Resin composition, film, polarizing sheet, and sunglasses

Abstract

Provided are a resin composition, a film, a polarizing sheet, and sunglasses. The resin composition comprises: a polyamide resin containing an alicyclic diamine unit and an aliphatic dicarboxylic acid unit having 7-20 carbons; and a polyalkylene glycol. The polyalkylene glycol contains an ethylene glycol unit and / or a propylene glycol unit at a total proportion of 50 mol% or more of all units and has a number average molecular weight of 100-3,500.

Description

Resin composition, film, polarizing sheet, and sunglasses

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

[0002] Polyamide resins have excellent mechanical properties such as rigidity and strength, as well as 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).

[0003] JP 2015-129271 A JP 2013-001906 A JP 2012-131977 A

[0004] As described above, polyamide resins are used in a wide variety of fields, but they generally have poor transparency and have not been used in applications requiring transparency. Under these circumstances, the present inventors investigated the use of polyamide resins in applications requiring transparency, such as protective films for polarizing films. However, when polyamide resins are molded into films, roll contamination may occur during film production. The present invention aims to solve this problem by providing a resin composition capable of providing a film that has excellent transparency and can effectively suppress roll contamination during film production, as well as a film, a polarizing sheet, and sunglasses.

[0005] In light of the above-mentioned problems, the present inventors have conducted research and found that the above-mentioned problems can be solved by blending a polyalkylene glycol containing ethylene glycol units and / or propylene glycol units in a total amount of 50 mol % or more of all units and having a number-average molecular weight of 100 to 3500 with a specified polyamide resin. Specifically, the above-mentioned problems have been solved by the following means. <1> A resin composition comprising a polyamide resin containing alicyclic diamine units and aliphatic dicarboxylic acid units having 7 to 20 carbon atoms, and a polyalkylene glycol, wherein the polyalkylene glycol contains ethylene glycol units and / or propylene glycol units in a total amount of 50 mol % or more of all units and has a number-average molecular weight of 100 to 3500. <2> The resin composition according to <1>, wherein the aliphatic dicarboxylic acid units having 7 to 20 carbon atoms include sebacic acid units and / or dodecanedioic acid units. <3> The resin composition according to <1> or <2>, wherein the alicyclic diamine constituting the alicyclic diamine unit contains two substituted or unsubstituted cyclohexane rings. <4> The resin composition according to <1> or <2>, wherein the alicyclic diamine unit contains a unit represented by formula (PA-1). (In formula (PA-1), R １are each independently an alkyl group having 1 to 5 carbon atoms, and each n1 is independently an integer of 0 to 3. * is a bonding site with another unit or an end group.) <5> The resin composition according to any one of <1> to <4>, wherein the content of the polyamide resin contained in the resin composition is 90 mass% or more. <6> The resin composition according to any one of <1> to <5>, wherein the content of the polyalkylene glycol contained in the resin composition is 0.01 to 5 mass%. <7> The resin composition according to any one of <1> to <6>, wherein the aliphatic dicarboxylic acid units having 7 to 20 carbon atoms include sebacic acid units and / or dodecanedioic acid units, the alicyclic diamine units include units represented by formula (PA-1), the content of the polyamide resin contained in the resin composition is 90 mass% or more, and the content of polyalkylene glycol contained in the resin composition is 0.01 to 5 mass% (with the proviso that the total amount of the polyamide resin and the polyalkylene glycol does not exceed 100 mass%). (In formula (PA-1), R １ are each independently an alkyl group having 1 to 5 carbon atoms, and n1 is each independently an integer of 0 to 3. * is a bonding site with another unit or an end group.) <8> The resin composition according to any one of <1> to <7>, wherein the polyamide resin is an amorphous resin. <9> The resin composition according to any one of <1> to <8>, wherein the resin composition has a haze of 3.0% or less when molded into a film with a thickness of 300 μm. <10> The resin composition according to any one of <1> to <9>, wherein the resin composition has a total light transmittance of 80% or more when molded into a film with a thickness of 300 μm. <11> The resin composition according to any one of <1> to <10>, wherein the resin composition is used for a protective film for a polarizing sheet. <12> A film formed from the resin composition according to any one of <1> to <11>. <13> A polarizing sheet comprising the film according to <12> and a polarizing film. <14> Sunglasses comprising the polarizing sheet according to <13>.

