Resin composition, film, polarizing sheet, method for manufacturing the resin composition, and method for manufacturing the film.

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. In particular, it relates to a resin composition containing a polyamide resin as a main component.

Background Art

[0002] Polyamide resins are excellent in mechanical properties such as rigidity and strength, and heat resistance, and are thus used in a wide variety of fields such as electric and electronic, automotive, machinery, and building materials (Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] As described above, polyamide resins are used in a wide variety of fields, but they are generally resins with poor transparency and have not been used in applications where transparency is required. Under such circumstances, the present inventor has considered using polyamide resins in transparent applications such as protective films for polarizing films. However, it has been found that when polyamide resins are formed into films, dirt is generated on the forming rolls or foreign substances are formed. Such roll dirt and foreign substances have not been a problem in conventional transparent members and transparent films such as food packaging materials where polyamide resins have been used, but have been found to be a problem in applications where very high transparency is required 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 molding rolls and prevent the formation of foreign matter on the film, even when formed into a film, as well as a method for manufacturing a film, a polarizing sheet, a resin composition, and a method for manufacturing a film. [Means for solving the problem]

[0005] Based on the above problems, the inventors conducted investigations and found that the above problems were solved by using a compound having 1 to 3 cyclic ether structures in one molecule. Specifically, the above problem was 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, wherein the haze when formed into a 200 μm thick film is 10% or less. <2> The filler content in the resin composition is 0 to 10% by mass. <1> The resin composition described above. <3> The polyamide resin includes an aliphatic polyamide resin. <1> or <2> The resin composition described above. <4> The compound having 1 to 3 of the aforementioned cyclic ether structures in one molecule includes an epoxy ring and / or an oxetane ring. <1> ~ <3> A resin composition as described in any one of the following. <5> The resin composition contains 0 to 10% by mass of filler, the polyamide resin includes an aliphatic polyamide resin, and the compound having 1 to 3 cyclic ether structures in one molecule includes an epoxy ring and / or an oxetane ring. <1> The resin composition described above. <6> It is for use as a protective film for polarizing sheets. <1> ~ <5> A resin composition as described in any one of the following. <7> <1> ~ <6> A film formed from any one of the resin compositions described in the following. <8> The thickness is 100 to 1000 μm. <7> The film described above. <9> This is a protective film for polarizing sheets. <7> or <8> The film described above. <10> It comprises a polarizing film and a protective film on at least one surface of the polarizing film, The aforementioned protective film <7> ~ <9> A polarizing sheet, which is a film described in one of the following terms. <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 per molecule to 100 parts by mass of a polyamide resin, and then melt-kneading the mixture. <12> The resin composition has a haze of 10% or less when it is made into a 200 μm thick film. <11> A method for producing the resin composition described above. <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 per molecule to 100 parts by mass of a polyamide resin, and melt-kneading the mixture. <14> The haze of the aforementioned film is 10% or less. <13> A method for manufacturing the film described above. [Effects of the Invention]

[0006] Even when forming into a film, the occurrence of contamination on the molding roll can be suppressed, and foreign matter is less likely to form on the film. This also provides a resin composition, a film, a polarizing sheet, a method for manufacturing the resin composition, and a method for manufacturing the film. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram showing the layer structure of the polarizing sheet in this embodiment. [Modes for carrying out the invention]

[0008] The following describes in detail embodiments for carrying out the present invention (hereinafter simply referred to as "this embodiment"). Note that the following embodiment is illustrative for explaining the present invention, and the present invention is not limited to this embodiment. In this specification, "~" is used to mean that the numbers before and after it are included as the lower and upper limits, respectively. In this specification, all physical properties and characteristic values ​​shall be those at 23°C unless otherwise specified. In this specification, unless otherwise specified, weight-average molecular weight and number-average molecular weight may be measured in accordance with paragraph 0047 of Japanese Patent Application Publication No. 2018-165298, which is incorporated herein by reference. In this specification, "film" and "sheet" refer to molded articles that are thin in thickness relative to their length and width, and are generally flat. Furthermore, "film" and "sheet" in this specification may be single-layer or multi-layer. If the measurement methods, etc., described in the standards shown herein differ from year to year, unless otherwise specified, the standards as of January 1, 2022 shall apply.

