that came out as a strand from the die provided at the extruder outlet was cooled in a water tank, And pelletized with a pelletizer.

[0157] (Resin manufacturing example 9)

Resin Production Example 8 except that the resin used was a polymethyl methacrylate-styrene copolymer having a melt viscosity of 4300 Poise at 260 ° C and 122 sec- ¹ and a monomethylamine supply of 20 parts by weight. The same procedure was followed.

[0158] (Resin Production Example 10)

The procedure was the same as in Resin Production Example 8 except that the resin used was a polymethyl methacrylate-styrene copolymer having a melt viscosity of 8200 Poise at 260 ° C. and 122 seconds- ¹ .

[0159] (Resin manufacturing example 11)

The procedure was performed in the same manner as in Resin Production Example 8 except that the resin used was a polymethyl methacrylate-styrene copolymer having a melt viscosity of 10500 Poise at 260 ° C. and 122 seconds- ¹ .

[0160] Table 3 shows the melt viscosity, imidation ratio, and glass transition temperature of the imide resins obtained in Resin Production Examples 8 to 11.

[0161] [Table 3]

(Example 8)

After drying imido-dani resin obtained in Resin Production Example 8 at 100 ° C for 5 hours, it was discharged at a cylinder and T-die temperature of 250 ° C using a 40mm φ single screw extruder and a 400mm width T-die. 20k Extruded with gZhr, the molten resin in sheet form is cooled with a cooling drum and the width is about 600 mm and the thickness is about

A 150 ^ m film was obtained.

(Example 9)

 A film having a thickness of about 150 m was obtained in the same manner as in Example 8, except that the imido-dani resin obtained in Resin Production Example 9 was used.

(Example 10)

 After drying the imidized resin obtained in Resin Production Example 8 at 100 ° C for 5 hours, the cylinder temperature was 250 ° C and the mold temperature was 50 using an injection molding machine (clamping pressure: 80 tons). An ASTM No. 1 dumbbell specimen having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was obtained at ° C.

(Example 11)

 An ASTM No. 1 dumbbell test piece having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was prepared in the same manner as in Example 10 except that the imido danji resin obtained in Resin Production Example 9 was used. Obtained.

Table 4 shows the total light transmittance, turbidity, thickness unevenness, and results of the appearance inspection of the films obtained in Examples 8 and 9, and the results of the appearance inspection of the dumbbells obtained in Examples 10 and 11. Shown in

[0167] [Table 4]

Imido resin Molded product Total light transmittance Turbidity Film thickness Fi / rem

 (%) (%) Unevenness (μπι) Appearance Inspection Appearance Inspection Example 8 Example of Resin Production Film 92.1 0.

 8

 Example 9 Resin production example Film 92.2 0.4.1.2 No defect

 9

Example 10 Resin production example Dumbbell No defect

 8

Example 11 Resin production example Dampenhole No defect

9

[0168] (Comparative Example 6)

 A film having a thickness of about 150 μm was obtained in the same manner as in Example 8, except that the imido-dani resin obtained in Resin Production Example 10 was used.

[0169] (Comparative Example 7)

 Resin production Example 10 was used, except that the resin was extruded at 280 ° C. using a 40 mm φ single screw extruder and a 400 mm width T-die, using the imido dani resin obtained in Example 10, except for a thickness of about 150 mm. m of film was obtained.

 (Comparative Example 8)

 A film having a thickness of about 150 μm was obtained in the same manner as in Example 8, except that the imido-dani resin obtained in Resin Production Example 11 was used.

[0171] (Comparative Example 9)

 The same procedure as in Example 8 was carried out except that the imidy dandelion resin obtained in Resin Production Example 11 was extruded at 280 ° C using a 40 mm φ single screw extruder and a 400 mm width T die, and a thickness of about 150 mm was used. m of film was obtained.

 [0172] (Comparative Example 10)

 An ASTM No. 1 dumbbell test piece having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was prepared in the same manner as in Example 10 except that the imido danji resin obtained in Resin Production Example 10 was used. Obtained.

[0173] (Comparative Example 11)

 A resin having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was produced in the same manner as in Example 10 except that the cylinder temperature was changed to 270 ° C. using the imido-dani resin obtained in Resin Production Example 10. An ASTM No. 1 dumbbell specimen was obtained.