[0006] It has become possible to provide a resin composition capable of providing a film that is excellent in transparency and can effectively prevent roll contamination during film production, as well as a film, a polarizing sheet, and sunglasses.

[0007] 1 is a schematic diagram illustrating an example of a layer structure of a hot-bent molded product according to an embodiment of the present invention. FIG.

[0008] Hereinafter, a detailed description of an embodiment of the present invention (hereinafter simply referred to as "the present embodiment") will be given. Note that the following present embodiment is an example for explaining the present invention, and the present invention is not limited to this embodiment. In this specification, the term "to" is used to mean that the numerical values ​​before and after it are included as the upper and lower limits. Furthermore, any combination of the upper and lower limit values ​​of numerical values ​​in this specification is cited as an example of this embodiment. In this specification, various physical property values ​​and characteristic values ​​are those at 23°C unless otherwise specified. In this specification, when a group (atomic group) is described without specifying whether it is substituted or unsubstituted, it encompasses both a group (atomic group) that has no substituent and a group (atomic group) that has a substituent. For example, the term "alkyl group" encompasses not only an alkyl group that has no substituent (unsubstituted alkyl group) but also an alkyl group that has a substituent (substituted alkyl group). In this specification, when a term without specifying whether it is substituted or unsubstituted, it is preferred that it be unsubstituted. Examples of the substituent in this specification are preferably a halogen atom, a cyano group, a nitro group, a hydroxy group, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a heterocyclic group, a heterocyclicoxy group, an alkenyl group, an alkylsulfanyl group, an arylsulfanyl group, an acyl group, or an amino group, more preferably a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an alkenyl group, or an acyl group, even more preferably an alkyl group, an aryl group, an aryloxy group, or an alkenyl group, and still more preferably an alkyl group. The formula weight of these substituents is preferably 15 or more, and preferably 200 or less. The formula weight is, for example, the formula weight of a methyl group (-CH ３) is 15. These substituents may further have a substituent, but it is preferable that they have no substituent.

[0009] In this specification, the term "film" refers to a generally flat molded product that is thin relative to its length and width, and is intended to include sheets. Furthermore, the term "film" in this specification may be either single-layer or multi-layer, with single-layer being preferred. If the measurement methods and other aspects described in the standards set forth in this specification vary from year to year, they shall be based on the standards in effect as of January 1, 2024, unless otherwise specified. If the measurement methods and other aspects described in the standards set forth in this specification are discontinued as of January 1, 2024, they shall be based on the standards in effect at the time of discontinuation. The scale of Figure 1 may not be consistent with reality.

[0010] <Resin Composition> The resin composition of this embodiment includes a polyamide resin containing alicyclic diamine units and aliphatic dicarboxylic acid units having 7 to 20 carbon atoms, and a polyalkylene glycol, wherein the polyalkylene glycol contains ethylene glycol units and / or propylene glycol units in a total proportion of 50 mol% or more of all units and has a number average molecular weight of 100 to 3500. This configuration provides a resin composition that can provide a film that is excellent in transparency and can effectively suppress roll contamination during film production. Roll contamination is thought to be caused, for example, by the polyamide resin remaining in the die during extrusion molding and adhering to the metal wall surface, resulting in decomposition of the polyamide resin. The inventors have conducted studies and found that by using a polyalkylene glycol containing ethylene glycol units and / or propylene glycol units in a total proportion of 50 mol% or more of all units and having a number-average molecular weight of 100 to 3500, retention of the polyamide resin in the die can be effectively suppressed, resulting in effective suppression of roll contamination. This is presumably because the inclusion of ethylene glycol units and / or propylene glycol units in a total proportion of 50 mol% or more of all units achieves adequate compatibility with the polyamide resin, and the inclusion of a polyalkylene glycol having a number-average molecular weight of 100 to 3500 facilitates the presence of the alkylene chain of the polyalkylene glycol on the metal wall surface side of the die in the resin composition. It is presumed that the use of a polyalkylene glycol with these characteristics resulted in a resin composition capable of providing a film that maintains transparency while effectively suppressing roll contamination during film production. Details of this embodiment are described below.