[0009] The resin composition of this embodiment is a resin composition comprising 100 parts by mass of polyamide resin and 0.05 to 10 parts by mass of a compound having 1 to 3 cyclic ether structures in one molecule, characterized in that the haze when formed into a 200 μm thick film is 10% or less. By adopting such a configuration, when the resin composition is formed into a film, the occurrence of contamination of the molding roll can be suppressed and foreign matter can be less likely to form on the film. The cause of the aforementioned roll fouling was presumed to be 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 presumed that the cause of the roll fouling was due to decomposition products that may be generated in small amounts when the resin composition is extruded into a film. Therefore, it was decided to incorporate a compound having 1 to 3 cyclic ether structures in one molecule (hereinafter sometimes referred to as "cyclic ether compound") into the polyamide resin. Such a cyclic ether compound reacts with the raw material monomers, diamines and aminocarboxylic acids, 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 presumed that the leakage of diamines and the like derived from the raw materials into the film could be effectively suppressed, thereby suppressing roll fouling. Furthermore, if the cyclic ether compound contains a large number of cyclic ether structures, when the cyclic ether compound reacts with the aforementioned diamines and the like, it can become foreign matter in the film. In this embodiment, it is presumed that the generation of foreign matter could be suppressed by limiting the number of cyclic ether structures in the cyclic ether compound to 3 or less. The following describes this embodiment.

[0010] <Polyamide resin> The resin composition of this embodiment includes a polyamide resin. The polyamide resin used in this embodiment is not particularly specified, as long as it does not depart from the spirit of the present invention, but from the viewpoint of transparency, an amorphous polyamide resin is preferred. Here, amorphous polyamide resin refers to a polyamide resin that does not have a clear melting point, and specifically, has a crystal melting enthalpy ΔHm of less than 5 J / g, preferably 3 J / g or less, and more preferably 1 J / g or less. The crystal melting enthalpy ΔHm shall be measured in accordance with JIS K7121 and K7122, and more specifically, according to paragraph 0101 of the specification of Japanese Patent No. 7021725. The polyamide resin used in this 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 still more preferably 98% by mass or more of the monomers as its raw materials are aliphatic monomers. Examples of the polyamide resin include polyamide resins synthesized from diamines and dicarboxylic acids, where the main component (e.g., 50% by mass or more, preferably 90% by mass or more) of the raw material monomers is composed of diamines and dicarboxylic acids; polyamide resins synthesized from aminocarboxylic acids, where the main component of the raw material monomers is aminocarboxylic acids; and polyamide resins synthesized from diamines, dicarboxylic acids, and aminocarboxylic acids. In particular, for the resin composition using such a polyamide resin in this embodiment, roll fouling can be suppressed particularly effectively.

[0011] Examples of the diamine units include linear or branched aliphatic diamines having 4 to 20 carbon atoms and alicyclic diamines having 6 to 25 carbon atoms, and alicyclic diamines having 6 to 25 carbon atoms are preferred. As the linear or branched aliphatic diamine having 4 to 20 carbon atoms, a linear aliphatic diamine having 4 to 20 carbon atoms is preferred. The number of carbon atoms constituting the linear or branched aliphatic diamine having 4 to 20 carbon atoms is preferably 6 or more, preferably 18 or less, more preferably 16 or less, still more preferably 14 or less, even more preferably 12 or less, and even 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, 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-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 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, 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., and adipic acid and sebacic acid are preferred, and sebacic acid is more preferred. The number of carbon atoms constituting the alicyclic dicarboxylic acid having 6 to 25 carbon atoms is preferably 6 or more, 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] Examples of the aminocarboxylic acid units include aminocarboxylic acid units having 4 to 20 carbon atoms. The aminocarboxylic acid preferably consists of 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 aminocarboxylic acid unit having 4 to 20 carbon atoms is preferably 6 or more, more preferably 8 or more, 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 an aminocarboxylic acid is 11-aminoundecanoic acid.

[0014] An example of a polyamide resin used in this embodiment is polyamide 11. Furthermore, as another example of the polyamide resin used in this embodiment, it is preferable that alicyclic diamine units having 6 to 25 carbon atoms and linear aliphatic dicarboxylic acid units having 4 to 20 carbon atoms account for 90% or more by mass of the total monomer units, more preferably 95% or more by mass, and may also account for 100% by 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. Specific examples of the polyamide resin used in this embodiment include a polyamide resin obtained from 1,3-bisaminomethylcyclohexane and / or 1,4-bisaminomethylcyclohexane and adipic acid. Furthermore, other examples of the polyamide resin used in this embodiment include a polyamide resin obtained from 1,3-bisaminomethylcyclohexane and / or 1,4-bisaminomethylcyclohexane, adipic acid and 1,4-cyclohexanedicarboxylic acid (preferably with a molar ratio of adipic acid to 1,4-cyclohexanedicarboxylic acid being 85-95:15-5). The polyamide resin may be partially substituted with other monomers (diamines, dicarboxylic acids, aminocarboxylic acids, lactams, etc.). The polyamide resin used in this embodiment may be a commercially available product. Examples of commercially available products include "TrogamidCX7323" manufactured by Daicel-Evonik Corporation, "Grilamid TR90" manufactured by M-Scheme Corporation, and "Rilsan® 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 descriptions in paragraphs 0169-0220 of International Publication No. 2021 / 140927 can be considered for polyamide resins, and these contents are incorporated herein by reference.

