JPWO2005108438A1 - IMIDE RESIN, ITS MANUFACTURING METHOD, AND MOLDED BODY USING SAME - Google Patents

Abstract

An object of the present invention is to provide an imide resin that is easy to manufacture, inexpensive, excellent in transparency and heat resistance, low in orientation birefringence, and sufficiently small in photoelastic coefficient. The present invention is, for example, an imidized resin obtained by reacting various methacrylic resins with monomethylamine (or butylamine). Moreover, this invention is also a method of manufacturing the imide resin characterized by processing a primary amine to a (meth) acrylic acid ester polymer or a (meth) acrylic acid ester-aromatic vinyl copolymer. The imide resin of the present invention has good heat resistance and transparency, has good workability, and is useful as a polarizer protective film.

Description

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

  In recent years, electronic devices have become more and more miniaturized, and have been used for various purposes by taking advantage of light weight and compactness, as represented by notebook personal 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 an increase in weight due to an increase in screen size.

  In applications that require transparency, such as electronic devices as described above, there is an increasing trend to replace members that have conventionally used glass with resins having good transparency.

  Various acrylic resins, such as polymethyl methacrylate, have excellent moldability and workability compared to glass, are difficult to break, and are lightweight and inexpensive, making them suitable for liquid crystal displays, optical disks, pickup lenses, etc. Are being developed and partly put into practical use.

  With the development of applications such as automotive headlamp covers and liquid crystal display members, 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 heat resistance is low, so the application range is limited in such applications. . For example, the glass transition temperature by a differential scanning calorimeter (DSC) such as polymethyl methacrylate or polystyrene is about 100 ° C.

  One method for improving the heat resistance of acrylic resins is to copolymerize methyl methacrylate and cyclohexylmaleimide. However, according to this method, since cyclohexylmaleimide, which is an expensive monomer, is used, there is a problem that the copolymer obtained becomes more expensive as the heat resistance is improved.

  As another method for improving the heat resistance of the acrylic resin, for example, as disclosed in Patent Document 1, Patent Document 2, and the like, a technique of treating a primary amine on an acrylic resin is disclosed. These relate to a stretched film made of a glutarimide resin having a glutarimide ring structure of 20% by weight or more. Further, Patent Document 3 relates to a stretched film made of glutarimide acrylic resin, and there is a description that by stretching, a film having improved mechanical strength and excellent transparency and heat shrinkage ratio is obtained. These publications do not mention orientation birefringence. However, as a result of studies by the present inventors, in the case of a composition having many glutarimide ring structures as described in these publications, it has been found that there is a problem that orientation birefringence occurs during stretching and optical distortion tends to occur. ing.

Moreover, as a method for improving the heat resistance of polymethyl methacrylate, polymethyl methacrylate (for example, see Patent Document 6) or methyl methacrylate-styrene copolymer (for example, Patent Documents 7 and 8) are used by using an extruder. , 9, 10), it is proposed that a primary amine is treated to imidize a methyl ester group in methyl methacrylate to obtain an imide resin. However, such an imide resin has a high glass transition temperature by a differential scanning calorimeter (DSC) and, accordingly, a high melt viscosity of the resin, so that a molded product having a complicated shape or a thin film is injection molded. The problem is that it is not suitable for precise molding such as 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 the melt extrusion method, only a film with a noticeable die line and a poor thickness distribution was obtained. Therefore, as a result of a film was formed by a similar method to the processing temperature down to increased melt viscosity 122 sec ^-1 · 10000Poise to 280 ° C., with the thermal decomposition of the resin volatile gas is generated, foaming, gases contaminated with such A good film could not be obtained. Although transparent and heat-resistant imide resins are expected to be used in a wide range of applications, thin film with good thickness distribution can be molded without causing foaming or gas contamination using imide resins. Is very difficult and has a problem of poor moldability.

  As a technique for eliminating the orientation birefringence of such a glutarimide acrylic resin, Patent Document 5 describes a film in which a glutarimide acrylic resin having a positive orientation birefringence and a styrene resin having a negative orientation birefringence are blended. Is disclosed. Such a resin is characterized in that it is difficult to develop a phase difference due to environmental changes, but because it is a blend, the manufacturing process is complicated, and the performance of the obtained film (for example, solvent resistance) is low. There was a problem of a drop.

  On the other hand, as another technique for eliminating the orientation birefringence of the transparent resin, Non-Patent Document 1 discloses random copolymerization of a polymer monomer exhibiting positive orientation birefringence and a polymer monomer exhibiting negative orientation birefringence at an appropriate ratio. And a method of doping a polymer with a low molecular compound having polarizability anisotropy has been proposed. However, a method of randomly copolymerizing a polymer exhibiting positive orientation birefringence and a polymer monomer exhibiting negative orientation birefringence at an appropriate ratio is a combination of benzyl methacrylate and methyl methacrylate, or 2,2,2- Expensive monomers are often used, such as a combination of trifluoroethyl methacrylate and methyl methacrylate. Moreover, in addition to the high cost of low molecular weight compounds, the method of doping low molecular weight compounds having polarizability anisotropy into the polymer often causes these low molecular weight compounds to bleed out from the molded product during long-term use. There are many challenges.

  Non-Patent Document 2 proposes, as a method for reducing the orientation birefringence of polycarbonate, a blend of polycarbonate and polystyrene, a method of graft copolymerizing polystyrene with polycarbonate, and the like. However, the former lacks uniformity in optical properties, and the latter is actually complicated due to graft polymerization.

  A polarizing plate is an example of the use of these transparent resins for liquid crystal display members. A polarizing plate is a material that has a function of transmitting only linearly polarized light having a specific vibration direction in light passing therethrough and shielding other linearly polarized light. A polarizer film and a polarizer protective film are laminated. Those having a configuration are generally used.

  The polarizer film is a film having a function of transmitting only linearly polarized light having a specific vibration direction. For example, a film of polyvinyl alcohol (hereinafter referred to as PVA) is stretched to obtain iodine, a dichroic dye, or the like. Films dyed with are generally used.

  The polarizer protective film has a function of holding the polarizer film and imparting practical strength to the entire polarizing plate, for example, a triacetyl cellulose (hereinafter referred to as PVA) film or the like. in use.

  In the polarizer protective film, a film having an unnecessary retardation (in-plane retardation and thickness direction retardation) is generally not preferable. This is because even if the polarizer film has a highly accurate linear polarization function, the retardation of the polarizer protective film and the optical axis shift give the elliptically polarized light to the linearly polarized light that has passed through the polarizer film. Because it will end up. The aforementioned TAC film also basically has a small phase difference. However, the TAC film is a film that easily generates a phase difference due to the action of external stress, and cannot be said to have a sufficiently small photoelastic coefficient. Further, the film has a relatively large thickness direction retardation. For this reason, particularly in a large-sized liquid crystal display device, there is a problem that the contrast in the peripheral portion is lowered.

Therefore, attempts have been made to use a film material having a smaller photoelastic coefficient than the TAC film as a polarizer protective film. For example (for example, Patent Document 4), the moisture permeability of 80 ° C. and 90% RH is 20 g · mm / m ² · 24 hr or less and the photoelastic coefficient is 1 × 10 ⁻¹¹ cm ² / N or less. A protective film is disclosed. However, in this case as well, there is a problem that the price is high because a complicated route is required for synthesis.