[0011] <Polyamide Resin Comprising Alicyclic Diamine Units and Aliphatic Dicarboxylic Acid Units Having 7 to 20 Carbon Atoms> The resin composition of this embodiment comprises a polyamide resin (sometimes referred to herein as "polyamide resin (A)") comprising alicyclic diamine units and aliphatic dicarboxylic acid units having 7 to 20 carbon atoms. The alicyclic structure of polyamide resin (A) improves the transparency of the polyamide resin itself, and the aliphatic dicarboxylic acid units having 7 to 20 carbon atoms increase compatibility with polyalkylene glycol, improving the transparency of the resulting resin composition.

[0012] In this embodiment, the alicyclic diamine constituting the alicyclic diamine unit is preferably a diamine containing a 5-membered alicyclic ring and / or a 6-membered alicyclic ring. The 5-membered ring and / or the 6-membered ring may or may not have a substituent. Furthermore, the alicyclic diamine is preferably composed solely of an aliphatic hydrocarbon group containing an alicyclic structure, except for the terminal amino group. The alicyclic diamine unit more preferably contains two or three or more substituted or unsubstituted cyclohexane rings, and even more preferably contains two substituted or unsubstituted cyclohexane rings, per unit. The alicyclic diamine unit preferably does not contain a carbon-carbon double bond or a carbon-carbon triple bond. The molecular weight of the alicyclic diamine constituting the alicyclic diamine unit is preferably 195 or more, more preferably 200 or more, and preferably 500 or less, more preferably 400 or less, and even more preferably 300 or less.

[0013] In this embodiment, it is more preferable that the alicyclic diamine unit contains at least one type represented by formula (PA-0). (In formula (PA-0), each R is independently a substituent, and each n is independently an integer of 0 to 5. L is a single bond or a divalent linking group. * is a bonding site with another unit or a terminal group.) In formula (PA-0), each R is independently a substituent, and is preferably an aliphatic group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, even more preferably a linear or branched alkyl group having 1 to 6 carbon atoms, even more preferably a methyl group, ethyl group, or propyl group, and even more preferably a methyl group. In formula (PA-0), each n is independently an integer of 0 to 5, and is preferably an integer of 1 or greater, and is preferably an integer of 4 or less, more preferably an integer of 3 or less, even more preferably an integer of 2 or less, and even more preferably an integer of 1 or less. In formula (PA-0), L represents a single bond or a divalent linking group, more preferably a single bond or a divalent aliphatic hydrocarbon group, more preferably a single bond or a divalent alkylene group, still more preferably a single bond or an alkylene group having 1 to 3 carbon atoms, still more preferably a single bond, a methylene group, an ethylene group, or an isopropylene group, and still more preferably a methylene group. * represents a bonding site with another unit or a terminal group. That is, it is usually bonded to -C(=O)- to form an amide bond together with NH in formula (PA-0), or bonded to a hydrogen atom to form a terminal amino group together with NH in formula (PA-0), or bonded to a terminal group.

[0014] In this embodiment, the alicyclic diamine unit more preferably contains a unit represented by formula (PA-1). (In formula (PA-1), R １ are each independently an alkyl group having 1 to 5 carbon atoms, and each n1 is independently an integer of 0 to 3. * is a bonding site with another unit or a terminal group.

[0015] In formula (PA-1), R １is an alkyl group having 1 to 5 carbon atoms, preferably a linear or branched alkyl group having 1 to 5 carbon atoms, more preferably a methyl group, an ethyl group, or a propyl group, and even more preferably a methyl group. In formula (PA-1), n1 is an integer of 0 to 3, preferably an integer of 1 or more, and also preferably an integer of 2 or less, and even more preferably 1.

[0016] Specific examples of the alicyclic diamine include 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis(4-aminocyclohexyl)methane, bis(4-amino-3-methylcyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, 2,2-bis(4-amino-3-methylcyclohexyl)propane, bis(aminomethyl)decalin, and bis(aminomethyl)tricyclodecane.

