JP2010284840A - Film attached with coating layer, polarizer protecting film and polarization plate using polarizer protecting film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems such as troubles of "break and blanching of a film", "inferior adhesion of a coating layer" in addition to an experimented method for coating the film surface in order to protect the film against scathing and prevent reflection of fluorescent lighting etc. <P>SOLUTION: A coating laminated film has a coating layer formed on at least one side of a film comprising an imide resin which contains the glutarimide unit and the methyl methacrylate unit, with the imidization rate of 0.5 to 5.0%, the acid value of ranging from 0.10 to 0.50 mmol/g, and the acrylic ester unit of less than 1 wt.%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a film having a coating layer made of an imide resin, and more specifically, a polarizer protective film in which a coating layer is applied to an imidized acrylic resin film, and the polarizer protection thereof. The present invention relates to a polarizing plate using a film.

  In recent years, electronic devices have become increasingly smaller, as represented by notebook personal computers, word processors, mobile phones, personal digital assistants, and the like. In an electronic device having a display device such as the electronic device exemplified above, a liquid crystal display device that takes advantage of light weight and compactness is often used.

  In these liquid crystal display devices, various films such as a polarizing film are used in order to maintain the display quality. Furthermore, in these liquid crystal display devices, in order to further reduce the weight of the liquid crystal display device for portable information terminals and mobile phones, a resin film or sheet (hereinafter, unless otherwise specified) A liquid crystal display device using a film) is also put into practical use.

  In this case, the resin film is required to be optically transparent, have low birefringence, and be optically homogeneous in order to handle polarized light. In other words, in a liquid crystal display device, a resin film used in place of a glass substrate is required to have a small phase difference expressed by the product of birefringence and thickness, and in addition to a film caused by external stress or the like. It is required that the phase difference is difficult to change.

  Conventionally, glass lenses have been used in various photographing devices such as cameras, film-integrated cameras, video cameras, optical pickup devices such as CDs and DVDs, and office automation equipment such as projectors. However, in recent years, lenses used in these devices have been replaced with resin lenses for the purpose of weight reduction.

  Such a resin lens is easily affected by a phase difference due to generation of a shift in focal length due to distortion caused by a use environment such as temperature and humidity, or generation of stress during processing such as injection molding. Therefore, the resin lens is also required to have a phase difference that hardly changes due to an external stress, as in the case of a resin film used in a liquid crystal display device or the like.

  By the way, in the liquid crystal display device, a resin film made of an amorphous thermoplastic resin is suitably used as the resin film. More specifically, for example, resin films made of engineering plastics such as polycarbonate, polyarylate, polysulfone, and polyethersulfone, and plastics of celluloses such as triacetyl cellulose can be given. Among them, many resin films made of triacetyl cellulose are disclosed as polarizer protective films in polarizing plates used in liquid crystal display devices, but triacetyl cellulose films have high moisture permeability and are used for polarizers. Since the polyvinyl alcohol impregnated with the dichroic dye is dissolved by water, the ability as a liquid crystal display device is greatly reduced. A number of films made of cyclic polyolefin resins have also been disclosed, but the durability as a polarizer protective film is low, such as significant deterioration against ultraviolet rays emitted from fluorescent lamps. A display device has a problem that its life is short, and therefore a large amount of waste is generated.

  Furthermore, the polarizer protective film may be used on the outermost surface of the liquid crystal panel. In this case, for example, when touched on a surface or in contact with a hard object such as a television or a personal computer, the polarizer protective film is scratched. A so-called visual field in which the color is reversed when viewed from the side, which is a weak point of the liquid crystal panel, in order to prevent it from becoming easily or to prevent reflection of a fluorescent lamp when used indoors. In order to solve the problem that the corner is low, a method of coating the surface of the polarizer protective film has been studied. Also, from the standpoint of preventing scratches, if the panel itself is not protected by a transparent protective material (glass or transparent plastic plate), such as a TV or personal computer, a polarizer protective film is used to improve the scratches. A method of coating the surface with a hard coat layer has been studied. However, in that case, when a triacetyl cellulose resin is used as a polarizer protective film, the solvent resistance is poor, and further, when coating is applied using a low boiling point solvent, problems such as film tearing occur. . In order to improve this, Patent Document 1, Patent Document 2, and Patent Document 3 use a high boiling point solvent such as methyl isobutyl ketone (MIBK). However, the high boiling point solvent has poor drying properties after coating and causes a decrease in productivity. Furthermore, in Patent Document 4, an acrylic resin film diluted with MIBK is used for the purpose of an anchor layer of a polarizing plate, but the anchor effect is insufficient for acrylic resins. Furthermore, a film made of a cyclic polyolefin resin has a drawback that an anchor effect cannot be obtained and a coating layer is not attached.

  Coatings for the purpose of preventing reflection are also disclosed in Patent Documents 5 and 6. The example of Patent Document 5 discloses a coating agent using methyl ethyl ketone (MEK) for a triacetyl cellulose resin film, but this method improves the anchor effect but takes time to dry. There is a problem that the cellulose film is easily broken. Patent Document 6 discloses a coating agent mainly composed of isopropanol on a triacetyl cellulose film, but the anchor effect is not obtained and the adhesion is insufficient.

  Further, Patent Literature 7 and Patent Literature 8 are disclosed as methods for improving the viewing angle. With these methods, a film with a high viewing angle can be obtained, but the acrylic resin of the example has low heat resistance and a large phase difference variation due to dimensional change due to heat. There is a problem that the lifetime is low.

WO06 / 106758 JP 2006-221188 A JP 2002-116323 A JP 2008-58768 A JP 2003-139904 A JP 2006-256310 A JP 2002-139623 A JP 2002-107541 A

The present invention has been made in view of the above-described problems, and is excellent in moisture permeability and can suppress the deterioration of the polarizer. There is no film breakage or whitening during coating, and the adhesion of the coating layer is improved. It is to obtain an excellent coating laminated film.

As a result of intensive studies in view of the above problems, the present inventors have found that the problem can be solved by coating using a diluent that uses a solvent for a specific acrylic resin, and have reached the present invention. That is, the present invention relates to the following.
(I) An imide resin containing a glutarimide unit represented by the following general formula (1) and a methyl methacrylate unit, with an imidization ratio of 2.5 to 5.0% and an acid value of 0.10 to 0.10. A coated laminated film having a coating layer on at least one surface of a film made of an imide resin having a range of 0.50 mmol / g and an acrylic ester unit content of less than 1% by weight.