(Comparative Example 12)

 A 3.2 mm thick (127 mm long, 12.7 mm wide) ASTM No. 1 dumbbell test piece was prepared in the same manner as in Example 10 except that the imido dani resin obtained in Resin Production Example 11 was used. Obtained.

(Comparative Example 13)

A resin having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was produced in the same manner as in Example 10 except that the cylinder temperature was changed to 270 ° C. using the imido-dani resin obtained in Resin Production Example 11. An ASTM No. 1 dumbbell specimen was obtained. Table 5 shows the results of the total light transmittance, turbidity, thickness unevenness, and results of the appearance inspection of the films obtained in Comparative Examples 6 to 9, and the results of the appearance inspection of the dumbbells obtained in Comparative Examples 10 to 13. Shown in

[0177] [Table 5]

Imido resin product Total light transmittance Turbidity Film thickness Film dumbbell

 (%) (%) Unevenness (wm) Appearance Inspection Appearance Inspection Comparative Example 6 Resin Production Example Finolem 92.10.3.

 10 Fish-yes Comparative example 7 Resin production example Film 92. 2 0.4.

 10 with foam

 Comparative Example 8 Resin Production Example Film 92.1 0.3.

 11 With fisheye Comparative example 9 Resin production example Film 92.2 0.4.2.7 With die line

 11 with foam

Comparative example 10 Resin production example Dambenore fish

 Ten

Comparative Example 11 Example of resin production

 Ten

Comparative Example 12 Resin Production Example Dumbbell With flow mark,

 11 Fits comparative example 13 Resin production example Dambenore Foaming

11

Next, an example of production using a (meth) acrylate polymer will be described.

 [0179] (Resin Production Example 12)

Using a (meth) acrylate resin having a melt viscosity of 4200 Poise at 260 ° C. and 122 sec- ¹ for 4200 Poise, and using monomethylamine as an imidizing agent, imido dani resin was produced. The extruder used was a twin-screw twin-screw extruder with a diameter of 15 mm. The set temperature of each temperature control zone of the extruder is 230 ° C, screw rotation speed is 300 rpm, (meth) acrylate resin is supplied at lkgZhr, and the supply amount of monomethylamine is (meth) acrylate ester. It was 40 parts by weight based on the resin. At this time, (meth) acrylate resin was injected from a hopper, and the resin was melted and filled with a kneading block, and then monomethylamine was injected from a nozzle cap. At the end of the reaction zone, a seal ring and a reverse flight were placed to fill the resin. The by-products after the reaction and excess methylamine were devolatilized by reducing the pressure at the vent port to 1.0 MPa. The resin that emerged as a strand from the die provided at the extruder outlet was cooled in a water bath and then pelletized with a pelletizer.

 [0180] (Resin manufacturing example 13)

Resin production example 12 except that the resin used was a (meth) acrylate ester resin having a melt viscosity of 7100 Poise at 260 ° C and 122 seconds- ¹ and the supply of monomethylamine was 20 parts by weight. Performed similarly.

 [0181] (Resin manufacturing example 14)

A resin production example 12 was used except that the resin used was a (meth) acrylate resin having a melt viscosity of 8500 Poise at 260 ° C and 122 seconds- ¹ and a monomethylamine supply of 30 parts by weight. Performed similarly.

 [0182] (Resin manufacturing example 15)

Resin production example 12 except that the resin used was a (meth) acrylate ester resin with a melt viscosity of lOPoOOise at 260 ° C for 122 seconds- ¹ and the supply amount of monomethylamine was 20 parts by weight. The same procedure was followed.

 [0183] Table 6 shows the melt viscosity, imidation ratio, and glass transition temperature of the imide resins obtained in Production Examples 12 to 15.

[0184] [Table 6] 0) O oo

 Molten melt rate Fat feedstock Resin gas transfer degree Desolated irami oil temperature Admisun i 〇

 〇 o o

 〇

 Melting viscosity 〇 〇

 00 o

 t-g

 Tree manufacturing fat example 21

 Fat manufacturing tree 13

 Resin production example 14

 CD <Production resin example 15

00

 cr-

ID

〇 〇 〇

 44 inches

o o

 w O 〇 〇

 〇 〇 〇 o

 t

 o LTD

 oo o

(Example 12)

The imidani resin obtained in Resin Production Example 12 was dried at 100 ° C for 5 hours, and then discharged at a cylinder and T-die temperature of 250 ° C using a 40mm φ single screw extruder and a 400mm width T-die. The resin was extruded at kgZhr, and the sheet-shaped molten resin was cooled by a cooling drum to obtain a film having a width of about 600 mm and a thickness of about 150 m.