[0016] The content of polyamide resin (preferably 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. Achieving a content above the lower limit tends to further improve chemical resistance. Furthermore, the upper limit of the polyamide resin (preferably amorphous polyamide resin) content in the resin composition of this embodiment is the amount at which the total amount of polyamide resin and cyclic ether compound reaches 100% by mass. The resin composition of this embodiment may contain only one type of polyamide resin (preferably amorphous polyamide resin), or it may contain two or more types. When two or more types are included, it is preferable that the total amount is within the above range.

[0017] <Compounds containing 1 to 3 cyclic ether structures in a single molecule> The resin composition of this 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 including the cyclic ether compound, it reacts with the raw material monomers remaining in the polyamide resin, such as diamine, dimers or trimers of the raw material monomers, or decomposition products, and effectively suppresses the adhesion of diamine and the like to the rolls and contamination of the rolls when the resin composition is formed into a film. In this embodiment, it is preferable that the number of cyclic ether structures in the cyclic ether compound be one or two. Furthermore, in this embodiment, it is preferable that the cyclic ether compound includes an epoxy ring and / or an oxetane ring. The molecular weight of the cyclic ether compound is preferably 180 or more, preferably 1000 or less, and more preferably 800 or less. Setting it above the lower limit more effectively suppresses the volatilization of the cyclic ether compound itself. Setting it below the upper limit reduces the mass per cyclic ether structure, allowing for a reduction in the amount of cyclic ether compound needed to suppress roll fouling. As a result, the heat resistance (glass transition temperature) of the resulting film can be improved. In this embodiment, when the resin composition contains two or more 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 its mass fraction.

[0018] In this embodiment, it is preferable that the cyclic ether compound used consists only of carbon atoms, hydrogen atoms, and oxygen atoms. This configuration makes it possible to more effectively suppress fouling of the rolls and prevent the generation of foreign matter. The cyclic ether compound used in this embodiment preferably has three or fewer aromatic rings per molecule, and more preferably does not contain any aromatic rings. A smaller number of aromatic rings tends to improve compatibility with polyamide resins (especially aliphatic polyamide resins), and the effects of the present invention tend to be more effectively exhibited.

[0019] The cyclic ether compound used in this embodiment preferably contains an epoxy ring and / or an oxetane ring, consists only of carbon atoms, hydrogen atoms, and oxygen atoms, has a molecular weight of 180 to 1000, and has three or fewer aromatic rings per molecule (preferably one or two). This configuration makes it possible to more effectively suppress roll fouling and the generation of foreign matter. In particular, the cyclic ether compound used in this embodiment preferably has a molecular weight of (molecular weight of a compound having 1 to 3 cyclic ether structures per molecule / number of cyclic ether structures) < 250.

[0020] The cyclic ether compound used in this embodiment may or may not have a group that reacts with an amino group other than the cyclic ether structure. An example of a cyclic ether compound used in this embodiment is a compound that does not have any groups that react with amino groups other than the cyclic ether structure. Another example of a 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 that can react with an amino group, wherein at least one of the functional groups that can react with an amino group is an epoxy group or an oxetanyl group. By adopting the above configuration, the effects of the present invention tend to be exhibited more effectively.