(Here, R1 and R2 each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R3 represents an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or 6 carbon atoms. Represents 10 to 10 aryl groups.)
(Ii) The coating laminated film according to (i), wherein the thickness is in the range of 10 to 300 μm.

  (Iii) The coating laminated film as described in (i) or (ii), wherein the coating layer is a hard coat layer.

  (Iv) The coating laminate film according to (iii), wherein the hard coat layer forming material contains urethane acrylate.

  (V) An optical film comprising the coating laminated film according to any one of (i) to (iv).

  (Vi) A polarizer protective film comprising the optical film according to (v).

  (Vii) A retardation film comprising the optical film described in (v).

  (Viii) A polarizing plate comprising at least one polarizer protective film according to (vi) and / or a retardation film according to (vii).

  By applying a coating agent diluted with a solvent to an acrylic resin containing an imidized unit according to the present invention, it is excellent in moisture permeability and can suppress the deterioration of the polarizer, and the film is broken during coating. Therefore, it is possible to obtain a coating laminated film excellent in adhesion of the coating layer and a polarizing plate using the same.

An embodiment of the present invention will be described as follows, but the present invention is not limited to this.
The imide resin of the present invention is an imide resin containing a glutarimide unit represented by the following general formula (1) and a methyl methacrylate unit, and the method for producing the imide resin has an acrylate unit of less than 1% by weight. It includes a step of heating and melting a certain polymethyl methacrylate resin and treating with 0.5 to 10 parts by weight of an imidizing agent with respect to 100 parts by weight of the polymethyl methacrylate resin.

(Here, R1 and R2 each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R3 represents an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or 6 carbon atoms. Represents 10 to 10 aryl groups.)
First, a polymethyl methacrylate resin is produced by polymerizing methyl methacrylate.

  In this step, in addition to methyl methacrylate, for example, methyl acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, (meth) Benzyl acrylate, cyclohexyl (meth) acrylate, and the like may be used in combination, but the acrylate unit is less than 1% by weight. More preferably, the methyl acrylate units are less than 0.5% by weight.

  In addition to the above monomers, copolymerize styrene monomers such as styrene, acrylonitrile and methacrylonitrile, and maleimide monomers such as maleimide, N-methylmaleimide, N-phenylmaleimide and N-cyclohexylmaleimide. Is also possible.

  The structure of the polymethyl methacrylate resin is not particularly limited, and may be any of linear (linear) polymer, block polymer, core-shell polymer, branched polymer, ladder polymer, and crosslinked polymer.

  In the case of a block polymer, it may be any of AB type, ABC type, ABA type, and other types of block polymers. In the case of the core-shell polymer, it may be composed of only one core and only one shell, or each may be composed of multiple layers.

The polymerization method is not particularly limited, and known methods such as a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, and a bulk polymerization method are used. Bulk polymerization with low productivity and high productivity is preferably used.
Next, the polymethyl methacrylate resin is heated and melted and treated with an imidizing agent.

  The method of melting by heating and treating with an imidizing agent is not particularly limited, and any conventionally known method can be used. For example, the polymethyl methacrylate resin can be imidized by a method using an extruder, a batch type reaction vessel (pressure vessel) or the like.

  When heat-melting using an extruder and processing with an imidizing agent, the extruder to be used is not particularly limited, and various extruders can be used. Specifically, for example, a single screw extruder, a twin screw extruder, a multi-screw extruder, or the like can be used.

  Among these, it is preferable to use a twin screw extruder. According to the twin screw extruder, it is possible to promote mixing of an imidizing agent (in the case where a ring closing accelerator is used) with respect to the polymethyl methacrylate resin.

  Examples of the twin-screw extruder include 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. Among them, it is preferable to use a meshing type co-rotating type. Since the meshing type co-rotating twin-screw extruder can rotate at a high speed, mixing of the imidizing agent (in the case of using a ring closure accelerator and an imidization agent and a ring closure accelerator) with the raw polymer is further improved. Can be promoted.

The above-exemplified extruders may be used alone, or a plurality of the extruders may be connected in series. For example, a tandem reaction extruder described in JP-A-2008-273140 can be used.
When imidization is performed in an extruder, for example, polymethyl methacrylate resin is charged from the raw material charging part of the extruder, the resin is melted, the inside of the cylinder is filled, and then imidized using an addition pump. By injecting the agent into the extruder, the imidization reaction can proceed in the extruder.
In this case, the reaction zone temperature (resin temperature) in the extruder is preferably 180 ° C. to 270 ° C., more preferably 200 to 250 ° C. When the temperature of the reaction zone (resin temperature) is less than 180 ° C., the imidization reaction hardly proceeds and the heat resistance tends to decrease. When the reaction zone temperature exceeds 270 ° C., the resin is significantly decomposed, so that the bending resistance of the film that can be formed from the obtained imidized resin tends to be lowered. Here, the reaction zone in the extruder refers to a region between the injection position of the imidizing agent and the resin discharge port (die part) in the cylinder of the extruder.
By increasing the reaction time in the reaction zone of the extruder, imidization can be further advanced. The reaction time in the reaction zone of the extruder is preferably longer than 10 seconds, and more preferably longer than 30 seconds. In the reaction time of 10 seconds or less, imidation may hardly proceed.
The resin pressure in the extruder is preferably in the range of atmospheric pressure to 50 MPa, and more preferably in the range of 1 MPa to 30 MPa. If it is less than 1 MPa, the solubility of the imidizing agent is low, and the progress of the reaction tends to be suppressed. On the other hand, if it is 50 MPa or more, the mechanical pressure limit of a normal extruder is exceeded, and a special apparatus is required, which is not preferable in terms of cost.
Moreover, when using an extruder, in order to remove an unreacted imidizing agent and a by-product, it is preferable to attach the vent hole which can be pressure-reduced below atmospheric pressure. According to such a configuration, unreacted imidizing agent, or by-products such as methanol and monomers can be removed.

  In addition, in the production of the imide resin, instead of an extruder, for example, a high viscosity 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. A corresponding reaction apparatus can also be suitably used.

  When manufacturing the said imide resin using a batch type reaction tank (pressure vessel), the structure of the batch type reaction vessel (pressure vessel) is not specifically limited.

  Specifically, the polymethyl methacrylate resin can be melted by heating and stirred, and an imidizing agent (in the case of using a ring closure accelerator, an imidizing agent and a ring closure accelerator) can be added. However, it is preferable to have a structure with good stirring efficiency.