[0017] The polyamide resin (A) contains alicyclic diamine units in a proportion of preferably 75 mol% or more, more preferably 80 mol% or more, even more preferably 85 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more, particularly preferably 99 mol% or more, and 100 mol% or less of the diamine units constituting the polyamide resin (A). The alicyclic diamine units may be of one type or a combination of two or more types.

[0018] Examples of diamines other than alicyclic diamines that can be used as raw material diamines for the polyamide resin (A) include aliphatic diamines such as tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, and 2,4,4-trimethylhexamethylenediamine; and diamines having an aromatic ring such as xylylenediamine, bis(4-aminophenyl)ether, paraphenylenediamine, and bis(aminomethyl)naphthalene. These can be used alone or in combination of two or more.

[0019] On the other hand, in this embodiment, the aliphatic dicarboxylic acid having 7 to 20 carbon atoms constituting the aliphatic dicarboxylic acid unit having 7 to 20 carbon atoms is preferably a linear or branched aliphatic dicarboxylic acid having 7 to 20 carbon atoms, more preferably a linear aliphatic dicarboxylic acid having 7 to 20 carbon atoms, and even more preferably an α,ω-linear aliphatic dicarboxylic acid having 7 to 20 carbon atoms. The number of carbon atoms in the aliphatic dicarboxylic acid having 7 to 20 carbon atoms (preferably a linear aliphatic dicarboxylic acid having 7 to 20 carbon atoms) is preferably 8 or more, more preferably 9 or more, and even more preferably 10 or more, and is preferably 18 or less, more preferably 16 or less, even more preferably 14 or less, even more preferably 13 or less, and even more preferably 12 or less. The aliphatic dicarboxylic acid having 7 to 20 carbon atoms is preferably HOOC-(CH ２ ) ｎ It is preferably represented by —COOH, where n is an integer of 5 to 18. The aliphatic dicarboxylic acid unit having 7 to 20 carbon atoms that can be used in this embodiment preferably contains at least one of a sebacic acid unit, an undecanedioic acid unit, and a dodecanedioic acid unit, and more preferably contains a sebacic acid unit and / or a dodecanedioic acid unit.

[0020] The polyamide resin (A) contains aliphatic dicarboxylic acid units having 7 to 20 carbon atoms in a proportion of preferably 75 mol % or more, more preferably 80 mol % or more, even more preferably 85 mol % or more, still more preferably 90 mol % or more, still more preferably 95 mol % or more, particularly preferably 99 mol % or more, and 100 mol % or less, of the dicarboxylic acid units constituting the polyamide resin (A). The aliphatic dicarboxylic acid units having 7 to 20 carbon atoms may be one type, or two or more types may be combined.

[0021] Examples of dicarboxylic acids other than aliphatic dicarboxylic acids having 7 to 20 carbon atoms include phthalic acid compounds such as isophthalic acid, terephthalic acid, and orthophthalic acid, and isomers of naphthalenedicarboxylic acid such as 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid, and these can be used alone or in combination of two or more.

[0022] The polyamide resin (A) used in this embodiment may further contain an aminocarboxylic acid unit. The inclusion of an aminocarboxylic acid unit tends to further improve the color of molded articles such as films. The type of aminocarboxylic acid constituting the aminocarboxylic acid unit is not particularly limited, and known aminocarboxylic acids can be used. In this embodiment, the aminocarboxylic acid is preferably composed solely of aliphatic hydrocarbon groups, except for the terminal amino and carboxylic acid groups. The molecular weight of the aminocarboxylic acid constituting the aminocarboxylic acid unit is preferably 180 or more, more preferably 190 or more, and preferably 400 or less, more preferably 300 or less, and even more preferably 250 or less.

[0023] In this embodiment, the aminocarboxylic acid constituting the aminocarboxylic acid unit is preferably represented by formula (PA-2). (In formula (PA-2), n is an integer of 5 to 20.) In formula (PA-2), n is an integer of 5 to 20, and is preferably 6 or more, more preferably 7 or more, even more preferably 8 or more, still more preferably 9 or more, and even more preferably 10 or more; and is preferably 18 or less, more preferably 16 or less, even more preferably 14 or less, still more preferably 13 or less, and even more preferably 12 or less.

