Resin composition, film, polarizing sheet, resin composition production method, and film manufacturing method

Abstract

To provide a resin composition which can suppress occurrence of stains on a molding roller and with which a foreign matter is unlikely to be formed in a film; a film; a polarizing sheet; a resin composition production method; and a film manufacturing method.SOLUTION: This resin composition contains, with respect to 100 pts.mass of a polyamide resin, 0.05-10 pts.mass of a compound having 1-3 cyclic ether structures per molecule, and exhibits a haze of 10% or less when being formed into a 200 μm-thick film.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a resin composition, a film, a polarizing sheet, a method for producing a resin composition, and a method for producing a film, and more particularly to a resin composition containing a polyamide resin as a main component. [Background technology]

[0002] Polyamide resins have excellent mechanical properties such as rigidity and strength, as well as excellent heat resistance, and are therefore used in a wide range of applications, including electrical and electronic applications, automobiles, machinery, and building materials (Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-129271 A [Patent Document 2] JP 2013-001906 A [Patent Document 3] JP 2012-131977 A Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, polyamide resins are used in a wide variety of fields, but they are generally poor in transparency and have not been used in applications where transparency is required. Under such circumstances, the present inventors have considered using polyamide resins for transparent applications such as protective films for polarizing films. However, they have found that when polyamide resins are molded into films, the molding rolls become dirty and foreign matter is produced. Although such roll dirt and foreign matter have not been a problem for transparent members and transparent films such as food packaging materials in which polyamide resins have traditionally been used, they have been found to be problematic for applications requiring extremely high transparency such as sunglasses. The present invention aims to solve these problems, and to provide a resin composition that can suppress the occurrence of contamination of a forming roll even when formed into a film, and that is less likely to produce foreign matter in the film, as well as methods for producing a film, a polarizing sheet, and a resin composition, and a method for producing a film. [Means for solving the problem]

[0005] In view of the above problems, the present inventors have conducted studies and have found that the above problems can be solved by using a compound having 1 to 3 cyclic ether structures in one molecule. Specifically, the above problems were solved by the following means. <1> A resin composition comprising 0.05 to 10 parts by mass of a compound having 1 to 3 cyclic ether structures in one molecule per 100 parts by mass of a polyamide resin, the resin composition having a haze of 10% or less when made into a 200 μm-thick film. <2> The content of the filler in the resin composition is 0 to 10% by mass. <1> The resin composition according to claim 1. <3> The polyamide resin includes an aliphatic polyamide resin. <1> or <2> The resin composition according to claim 1. <4> The compound having 1 to 3 cyclic ether structures in one molecule contains an epoxy ring and / or an oxetane ring. <1> ~ <3> 10. The resin composition according to claim 9 . <5> The resin composition has a filler content of 0 to 10% by mass, the polyamide resin contains an aliphatic polyamide resin, and the compound having 1 to 3 cyclic ether structures in one molecule contains an epoxy ring and / or an oxetane ring. <1> The resin composition according to claim 1. <6> For use as a protective film for polarizing sheets. <1> ~ <5> 10. The resin composition according to claim 9 . <7> <1> ~ <6> 2. A film formed from the resin composition according to claim 1. <8> The thickness is 100 to 1000 μm. <7> The film according to claim 1. <9> This is a protective film for polarizing sheets. <7> or <8> The film according to claim 1. <10> A polarizing film and a protective film on at least one surface of the polarizing film, The protective film <7> ~ <9> 2. A polarizing sheet, which is a film according to any one of claims 1 to 11. <11> A method for producing a resin composition, comprising adding 0.05 to 10 parts by mass of a compound having 1 to 3 cyclic ether structures in one molecule to 100 parts by mass of a polyamide resin, and melt-kneading the mixture. <12> The resin composition has a haze of 10% or less when made into a film having a thickness of 200 μm. <11> A method for producing the resin composition according to claim 1. <13> A method for producing a film, comprising adding 0.05 to 10 parts by mass of a compound having 1 to 3 cyclic ether structures in one molecule to 100 parts by mass of a polyamide resin, and melt-kneading the mixture. <14> The haze of the film is 10% or less. <13> A method for producing the film according to claim 1. Effect of the Invention