Recently, as a transparent resin, a cyclic olefin homopolymer (or a hydrogenated product thereof), a cyclic olefin copolymer obtained by copolymerizing a cyclic olefin with an olefin other than the cyclic olefin (or a hydrogenated product thereof), and the like have been proposed. ing. These polymers have characteristics such as low birefringence, low hygroscopicity, and heat resistance, and are being developed as optical materials. Since these polymers have a relatively small photoelastic coefficient, it has been reported that their optical properties hardly change even when the environment changes. However, in general, such a cyclic olefin-based polymer has a problem of high cost because it requires a complicated route for synthesis. Further, such a cyclic olefin polymer has a problem of low solubility in a solvent.
Japanese Patent Laid-Open No. 06-240017 Japanese Patent Laid-Open No. 06-297558 Japanese Patent Laid-Open No. 06-256537 Japanese Patent Application Laid-Open No. 07-77608 WO01 / 37007 U.S. Pat. No. 4,246,374 U.S. Pat. No. 4,727,117 US Pat. No. 4,954,574 US Pat. No. 5,004,777 U.S. Pat. No. 5,264,483 Molding Volume 15 Issue 3 Page 194 56 pages of the Nikkei New Material September 26, 1988 issue

  The present invention has been made in view of the above-described problems of the prior art, is easy to manufacture, has excellent transparency and heat resistance, and is optically distorted (birefringence) even under stress during molding and use. ), And an optical resin composition using the same, and molded articles such as a polarizer protective film.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive research and obtained an imide resin having a specific imidization reaction rate or melt viscosity obtained by a method of treating a primary amine to an acrylic resin. Thus, the present inventors have found that it is inexpensive, excellent in transparency and heat resistance, low in orientation birefringence, excellent in moldability, and sufficiently small in photoelastic coefficient.

  That is, this invention relates to the imide resin characterized by containing the repeating unit represented by the following general formula (1), (2).

(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 or a cycloalkyl group having 3 to 12 carbon atoms. Or an aryl group having 6 to 10 carbon atoms.)

(Wherein R ⁴ and R ⁵ each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms; R ⁶ represents hydrogen or an alkyl group having 1 to 18 carbon atoms; Represents an alkyl group or an aryl group having 6 to 10 carbon atoms.)
Further, the imide resin of the present invention preferably has an orientation birefringence of 0.0001 or less, and more preferably an orientation birefringence of 0.00001 or less.

Further, the imide resin of the present invention preferably has a melt viscosity of 14000 poise or less at 260 ° C. and 122 sec ⁻¹ .

  Moreover, it is preferable that the imide resin of this invention contains the repeating unit represented by following General 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.)
Moreover, it is preferable that the imide resin of this invention is what was manufactured using the (meth) acrylic acid ester polymer, Furthermore, the said (meth) acrylic acid ester polymer is a methyl methacrylate polymer. Is more preferable.

  Moreover, it is preferable that the imide resin of this invention is manufactured using the (meth) acrylic acid ester-aromatic vinyl copolymer, Furthermore, the said (meth) acrylic acid ester-aromatic vinyl copolymer is preferable. Is more preferably a methyl methacrylate-styrene copolymer.

Moreover, it is preferable that the melt viscosity in 260 degreeC and 122 second- ¹ of the said (meth) acrylic acid ester polymer and the said (meth) acrylic acid ester-aromatic vinyl copolymer is 7000 poise or less.

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

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

  The present invention also provides an imide resin characterized by treating a primary amine with a (meth) acrylic acid ester polymer or a (meth) acrylic acid ester-aromatic vinyl copolymer in the absence of a solvent. On how to do.

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

  Moreover, this invention relates to the molded object which consists of the said optical resin composition.

  The present invention also relates to a polarizer protective film comprising an optical resin composition.

  The present invention also relates to a polarizer protective film comprising the imide resin, having an in-plane retardation of the film of 10 nm or less and a thickness direction retardation of 20 nm or less.

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

  It is preferable that the polarizer protective film of this invention consists of imide resin which contains 1-5 mol% of repeating units represented by General formula (1).

In the polarizer protective film of the present invention, the photoelastic coefficient of the imide resin is preferably 10 × 10 ⁻¹² m ² / N or less.

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

  Moreover, this invention relates to the polarizing plate using the said polarizer protective film.

  According to the present invention as described above, an imide resin that is easy to manufacture, inexpensive, excellent in transparency and heat resistance, low in orientation birefringence, and sufficiently small in photoelastic coefficient can be provided. A molded product that is excellent in properties and does not cause optical distortion even when stress occurs during molding or use can be obtained. In addition, by using the imide resin of the present invention, it can be developed into a molded body that requires transparency, heat resistance and weight reduction, and can be used as a glass substitute. Moreover, it becomes possible to provide a polarizer protective film with small optical anisotropy. In addition, by using the polarizer protective film of the present invention, it is possible to realize a good display by suppressing a decrease in contrast in a peripheral portion even in a large liquid crystal display device.

  The present invention relates to an imide resin containing repeating units represented by the following general formulas (1) and (2).

(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 or a cycloalkyl group having 3 to 12 carbon atoms. Or an aryl group having 6 to 10 carbon atoms.)

(Wherein R ⁴ and R ⁵ each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms; R ⁶ represents hydrogen or an alkyl group having 1 to 18 carbon atoms; Represents an alkyl group or an aryl group having 6 to 10 carbon atoms.)
The first structural unit constituting the imide resin of the present invention is represented by the following general formula (1), and is generally called a glutarimide unit (hereinafter referred to as general formula (1)). Sometimes abbreviated as glutarimide unit).

(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 or a cycloalkyl group having 3 to 12 carbon atoms. Or an aryl group having 6 to 10 carbon atoms.)
As preferred glutarimide units, R ¹ and R ² are hydrogen or a methyl group, and R ³ is hydrogen, a methyl group, an n-butyl group, a cyclohexyl group, from the viewpoint of availability of raw materials, cost, heat resistance, and the like. Benzyl group. The case where 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 is particularly preferable.

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

  The second structural unit constituting the imide resin of the present invention is a (meth) acrylic acid ester or (meth) acrylic acid unit represented by the following general formula (2). ) Acrylic acid ester unit (referred to here as (meth) acrylic acid ester means acrylic acid ester and / or methacrylic acid ester. General formula (2) is hereinafter referred to as (meth) acrylic acid ester) Sometimes abbreviated as unit.)

(Wherein R ⁴ and R ⁵ each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms; R ⁶ represents hydrogen or an alkyl group having 1 to 18 carbon atoms; Represents an alkyl group or an aryl group having 6 to 10 carbon atoms.)
From the viewpoint of preferable (meth) acrylic acid ester or availability of raw materials, cost, etc., as the (meth) acrylic acid unit, R ⁴ and R ⁵ are hydrogen or a methyl group, R ⁶ is hydrogen, a methyl group, n-butyl group, cyclohexyl group and benzyl group. The case where R ¹ is a methyl group, R ² is a methyl group, and R ³ is a methyl group is particularly preferred.

These second structural units may be of a single type, and may include a plurality of types in which R ⁴ , R ⁵ , and R ⁶ are different.

  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 orientation birefringence is more preferably 0.00001 or less. By setting the orientation birefringence to 0.0001 or less, birefringence does not substantially occur even when stress is generated during molding or use, and a molded article free from optical distortion can be obtained.

Here, the orientation birefringence is a birefringence that appears when uniaxial stretching is performed at a predetermined temperature and a predetermined stretching ratio, and is the product of the intrinsic birefringence derived from the polymer structure and the orientation distribution function derived from the molecular orientation state. is there. In this specification, the phase difference Re (nm), which is defined as the difference between the refractive index (nx) in the maximum refractive index direction and the refractive index (ny) in the axial direction perpendicular to the refractive index, is measured by a phase difference meter. It is a value divided by the thickness d (μm) of the test piece at the time of measurement, and is represented by the following formula.
Orientation birefringence Δn _or = nx−ny = Re / d
In the present specification, unless otherwise specified, it means birefringence that develops when stretched 100% at a temperature 5 ° C. higher than the glass transition temperature of the imide resin (stretch ratio 2 times). .