[0021] The content of the cyclic ether compound in the resin composition of this 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, per 100 parts by mass of polyamide resin. Setting the content above the lower limit tends to more effectively suppress roll fouling. 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 be less than 2 parts by mass or 1.5 parts by mass or less, per 100 parts by mass of polyamide resin. Setting the content below the upper limit effectively suppresses a decrease in the glass transition temperature of the resin composition or film. In particular, it is highly valuable that roll fouling can be suppressed even when a small amount of less than 2 parts by mass is added. The resin composition of this embodiment may contain only one cyclic ether compound or two or more. When two or more are included, it is preferable that the total amount is within the above range. The resin composition of this embodiment preferably contains substantially no compounds having four or more cyclic ether structures in one molecule. Substantially no 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 one to three cyclic ether structures in one molecule, 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 this embodiment may also contain light stabilizers, heat stabilizers, antioxidants, infrared absorbers, hydrolysis resistance improvers, ultraviolet absorbers, antistatic agents, color inhibitors, gelation inhibitors, photochromic dyes, and the like. If the resin composition of this embodiment contains components other than the polyamide resin and cyclic ether compound, the total content of these components is preferably 0.001% by mass or more, more 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, even more preferably less than 0.2% by mass, and even more preferably less than 0.1% by mass. With such a configuration, the effects of the present invention tend to be exhibited more effectively. Each of these ingredients may be used individually or in combination of two or more. Furthermore, the filler content 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 absent. Substantially absent means, for example, that the content of cyclic ether compounds 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. Furthermore, in the resin composition of this embodiment, it is preferable that the total amount of polyamide resin and cyclic ether compound accounts for 99% or more by mass of the resin composition. The resin composition of this embodiment is preferably a thermoplastic resin composition. The resin composition of this embodiment is preferably substantially solvent-free. Substantially solvent-free means that the solvent content 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] <Hayes> The resin composition of this embodiment has high transparency. Specifically, when the resin composition is made into a 200 μm thick film, the haze is 10% or less. Such haze is achieved by using a polyamide resin that inherently has high transparency, and by keeping the filler content in the resin composition to 10% by mass or less. When the resin composition is made into a 200 μm thick film, 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. Compared to the haze of polyamide resin films used for packaging materials and the like, which is usually over 10%, the haze of the resin composition of this embodiment is significantly lower.

[0024] <Method for producing resin compositions> Any method can be used to manufacture the resin composition of this embodiment. 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 per molecule to 100 parts by mass of polyamide resin and melt-kneading. More specifically, a method can be used in which polyamide resin, a compound having 1 to 3 cyclic ether structures per molecule, and other components added as needed are mixed using a mixing means such as a V-type blender to prepare a blended product, which is then melt-kneaded in a vented extruder to form pellets.

[0025] <film> The film of this embodiment is formed from the resin composition of this embodiment. The thickness of the film in 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. Furthermore, the thickness of the film in 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 also be 300 μm or less. The film of this embodiment preferably has excellent 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. Compared to polyamide resin films used for packaging materials, which typically have a haze of over 10%, the haze of the film of this embodiment is significantly lower.

[0026] The film of this embodiment is typically manufactured by extrusion molding, i.e., it is an extruded product. Furthermore, the film of this embodiment is typically formed using a roll. The film in this embodiment is preferably a continuous film. A continuous film is, for example, a film with a length of 10 m or more (preferably 10,000 m or less). The continuous film can be wound onto a roll to form a reel.

[0027] The film of this embodiment is used in applications where high transparency is required. Specifically, it is preferably used as a protective film for polarizing sheets, and more preferably for use as a protective film for polarizing sheets. It is particularly preferably used in sunglasses and goggles. In other words, in this embodiment, a polarizing sheet is provided which comprises a polarizing film and a protective film on at least one surface of the polarizing film, wherein the protective film is the film of this embodiment. Figure 1 is a schematic diagram showing the layer structure of the polarizing sheet of this embodiment, where 1 is the polarizing film, 2 is the protective film (the film of this embodiment), and 3 is the adhesive layer that bonds the polarizing film and the protective film.

[0028] A polyvinyl alcohol-based resin film is preferably used as the polarizing film. Examples of polyvinyl alcohol-based resins include polyvinyl alcohol (PVA) and its derivatives or analogs such as polyvinyl formal, polyvinyl acetal, and poly(ethylene-vinyl acetate) copolymer saponified 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, preferably 350,000 or less, and more preferably 300,000 or less. Furthermore, the polarizing film is preferably made by stretching and dyeing a polyvinyl alcohol-based resin film or the like. The stretching ratio is preferably 2 times or more, more preferably 3 times or more, preferably 8 times or less, and 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, preferably 50 μm or less, and more preferably 40 μm or less.

[0029] When laminating the film of this embodiment to both sides of the polarizing film, an adhesive can be used. Suitable adhesives include polyvinyl alcohol resin-based materials, acrylic resin-based materials, urethane resin-based materials, polyester resin-based materials, melamine resin-based materials, epoxy resin-based materials, silicone-based materials, etc., but a urethane resin-based material is preferred.