  According to such a batch-type reaction vessel (pressure vessel), it is possible to prevent the polymer viscosity from increasing due to the progress of the reaction and the stirring to be insufficient. As a batch type reaction tank (pressure vessel) having such a structure, for example, a stirred tank Max Blend manufactured by Sumitomo Heavy Industries, Ltd. can be exemplified.

  According to the method as described above, an imide resin in which the ratio of glutarimide units, methyl methacrylate units, carboxylic acid or carboxylic anhydride units is controlled as desired can be easily produced.

  The imidizing agent is not particularly limited as long as it can generate the glutarimide unit represented by the general formula (1). Specifically, for example, an amine containing an aliphatic hydrocarbon group such as methylamine, ethylamine, n-propylamine, i-propylamine, n-butylamine, i-butylamine, tert-butylamine, n-hexylamine, aniline, Mention may be made of aromatic hydrocarbon group-containing amines such as benzylamine, toluidine and trichloroaniline, and alicyclic hydrocarbon group-containing amines such as cyclohexylamine.

  In addition, urea-based compounds that generate amines exemplified above by heating, such as urea, 1,3-dimethylurea, 1,3-diethylurea, and 1,3-dipropylurea, can also be used.

  Of the imidizing agents exemplified above, methylamine, ammonia, and cyclohexylamine are preferably used from the viewpoint of cost and physical properties, and methylamine is particularly preferably used.

  In this imidization step, a ring closure accelerator may be added as necessary in addition to the imidizing agent.

  In this imidization step, the imidizing agent is preferably 0.5 to 10 parts by weight, more preferably 0.5 to 6 parts by weight, based on 100 parts by weight of the polymethyl methacrylate resin. If the addition amount of the imidizing agent is less than 0.5 parts by weight, the imidization rate of the finally obtained resin composition is lowered, so that its heat resistance is remarkably lowered, and appearance defects after molding may be induced. . On the other hand, when the amount exceeds 10 parts by weight, the imidizing agent may remain in the resin and induce appearance defects and foaming after molding.

  In the manufacturing method of this invention, in addition to the said imidation process, the process processed with an esterifying agent can be included.

  Examples of esterifying agents include dimethyl carbonate, 2,2-dimethoxypropane, dimethyl sulfoxide, triethyl orthoformate, trimethyl orthoacetate, trimethyl orthoformate, diphenyl carbonate, dimethyl sulfate, methyl toluene sulfonate, methyl trifluoromethyl sulfonate. , Methyl acetate, methanol, ethanol, methyl isocyanate, p-chlorophenyl isocyanate, dimethylcarbodiimide, dimethyl-t-butylsilyl chloride, isopropenyl acetate, dimethylurea, tetramethylammonium hydroxide, dimethyldiethoxysilane, tetra-N-butoxy Silane, dimethyl (trimethylsilane) phosphite, trimethyl phosphite Trimethyl phosphate, tricresyl phosphate, diazomethane, ethylene oxide, propylene oxide, cyclohexene oxide, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and benzyl glycidyl ether. Among these, dimethyl carbonate is preferable from the viewpoints of cost, reactivity, and the like.

  There is no restriction | limiting in particular as addition amount of an esterifying agent, It sets so that the acid value of imide resin may become a desired value.

  In addition to the esterifying agent, a catalyst may be used in combination. The type of the catalyst is not particularly limited, and examples thereof include trimethylamine, triethylamine, and tributylamine. Among these, triethylamine is preferable from the viewpoint of cost and reactivity.

  The imide resin of the present invention is an imide resin containing a glutarimide unit represented by the following general formula (1) and a methyl methacrylate unit, and has a specific imidization ratio, acid value, and acrylate unit content. It is characterized by being.

  In the general formula (1), R1 and R2 are each independently hydrogen or a methyl group, R3 is preferably hydrogen, a methyl group, a butyl group, or a cyclohexyl group, and R1 is a methyl group R2 is more preferably hydrogen and R3 is more preferably a methyl group.

  The glutarimide resin may include only a single type as a glutarimide unit, or may include a plurality of types in which R1, R2, and R3 in the general formula (1) are different.

The imidation ratio in the imide resin is represented by a ratio of glutarimide units to methyl methacrylate units. This ratio can be measured by, for example, the NMR spectrum, IR spectrum, or other methods of the imide resin. The imidation ratio of the present invention can be measured using ¹ H-NMR BRUKER Avance III (400 MHz). ¹ H-NMR measurement was performed. From the peak area A derived from O-CH ₃ protons of methyl methacrylate in the vicinity of 3.5 to 3.8 ppm and the peak area B derived from N-CH ₃ protons of glutarimide in the vicinity of 3.0 to 3.3 ppm, Obtained by the following equation.

Im% = B / (A + B) × 100
Here, the “imidization rate” refers to the ratio of the imide carbonyl group in the total carbonyl group.
The imidation ratio needs to be 2.5 to 5.0%, preferably 2.5% to 4.5%, and more preferably 3.0 to 4.5%. preferable.

  If the imidation ratio is within the above range, the heat resistance and transparency of the resulting imide resin will not decrease, and the moldability and mechanical strength when processed into a film will not decrease.

  On the other hand, when the imidation ratio is less than the above range, the resulting imide resin tends to have insufficient heat resistance or the transparency may be impaired. On the other hand, if the amount is larger than the above range, the heat resistance and melt viscosity are unnecessarily increased, the molding processability is deteriorated, the mechanical strength during film processing becomes extremely brittle, or the transparency is impaired. Tend.

  The acid value of the imide resin of the present invention represents the content of carboxylic acid units and carboxylic anhydride units in the imide resin. The acid value can be calculated by, for example, a titration method described in WO2005-054311.

  The acid value of the imide resin is required to be 0.10 to 0.50 mmol / g, and preferably 0.15 to 0.45 mmol / g. If the acid value is within the above range, an imide resin having an excellent balance of heat resistance, mechanical properties and molding processability can be obtained.

On the other hand, for example, when the acid value is larger than the above range, foaming of the resin at the time of melt extrusion tends to occur, the moldability tends to be lowered, and the productivity of the molded product tends to be lowered. If the acid value is smaller than the above range, it is necessary to spend more modifying agent to adjust to the acid value, which may increase the cost or induce the generation of a gel-like material due to the remaining of the modifying agent. Therefore, it is not preferable.
The acid value of the imide resin of the present invention represents the content of carboxylic acid units and carboxylic anhydride units in the imide resin. The acid value can be calculated by, for example, a titration method described in JP-A-2005-23272.
The acrylate unit contained in the glutarimide resin of the present invention is less than 1% by weight, preferably less than 0.5% by weight.
If the acrylate unit is within the above range, the imide resin will have excellent thermal stability, but if it exceeds the above range, the thermal stability will deteriorate, and the resin molecular weight and viscosity during resin production or molding will be reduced. There exists a tendency for a fall to fall and for a physical property to deteriorate.
If necessary, the imide resin may further be copolymerized with other units other than glutarimide units, methyl methacrylate units, carboxylic acid or carboxylic anhydride units, and acrylate units.