The content of the glutarimide 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). % Is preferred. When the aromatic vinyl unit represented by the general formula (3) is not included, particularly when an imide resin having substantially no orientation birefringence is obtained, the glutarimide unit represented by the general formula (1) The content is preferably 1 to 40% by weight, particularly preferably 3 to 30% by weight, and further preferably 5 to 20% by weight. On the other hand, when the aromatic vinyl unit represented by the general formula (3) is included, when obtaining an imide resin having substantially no orientation birefringence, the content of the glutarimide unit represented by the general formula (1) Is preferably increased in accordance with the amount of the aromatic vinyl unit represented by the general formula (3), preferably 20% by weight or more, more preferably 40% by weight or more, and particularly preferably 50% by weight or more. When the ratio of a glutarimide unit is smaller than this range, the heat resistance of the imide resin obtained may be insufficient, or transparency may be impaired. In addition, if it exceeds this range, heat resistance and melt viscosity are unnecessarily increased and molding processability is deteriorated, and the mechanical strength of the obtained molded article becomes extremely fragile, and transparency may be impaired. .

Further, the imide resin of the present invention preferably has a melt viscosity of 14000 poise or less at 260 ° C. and 122 sec ⁻¹ . The melt viscosity in the present invention is a flow characteristic when a thermoplastic resin (imide resin) is melted by heat, and means 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 sec ⁻¹ to 14000 poise or less, the moldability of the resulting imide resin becomes good, and a precise molded product can be obtained.

  In the present invention, the good processability of imide resin means that the imide resin can be molded by various plastic processing methods such as injection molding, melt extrusion film molding, inflation molding, blow molding, compression molding, and spinning molding. When processing into a product, it refers to the characteristics that defects such as transfer defects, silver, fish eyes, die lines, uneven thickness, and foaming are less likely to occur and precise molding is easy.

  The third structural unit contained in the imide resin of the present invention as necessary is represented by the following general formula (3), and is generally called an aromatic vinyl unit (hereinafter, generally referred to as general vinyl). Formula (3) may be abbreviated as an aromatic vinyl unit.

(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.)
Preferred aromatic vinyl units include styrene, α-methylstyrene and the like. Among these, styrene is particularly preferable from the viewpoints of availability of raw materials and cost.

These third structural units may be of a single type or may include a plurality of types in which R ⁷ and R ⁸ are different.

  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 unit of the imide resin. The preferable content of the aromatic vinyl unit is 10 to 40% by weight, more preferably 15 to 30% by weight, and still more preferably 15 to 25% by weight. When the aromatic vinyl unit is larger than this range, the resulting imide resin may have insufficient heat resistance.

  By adjusting the proportions of the general formulas (1), (2), and (3), various required physical properties can be adjusted. For example, when the imide resin of the present invention is formed by first polymerizing a (meth) acrylic acid ester-aromatic vinyl copolymer such as methyl methacrylate-styrene copolymer and then imidizing, for example, (meth) acrylic The ratio of the general formula (3) is determined by adjusting the polymerization ratio of the acid ester and the aromatic vinyl (the ratio of the general formula (3) can be set to 0), and further, the primary amine is added during the post-imidation By adjusting the ratio, the ratios of the general formulas (1) and (2) can be further adjusted.

In the imide resin of the present invention, the type containing the general formula (3) is a imide resin 260 by adjusting the content of each constituent unit and glutarimide unit in the methyl methacrylate-styrene copolymer. It is also possible to impart a characteristic that the melt viscosity at 122 ° C. at ¹ ° C. is 14000 poise or less and substantially has no orientation birefringence. In order to obtain an imide resin having a melt viscosity of 14000 poise or less at 260 ° C. and 122 sec ⁻¹ and having substantially no orientation birefringence, (meth) acrylic acid such as methyl methacrylate-styrene copolymer is used. It is necessary to adjust the amount of each structural unit in the ester-aromatic vinyl copolymer and further adjust the degree of imidization. The repeating unit represented by the general formula (1) and the general formula (3) are required. The repeating unit is preferably in the range of 2.0: 1.0 to 4.0: 1.0 by weight, more preferably in the range of 2.5: 1.0 to 4.0: 1.0. 3.0: 1.0 to 3.5: 1.0 is more preferable.

  If necessary, the imide resin of the present invention may further be copolymerized with a fourth structural unit. A constitution obtained by copolymerizing a nitrile monomer such as acrylonitrile and methacrylonitrile, and a maleimide monomer such as maleimide, N-methylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide as the fourth structural unit Units can be used. These may be directly copolymerized in the imide resin or may be graft copolymerized.

The imide resin of the present invention preferably has a weight average molecular weight of 1 × 10 ⁴ to 5 × 10 ⁵ . When the weight average molecular weight is less than 1 × 10 ⁴ , the mechanical strength in the case of forming a film is insufficient, and when it exceeds 5 × 10 ⁵ , the viscosity at the time of melting is high and the productivity of the film decreases. 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 value of molecular weights from a branch to the next branch point in a polymer having a branched structure, and is defined using the Z average molecular weight. It is also useful to lower the melt viscosity by increasing the ratio (dispersity) between the weight average molecular weight and the number average molecular weight of the raw material methacrylic resin used. The weight average molecule is preferably 2.1 times or more, and more preferably 2.5 times or more with respect to the number average molecular weight. In the case of the above value or less, the resulting imide resin has a high melt viscosity, and processing defects may occur during molding.

  The glass transition temperature of the imide resin of the present invention is preferably 100 ° C. or higher, more preferably 110 ° C. or higher, and further preferably 120 ° C. or higher. When the glass transition temperature is less than 100 ° C., the application range is limited in applications where heat resistance is required.

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

  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.

  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, an acrylic resin ((meth) acrylic acid ester-aromatic vinyl copolymer in a molten state is used by using an extruder in the absence of a solvent. Etc.) can be obtained by adding an imidizing agent. Further, for example, as described in Japanese Patent No. 2505970, an acrylic resin ((meth) acrylic acid ester-aromatic vinyl copolymer, etc.) can be dissolved in the presence of a solvent. It can also be obtained by adding an imidizing agent to a solution state acrylic resin ((meth) acrylic acid ester-aromatic vinyl copolymer or the like) using a reactive solvent.

  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 glutarimide unit. For example, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) (Meth) acrylic acid esters such as butyl acrylate, (meth) acrylic acid such as acrylic acid and methacrylic acid, maleic acid, itaconic acid, crotonic acid, fumaric acid, citraconic acid and other α, β-ethylenically unsaturated carboxylic acids Acid, maleic anhydride and other acid anhydrides or half esters of them with linear or branched alcohols having 1 to 20 carbon atoms can be imidized, and homopolymers and copolymers thereof. Or a copolymer composed of other copolymerization components. Among these, polymethyl methacrylate is preferable from the viewpoints of cost, physical properties, and the like.

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

  When using an extruder especially for producing the imide resin of the present invention, various types of extruders such as a single screw extruder, a twin screw extruder or a multi-screw extruder can be used. A twin screw extruder is preferred as an extruder capable of promoting the mixing of the agent. The twin screw extruder includes a non-meshing type same direction rotating type, a meshing type same direction rotating type, a non-meshing type different direction rotating type, and a meshing type different direction rotating type. In the twin screw extruder, the meshing type 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. The extruder is preferably equipped with a vent port that can be depressurized below atmospheric pressure in order to remove unreacted imidizing agent and by-products.

  Instead of the extruder, a high-viscosity reactor such as a horizontal biaxial reactor such as Violac manufactured by Sumitomo Heavy Industries, Ltd. or a vertical biaxial agitation tank such as Super Blend can be suitably used.