(Example 13)

 A film having a thickness of about 150 μm was obtained in the same manner as in Example 12, except that the imido-dani resin obtained in Resin Production Example 13 was used.

(Example 14)

 After drying the imido dani resin obtained in Resin Production Example 12 at 100 ° C for 5 hours, using an injection molding machine (clamping pressure: 80 tons), the cylinder temperature was 250 ° C and the mold temperature was 50 ° C. An ASTM No. 1 dumbbell specimen having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was obtained at ° C.

(Example 15)

 ASTM No. 1 dumbbell test piece having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was prepared in the same manner as in Example 14 except for using the imido dani resin obtained in Resin Production Example 13. Obtained.

[0189] Table 7 shows the total light transmittance, turbidity, thickness unevenness, and the results of the appearance inspection of the films obtained in Examples 12 and 13, and the results of the appearance inspection of the dumbbells obtained in Examples 14 and 15. Show.

[0190] [Table 7]

Imido resin Molded product Total light transmittance Turbidity Film thickness Finolene tumble

 (%) (%) Unevenness, m) Appearance inspection Appearance inspection Example 1 2 Resin production example Film 92, 1 0.3. 1.6 No defect

 1 2

Example 13 Resin Production Example Film 92.2.0.2.1.2 No defects

 13

Example 14 Resin production example No damage

 12

Example 15 Resin production example Gunbenore No defect

13

[0191] (Comparative Example 14)

 A film having a thickness of about 150 μm was obtained in the same manner as in Example 12, except that the imido-dani resin obtained in Resin Production Example 14 was used.

[0192] (Comparative Example 15)

 Using the imido tan resin obtained in Resin Production Example 14 and extruding at 280 ° C using a 40 mm φ single screw extruder and a 400 mm wide T-die, a thickness of about 150 m of film was obtained.

 [0193] (Comparative Example 16)

 A film having a thickness of about 150 μm was obtained in the same manner as in Example 12, except that the imido dani resin obtained in Resin Production Example 15 was used.

(Comparative Example 17)

 Resin Production Example 15 The thickness of about 150 was obtained in the same manner as in Example 12, except that the resin was extruded at 280 ° C. using a 40 mm φ single screw extruder and a 400 mm width T-die, using the imido dani resin obtained in Resin 15. m of film was obtained.

 (Comparative Example 18)

 A ASTM No. 1 dumbbell test piece having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was prepared in the same manner as in Example 14 except that the imido dani resin obtained in Resin Production Example 14 was used. Obtained.

[0196] (Comparative Example 19)

 A resin having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was prepared in the same manner as in Example 14 except that the imidy resin obtained in Resin Production Example 14 was used and the cylinder temperature was changed to 270 ° C. An ASTM No. 1 dumbbell specimen was obtained.

(Comparative Example 20)

 A ASTM No. 1 dumbbell test piece having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was prepared in the same manner as in Example 14 except that the imido danji resin obtained in Resin Production Example 15 was used. Obtained.

(Comparative Example 21)

A resin having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was prepared in the same manner as in Example 14 except that the cylinder temperature was changed to 270 ° C. using the imido-dani resin obtained in Resin Production Example 15. An ASTM No. 1 dumbbell specimen was obtained. [0199] Table 8 shows the total light transmittance, turbidity, thickness unevenness, and results of the appearance inspection of the films obtained in Comparative Examples 14 to 17, and the results of the appearance inspection of the dumbbells obtained in Comparative Examples 18 to 21. Show.

[0200] [Table 8]

Imido Resin Molded Product Total Light Transmittance Turbidity Fi / REM Thickness

 (%) (%) Unevenness (μm) Appearance inspection Appearance inspection Comparative example 14 Resin production example Film 92.10.3.