[0024] Although the polyamide resin (A) primarily contains diamine units and dicarboxylic acid units, other monomer units are not completely excluded. It goes without saying that the polyamide resin (A) may contain lactam units such as ε-caprolactam and laurolactam, and aliphatic aminocarboxylic acid units such as aminocaproic acid and aminoundecanoic acid. In particular, the polyamide resin (A) used in this embodiment preferably contains aminocarboxylic acid units. In this embodiment, among the monomer units constituting the polyamide resin (A), the total mass of the diamine units, dicarboxylic acid units, and optionally included aminocarboxylic acid units preferably accounts for 90% by mass or more of the total monomer units, more preferably 95% by mass or more, even more preferably 97% by mass or more, and even more preferably 99% by mass or more. The molar ratio of diamine units to dicarboxylic acid units in the polyamide resin (A) is preferably 40:60 to 60:40, and more preferably 45:55 to 55:45. Furthermore, in the present embodiment, when the polyamide resin (A) contains an aminocarboxylic acid unit, the proportion of the aminocarboxylic acid unit among all the monomer units constituting the polyamide resin (A) is preferably 1 mol% or more, more preferably 5 mol% or more, and even more preferably 10 mol% or more, and is preferably 50 mol% or less, more preferably 40 mol% or less, even more preferably 30 mol% or less, and even more preferably 20 mol% or less.

[0025] The polyamide resin (A) is preferably an amorphous resin. An amorphous resin is a resin that does not have a clear melting point. Specifically, the crystalline melting enthalpy ΔHm is less than 5 J / g, and the ΔHm is preferably 3 J / g or less, more preferably 1 J / g or less. The crystalline melting enthalpy ΔHm is measured in accordance with JIS K7121 and K7122 during the heating process. Specifically, the polyamide resin is measured using a differential scanning calorimeter (DSC) in a nitrogen stream by heating from room temperature to 250°C at a heating rate of 10°C / min, immediately cooling to below room temperature, and then heating again from room temperature to 250°C at a heating rate of 10°C / min.

[0026] It is also preferable to use a polyamide resin (biomass polyamide resin) produced using biomass raw materials as the polyamide resin (A). The use of biomass polyamide resins can reduce the environmental impact. The polyamide resin (A) can also be made from mass balance certified (ISCC PLUS) monomer raw materials. Mass balance certification means that the amount of renewable raw materials or bio-based raw materials used in each factory or production facility and the amount of products produced or shipped are quantified and guaranteed along with their quality. Furthermore, the polyamide resin (A) may be recycled products (including recovered products, material recycled products, chemical recycled products, etc.), rejected products, or scraps generated during the molding of the polyamide resin (A) or the resin composition of this embodiment.

[0027] The content of polyamide resin (A) in the resin composition of this embodiment is preferably 90% by mass or more, more preferably 95% 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, based on 100% by mass of the resin composition. By setting the content at or above the lower limit, the glass transition temperature tends to be higher. Furthermore, the content of polyamide resin (A) in the resin composition of this embodiment is preferably 99.999% by mass or less, based on 100% by mass of the resin composition. By setting the content at or below the upper limit, the transparency of the obtained film tends to be further improved. Furthermore, the resin composition of this embodiment may contain only one type of polyamide resin (A) or two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0028] The resin composition of this embodiment may or may not contain a polyamide resin other than the polyamide resin (A). Examples of polyamide resins other than the polyamide resin (A) include aliphatic polyamide resins other than the polyamide resin (A) and aromatic polyamide resins. Examples of aliphatic polyamide resins include polyamide 4, polyamide 46, polyamide 6, polyamide 66, polyamide 666, polyamide 610, polyamide 11, polyamide 116, polyamide 12, and polyamide 612. Examples of aromatic polyamide resins include polyhexamethylene terephthalamide (polyamide 6T), polyhexamethylene isophthalamide (polyamide 6I), polyamide 66 / 6T, polyamide 9T, polyamide 9MT, polyamide 10T, polyamide 6I / 6T, and xylylenediamine-based polyamide resins (e.g., MXD6).