  The batch-type reaction vessel (pressure vessel) used for producing the imide resin of the present invention is not particularly limited as long as it has a structure capable of heating and stirring a solution in which a raw material polymer is dissolved and adding an imidizing agent. As a result, the viscosity of the polymer solution may increase, and it is preferable that the stirring efficiency is good. For example, Sumitomo Heavy Industries Co., Ltd. agitation tank Max blend etc. can be illustrated.

  When the imide resin of the present invention is produced in the presence of a solvent, an imidizing agent can be added to the acrylic resin in a solution state by using a non-reactive solvent for the imidization reaction, which can dissolve the acrylic resin. Obtained by.

  Non-reactive solvents for imidization reactions include aliphatic alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol and isobutyl alcohol, and aromatic carbonization such as benzene, toluene, xylene, chlorobenzene and chlorotoluene. Examples thereof include ketones such as hydrogen, methyl ethyl ketone, tetrahydrofuran and dioxane, and ether compounds. These may be used singly or may be a mixture of at least two. Among these, toluene and a mixed solvent of toluene and methyl alcohol are preferable.

  A smaller concentration of the acrylic resin relative to the non-reactive solvent is preferable from the viewpoint of production cost, and the solid content concentration is preferably 10 to 80%, particularly preferably 20 to 70%.

  The imidizing agent used in the present invention is not particularly limited as long as it can imidize an acrylic resin. For example, methylamine, ethylamine, n-propylamine, i-propylamine, n-butylamine, i-butylamine, Examples thereof include aliphatic hydrocarbon group-containing amines such as tert-butylamine and n-hexylamine, aromatic hydrocarbon group-containing amines such as aniline, toluidine and trichloroaniline, and alicyclic hydrocarbon group-containing amines such as cyclohexylamine. . Urea compounds that generate these amines by heating, such as urea, 1,3-dimethylurea, 1,3-diethylurea, 1,3-dipropylurea, can also be used. Of these imidizing agents, methylamine is preferable from the viewpoint of cost and physical properties.

  When the acrylic resin is imidized with an imidizing agent, the reaction temperature is in the range of 150 to 400 ° C. in order to advance imidization and to suppress decomposition and coloring of the resin due to excessive heat history. 180-320 degreeC is preferable, Furthermore, 200-280 degreeC is preferable.

  When an acrylic resin is imidized with an imidizing agent, generally used catalysts, antioxidants, heat stabilizers, plasticizers, lubricants, ultraviolet absorbers, antistatic agents, coloring agents, antishrinking agents, etc. You may add in the range which does not impair the objective of invention.

In producing the imide resin of the present invention, a (meth) acrylic acid ester polymer such as a methyl methacrylate polymer having a melt viscosity of 7000 poise or less at 260 ° C. and 122 sec ⁻¹ , or a methyl methacrylate-styrene copolymer. It is preferable to use a (meth) acrylic acid ester-aromatic vinyl copolymer such as a polymer because the imide resin of the present invention can be easily produced.

  When the imide resin of the present invention is produced, first, a (meth) acrylic acid ester polymer or a (meth) acrylic acid ester-aromatic vinyl copolymer is polymerized, followed by post-imidization, In particular, the raw material for giving a (meth) acrylic acid ester unit as a residue is not particularly limited. For example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) Examples include acrylate, t-butyl (meth) acrylate, benzyl (meth) acrylate, and cyclohexyl (meth) acrylate. Of these, methyl methacrylate is particularly preferred.

  Further, it is more preferable to treat these copolymers 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) acrylic acid ester-aromatic vinyl copolymer such as methyl methacrylate-styrene copolymer or a (meth) acrylic acid ester such as methyl methacrylate polymer is used. A (meth) acrylic acid ester-aromatic vinyl copolymer and (meth) acrylic acid ester polymer that can be used for polymerizing a polymer and converting it to an imide resin are capable of imidization reaction. The polymer may be a linear (linear) polymer, or may be a block polymer, a core-shell polymer, a branched polymer, a ladder polymer, or a crosslinked polymer. The block polymer may be an AB type, an ABC type, an ABA type, or any other type of block polymer. The core-shell polymer may be composed of only one core and only one shell, or each may be a multilayer.

  The imide resin of the present invention (which may be a single product or a blended product with another thermoplastic polymer) may be produced by various plastic processing methods such as injection molding, melt extrusion film molding, inflation molding, blow molding, compression molding, and spinning molding. Can be processed into various molded products. It can also be molded by a casting method or a spin coating method using a polymer solution obtained by dissolving the imide resin of the present invention in a solvent such as methylene chloride.

  When molding, generally used antioxidants, heat stabilizers, plasticizers, lubricants, UV absorbers, antistatic agents, colorants, shrinkage inhibitors, etc. are added within the range that does not impair the purpose of the present invention. May be.

  The molded product obtained from the imide resin of the present invention is, for example, a video camera such as a camera, a VTR, a projector lens, a finder, a filter, a prism, a Fresnel lens, or an optical disc pickup such as a CD player, a DVD player, or an MD player. Information equipment such as lenses such as lenses, optical recording fields for optical discs such as CD players, DVD players, and MD players, liquid crystal light guide plates, liquid crystal display films such as polarizer protective films and retardation films, and surface protective films Field, optical communication field such as optical fiber, optical switch, optical connector, etc., automotive headlight, tail lamp lens, inner lens, instrument cover, sunroof, etc., vehicle field, glasses, contact lens, internal vision lens, need for sterilization Doctor Medical equipment field such as supplies, road translucent plates, paired glass lenses, lighting windows and carports, lighting lenses and covers, building materials such as sizing for building materials, microwave cooking containers (tableware), home appliances It can be used for housings, toys, sunglasses, stationery, etc.

  The polarizer protective film of the present invention comprises the imide resin of the present invention, that is, the imide resin characterized by containing a repeating unit represented by the following general formulas (1) and (2). Is.

(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 or a cycloalkyl group having 3 to 12 carbon atoms. Or an aryl group having 6 to 10 carbon atoms.)

(Here, 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 or a cycloalkyl group having 3 to 12 carbon atoms. Or an aryl group having 6 to 10 carbon atoms.)
As long as the imide resin used in the polarizer protective film of the present invention is the imide resin of the present invention containing the repeating unit represented by the general formulas (1) and (2), those having various forms described above can be used. Of course, it can be used and is not particularly limited. For example, in addition to the repeating units represented by the general formulas (1) and (2), a repeating unit represented by the following general formula (3) may be contained.

  The polarizer protective film of the present invention is characterized by low optical anisotropy. The polarizer protective film may be required to have small optical anisotropy in the thickness direction as well as in the in-plane direction (length direction and width direction) of the film. That is, the direction in which the in-plane refractive index is 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 index in each axial direction is nx, ny, nz, film In-plane retardation Re = (nx−ny) × d and thickness direction retardation Rth = | (nx + ny) / 2−nz | × d (where || represents an absolute value). (In an ideal film, which is completely optically isotropic in the three-dimensional direction, both the in-plane retardation Re and the thickness direction retardation Rth are zero).

  The polarizer protective film of the present invention preferably has an in-plane retardation of the film of 10 nm or less and a thickness direction retardation of 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 10 nm or less. When a polarizer protective film having an in-plane retardation of the film exceeding 10 nm or a retardation in the thickness direction exceeding 20 nm is used as a polarizing plate, a problem such as a decrease in contrast may occur in a liquid crystal display device. .

  In order to obtain a polarizer protective film with small optical anisotropy of the present invention, it is necessary to adjust the amount of each constituent unit in the imide resin. The repeating unit represented by the general formula (1) is preferably 1 to 10 mol%, particularly preferably 1 to 5 mol%, and further preferably 3 to 4 mol% of the imide resin. If it is out of this range, it is difficult to obtain a film having small optical anisotropy.