[0006] It is now possible to provide a resin composition that can suppress the occurrence of contamination of the forming roll even when formed into a film, and that is less likely to produce foreign matter in the film, as well as methods for producing a film, a polarizing sheet, and a resin composition, and a method for producing a film. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a schematic diagram showing a layer structure of the polarizing sheet of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention (hereinafter, simply referred to as "the present embodiment") will be described in detail. Note that the present embodiment is an example for explaining the present invention, and the present invention is not limited to the present embodiment. In this specification, the use of "to" means that the numerical values ​​before and after it are included as the lower limit and upper limit. In this specification, various physical properties and characteristic values ​​are those at 23° C. unless otherwise specified. In this specification, unless otherwise specified, the weight average molecular weight and the number average molecular weight can be measured according to the description in paragraph 0047 of JP2018-165298A, the contents of which are incorporated herein by reference. The terms "film" and "sheet" as used herein refer to generally flat molded bodies that are thin relative to their length and width. The terms "film" and "sheet" as used herein may be single-layer or multi-layer. If the measurement methods, etc. described in the standards shown in this specification vary from year to year, they will be based on the standards as of January 1, 2022, unless otherwise stated.

[0009] The resin composition of the present embodiment is a resin composition containing 0.05 to 10 parts by mass of a compound having 1 to 3 cyclic ether structures in one molecule relative to 100 parts by mass of a polyamide resin, and is characterized in that the haze of the resin composition when made into a film having a thickness of 200 μm is 10% or less. By adopting such a constitution, when the resin composition is molded into a film, the generation of dirt on the molding roll can be suppressed, and foreign matter can be prevented from being generated in the film. It was speculated that the cause of the roll stain was due to diamines and aminocarboxylic acids derived from the raw materials contained in the polyamide resin, or dimers and trimers of the raw material monomers. It was also speculated that the cause of the roll stain was due to decomposition products that may be generated in small amounts when the resin composition is extruded into a film. Therefore, a compound having 1 to 3 cyclic ether structures in one molecule (hereinafter sometimes referred to as a "cyclic ether compound") was blended into the polyamide resin. Such a cyclic ether compound reacts with diamines and aminocarboxylic acids, which are raw material monomers, dimers and trimers of the raw material monomers, or decomposition products that may be generated when the resin composition is extruded into a film. As a result, it was speculated that the diamines and the like derived from the raw materials could be effectively prevented from going out of the film, and the staining of the roll could be suppressed. In addition, if the cyclic ether compound contains a large number of cyclic ether structures, the cyclic ether compound becomes a foreign matter in the film when it reacts with the diamines and the like. In this embodiment, it is speculated that the generation of foreign matter could be suppressed by setting the number of cyclic ether structures in the cyclic ether compound to 3 or less. The present embodiment will be described below.