 14 Fish-A Yuichi Comparative Example 15 Resin production example Finnolem 92.2 0.3.1.4 Die line available

 14 with foam

Comparative Example 16 Resin Production Example Film 92.1 0.4.

 15 Fish-yes Comparative example 17 Resin production example Film 92.2 0.32 Die-line available

 15 with foam

Comparative Example 18 Example of resin production

 14

Comparative Example 19 Resin Production Example

 14

Comparative Example 20 Example of resin production

 15 ― with bush comparative example 21 resin production example

15

As described above, all of the imide resins of the present invention have good heat resistance and transparency, and also have good workability and are useful as polarizer protective films.

Claims

The scope of the claims

 [1] An imide resin comprising a repeating unit represented by the following general formulas (1) and (2).

 [Formula 12]

(Where R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ³ represents an alkyl group having 1 to 18 carbon atoms and a cycloalkyl group having 3 to 12 carbon atoms. Or an aryl group having 6 to 10 carbon atoms.)

 [Formula 13]

(Where R ⁴ and R ⁵ each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁶ represents hydrogen or an alkyl group having 1 to 18 carbon atoms, and a cycloalkyl having 3 to 12 carbon atoms. Represents a aryl group or an aryl group having 6 to 10 carbon atoms.)

[2] The imide resin according to claim 1, wherein the orientation birefringence is 0.0001 or less.

[3] The imide resin according to claim 1, wherein the orientation birefringence is 0.00001 or less.

[4] The melt viscosity at 260 ° C and 122 seconds- ¹ is 14000 Poise or less. The imide resin according to claim 1.

[5] The imide resin according to claim 4, further comprising a repeating unit represented by the general formula (3).

 [Formula 14]

(Here, R ⁷ represents hydrogen or an alkyl group having 1 to 8 carbon atoms, and R. represents an aryl group having 6 to 10 carbon atoms.)

 6. The imide resin according to claim 4, wherein the imide resin is produced using a (meth) acrylate polymer.

 [7] The imide resin according to claim 6, wherein the (meth) acrylate polymer is a methyl methacrylate polymer.

[8] The imide resin according to claim 5, produced using a (meth) acrylic ester-aromatic vinyl copolymer.

[9] The imide resin according to claim 8, wherein the (meth) acrylate-aromatic vinyl copolymer is a methyl methacrylate-styrene copolymer.

[10] The melt viscosity of the (meth) acrylate polymer at 260 ° C and 122 seconds- ¹ is 70.

7. The imide resin according to claim 6, which is not more than OOPoise.

11. The imide resin according to claim 8, wherein the melt viscosity of the (meth) acrylate-aromatic vinyl copolymer at 260 ° C. and 122 seconds- ¹ is 7000 Poise or less. .

[12] The imide resin according to any one of claims 1 to 11, wherein the imide resin is produced by treating an acrylic resin with a primary amine in the absence of a solvent.

[13] The imide resin according to any one of claims 1 to 11, wherein the imide resin is produced by treating an acrylic resin with a primary amine in the presence of a solvent.

[14] The imide resin according to claim 1, wherein the glass transition temperature is 110 ° C or higher.

[15] The method according to claim 1, wherein the (meth) acrylate polymer or the (meth) acrylate aromatic vinyl copolymer is treated with a primary amine in the absence of a solvent. 2. The method for producing the imide resin according to claim 1.

 [16] An optical resin composition comprising the imide resin according to any one of claims 2 to 11 as a main component.

 [17] A molded article comprising the optical resin composition according to claim 16.

 [18] A polarizer protective film which also has the optical resin composition power according to claim 16.

 [19] Claim 2-: It is made of the imide resin according to any one of L1, characterized in that the in-plane retardation force of the film is SlOnm or less and the thickness direction retardation is 20 nm or less. Polarizer protection film.

 [20] The polarizer protective film according to claim 19, which is stretched.

 [21] The polarizer protective film according to claim 19, comprising an imide resin containing 1 to 5 mol% of the repeating unit represented by the general formula (1).

22. The polarizer protective film according to claim 19, wherein the imide resin has a photoelastic coefficient of 10 × 10 to ¹² m ² ZN or less.

23. The polarizer protective film according to claim 19, wherein the glass transition temperature of the imide resin is 110 ° C. or higher.

[24] A polarizing plate using the polarizer protective film according to claim 19.