The imide resin used for the polarizer protective film of the present invention preferably has a small photoelastic coefficient. The photoelastic coefficient of the imide resin used in the present invention is preferably 20 × 10 ⁻¹² m ² / N or less, more preferably 10 × 10 ⁻¹² m ² / N or less, and 5 × 10 ⁻ More preferably, it is ¹² m ² / N or less. When the absolute value of the photoelastic coefficient is larger than 20 × 10 ⁻¹² m ² / N, optical distortion occurs due to stress, and light leakage tends to occur. In particular, the tendency becomes remarkable in a high temperature and high humidity environment.

The photoelastic coefficient means that when an external force is applied to an isotropic solid to cause stress (ΔF), it temporarily exhibits optical anisotropy and exhibits birefringence (Δn). The ratio of stress to birefringence is called the photoelastic coefficient (c), and the following formula is given: c = Δn / ΔF
Indicated by

  As a method for forming the imide resin into the form of the polarizer protective film of the present invention, any conventionally known method can be used. Examples thereof include a solution casting method and a melt extrusion method. Any of them can be adopted. The solution casting method is suitable for the production of a film with little resin deterioration and good surface properties, 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 preferably used. Examples of the melt molding method include a melt extrusion method and an inflation method.

  The thickness of the polarizer protective film of the present invention is preferably 20 μm to 300 μm, more preferably 30 μm to 200 μm. More preferably, it is 50 μm to 100 μm. The thickness unevenness of the film is preferably 10% or less, more preferably 5% or less of the average thickness.

  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 still more preferably 0.5% or less.

  In the present specification, for convenience of explanation, a film after the imide resin is formed into a film and before being stretched may be referred to as a “raw material film”.

  The raw material film can be a polarizer protective film as it is without being stretched. However, in the production of the polarizer protective film of the present invention, after forming the film by the above-mentioned method, it is uniaxially stretched or biaxially stretched. It is preferable to manufacture a film having a predetermined thickness. By stretching, the mechanical properties of the film are further improved. If an example of an embodiment is given, after manufacturing a 150-micrometer-thick raw material film by such melt extrusion molding, a 40-micrometer-thick film can be manufactured by vertical and horizontal biaxial stretching.

  The film may be stretched continuously immediately after forming the raw material film. Here, the state of the “raw material film” may exist only momentarily. When it exists only momentarily, the state after the film is formed and then stretched is called a raw material film. In addition, the raw material film only needs to be in a film shape enough to be stretched thereafter, and does not need to be in a complete film state. Of course, it does not have performance as a completed film. May be. Moreover, after shaping | molding a raw material film as needed, you may store or move a film once, and may extend a film after that. As a method of stretching the raw material film, any conventionally known stretching method can be adopted. Specifically, for example, there are longitudinal stretching using a roll or a hot stove, transverse stretching using a tenter, and sequential biaxial stretching in which these are sequentially combined. Moreover, the simultaneous biaxial stretching method of extending | stretching length and width simultaneously is also employable. You may employ | adopt the method of performing horizontal extending | stretching by a tenter after performing roll longitudinal stretching.

  The polarizer protective film of this invention can be made into a final product in the state of a uniaxially stretched film. Furthermore, it is good also as a biaxially stretched film by combining and extending | stretching a process. When biaxial stretching is performed, stretching conditions such as longitudinal stretching and transverse stretching temperatures and magnifications may be the same as necessary, and mechanical anisotropy can be achieved by intentionally changing the stretching conditions. May be given.

  The stretching temperature and 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 in the range of (Tg-30 ° C.) to (Tg + 30 ° C.), where Tg is the glass transition temperature of the film obtained 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 (Tg ° C.) to (Tg + 20 ° C.). When 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 tend to be insufficient. Moreover, the trouble that the film adheres to the roll is likely to occur. On the other hand, when the stretching temperature is too low, the turbidity of the stretched film tends to be high, and in the extreme case, it tends to cause problems in the process such as tearing or cracking of the film. The preferred draw ratio depends on the drawing temperature, but is selected in the range of 1.1 to 3 times. More preferably, it is 1.3 times to 2.5 times. More preferably, it is 1.5 times to 2.3 times.

  In addition, when forming into a film, it may contain a heat stabilizer, a UV absorber, a processability improver such as a lubricant, or a known additive such as a filler or other polymers as necessary. . In particular, a filler may be contained for the purpose of improving the slipperiness of the film. As the filler, inorganic or organic fine particles can be used. Examples of inorganic fine particles include metal oxide fine particles such as silicon dioxide, titanium dioxide, aluminum oxide and zirconium oxide, silicate fine particles such as calcined calcium silicate, hydrated calcium silicate, aluminum silicate and magnesium silicate, Calcium carbonate, talc, clay, calcined kaolin, calcium phosphate, and the like can be used. As the organic fine particles, resin fine particles such as silicon resin, fluorine resin, acrylic resin, and cross-linked styrene resin can be used.

  By including an ultraviolet absorber in 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 the liquid crystal display device using the polarizer protective film of the present invention is also improved. This is preferable in practice. Examples of the ultraviolet absorber include benzotriazole-based ultraviolet absorbers such as 2- (2H-benzotriazol-2-yl) -p-cresol and 2-benzotriazol-2-yl-4,6-di-t-butylphenol, Triazine-based UV absorbers such as 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol, benzophenone-based UV absorbers such as octabenzone, etc. Benzoate light stabilizers such as 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate and bis (2,2,6,6-tetramethyl) Light stabilizers such as hindered amine light stabilizers such as -4-piperidyl) sebacate can also be used.

  The polarizer protective film of the present invention can be subjected to a surface treatment as necessary to improve adhesion with other materials. As the surface treatment method, any conventionally known method is possible. For example, electrical treatment such as corona discharge treatment and spark treatment, plasma treatment under low pressure or normal pressure, ultraviolet irradiation treatment in the presence or absence of ozone, acid treatment with chromic acid, alkali saponification treatment, flame 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 50 dyne / cm or more.

  Moreover, in order to improve affinity with an adhesive agent or an adhesive, an easily bonding layer can be provided in the single side | surface or both surfaces of a film. As a preferred easy-adhesion layer, a copolymer polyester, a urethane-modified one thereof, a copolymer polyester having a carboxyl group or a sulfonic acid group, a solution such as polyvinyl alcohol, or an aqueous dispersion was applied and dried. Layers can be used. Moreover, the method of providing a cellulose-ester resin etc. as an easily bonding layer, performing this for an alkali saponification process, and improving affinity can also be used.

  The polarizer protective film of the present invention can be subjected to a coating treatment such as a hard coat, an antiglare coat, a non-reflective coat, and other functional coats as necessary.

  EXAMPLES Although this invention is demonstrated further in detail based on an Example, this invention is not limited only to these Examples. In addition, each measuring method of the physical property measured in the following Examples and Comparative Examples is as follows.

(1) Quantification of imidation ratio by infrared spectrophotometer (IR) The IR spectrum was measured at room temperature by using TravelIR manufactured by SensIR Technologies, using the pellet of the product as it was. From the obtained spectrum, the absorption intensity (Abs _Ester) attributed to the ester carbonyl group of 1720 cm ^-1, the ratio of the absorption intensity assignable to an imide carbonyl group of 1660cm ^-1 (Abs _imide), the following numbers 1 Was used to determine the imidization ratio (Im% (IR)).

(2) Quantification of imidation ratio by ¹ H-NMR 10 mg of a product obtained using methylamine was dissolved in 1 g of CDCl ₃ and ¹ H at room temperature using a Varian NMR measuring apparatus Gemini-300. -NMR was measured. From the obtained spectrum, from the ratio of the integral intensity attributed to the methyl group of the methyl ester moiety (CH _{3 (ester)} ) and the integral intensity attributed to the methyl group of the N-methylimide ring structure (CH _{3 (imide)} ). The imidation ratio (Im% (NMR)) was determined by the following formula 2.