[0010] <Polyamide resin> The resin composition of the present embodiment contains a polyamide resin. The polyamide resin used in the present embodiment is not particularly limited as long as it does not deviate from the spirit of the present invention, but is preferably an amorphous polyamide resin from the viewpoint of transparency. Here, the amorphous polyamide resin is a polyamide resin that does not have a clear melting point, specifically, a crystalline melting enthalpy ΔHm of less than 5 J / g, preferably 3 J / g or less, more preferably 1 J / g or less. The crystalline melting enthalpy ΔHm is measured in the temperature rise process in accordance with JIS K7121 and K7122, more specifically, according to the description in paragraph 0101 of the specification of Japanese Patent No. 7021725. The polyamide resin used in the present embodiment may be a semi-aromatic polyamide resin or an aliphatic polyamide resin, but is preferably an aliphatic polyamide resin. The aliphatic polyamide resin means that preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 98% by mass or more of the monomers that are the raw materials thereof are aliphatic monomers. Examples of polyamide resins include polyamide resins in which the main components of raw material monomers (for example, 50% by mass or more, preferably 90% by mass or more) are synthesized from diamine and dicarboxylic acid, polyamide resins in which the main components of raw material monomers are synthesized from aminocarboxylic acid, and polyamide resins in which the main components of raw material monomers are synthesized from diamine, dicarboxylic acid, and aminocarboxylic acid. In particular, the polyamide resin used in this embodiment is preferably synthesized from diamine and dicarboxylic acid in which 90% by mass or more (preferably 95% by mass or more, and 100% by mass or less) of the raw material monomers are synthesized. In this embodiment, roll staining can be particularly effectively suppressed for resin compositions using such polyamide resins.

[0011] Examples of the diamine unit include linear or branched aliphatic diamines having 4 to 20 carbon atoms and alicyclic diamines having 6 to 25 carbon atoms, with alicyclic diamines having 6 to 25 carbon atoms being preferred. The linear or branched aliphatic diamine having 4 to 20 carbon atoms is preferably a linear aliphatic diamine having 4 to 20 carbon atoms. The number of carbon atoms constituting the linear or branched aliphatic diamine having 4 to 20 carbon atoms is preferably 6 or more, and is preferably 18 or less, more preferably 16 or less, even more preferably 14 or less, still more preferably 12 or less, and still more preferably 10 or less. Specific examples of the aliphatic diamine having 4 to 20 carbon atoms include 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, and 1,10-decamethylenediamine. The number of carbon atoms constituting the alicyclic diamine having 6 to 25 carbon atoms is preferably 6 or more, more preferably 8 or more, and is preferably 22 or less, more preferably 20 or less, and even more preferably 18 or less. Specific examples of the alicyclic diamine having 6 to 25 carbon atoms include 1,3-bisaminomethylcyclohexane, 1,4-bisaminomethylcyclohexane, 4,4'-methylenebis(2-methylcyclohexylamine), and isophoronediamine.

[0012] Examples of the dicarboxylic acid unit include linear or branched aliphatic dicarboxylic acids having 4 to 20 carbon atoms and alicyclic dicarboxylic acids having 6 to 25 carbon atoms, and linear or branched aliphatic dicarboxylic acids having 4 to 20 carbon atoms are preferred. The linear or branched aliphatic dicarboxylic acid having 4 to 20 carbon atoms is preferably a linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. The number of carbon atoms constituting the linear or branched aliphatic dicarboxylic acid having 4 to 20 carbon atoms is preferably 6 or more, and is preferably 22 or less, more preferably 20 or less, and even more preferably 18 or less. Specific examples of the linear or branched aliphatic dicarboxylic acid having 4 to 20 carbon atoms include adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedioic acid, dodecanedioic acid, etc., with adipic acid and sebacic acid being preferred, and sebacic acid being more preferred. The number of carbon atoms constituting the alicyclic dicarboxylic acid having 6 to 25 carbon atoms is preferably 6 or more, and is preferably 18 or less, more preferably 16 or less, even more preferably 14 or less, still more preferably 12 or less, and even more preferably 10 or less. Specific examples of the alicyclic dicarboxylic acid having 6 to 25 carbon atoms include 1,3-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid.

[0013] The amino carboxylic acid unit is exemplified by an amino carboxylic acid unit having 4 to 20 carbon atoms. The amino carboxylic acid preferably comprises an amino group, a carboxyl group, and an aliphatic group (preferably an alkylene group, more preferably a linear alkylene group). The number of carbon atoms constituting the amino carboxylic acid unit having 4 to 20 carbon atoms is preferably 6 or more, more preferably 8 or more, and is preferably 18 or less, more preferably 16 or less, even more preferably 14 or less, and even more preferably 13 or less. A specific example of the amino carboxylic acid is 11-aminoundecanoic acid.