  Examples of other units include aromatic vinyl monomers such as styrene, nitrile monomers such as acrylonitrile and methacrylonitrile, maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide. A structural unit obtained by copolymerizing a maleimide monomer can be exemplified.

  These other units may be directly copolymerized or graft-copolymerized in the imide resin.

The weight average molecular weight of the imide resin is not particularly limited, but is preferably 1 × 10 ^{4 to} 5 × 10 ⁵ , and more preferably 5 × 10 ⁴ to 2 × 10 ⁵ . If it is in the said range, moldability will not fall or the mechanical strength at the time of film processing will not be insufficient.

  On the other hand, when the weight average molecular weight is smaller than the above range, the mechanical strength when formed into a film tends to be insufficient. Moreover, when larger than the said range, the viscosity at the time of melt-extrusion is high, there exists a tendency for the moldability to fall and for the productivity of a molded article to fall.

  The glass transition temperature of the imide resin is not particularly limited, but is preferably 110 ° C. or higher, and more preferably 120 ° C. or higher. Below this range, the heat resistance when formed into a molded body or film is inferior, so that the change in physical properties at high temperatures becomes large, and the application range becomes narrow. For example, when used in optical applications, if the glass transition temperature is lower than the above range, the molded product or film is likely to be distorted in a high temperature environment, and stable optical characteristics tend not to be obtained. It is not preferable.

  Since the imide resin according to the present invention has the above-described configuration, when forming into a film by the melt extrusion method, it is possible to reduce contamination of a roll of a molding machine and prevent the occurrence of film defects. That is, according to the thermoplastic resin composition of the present invention, a film with few film defects can be produced without contaminating the roll of a molding machine or the like even by film forming by melt extrusion.

  Therefore, the present invention includes a film formed by molding the imide resin according to the present invention.

  Thus, according to the imide resin concerning this invention, the film which can be utilized as an optical film can be manufactured. That is, as a preferred embodiment of the film according to the present invention, an optical film formed by molding the imide resin according to the present invention can be exemplified. Therefore, hereinafter, as an embodiment of the present invention, an optical film according to the present invention will be described, but the present invention is not limited to this. That is, the film according to the present invention may be a film used for any application as long as it is a film formed by molding the imide resin according to the present invention.

  Although the optical film concerning this invention should just be formed by shape | molding the imide resin concerning this invention demonstrated above, it is preferable that it is a stretched film, ie, a stretched film.

  According to the stretched film, the mechanical properties can be improved. Conventionally, in stretched films, it has been difficult to avoid the occurrence of retardation. However, according to the imide resin according to the present invention, even when subjected to a stretching treatment, the retardation is not substantially generated, and the mechanical characteristics are reduced. A stretched film with improved can be produced.

  In addition, when the optical film concerning this invention is a stretched film, the uniaxially stretched film uniaxially stretched may be sufficient, and the biaxially stretched film obtained by combining a extending process may be sufficient.

  When the optical film according to the present invention is a stretched film, the thickness thereof is 10 to 300 μm, preferably 20 to 250 μm, more preferably 25 to 150 μm, and more preferably 30 to 100 μm. Further preferred.

  When the thickness of the film is within the above range, an optical film having uniform optical characteristics and good haze can be obtained.

  On the other hand, if the thickness of the film exceeds the above range, the cooling of the film becomes non-uniform and the optical characteristics tend to be non-uniform. Moreover, when the thickness of the film is less than the above range, the draw ratio becomes excessive, and the haze tends to deteriorate.

  The optical film according to the present invention preferably has a haze of 1% or less, more preferably 0.7% or less, and even more preferably 0.5% or less.

  If the haze of the optical film according to the present invention is within the above range, the transparency of the film can be increased. Therefore, the optical film according to the present invention can be suitably used for applications requiring transparency.

  The optical film according to the present invention preferably has a total light transmittance of 85% or more, and more preferably 88% or more.

  If the total light transmittance is within the above range, the transparency of the film can be increased. Therefore, the optical film according to the present invention can be suitably used for applications requiring transparency.

  The optical film according to the present invention preferably has a small optical anisotropy. In particular, it is preferable that not only the optical anisotropy in the in-plane direction (length direction, width direction) of the film but also the optical anisotropy in the thickness direction is small. In other words, it is preferable that both the in-plane retardation and the thickness direction retardation are small.

  More specifically, the in-plane retardation is preferably 10 nm or less, more preferably 5 nm or less, and further preferably 3 nm or less with respect to the raw material film. The in-plane retardation of the stretched film is preferably 10 nm or less, more preferably 6 nm or less, and further preferably 5 nm or less.

  The thickness direction retardation is preferably 50 nm or less, more preferably 10 nm or less, and further preferably 5 nm or less with respect to the raw material film. Moreover, regarding the stretched film, the thickness direction retardation is preferably 50 nm or less, more preferably 20 nm or less, and further preferably 10 nm or less.

  If it is set as the structure which has such an optical characteristic, the optical film concerning this invention can be used as a polarizer protective film with which the polarizing plate of a liquid crystal display device is equipped.

On the other hand, when the in-plane retardation of the film exceeds 10 nm or the thickness direction retardation exceeds 50 nm, the polarizer protective film using the optical film according to the present invention is used as a polarizing plate of a liquid crystal display device. In some cases, problems such as a decrease in contrast occur in the liquid crystal display device.
In the present specification, for convenience of explanation, a film after the imide resin according to the present invention is formed into a film and before being stretched, that is, an unstretched film is referred to as a “raw film”. It should be noted that the raw film is also an embodiment of the film according to the present invention.

  The in-plane retardation (Re) and the thickness direction retardation (Rth) can be calculated by the following equations, respectively. That is, in an ideal film that is completely optically isotropic in the three-dimensional direction, both the in-plane retardation Re and the thickness direction retardation Rth are zero.

Re = (nx−ny) × d
Rth = | (nx + ny) / 2−nz | × d
In the above formula, nx, ny, and nz are respectively the direction in which the in-plane refractive index is the maximum as the X axis, the direction perpendicular to the X axis as the Y axis, and the thickness direction of the film as the Z axis. Represents the refractive index in each axial direction. D represents the thickness of the film, and || represents an absolute value.