  In addition, about the product obtained using amines other than methylamine, since assignment is difficult, Im% (NMR) is not calculated | required.

(3) Content of glutarimide unit (Im%)
With respect to the resin for which the imidation ratio by ¹ H-NMR was determined, this value was defined as the content (Im%) of the glutarimide unit. For resins for which the imidation rate by ¹ H-NMR was not determined, the correlation between Im% (IR) and Im% (NMR) measured for the product obtained using methylamine was determined, and Im% ( The value converted from the measured value of (IR) was taken as the content (Im%) of the glutarimide unit.

(4) Glass transition temperature (Tg)
Using 10 mg of the product, a differential scanning calorimeter (DSC, model DSC-50 manufactured by Shimadzu Corporation) was used and measured at a heating rate of 20 ° C./min in a nitrogen atmosphere and determined by the midpoint method.

(5) Melt viscosity of resin 40 g of resin was measured for melt viscosity at a shear rate of 122 sec ⁻¹ and a temperature of 260 ° C. according to JIS K7199 using a capillograph manufactured by Toyo Seiki Seisakusho and a capillary with a diameter of 1 mm and a length of 10 mm. did.

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

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

(9) Oriented 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 stretch ratio of 2 and a temperature 5 ° C. higher than the glass transition temperature. A test piece of 35 mm × 35 mm was cut out from the center in the TD direction of this uniaxially stretched film. The phase difference of this test piece was measured using an automatic birefringence meter (KOBRA-WR manufactured by Oji Scientific Instruments Co., Ltd.) 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 °. . The value obtained by dividing this phase difference by the thickness of the test piece measured using a digimatic indicator (manufactured by Mitutoyo Corporation) was defined as orientation birefringence.

(10) In-plane retardation Re and thickness direction retardation Rth
A 40 mm × 40 mm test piece was cut out from the film. Using an automatic birefringence meter (KOBRA-WR manufactured by Oji Scientific Co., Ltd.), the in-plane retardation Re 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 °. It was measured. The thickness d of the test piece measured using a digimatic indicator (manufactured by Mitutoyo Corporation), the refractive index n measured by an Abbe refractometer (manufactured by Atago Co., Ltd. 3T), the wavelength 590 nm measured by an automatic birefringence meter, and the surface The three-dimensional refractive index nx, ny, nz is obtained from the internal phase difference Re and the phase difference value in the 40 ° tilt direction, and the thickness direction phase difference Rth = | (nx + ny) / 2−nz | × d (|| is the absolute value) Represents).

(11) Photoelastic coefficient A test piece was cut out in a strip shape having a width of 15 mm and a length of 60 mm from the film, and the temperature was 23 ± 2 ° C. and the humidity was 50 ± using an automatic birefringence meter (KOBRA-WR manufactured by Oji Scientific Co., Ltd.). In 5%, it measured at wavelength 590nm. One side of the film was fixed, and the other side was subjected to birefringence measurement in a state where a load was applied every 100 gf from no load to 1000 gf, and the amount of change in birefringence due to unit stress was calculated from the obtained results.

(12) Unevenness of 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 full width in the TD direction was measured using an Anritsu contact type continuous thickness meter KB601B. From the measured thickness, the following formula was used to determine the thickness unevenness for a target film thickness of 150 μm.
(Thickness unevenness) = | Maximum thickness−Minimum thickness | / 2
(13) Film appearance inspection Two samples having a length of 500 mm in the TD direction and a length of 500 mm in the MD direction are cut out from the film and irradiated with light from a desk stand (National SQ948H, fluorescent lamp 27W) in the dark room. The presence or absence of die lines, foaming, and fish eyes was visually evaluated.

(14) ASTM No. 1 dumbbell specimen appearance inspection The surface of ten dumbbell specimens was visually observed to evaluate the presence or absence of flow marks, fish eyes, and foaming.

(Resin production example 1)
An imidized resin was produced using a methacrylic resin (Sumitex MH manufactured by Sumitomo Chemical Co., Ltd.) and monomethylamine (Mitsubishi Gas Chemical Co., Ltd.) as an imidizing agent. The extruder used was a meshing type co-rotating twin screw extruder having a diameter of 15 mm. The set temperature of each temperature control zone of the extruder was 230 ° C., the screw rotation speed was 150 rpm, the methacrylic resin was supplied at 1.0 kg / hr, and the supply amount of monomethylamine was 3 parts by weight with respect to the methacrylic resin. A methacrylic resin was introduced from a hopper, and the resin was melted and filled with a kneading block, and then monomethylamine was injected from a nozzle. A seal ring was placed at the end of the reaction zone to fill the resin. By-products after the reaction and excess methylamine were devolatilized by reducing the pressure at the vent port to -0.08 MPa. The resin that came out as a strand from a die provided at the exit of the extruder was cooled in a water tank and then pelletized with a pelletizer.

(Resin production example 2)
The same procedure as in Resin Production Example 1 was carried out except that the methacrylic resin was made from Atfina Atglass HT121.

(Resin production example 3)
Resin Production Example 1 except that the methacrylic resin is Acrypet VH manufactured by Mitsubishi Rayon Co., Ltd., the supply amount of the resin is 2 kg / hr, n-butylamine is used instead of monomethylamine, and the supply amount is 20 parts by weight. As well.

(Resin production example 4)
The methacrylic resin is Acrypet VH manufactured by Mitsubishi Rayon Co., Ltd., the supply amount of the resin is 2 kg / hr, c-hexylamine (manufactured by Guangei Chemical Co., Ltd.) is used instead of monomethylamine, and the supply amount is 30 parts by weight. The same procedure as in Resin Production Example 1 was carried out except that.

(Resin production example 5)
Using TEM-V1000N (200 mL pressure vessel) manufactured by Pressure Glass Industrial Co., Ltd., 100 parts by weight of methacrylic resin (Sumitex LG, manufactured by Sumitomo Chemical Co., Ltd.) was dissolved in 100 parts by weight of toluene / 10 parts by weight of methyl alcohol. The reaction vessel was immersed in a dry ice-methanol mixed solution, 5 parts by weight of monomethylamine was added in a cooled state, and then reacted 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.

(Resin production example 6)
The same procedure as in Resin Production Example 1 was carried out except that the amount of resin supplied was 1 kg / hr and the amount of monomethylamine was 10 parts by weight.

(Resin Production Example 7)
The same procedure as in Resin Production Example 3 was performed except that the amount of resin supplied was 1.5 kg / hr and the amount of n-butylamine was 45 parts by weight.

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

(Example 1)
The imide resin obtained in Resin Production Example 1 was dissolved in methylene chloride (resin concentration 25 wt%), applied onto a PET film, and dried to prepare a cast film. A sample having a width of 50 mm and a length of 150 mm was cut out from this film, and a uniaxially stretched film was prepared at a stretching ratio of 2 and a temperature 5 ° C. higher than the glass transition temperature. Table 2 shows the total light transmittance, turbidity, orientation birefringence, in-plane retardation, and thickness direction retardation of this uniaxially stretched film. Moreover, it was 3 * 10 < ^-12 > m < ² > / N when the photoelastic coefficient of this uniaxially stretched film was measured.

(Example 2)
A cast film prepared using the same imide resin as in Example 1 was stretched twice (longitudinal and lateral) and simultaneously biaxially stretched at a temperature 20 ° C. higher than the glass transition temperature (biaxial stretching apparatus X4HD manufactured by Toyo Seiki Co., Ltd.) To prepare a biaxially stretched film. Table 2 shows the total light transmittance, turbidity, in-plane retardation, and thickness direction retardation of this biaxially stretched film.