[0014] An example of the polyamide resin used in this embodiment is polyamide 11. In addition, in another example of the polyamide resin used in the present embodiment, alicyclic diamine units having 6 to 25 carbon atoms and linear aliphatic dicarboxylic acid units having 4 to 20 carbon atoms preferably account for 90 mass% or more of all monomer units, more preferably 95 mass% or more, and may even account for 100 mass%. A specific example of the polyamide resin used in this embodiment is a polyamide resin obtained from 4,4'-methylenebis(2-methylcyclohexylamine) and sebacic acid. A specific example of the polyamide resin used in this embodiment is a polyamide resin obtained from 1,3-bisaminomethylcyclohexane and / or 1,4-bisaminomethylcyclohexane and adipic acid. Another example of the polyamide resin used in this embodiment is a polyamide resin obtained from 1,3-bisaminomethylcyclohexane and / or 1,4-bisaminomethylcyclohexane and adipic acid and 1,4-cyclohexanedicarboxylic acid (the molar ratio of adipic acid to 1,4-cyclohexanedicarboxylic acid is preferably 85-95:15-5). The polyamide resin may be partially substituted with other monomers (diamine, dicarboxylic acid, aminocarboxylic acid, lactam, etc.). The polyamide resin used in the present embodiment may be a commercially available product. Examples of commercially available products include "Trogamid CX7323" manufactured by Daicel-Evonik Co., Ltd., "Grilamide TR90" manufactured by M-Chemie Co., Ltd., and "Rilsan (registered trademark) Clear G350", "Rilsan Clear G850", and "Rilsan Clear G820" manufactured by Arkema, with "Rilsan Clear G850" being particularly preferred.

[0015] In addition to the above, the polyamide resin can be referred to in paragraphs 0169 to 0220 of WO 2021 / 140927, the contents of which are incorporated herein by reference.

[0016] The content of the polyamide resin (preferably an amorphous polyamide resin) in the resin composition of this embodiment is preferably 95% by mass or more, more preferably 96% by mass or more, even more preferably 97% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more in the resin composition. By making it equal to or more than the lower limit, chemical resistance tends to be further improved. In addition, the upper limit of the content of the polyamide resin (preferably an amorphous polyamide resin) in the resin composition of this embodiment is the amount in which the total amount of the polyamide resin and the cyclic ether compound is 100% by mass. The resin composition of the present embodiment may contain only one type of polyamide resin (preferably an amorphous polyamide resin), or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0017] <Compounds having 1 to 3 cyclic ether structures in one molecule> The resin composition of the present embodiment contains 0.05 to 10 parts by mass of a compound having 1 to 3 cyclic ether structures in one molecule (cyclic ether compound) per 100 parts by mass of polyamide resin. By containing the cyclic ether compound, it is possible to effectively prevent the diamine, etc. from adhering to a roll and contaminating the roll when the resin composition is molded into a film by reacting with the diamine, dimers and trimers of the raw material monomers, or decomposition products remaining in the polyamide resin. In this embodiment, the cyclic ether compound preferably has one or two cyclic ether structures. In the present embodiment, the cyclic ether compound preferably contains an epoxy ring and / or an oxetane ring. The molecular weight of the cyclic ether compound is preferably 180 or more, and more preferably 1000 or less, and more preferably 800 or less. By making it equal to or more than the lower limit, the cyclic ether compound itself can be more effectively prevented from volatilizing. In addition, by making it equal to or less than the upper limit, the mass per cyclic ether structure can be reduced, and the amount of the cyclic ether compound to suppress roll staining can be reduced. As a result, the heat resistance (glass transition temperature) of the obtained film can be improved. In this embodiment, when the resin composition contains two or more kinds of cyclic ether compounds, the molecular weight of the cyclic ether compound is the sum of the values ​​obtained by multiplying the molecular weight of each cyclic ether compound by the mass fraction.