The optical film according to the present invention, the value of the orientation birefringence is preferably from 0 to 0.1 × ^{10 -3,} more preferably 0 to 0.01 × ^{10 -3.}

  If the orientation birefringence is within the above range, stable optical characteristics can be obtained without causing birefringence during molding even when the environment changes.

  In the present specification, unless otherwise specified, “orientation birefringence” is intended to mean birefringence that develops when stretched 100% at a temperature 5 ° C. higher than the glass transition temperature of a thermoplastic resin. The orientation birefringence (Δn) is defined by Δn = nx−ny = Re / d and can be measured by a phase difference meter, using nx and ny described above.

In the optical film according to the present invention, the absolute value of the photoelastic coefficient is preferably 20 × 10 ⁻¹² m ² / N or less, more preferably 10 × 10 ⁻¹² m ² / N or less, More preferably, it is 5 × 10 ⁻¹² m ² / N or less.

  If the photoelastic coefficient is within the above range, even if the optical film according to the present invention is used in a liquid crystal display device, phase difference unevenness occurs, contrast at the periphery of the display screen decreases, or light leakage occurs. There is nothing to do.

On the other hand, when the absolute value of the photoelastic coefficient is larger than 20 × 10 ⁻¹² m ² / N, when the optical film according to the present invention is used in a liquid crystal display device, unevenness in phase difference occurs, There is a tendency that the contrast of the light is reduced or light leakage is likely to occur. This tendency becomes particularly remarkable in a high temperature and high humidity environment.

  In addition, when an external force is applied to an isotropic solid to generate stress (ΔF), it temporarily exhibits optical anisotropy and exhibits birefringence (Δn). By “photoelastic coefficient” is intended the ratio of stress to birefringence. That is, the photoelastic coefficient (c) is calculated by the following equation.

c = △ n / △ F
However, in the present invention, the photoelastic coefficient is a value measured at 23 ° C. and 50% RH at a wavelength of 515 nm by the Senarmon method.

  The optical film according to the present invention is characterized by being subjected to a surface treatment. Specifically, for example, when the optical film according to the present invention is used by applying surface processing such as coating processing to the surface or laminating another film on the surface, the optical film according to the present invention is used. It is preferable to perform a surface treatment.

  By performing such a surface treatment, mutual adhesion between the optical film according to the present invention and another film to be coated or laminated can be improved.

  In addition, the objective of the surface treatment with respect to the optical film concerning this invention is not limited to what aims at an effect. That is, the optical film according to the present invention may be subjected to a surface treatment regardless of its use.

  The surface treatment is not particularly limited, and examples thereof include corona treatment, plasma treatment, ultraviolet irradiation, and alkali treatment. Among these, corona treatment is preferable.

  Moreover, according to the imide resin concerning this invention, a film with a big phase difference can be manufactured by changing the composition ratio of the glutarimide unit represented by the said Chemical formula (1), and a methyl methacrylate unit. That is, the thermoplastic resin composition according to the present invention can be suitably used for producing an optical compensation film such as a retardation film.

  Since the optical film according to the present invention has the characteristics as described above, it can be used as it is as a final product for various applications. Moreover, the range of uses can be expanded by performing various processes as described above.

  Although the use of the optical film according to the present invention is not particularly limited, specifically, for example, imaging fields such as cameras, VTRs, projectors, viewfinders, filters, prisms, and Fresnel lenses, CDs, etc. Optical field for optical discs such as optical discs for CD players, DVD players, MD players, liquid crystal light guide plates, polarizer protective films, retardation films, etc. Information equipment field such as LCD display film and surface protection film, optical communication field such as optical fiber, optical switch and optical connector, automotive field such as automobile headlight, tail lamp lens, inner lens, instrument cover, sunroof, glasses and contact Len , Endoscopic lenses, medical devices such as medical supplies that require sterilization, road translucent plates, pair glass lenses, lighting windows and carports, lighting lenses and covers, and building material sizing It can be suitably used in the field of building materials, microwave cooking containers (tableware) and the like.

  As described above, the optical film according to the present invention is excellent in optical characteristics such as optical homogeneity and transparency. Therefore, it can use especially suitably for well-known optical uses, such as a liquid crystal display periphery, such as an optically isotropic film, a polarizer protective film, and a transparent conductive film, using these optical characteristics.

  The optical film of the present invention can be used as a polarizing plate by being attached to a polarizer. That is, the optical film according to the present invention can be used as a polarizer protective film for a polarizing plate. The polarizer is not particularly limited, and any conventionally known polarizer can be used. Specific examples include a polarizer obtained by adding iodine to stretched polyvinyl alcohol.

  Here, although one Embodiment of the method to manufacture the film concerning this invention is described, this invention is not limited to this. That is, any conventionally known method can be used as long as it is a method capable of producing a film by molding the imide resin according to the present invention.

  Specific examples include injection molding, melt extrusion film molding, inflation molding, blow molding, compression molding, and spinning molding.

  The film according to the present invention can be produced by a solution casting method or a spin coating method in which the imide resin according to the present invention is dissolved in a soluble solvent and then molded.

  Among them, it is preferable to use a melt extrusion method that does not use a solvent. According to the melt extrusion method, it is possible to reduce the burden on the global environment and the working environment due to manufacturing costs and solvents.

  In addition, since the imide resin according to the present invention is used, a film can be produced without causing contamination of the molding machine or film defects due to scattering of the UV absorber even under high temperature molding conditions such as using a T-die film. can do.

  Hereinafter, as an embodiment of a method for producing a film according to the present invention, a method for producing a film by molding the imide resin according to the present invention by a melt extrusion method will be described in detail. In the following description, a film formed by the melt extrusion method is distinguished from a film formed by another method such as a solution casting method and is referred to as a “melt extrusion film”.

  When the imide resin according to the present invention is formed into a film by a melt extrusion method, first, the imide resin according to the present invention is supplied to an extruder and the imide resin is heated and melted.

  The imide resin is preferably pre-dried before being supplied to the extruder. By performing such preliminary drying, foaming of the resin extruded from the extruder can be prevented.

  Although the method of preliminary drying is not particularly limited, for example, the raw material (that is, the imide resin according to the present invention) may be formed into pellets or the like and then performed using a hot air dryer or the like.

  Next, the imide resin heated and melted in the extruder is supplied to the T die through a gear pump and a filter. At this time, if a gear pump is used, the uniformity of the extrusion amount of the resin can be improved and thickness unevenness can be reduced. On the other hand, if a filter is used, the foreign material in an imide resin can be removed and the film excellent in the external appearance without a defect can be obtained.