(Example 3)
Table 1 shows the total light transmittance, turbidity, orientation birefringence, in-plane retardation, and thickness direction retardation of a uniaxially stretched film produced by the same method as in Example 1 using the imide resin obtained in Resin Production Example 2. It is shown in 2.

Example 4
Table 2 shows the total light transmittance, turbidity, in-plane retardation, and thickness direction retardation of a biaxially stretched film prepared by the same method as in Example 2 using the imide resin obtained in Resin Production Example 2. .

(Example 5)
Table 1 shows the total light transmittance, turbidity, orientation birefringence, in-plane retardation, and thickness direction retardation of a uniaxially stretched film prepared by the same method as in Example 1 using the imide resin obtained in Resin Production Example 3. It is shown in 2.

(Example 6)
Table 1 shows the total light transmittance, turbidity, orientation birefringence, in-plane retardation, and thickness direction retardation of a uniaxially stretched film prepared by the same method as in Example 1 using the imide resin obtained in Resin Production Example 4. It is shown in 2.

(Example 7)
Table 1 shows the total light transmittance, turbidity, orientation birefringence, in-plane retardation, and thickness direction retardation of a uniaxially stretched film prepared by the same method as in Example 1 using the imide resin obtained in Resin Production Example 5. It is shown in 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. When the photoelastic coefficient of this film was measured, it was 15 × 10 ⁻¹² m ² / N.

(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 thickness direction retardation of a uniaxially stretched film prepared using this resin in the same manner as in Example 1.

(Comparative Example 3)
The glass transition temperature of Atglass HT121 used in Resin Production Example 2 was 128 ° C. Table 2 shows the total light transmittance, turbidity, orientation birefringence, in-plane retardation, and thickness direction retardation of a uniaxially stretched film prepared using this resin in the same manner as in Example 1.

(Comparative Example 4)
Table 1 shows the imidization ratio and glass transition temperature of the imidized resin obtained in Resin Production Example 6. Table 2 shows the total light transmittance, turbidity, orientation birefringence, in-plane retardation, and thickness direction retardation of a uniaxially stretched film prepared using this resin in the same manner as in Example 1.

(Comparative Example 5)
Table 1 shows the imidization ratio and glass transition temperature of the imidized resin obtained in Resin Production Example 7. Table 2 shows the total light transmittance, turbidity, orientation birefringence, in-plane retardation, and thickness direction retardation of a uniaxially stretched film prepared using this resin in the same manner as in Example 1.

  From the above, it can be seen that all of the imide resins of the present invention have good heat resistance and transparency, have small optical anisotropy, and are useful as a polarizer protective film.

  Next, it shows about the example manufactured using a (meth) acrylic acid ester-aromatic vinyl copolymer.

(Resin production example 8)
An imidized resin was produced using a polymethyl methacrylate-styrene copolymer having a melt viscosity of 5100 poise at 260 ° C. and 122 sec ^{−1 and} monomethylamine as an imidizing agent. The extruder used was a meshing type co-rotating twin screw extruder having 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, polymethyl methacrylate-styrene copolymer is supplied at 1 kg / hr, and the supply amount of monomethylamine is polymethyl methacrylate-styrene copolymer The amount was 30 parts by weight based on the coalescence. At this time, a polymethyl methacrylate-styrene copolymer was introduced from a hopper, the resin was melted and filled with a kneading block, and then monomethylamine was injected from a nozzle. A seal ring and a reverse flight were placed at the end of the reaction zone to fill the resin. By-products 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 a die provided at the exit of the extruder was cooled in a water tank and then pelletized with a pelletizer.

(Resin production example 9)
Resin used was a polymethyl methacrylate-styrene copolymer having a melt viscosity of 4300 poise at 260 ° C. and 122 sec ^{−1, and} the same procedure as in Resin Production Example 8 except that the amount of monomethylamine was 20 parts by weight. .

(Resin production example 10)
The same procedure as in Resin Production Example 8 was performed except that the resin used was a polymethyl methacrylate-styrene copolymer having a melt viscosity of 8200 poise at 260 ° C. and 122 sec ⁻¹ .

(Resin Production Example 11)
The same procedure as in Resin Production Example 8 was performed except that the resin used was a polymethyl methacrylate-styrene copolymer having a melt viscosity of 10500 poise at 260 ° C. and 122 sec ⁻¹ .

  Table 3 shows the melt viscosity, imidization rate, and glass transition temperature of the imide resins obtained in Resin Production Examples 8 to 11.

(Example 8)
The imidized resin obtained in Resin Production Example 8 was dried at 100 ° C. for 5 hours and then extruded at a discharge rate of 20 kg / hr at a cylinder and T die temperature of 250 ° C. using a 40 mmφ single screw extruder and a 400 mm wide T die. Then, the sheet-like molten resin was cooled with a cooling drum to obtain a film having a width of about 600 mm and a thickness of about 150 μm.

Example 9
A film having a thickness of about 150 μm was obtained in the same manner as in Example 8 except that the imidized resin obtained in Resin Production Example 9 was used.

(Example 10)
After the imidized resin obtained in Resin Production Example 8 was dried at 100 ° C. for 5 hours, the cylinder temperature was 250 ° C. and the mold temperature was 50 ° C. using an injection molding machine (clamping pressure: 80 tons). An ASTM No. 1 dumbbell test piece of 3.2 mm (length: 127 mm, width: 12.7 mm) was obtained.

(Example 11)
An ASTM No. 1 dumbbell specimen having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was obtained in the same manner as in Example 10 except that the imidized resin obtained in Resin Production Example 9 was used.

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

(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 imidized resin obtained in Resin Production Example 10 was used.

(Comparative Example 7)
A film having a thickness of about 150 μm was obtained in the same manner as in Example 8 except that the imidized resin obtained in Resin Production Example 10 was used and extruded at 280 ° C. using a 40 mmφ single screw extruder and a 400 mm wide T die. It was.

(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 imidized resin obtained in Resin Production Example 11 was used.

(Comparative Example 9)
A film having a thickness of about 150 μm was obtained in the same manner as in Example 8, except that the imidized resin obtained in Resin Production Example 11 was used and extruded at 280 ° C. using a 40 mmφ single screw extruder and a 400 mm wide T die. It was.

(Comparative Example 10)
An ASTM No. 1 dumbbell specimen having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was obtained in the same manner as in Example 10 except that the imidized resin obtained in Resin Production Example 10 was used.

(Comparative Example 11)
ASTM No. 1 dumbbell having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) in the same manner as in Example 10 except that the imidized resin obtained in Resin Production Example 10 was used and the cylinder temperature was 270 ° C. A specimen was obtained.

(Comparative Example 12)
An ASTM No. 1 dumbbell specimen having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was obtained in the same manner as in Example 10 except that the imidized resin obtained in Resin Production Example 11 was used.

(Comparative Example 13)
ASTM No. 1 dumbbell with a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) in the same manner as in Example 10 except that the imidized resin obtained in Resin Production Example 11 was used and the cylinder temperature was 270 ° C. A specimen was obtained.

  Table 5 shows the total light transmittance, turbidity, thickness unevenness, results of appearance inspection of the films obtained in Comparative Examples 6 to 9, and results of appearance inspection of the dumbbells obtained in Comparative Examples 10 to 13.

  Next, it shows about the example manufactured using a (meth) acrylic acid ester polymer.