[0018] The cyclic ether compound used in the present embodiment preferably contains only carbon atoms, hydrogen atoms, and oxygen atoms as constituent elements. By adopting such a constitution, it is possible to more effectively suppress the contamination of the roll and the generation of foreign matter. The cyclic ether compound used in the present embodiment preferably has three or less aromatic rings in one molecule, and more preferably does not contain any aromatic rings. The fewer aromatic rings, the more likely it is that the compatibility with polyamide resins (particularly aliphatic polyamide resins) will be improved, and the more likely it is that the effects of the present invention will be exhibited.

[0019] The cyclic ether compound used in this embodiment preferably contains an epoxy ring and / or an oxetane ring, is composed of only carbon atoms, hydrogen atoms, and oxygen atoms, has a molecular weight of 180 to 1000, and has 3 or less aromatic rings (preferably 1 or 2) in one molecule. This configuration more effectively prevents the roll from being soiled and prevents the generation of foreign matter. In particular, the cyclic ether compound used in this embodiment preferably has a molecular weight of a compound having 1 to 3 cyclic ether structures in one molecule / number of cyclic ether structures<250.

[0020] The cyclic ether compound used in this embodiment may or may not have a group reactive with an amino group other than the cyclic ether structure. An example of the cyclic ether compound used in this embodiment is a compound that does not have a group reactive with an amino group other than a cyclic ether structure. Another example of the cyclic ether compound used in this embodiment is a compound that does not have an allyl group. The cyclic ether compound used in this embodiment is also preferably a compound having one or two functional groups capable of reacting with an amino group, and at least one of the functional groups capable of reacting with an amino group is an epoxy group or an oxetanyl group. By adopting the above-mentioned configuration, the effects of the present invention tend to be more effectively exhibited.

[0021] The content of the cyclic ether compound in the resin composition of the present embodiment is 0.05 parts by mass or more, preferably 0.08 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 0.2 parts by mass or more, even more preferably 0.3 parts by mass or more, and even more preferably 0.4 parts by mass or more, relative to 100 parts by mass of the polyamide resin. By making it equal to or more than the lower limit, roll dirt tends to be more effectively suppressed. In addition, the upper limit of the content of the cyclic ether compound is 10 parts by mass or less, preferably 8 parts by mass or less, more preferably 5 parts by mass or less, even more preferably 3 parts by mass or less, and may even be less than 2 parts by mass or 1.5 parts by mass or less, relative to 100 parts by mass of the polyamide resin. By making it equal to or less than the upper limit, the glass transition temperature of the resin composition or film can be effectively suppressed from decreasing. In particular, even if a small amount of less than 2 parts by mass is blended, it is highly valuable in that roll dirt can be suppressed. The resin composition of the present embodiment may contain only one type of cyclic ether compound, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range. The resin composition of the present embodiment preferably does not substantially contain compounds having four or more cyclic ether structures in one molecule. "Substantially free" means that the content of compounds having four or more cyclic ether structures in one molecule is less than 10% by mass of the content of compounds having 1 to 3 cyclic ether structures in one molecule, and is preferably 5% by mass or less, more preferably 3% by mass or less, and may be 1% by mass or less.