  Next, the imide resin supplied to the T die is extruded from the T die as a sheet-like molten resin. Then, the sheet-like molten resin is sandwiched between two cooling rolls and cooled to form a film.

  One of the two cooling rolls sandwiching the sheet-like molten resin is a rigid metal roll having a smooth surface, and the other has a metal elastic outer cylinder having a smooth surface and capable of elastic deformation. A flexible roll is preferred.

  With such a rigid metal roll and a flexible roll having a metal elastic outer cylinder, the sheet-like molten resin is sandwiched and cooled to form a film, thereby correcting minute surface irregularities and die lines. Thus, a film having a smooth surface and thickness unevenness of 5 μm or less can be obtained.

  In this specification, “cooling roll” is used to mean “touch roll” and “cooling roll”.

  Even when the rigid metal roll and the flexible roll are used, since the surface of each cooling roll is metal, when the film to be formed is thin, the surfaces of the cooling roll come into contact with each other. The outer surface may be scratched, or the cooling roll itself may be damaged.

  Therefore, when forming a film by sandwiching the sheet-like molten resin between the two cooling rolls as described above, first, the sheet-like molten resin is sandwiched and cooled by the two cooling rolls, and the film is relatively thick. Obtain raw material film once. Thereafter, the raw film is preferably uniaxially or biaxially stretched to produce a film having a predetermined thickness.

  More specifically, when an optical film having a thickness of 40 μm is produced, the sheet-like molten resin is sandwiched and cooled by the two cooling rolls, and a raw material film having a thickness of 150 μm is once obtained. Thereafter, the raw material film may be stretched by biaxial stretching in the vertical and horizontal directions to produce a film having a thickness of 40 μm.

  Thus, when the film according to the present invention is a stretched film, the imide resin according to the present invention is once formed into an unstretched raw material film, and then subjected to uniaxial stretching or biaxial stretching, thereby stretching the film. Can be manufactured.

  When stretching the raw material film, the raw material film may be stretched immediately after the raw material film is formed, or after the raw material film is molded, the raw material film is temporarily stored or moved to stretch the raw material film. You may go.

  In addition, when the raw material film is stretched immediately after being formed into a raw material film, the state of the raw material film may exist only for a very short time (in some cases, instantaneously) in the film manufacturing process.

  Moreover, when the said raw material film is extended | stretched after that, what is necessary is just to maintain the film form of a grade sufficient to be extended | stretched, and does not need to be the state of a perfect film. Moreover, the said raw material film does not need to have the performance as a film which is a finished product.

  The method for stretching the raw material film is not particularly limited, and any conventionally known stretching method may be used. Specifically, for example, transverse stretching using a tenter, longitudinal stretching using a roll, sequential biaxial stretching in which these are sequentially combined, and the like can be used.

  Moreover, the simultaneous biaxial stretching method which extends | stretches the length and the width | variety simultaneously can be used, or the method of performing the horizontal extending | stretching by a tenter can be used after performing roll vertical stretching.

  When the raw material film is stretched, it is preferable that the raw material film is once preheated to a temperature 0.5 to 5 ° C., preferably 1 to 3 ° C. higher than the stretching temperature, and then cooled and stretched to the stretching temperature.

  By preheating within the above range, the thickness of the raw material film can be maintained with high accuracy, and the thickness accuracy of the stretched film does not decrease and thickness unevenness does not occur. Further, the raw material film does not stick to the roll and does not loosen due to its own weight.

  On the other hand, if the preheating temperature of the raw material film is too high, there is a tendency that the raw material film sticks to the roll or is loosened by its own weight. Moreover, if the difference between the preheating temperature and the stretching temperature of the raw material film is small, it tends to be difficult to maintain the thickness accuracy of the raw material film before stretching, thickness unevenness increases, or the thickness accuracy tends to decrease.

  In addition, when the imide resin according to the present invention is stretched after being formed into a raw material film, it is difficult to improve the thickness accuracy by utilizing a necking phenomenon. Therefore, in the present invention, it is important to manage the preheating temperature in order to maintain or improve the thickness accuracy of the obtained optical film.

  The stretching temperature when stretching the raw material film is not particularly limited, and may be changed according to the mechanical strength, surface property, thickness accuracy, and the like required for the stretched film to be produced.

  In general, when the glass transition temperature of the raw material film obtained by the DSC method is defined as Tg, a temperature range of (Tg−30 ° C.) to (Tg + 30 ° C.) is preferable, and (Tg−20 ° C.) to (T Tg + 20 ° C. is more preferable, and a temperature range of (Tg) to (Tg + 20 ° C.) is more preferable.

  When the stretching temperature is within the above temperature range, thickness unevenness of the obtained stretched film can be reduced, and further, mechanical properties such as elongation, tear propagation strength, and fatigue resistance can be improved. Moreover, generation | occurrence | production of the trouble that a film adheres to a roll can be prevented.

  On the other hand, when the stretching temperature is higher than the above temperature range, the thickness unevenness of the stretched film obtained becomes large, or the mechanical properties such as elongation rate, tear propagation strength, and fatigue resistance cannot be sufficiently improved. There is. Furthermore, there is a tendency that troubles such as the film sticking to the roll tend to occur.

  In addition, when the stretching temperature is lower than the above temperature range, the haze of the stretched film to be obtained becomes large, or in extreme cases, there is a tendency that process problems such as tearing or cracking of the film occur. is there.

  When the raw material film is stretched, the stretch ratio is not particularly limited, and may be determined according to the mechanical strength, surface properties, thickness accuracy, and the like of the stretched film to be produced. Although it depends on the stretching temperature, the stretching ratio is generally preferably selected in the range of 1.1 to 3 times, more preferably in the range of 1.3 to 2.5 times. Preferably, it is more preferable to select in the range of 1.5 times to 2.3 times.

  If the draw ratio is within the above range, the mechanical properties such as the elongation rate of the film, tear propagation strength, and fatigue resistance can be greatly improved. Therefore, it is possible to produce a stretched film having a thickness unevenness of 5 μm or less, a birefringence of substantially zero, and a haze of 1% or less.

  In the imide resin according to the present invention, the mixing ratio of the imide resin and the ultraviolet absorber is adjusted in the above range, and by selecting appropriate stretching conditions, substantially without causing birefringence, And a film with small thickness nonuniformity can be manufactured easily, without accompanying the increase in haze substantially.