(Resin Production Example 12)
An imidized resin was produced using a (meth) acrylic acid ester resin having a melt viscosity of 4200 poise at 260 ° C. and 122 sec ^{−1 and} monomethylamine as an imidizing agent. The extruder used was a meshing type co-rotating twin screw extruder having a diameter of 15 mm. The set temperature of each temperature control zone of the extruder is 230 ° C., the screw rotation speed is 300 rpm, the (meth) acrylic ester resin is supplied at 1 kg / hr, and the supply amount of monomethylamine is the (meth) acrylic ester resin. The amount was 40 parts by weight. At this time, a (meth) acrylic ester resin was introduced from the hopper, and the resin was melted and filled with a kneading block, and then monomethylamine was injected from the nozzle. A seal ring and a reverse flight were placed at the end of the reaction zone to fill the resin. By-products after the reaction and excess methylamine were devolatilized by reducing the pressure at the vent port to -0.08 MPa. The resin that came out as a strand from a die provided at the exit of the extruder was cooled in a water tank and then pelletized with a pelletizer.

(Resin Production Example 13)
The resin used was a (meth) acrylic acid ester resin having a melt viscosity of 7100 poise at 260 ° C. and 122 sec ^{−1, and} the same procedure as in Resin Production Example 12 except that the amount of monomethylamine supplied was 20 parts by weight.

(Resin Production Example 14)
The resin used was a (meth) acrylic acid ester resin having a melt viscosity of 8500 poise at 260 ° C. and 122 sec ^{−1, and} the same procedure as in Resin Production Example 12 except that the amount of monomethylamine supplied was 30 parts by weight.

(Resin Production Example 15)
The resin used was a (meth) acrylic acid ester resin having a melt viscosity of 10100 poise at 260 ° C. and 122 sec ^{−1, and} the same procedure as in Resin Production Example 12 except that the amount of monomethylamine supplied was 20 parts by weight.

  Table 6 shows the melt viscosity, imidization rate, and glass transition temperature of the imide resins obtained in Production Examples 12 to 15.

(Example 12)
The imidized resin obtained in Resin Production Example 12 was dried at 100 ° C. for 5 hours and then extruded at a discharge rate of 20 kg / hr at a cylinder and T die temperature of 250 ° C. using a 40 mmφ single screw extruder and a 400 mm wide T die. Then, the sheet-like molten resin was cooled with a cooling drum to obtain a film having a width of about 600 mm and a thickness of about 150 μm.

(Example 13)
A film having a thickness of about 150 μm was obtained in the same manner as in Example 12 except that the imidized resin obtained in Resin Production Example 13 was used.

(Example 14)
After the imidized resin obtained in Resin Production Example 12 was dried 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 test piece of 3.2 mm (length: 127 mm, width: 12.7 mm) was obtained.

(Example 15)
An ASTM No. 1 dumbbell test piece having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was obtained in the same manner as in Example 14 except that the imidized resin obtained in Resin Production Example 13 was used.

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

(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 imidized resin obtained in Resin Production Example 14 was used.

(Comparative Example 15)
A film having a thickness of about 150 μm was obtained in the same manner as in Example 12 except that the imidized resin obtained in Resin Production Example 14 was extruded at 280 ° C. using a 40 mmφ single screw extruder and a 400 mm wide T-die. It was.

(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 imidized resin obtained in Resin Production Example 15 was used.

(Comparative Example 17)
A film having a thickness of about 150 μm was obtained in the same manner as in Example 12 except that the imidized resin obtained in Resin Production Example 15 was used and extruded at 280 ° C. using a 40 mmφ single screw extruder and a 400 mm wide T die. It was.

(Comparative Example 18)
An ASTM No. 1 dumbbell specimen having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was obtained in the same manner as in Example 14 except that the imidized resin obtained in Resin Production Example 14 was used.

(Comparative Example 19)
ASTM No. 1 dumbbell with a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) in the same manner as in Example 14 except that the imidized resin obtained in Resin Production Example 14 was used and the cylinder temperature was 270 ° C. A specimen was obtained.

(Comparative Example 20)
An ASTM No. 1 dumbbell test piece having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) was obtained in the same manner as in Example 14 except that the imidized resin obtained in Resin Production Example 15 was used.

(Comparative Example 21)
ASTM No. 1 dumbbell having a thickness of 3.2 mm (length: 127 mm, width: 12.7 mm) in the same manner as in Example 14 except that the imidized resin obtained in Resin Production Example 15 was used and the cylinder temperature was 270 ° C. A specimen was obtained.

  Table 8 shows the total light transmittance, turbidity, thickness unevenness, results of appearance inspection of the films obtained in Comparative Examples 14 to 17, and results of appearance inspection of the dumbbells obtained in Comparative Examples 18 to 21.

From the above, it can be seen that each of the imide resins of the present invention has good heat resistance and transparency, has good workability, and is useful as a polarizer protective film.

Claims (24)

An imide resin containing repeating units represented by the following general formulas (1) and (2).

(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 or a cycloalkyl group having 3 to 12 carbon atoms. Or an aryl group having 6 to 10 carbon atoms.)

(Wherein R ⁴ and R ⁵ each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms; R ⁶ represents hydrogen or an alkyl group having 1 to 18 carbon atoms; Represents an alkyl group or an aryl group having 6 to 10 carbon atoms.)   The imide resin according to claim 1, wherein the orientation birefringence is 0.0001 or less.   The imide resin according to claim 1, wherein the orientation birefringence is 0.00001 or less. The imide resin according to claim ^1, wherein the melt viscosity at 260 ° C. and 122 sec ⁻¹ is 14000 poise or less. Furthermore, the imide resin of Claim 4 containing the repeating unit represented by General 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.)   The imide resin according to claim 4, which is produced using a (meth) acrylic acid ester polymer.   The imide resin according to claim 6, wherein the (meth) acrylic acid ester polymer is a methyl methacrylate polymer.   6. The imide resin according to claim 5, which is produced using a (meth) acrylic acid ester-aromatic vinyl copolymer.   The imide resin according to claim 8, wherein the (meth) acrylic acid ester-aromatic vinyl copolymer is a methyl methacrylate-styrene copolymer. 7. The imide resin according to claim 6, wherein the (meth) acrylic acid ester polymer has a melt viscosity of 7000 poise or less at 260 ° C. and 122 sec ⁻¹ . The imide resin according to claim 8, wherein the (meth) acrylic ester-aromatic vinyl copolymer has a melt viscosity of 7000 poise or less at 260 ° C. and 122 sec ⁻¹ .   It manufactures by the method of processing a primary amine to acrylic resin in absence of a solvent, The imide resin of any one of Claims 1-11 characterized by the above-mentioned.   It manufactures by the method of processing a primary amine to acrylic resin in solvent presence, The imide resin of any one of Claims 1-11 characterized by the above-mentioned.   Glass transition temperature is 110 degreeC or more, Imide resin of any one of Claims 1-11 characterized by the above-mentioned.   The primary amine is treated with a (meth) acrylic acid ester polymer or a (meth) acrylic acid ester-aromatic vinyl copolymer in the absence of a solvent. A method for producing the imide resin described in 1.   The optical resin composition which has as a main component the imide resin as described in any one of Claims 2-11.   A molded body comprising the optical resin composition according to claim 16.   A polarizer protective film comprising the optical resin composition according to claim 16.   A polarizer protective film comprising the imide resin according to any one of claims 2 to 11, wherein an in-plane retardation of the film is 10 nm or less, and a thickness direction retardation is 20 nm or less. .   The polarizer protective film according to claim 19, wherein the polarizer protective film is stretched.   The polarizer protective film of Claim 19 which consists of imide resin which contains 1-5 mol% of repeating units represented by General formula (1). The polarizer protective film according to claim 19, wherein the photoelastic coefficient of the imide resin is 10 × 10 ⁻¹² m ² / N or less.   The polarizer protective film according to claim 19, wherein the glass transition temperature of the imide resin is 110 ° C. or higher. A polarizing plate using the polarizer protective film according to claim 19.