[0030] The polarizing sheet of this embodiment is not limited to the range described above. For example, the adhesive layer, which includes an adhesive for bonding the polarizing film and the protective film of this embodiment, may contain appropriately dissolved light stabilizers, heat stabilizers, antioxidants, infrared absorbers, hydrolysis resistance modifiers, ultraviolet absorbers, antistatic agents, color inhibitors, gelation inhibitors, photochromic dyes, and other substances.

[0031] Regarding the manufacture of polarizing sheets and their applications, in addition to the above, refer to International Publication No. 2019 / 054295 and International Publication No. 2014 / 115705, which are incorporated herein by reference.

[0032] <Film manufacturing method> The method for producing the film of this embodiment involves adding 0.05 to 10 parts by mass of a compound having 1 to 3 cyclic ether structures per molecule to 100 parts by mass of polyamide resin, and then melt-kneading the mixture. The resulting film preferably satisfies the requirements of the film of this embodiment described above. More specifically, the film can be manufactured by extruding a molten resin composition into a sheet and transporting it on a roll. The resin composition preferably satisfies the requirements of the resin composition of this embodiment described above. [Examples]

[0033] The present invention will be described in more detail below with reference to examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate, as long as they do not depart 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 other reasons, measurements can be taken using other instruments with equivalent performance.

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

[0035] 2. Examples 1-5, Comparative Examples 1, 2 <Film Manufacturing> Polyamide resin film was manufactured using the following method. Each component listed in Table 1 was weighed to the amount indicated in Table 1 (Table 1 shows amounts in parts by mass). After mixing in a tumbler for 15 minutes, a T-die melt extruder consisting of a twin-screw segment extruder with a barrel diameter of 25 mm and a screw L / D = 30 (Toyo Seiki Co., Ltd., "2D30W2") was used to extrude the material into a molten state at a discharge rate of 8 kg / h and a screw rotation speed of 100 rpm. The material was then cooled and solidified using only the first roll of a film / sheet take-up device (Toyo Seiki Co., Ltd., "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 roll speed of the first roll.

[0036] <Roller stains> Roll contamination was visually checked for the presence or absence of contamination on the first roll 20 minutes after the resin began to be taken up by the film / sheet take-up device. The evaluation was as follows: A: No dirt was found on the roll. B: Dirt was found on the roll.

[0037] <Foreign object> The obtained films were visually inspected under fluorescent light to check for foreign matter. Five experts evaluated them, and the decision was made by majority vote. A: No foreign objects were found. B: A foreign object was found.

[0038] <Hayes> For the films obtained above, the haze (in %) was measured using a haze meter under the condition of a D65 light source and a 10° field of view. A haze meter, model "HM-150" manufactured by Murakami Color Technology Research Institute, was used.

[0039] [Table 1]

[0040] In Table 1 above, the unit for each component is parts by mass. When manufacturing a film formed from the resin composition of this embodiment, no roll contamination was observed, and no foreign matter was found in the resulting film. Furthermore, the film formed from the resin composition of this embodiment exhibited 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, per 100 parts by mass of a polyamide resin, The polyamide resin is an amorphous polyamide resin, and 90% by mass or more of the raw material monomers consist of alicyclic diamines having 6 to 25 carbon atoms and linear or branched aliphatic dicarboxylic acids having 4 to 20 carbon atoms. The compound having one to three of the aforementioned cyclic ether structures in one molecule is a compound having one to three functional groups that can react with an amino group, whose constituent elements consist only of carbon atoms, hydrogen atoms, and oxygen atoms, which does not contain an aromatic ring, and whose molecular weight is 180 or more and 1000 or less. A resin composition having a haze of 1.1% or less when formed into a 200 μm thick film.

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 compound having 1 to 3 of the aforementioned cyclic ether structures in one molecule comprises an epoxy ring and / or an oxetane ring.

4. The filler content in the resin composition is 0 to 10% by mass. The resin composition according to claim 1, wherein the compound having one to three of the aforementioned cyclic ether structures in one molecule comprises an epoxy ring and / or an oxetane ring.

5. A resin composition according to claim 1, 2, or 4, for use as a protective film for polarizing sheets.

6. A film formed from the resin composition according to claim 1, 2, or 4.

7. The film according to claim 6, wherein the thickness is 100 to 1000 μm.

8. The film according to claim 6, which is a protective film for a polarizing sheet.

9. It comprises a polarizing film and a protective film on at least one surface of the polarizing film, A polarizing sheet wherein the protective film is the film described in claim 6.

10. A method for producing the resin composition according to claim 1, 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.

11. A method for producing a film according to claim 6, 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.

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