[0022] <Other ingredients> In addition to the above, the resin composition of the present embodiment may contain a light stabilizer, a heat stabilizer, an antioxidant, an infrared absorber, a hydrolysis resistance improver, an ultraviolet absorber, an antistatic agent, a coloring inhibitor, an antigelling agent, a photochromic dye, and the like. When the resin composition of the present embodiment contains components other than the polyamide resin and the cyclic ether compound, the total content of the components is preferably 0.001% by mass or more of the resin composition, and is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, even more preferably 3% by mass or less, even more preferably 1% by mass or less, more preferably less than 0.2% by mass, and even more preferably less than 0.1% by mass. By adopting such a configuration, the effect of the present invention tends to be more effectively exhibited. These components may be used alone or in combination of two or more. The content of the filler in the resin composition is preferably 0 to 10% by mass, more preferably 0 to 5% by mass, even more preferably 0 to 3% by mass, even more preferably 0 to 1% by mass, even more preferably 0 to 0.1% by mass, even more preferably 0 to 0.01% by mass, and even more preferably substantially free. Substantially free means, for example, that the content of the cyclic ether compound contained in the resin composition is 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less. In addition, in the resin composition of the present embodiment, the total of the polyamide resin and the cyclic ether compound preferably accounts for 99 mass % or more of the resin composition. The resin composition of the present embodiment is preferably a thermoplastic resin composition. The resin composition of the present embodiment is preferably substantially free of a solvent. Substantially free of a solvent means that the content of the solvent is, for example, 10% by mass or less of the content of the cyclic ether compound contained in the resin composition, preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less.

[0023] <Haze> The resin composition of the present embodiment has high transparency. Specifically, the haze of the resin composition when made into a film having a thickness of 200 μm is 10% or less. Such a haze is achieved by using a polyamide resin that is inherently highly transparent, by making the content of the filler in the resin composition 10% by mass or less, and the like. When the resin composition is made into a film having a thickness of 200 μm, the haze is preferably 5% or less, more preferably 3% or less, even more preferably 1.1% or less, even more preferably 0.8% or less, and even more preferably 0.6% or less. The haze of the polyamide resin film for packaging material applications is usually more than 10%, whereas the haze of the resin composition of the present embodiment is remarkably low.

[0024] <Method of producing resin composition> As a method for producing the resin composition of the present embodiment, any method may be adopted. For example, it can be obtained by adding 0.05 to 10 parts by mass of a compound having 1 to 3 cyclic ether structures in one molecule to 100 parts by mass of a polyamide resin, and melt-kneading the mixture. More specifically, the polyamide resin, the compound having 1 to 3 cyclic ether structures in one molecule, and other components added as necessary are mixed using a mixing means such as a V-type blender to prepare a lump-sum blend, which is then melt-kneaded in a vented extruder and pelletized.

[0025] <Film> The film of the present embodiment is formed from the resin composition of the present embodiment. The thickness of the film of this embodiment is preferably 100 μm or more, more preferably 120 μm or more, even more preferably 140 μm or more, even more preferably 160 μm or more, and even more preferably 180 μm or more. The thickness of the film of this embodiment is preferably 1000 μm or less, more preferably 900 μm or less, even more preferably 800 μm or less, even more preferably 600 μm or less, even more preferably 500 μm or less, and may be 300 μm or less. The film of the present embodiment is preferably excellent in transparency. Specifically, the haze is preferably 10% or less, more preferably 5% or less, even more preferably 3% or less, even more preferably 1.1% or less, even more preferably 0.8% or less, and even more preferably 0.6% or less. While the haze of polyamide resin films used for packaging materials and the like is usually more than 10%, the haze of the film of the present embodiment is remarkably low.

[0026] The film of the present embodiment is generally produced by extrusion molding, i.e., is an extrusion molded product. The film of the present embodiment is generally formed using a roll. The film of the present embodiment is preferably, for example, a continuous film. A continuous film is, for example, a film having a length of 10 m or more (preferably 10,000 m or less). The continuous film can be wound into a roll to form a wound body.

[0027] The film of the present embodiment is used in applications requiring high transparency. Specifically, it is preferably used as a protective film for a polarizing sheet, more preferably used as a protective film for a polarizing sheet. In particular, it is preferably used for sunglasses and goggles. That is, in this embodiment, a polarizing sheet is exemplified, which has a polarizing film and a protective film on at least one surface of the polarizing film, and the protective film is the film of this embodiment. FIG. 1 is a schematic diagram showing the layer structure of the polarizing sheet of the present embodiment, in which 1 indicates a polarizing film, 2 indicates a protective film (the film of the present embodiment), and 3 indicates an adhesive layer that bonds the polarizing film and the protective film.