  The present invention is characterized by having a coating layer on at least one surface of a film made of the imide resin according to the present invention. Specific examples of the method for forming the coating layer include a method of laminating another film with an adhesive or the like, and a method of forming a coating layer such as a hard coat layer on the surface, but is not limited thereto. It is not something.

  The types of surface treatment are as described above. In the film according to the present invention, when the surface treatment is performed, the degree of the surface treatment is not particularly limited, but is preferably 50 dyn / cm or more, and is 50 dyn / cm to 80 dyn / cm or less. It is more preferable.

  With such a surface treatment, the surface treatment can be performed using a conventionally known surface treatment facility. Examples thereof include a bar coater method, a die coater method, a gravure method, and a micro gravure method. An official method can be selected according to the viscosity of the coating liquid to be used and the thickness to be coated.

  The hard coat layer described above includes fluorine-containing polyfunctional oligomers, silicon-containing polyfunctional oligomers, urethane acrylate polyfunctional oligomers, etc., but from the viewpoint of cost and ease of handling, urethane acrylate polyfunctional Oligomers are preferably used.

  The solvent for dilution used for the surface treatment is not particularly limited, but any one of ethyl acetate, toluene, 2-butanone, 4-methyl-2-pentanone, acetone, methylene chloride, chloroform, or A mixture of two or more is preferred. With solvents other than these, the adhesiveness of the coating layer tends to decrease or the film is torn.

  There is no problem if the drying temperature is adjusted according to the boiling point of the solvent used, and a known drying furnace or drying oven may be used. A solvent having a high boiling point is not preferable because the drying temperature increases and the film melts.

  The method for curing the coating layer is not particularly limited, and examples thereof include a known thermosetting method, ultraviolet irradiation method, electron beam irradiation method, and moisture absorption curing method. In particular, the ultraviolet irradiation method is preferably used in terms of versatility, productivity, and cost.

  The present invention is not limited to the configurations described above, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments are appropriately combined. The obtained embodiment is also included in the technical scope of the present invention.

  The present invention will be described more specifically based on examples and comparative examples, but the present invention is not limited to this. Those skilled in the art can make various changes, modifications, and alterations without departing from the scope of the present invention.

(TGA measurement)
Using a thermogravimetry apparatus (TGA-50; Shimadzu Corporation), the sample was heated on an open aluminum pan under a nitrogen stream (flow rate: 50 mL / min) at a rate of temperature increase of 10 ° C./min. The weight when the temperature reached 100 ° C. was 100%. Further, the temperature was increased, and the temperature when the weight decreased by 1% was defined as a 1% weight loss temperature (TGA).

(Calculation of imidization rate)
¹ H-NMR ¹ H-NMR measurement of the resin was performed using BRUKER Avance III (400 MHz). From the peak area A derived from O-CH ₃ protons of methyl methacrylate in the vicinity of 3.5 to 3.8 ppm and the peak area B derived from N-CH ₃ protons of glutarimide in the vicinity of 3.0 to 3.3 ppm, Obtained by the following equation.

Im% = B / (A + B) × 100
Here, the “imidization rate” refers to the ratio of the imide carbonyl group in the total carbonyl group.
(Calculation of styrene content)
The raw material MS resin (about 10 mg) was dissolved in deuterated chloroform (about 4 mL), and a ¹ H-NMR spectrum of the solution was measured using a Varian NMR measuring apparatus Gemini-300.

From the obtained ¹ H-NMR spectrum, it is attributed to the aromatic-derived proton of the styrene unit at δ = 7.4 to 6.8 and the ester of the methyl methacrylate unit at δ = 3.8 to 2.2. The amount of styrene was determined from the integral intensity ratio of protons.

(Glass-transition temperature)
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.

(Haze measurement)
Based on the method of JIS K7136, it measured using Nippon Denshoku Industries Co., Ltd. turbidimeter NDH-300A.

(Total light transmittance measurement)
Based on the method of JIS K 7361-1, it measured using Nippon Denshoku Industries Co., Ltd. turbidimeter NDH-300A.

(In-plane retardation Re and thickness direction retardation Rth measurement)
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).
(Acid value measurement)
0.3 g of the resin was dissolved in 37.5 mL of methylene chloride, and 37.5 mL of methanol was further added. Next, 5 mL of 0.1 mmol% sodium hydroxide aqueous solution and several drops of ethanol solution of phenolphthalein were added. Next, back titration was performed using 0.1 mmol% hydrochloric acid, and the acid value was determined from the amount of hydrochloric acid required for neutralization.

The performance of the coating film was determined by the following method.
(Coating performance)
When a coating agent containing a solvent was applied, film tearing and whitening were visually evaluated from the following viewpoints.
○: No tearing or whitening ×: Tearing or whitening is observed (pencil hardness)
The load was set to 4.9 N, and the measurement was performed according to JIS K 5400-5-4. Moreover, the tear of the base material in that case was evaluated visually from the following viewpoint.
○: No tear ×: There is tear (adhesion)
In accordance with JIS G 3312, a cross-cut test using slits was performed. In order not to damage the base film, the number of peeled pieces in a total of 100 squares of 10 × 10 squares with an interval of 1 mm of 120 mm × 120 mm was expressed numerically using a slit plate. The unit is pieces / 100 pieces. When tearing to the base film, it was written as “x”.
(Degradation of polarizing plate)
http: // www. asahi-net. or. jp / ˜uu9m-hrt / henkou / henkouban. Create a polarizer according to “Production of Polarized Teaching Material and Polarizing Plate (Film)” written by html (Osaka Prefectural Education Center Science 1st Room, Satoshi Hirata). It was left for 2000 hours in an environment of ° C and 95% RH. The color tone of the polarizing plate after standing was visually determined from the following viewpoint.
○: No change was observed even after 2000 hours.
Δ: The color of the polarizer is slightly faded after 2000 hours.
X: After 2000 hours, the polarizer has no color, or the polarizer base material (polyvinyl alcohol) has disappeared.
(Production Example 1)
A resin was produced using a tandem reaction extruder in which two extrusion reactors were arranged in series. As for the tandem type reactive extruder, the first extruder (1) and the second extruder (2) are both in the same direction meshing type with a diameter of 75 mm and L / D (ratio of the length L to the diameter D of the extruder) of 74. Using a twin-screw extruder, the raw material resin was supplied to the raw material supply port of the first extruder using a constant weight feeder (manufactured by Kubota Corporation). The degree of vacuum of each vent in the first extruder and the second extruder was set to -0.095 MPa. Further, the pressure control mechanism in the component connecting the first extruder and the second extruder with a pipe having a diameter of 38 mm and a length of 2 m and connecting the resin discharge port of the first extruder and the raw material supply port of the second extruder includes A constant flow pressure valve was used. The resin (strand) discharged from the second extruder was cooled by a cooling conveyor and then cut by a pelletizer to form pellets. Here, the outlet of the first extruder, the first extruder and the second extruder are used to adjust the pressure in the part connecting the resin discharge port of the first extruder and the raw material supply port of the second extruder, or to determine the fluctuation of the extrusion. A resin pressure gauge was provided at the center of the machine connecting part and at the outlet of the second extruder.
Regarding the first extruder, a polymethyl methacrylate resin (Mw: 105,000) was used as a raw material resin, and monomethylamine was used as an imidizing agent to produce an imide resin intermediate 1. At this time, the maximum temperature of the extruder was 280 ° C., the screw rotation speed was 55 rpm, the raw material resin supply amount was 150 kg / hour, and the addition amount of monomethylamine was 2.0 parts with respect to 100 parts of the raw material resin. Moreover, the constant flow pressure valve was installed just before the 2nd extruder raw material supply port, and the 1st extruder monomethylamine press-fit part pressure was adjusted so that it might be set to 8 Mpa.
Regarding the second extruder, after devolatilizing the imidization reaction reagent and by-products remaining in the rear vent and vacuum vent, a mixed solution of dimethyl carbonate and triethylamine is added as an esterifying agent to produce an imide resin intermediate 2 did. At this time, each barrel temperature of the extruder was 260 ° C., the screw rotation speed was 55 rpm, the addition amount of dimethyl carbonate was 3.2 parts with respect to 100 parts of the raw material resin, and the addition amount of triethylamine was 0. 8 parts. Furthermore, after removing the esterifying agent with a vent, the resin composition was obtained by extruding from a strand die, cooling in a water tank, and pelletizing with a pelletizer.
The imidation ratio of this resin composition was 3.7%, and the acid value was 0.29 mmol / g.
After drying this pellet-shaped resin composition at 100 ° C. for 5 hours, the sheet-shaped molten resin obtained by extruding at 270 ° C. using a 40 mmφ single screw extruder and a 400 mm wide T-die is cooled with a cooling roll. Upon cooling, a film having a width of 300 mm and a thickness of 130 μm was obtained.
The film was subjected to simultaneous biaxial stretching (biaxial stretching device X4HD manufactured by Toyo Seiki Co., Ltd.) at a stretching ratio of 2 times (longitudinal and lateral) and a temperature 10 ° C. higher than the glass transition temperature to prepare a biaxially stretched film.
This biaxially stretched film had an in-plane retardation of 0.1 nm and a thickness direction retardation of 3.4 nm.
Example 1
UV-1700B (manufactured by Nippon Gosei Kagaku), a commercial product of urethane acrylate oligomer, is dissolved in ethyl acetate at a concentration of 33%, and Irgacure 184 (manufactured by Ciba, photopolymerization) with respect to 100 parts by weight of UV-1700B. 5 parts of an initiator was added and dissolved to obtain a coating liquid (a). The biaxially stretched film (A) obtained in Production Example 1 is cut into an A4 size and allowed to stand, and a coating liquid (a) is applied on the wet base to a thickness of 15 μm using a bar coater # 6. did. The coating film was left in a drying oven adjusted to 90 ° C. for 1 minute to dry the solvent. Using a UV irradiator equipped with a metal halide lamp, this dried product was photocured with an irradiation energy of 300 mJ / cm 2 to obtain a coating film (B-1) having a coating layer of 5 μm. The coating performance, pencil hardness, adhesion, and deterioration of the polarizing plate of the obtained coating film (B-1) were evaluated by the above methods. The results are shown in Table 1.
(Example 2)
The same method as in Example 1 was used except that Kayanova FOP-4000 (manufactured by Nippon Kayaku Co., Ltd., coating liquid for coating, toluene, 2-butanone-containing 50% solution) was used as the coating liquid. A coating film (B-2) having a coating layer of 7.5 μm was obtained. The coating performance, pencil hardness, adhesion, and deterioration of the polarizing plate of the obtained coating film (B-2) were evaluated by the above methods. The results are shown in Table 1.
(Comparative Example 1)
A resin film was coated in the same manner as in Example 1 except that KC4UY (manufactured by Konica Minolta Opto), which is a 40 μm thick triacetyl cellulose film, was used, and a coating film (B-3) having a coating layer of 5 μm was used. ) The coating performance of the obtained coating film (B-3), pencil hardness, adhesion, and deterioration of the polarizing plate were evaluated by the above methods. The results are shown in Table 1.
(Comparative Example 2)
A coating film (B-4) having a coating layer of 5 μm was applied in the same manner as in Example 1 except that the resin film was an acrylic resin film having a thickness of 40 μm, Sanduren 014NRT (manufactured by Kaneka Corporation). Got. The coating performance, pencil hardness, adhesion, and deterioration of the polarizing plate of the obtained coating film (B-4) were evaluated by the above methods. The results are shown in Table 1.
(Comparative Example 3)
The resin film was coated in the same manner as in Example 2 except that a 50 μm thick polyethylene sheet (manufactured by Tokai Polytechnics) was used to obtain a coating film (B-5) having a coating layer of 7.5 μm. It was. The coating performance of the obtained coating film (B-5), pencil hardness, adhesion, and deterioration of the polarizing plate were evaluated by the above methods. The results are shown in Table 1.

From Table 1, it can be seen that the coating film of the present invention is excellent in surface hardness, has good adhesion to the substrate film, and suppresses deterioration of the polarizing plate.

Claims (8)

It is an imide resin containing a glutarimide unit represented by the following general formula (1) and a methyl methacrylate unit, the imidation ratio is 2.5 to 5.0%, and the acid value is 0.10 to 0.50 mmol. A coating laminated film comprising a coating layer on at least one surface of a film made of an imide resin having an acrylic ester unit content of less than 1% by weight in a / g range.

(Here, R1 and R2 each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R3 represents an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or 6 carbon atoms. Represents 10 to 10 aryl groups.) The coating laminated film according to claim 1, wherein the thickness is in the range of 10 to 300 μm. The coating laminated film according to claim 1 or 2, wherein the coating layer is a hard coat layer. The coating laminated film according to claim 3, wherein the hard coat layer forming material contains urethane acrylate. An optical film comprising the coating laminated film according to claim 1. A polarizer protective film comprising the optical film according to claim 5. A retardation film comprising the optical film according to claim 5. A polarizing plate comprising at least one polarizer protective film according to claim 6 and / or a retardation film according to claim 7.