[0028] As the polarizing film, a polyvinyl alcohol-based resin film is preferably used. Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol (PVA) and its derivatives or analogues such as polyvinyl formal, polyvinyl acetal, and poly(ethylene-vinyl acetate) copolymer saponification products, with PVA being preferred. The weight-average molecular weight of the PVA film is preferably 50,000 or more, more preferably 150,000 or more, and is preferably 350,000 or less, more preferably 300,000 or less. The polarizing film is preferably one obtained by stretching and dyeing a polyvinyl alcohol-based resin film, etc. The stretching ratio is preferably 2 times or more, more preferably 3 times or more, and is preferably 8 times or less, more preferably 6.5 times or less. Furthermore, the thickness of the polarizing film is preferably 10 μm or more, more preferably 20 μm or more, and is preferably 50 μm or less, more preferably 40 μm or less.

[0029] When the film of the present embodiment is attached to both sides of the polarizing film, an adhesive can be used. As the adhesive, a polyvinyl alcohol resin-based material, an acrylic resin-based material, a urethane resin-based material, a polyester resin-based material, a melamine resin-based material, an epoxy resin-based material, a silicone-based material, or the like can be used, and a urethane resin-based material is preferable.

[0030] The polarizing sheet of the present embodiment is not limited to the above-mentioned range, and for example, an adhesive layer containing an adhesive that bonds the polarizing film and the film of the present embodiment, which is a protective film, may contain an appropriate amount of a light stabilizer, a heat stabilizer, an antioxidant, an infrared absorbing agent, a hydrolysis resistance improving agent, an ultraviolet absorbing agent, an antistatic agent, a coloring inhibitor, an antigelling agent, a photochromic dye, and the like dissolved therein.

[0031] In addition to the above, the manufacture of polarizing sheets and their uses can be described in International Publication No. 2019 / 054295 and International Publication No. 2014 / 115705, the contents of which are incorporated herein by reference.

[0032] <Film manufacturing method> The method for producing the film of the present embodiment includes adding 0.05 to 10 parts by mass of a compound having 1 to 3 cyclic ether structures in one molecule to 100 parts by mass of a polyamide resin, and melt-kneading the mixture. The obtained film preferably satisfies the above-mentioned film of the present embodiment. More specifically, the film can be produced by extruding the molten resin composition into a sheet and transporting it on a roll. The resin composition preferably satisfies the above-mentioned resin composition of the present embodiment. EXAMPLES

[0033] The present invention will be described in more detail below with reference to examples. The materials, amounts, ratios, processing contents, processing procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments used in the examples are difficult to obtain due to discontinuation or the like, measurements can be made using other instruments with equivalent performance.

[0034] 1. Raw materials The following raw materials were used: A1: Rilsan Clear G850, manufactured by Arkema, a polyamide resin obtained from 4,4'-methylenebis(2-methylcyclohexylamine) and sebacic acid B1: OXT-221, manufactured by Toagosei [ka] B2:2021P, manufactured by Daicel Corporation [ka] B3: OXT-121, manufactured by Daicel [ka] B4:OXT-212, manufactured by Toagosei Co., Ltd. [ka] n is a mixture of 1 to 3. B5: Epogosey PT, manufactured by Yokkaichi Synthetic Co., Ltd. [ka] n is a mixture of 1 to 25. B6: TETRAD-X, manufactured by Mitsubishi Gas Chemical Company, Inc. [ka]

[0035] 2. Examples 1 to 5, Comparative Examples 1 and 2 <Film manufacturing> A polyamide resin film was produced by the following method. Each component listed in Table 1 was weighed out so as to obtain the amount of addition listed in Table 1 (Table 1 shows the amount in parts by mass). After that, the mixture was mixed in a tumbler for 15 minutes, and then extruded into a molten state using a T-die melt extruder consisting of a vented twin-segment extruder (manufactured by Toyo Seiki, "2D30W2") with a barrel diameter of 25 mm and a screw L / D of 30 at a discharge rate of 8 kg / h and a screw rotation speed of 100 rpm. The mixture was then cooled and solidified only by the first roll of a film / sheet take-up device (manufactured by Toyo Seiki, "FT3W20") to produce a polyamide resin film. The cylinder / die head temperature was 290°C, and the roll temperature was 130°C. The final film thickness was adjusted to 200 μm by changing the rolling speed of the first roll.

[0036] <Roll stains> Roll contamination was evaluated by visually checking the presence or absence of roll contamination on the first roll 20 minutes after the start of taking up the resin with the film / sheet take-up device. The evaluation was made as follows: A: No dirt was found on the roll. B: Dirt was found on the roll.

[0037] <Foreign object> The obtained film was visually inspected under fluorescent light to check for the presence of foreign matter. Five experts evaluated the film and the majority vote was used. A: No foreign matter was found B: Foreign matter was found

[0038] <Haze> The haze (unit: %) of the film obtained above was measured using a haze meter under conditions of a D65 light source and a 10° viewing angle. The haze meter used was "HM-150" manufactured by Murakami Color Research Laboratory.

[0039] [Table 1]

[0040] In the above Table 1, the unit of each component is parts by mass. When producing a film formed from the resin composition of this embodiment, no roll stain was observed, and no foreign matter was observed in the obtained film. In addition, the film formed from the resin composition of this embodiment had excellent transparency. [Explanation of symbols]

[0041] 1. Polarizing film 2 Protective film 3 Adhesive layer

Claims

1. A resin composition comprising 0.05 to 10 parts by mass of a compound having 1 to 3 cyclic ether structures in one molecule with respect to 100 parts by mass of a polyamide resin, wherein the resin composition has a haze of 10% or less when formed into a film with a thickness of 200 μm.

2. The resin composition according to claim 1, wherein the filler content in the resin composition is 0 to 10% by mass.

3. The resin composition according to claim 1 or 2, wherein the polyamide resin contains an aliphatic polyamide resin.

4. The resin composition according to claim 1 or 2, wherein the compound having 1 to 3 cyclic ether structures in one molecule contains an epoxy ring and / or an oxetane ring.

5. The filler content in the resin composition is 0 to 10% by mass, the polyamide resin contains an aliphatic polyamide resin, and the compound having 1 to 3 cyclic ether structures in one molecule contains an epoxy ring and / or an oxetane ring. The resin composition according to claim 1.

6. The resin composition according to claim 1, 2 or 5, which is used for a protective film of a polarizing sheet.

7. A film formed from the resin composition according to claim 1, 2 or 5.

8. The film according to claim 7, having a thickness of 100 to 1000 μm.

9. The film according to claim 7, which is a protective film of a polarizing sheet.

10. A polarizing sheet having a polarizing film and a protective film provided on at least one surface of the polarizing film, wherein the protective film is the film according to claim 7.

11. A method for producing a resin composition, comprising adding 0.05 to 10 parts by mass of a compound having 1 to 3 cyclic ether structures in one molecule with respect to 100 parts by mass of a polyamide resin and melt-kneading.

12. The method for producing a resin composition according to claim 11, wherein the resin composition has a haze of 10% or less when formed into a film with a thickness of 200 μm.

13. A method for producing a film, comprising adding 0.05 to 10 parts by mass of a compound having 1 to 3 cyclic ether structures in one molecule with respect to 100 parts by mass of a polyamide resin and melt-kneading.

14. The method for producing a film according to claim 13, wherein the film has a haze of 10% or less.

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