[0029] It is also preferable that the aliphatic polyamide resin and aromatic polyamide resin other than the polyamide resin (A) are polyamide resins (biomass thermoplastic resins) produced using recycled resins or biomass raw materials. Furthermore, it is preferable that the resin composition of this embodiment substantially does not contain any polyamide resin other than the polyamide resin (A). Specifically, the content of polyamide resins other than the polyamide resin (A) contained in the resin composition of this embodiment is preferably less than 10% by mass, more preferably less than 5% by mass, even more preferably less than 3% by mass, even more preferably less than 1% by mass, and even more preferably less than 0.1% by mass, based on 100% by mass of the resin composition.

[0030] <Polyalkylene Glycol> The resin composition of the present embodiment contains a polyalkylene glycol (hereinafter sometimes referred to as "polyalkylene glycol (B)") that contains ethylene glycol units and / or propylene glycol units in a total proportion of 50 mol % or more of all units and has a number average molecular weight of 100 to 3500. By using such a polyalkylene glycol (B) in combination with the polyamide resin (A), a resin composition can be obtained that can provide a film that is excellent in transparency and can effectively suppress roll contamination during film production.

[0031] In this embodiment, the polyalkylene glycol (B) contains ethylene glycol units and / or propylene glycol units in total of 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, still more preferably 95 mol% or more, and particularly preferably 99 mol% or more of the total units, and all units other than the terminal groups may be ethylene glycol units and / or propylene glycol units. By setting the content at or above the lower limit, the polyalkylene glycol (B) is more likely to bleed out onto the resin surface (for example, the surface of a molded product such as a film) during molding, and the retention of the resin composition is suppressed due to improved slippage with the inner wall of the molding machine, which tends to further suppress roll contamination. On the other hand, by making the ethylene glycol units and / or propylene glycol units account for 50 mol % or more in total of all units, the polyalkylene glycol (B) becomes more appropriately compatible with the polyamide resin (A), and excessive bleeding out of the polyalkylene glycol (B) onto the resin surface during molding is effectively suppressed, which tends to effectively suppress roll contamination caused by the polyalkylene glycol (B) itself.

[0032] The polyalkylene glycol (B) used in this embodiment may contain other monomer units in addition to ethylene glycol units and propylene glycol units. The other monomer units are preferably alkylene glycol units other than ethylene glycol units and propylene glycol units. Examples of other alkylene glycol units include methylene glycol, butylene glycol, pentylene glycol, hexylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, neopentyl glycol, 3-methyltetramethylene glycol, and hexamethylene glycol.

[0033] The polyalkylene glycol (B) used in this embodiment may have its terminals modified with an optional substituent. The terminals may be modified at only one end of the polyalkylene glycol or at both ends. The optional substituent may include a carboxyl group, a hydroxyl group, an alkyl ether, an aryl ether, an aralkyl ether, a fatty acid ester, and an aryl ester.

[0034] The number-average molecular weight of the polyalkylene glycol (B) used in this embodiment is 100 to 3500, with a lower limit of preferably 300 or more, more preferably 500 or more, even more preferably 800 or more, and even more preferably 1000 or more. The upper limit is preferably 3000 or less, more preferably 2000 or less, and even more preferably 1500 or less. By setting the number-average molecular weight at or above the lower limit, volatilization of the polyalkylene glycol (B) tends to be effectively suppressed. On the other hand, by setting the number-average molecular weight at or below the upper limit, deterioration of transparency tends to be more effectively suppressed. This is presumably because the polyalkylene glycol (B) is not completely compatible with the polyamide resin (A), forming a sea-island structure. When the number-average molecular weight of the polyalkylene glycol (B) is high, the island portions expand, the refractive index difference increases, and transparency decreases. The number-average molecular weight is measured in accordance with JIS K1577.

[0035] Specific examples of the polyalkylene glycol (B) used in this embodiment include polyethylene glycol, polypropylene glycol, or a copolymer containing ethylene glycol units and / or propylene glycol units and other alkylene glycol units, with polyethylene glycol or polypropylene glycol being preferred, and polypropylene glycol being more preferred from the viewpoint of ease of production.

[0036] The polyalkylene glycol (B) used in the present embodiment is not particularly limited, and may be produced by a known method, or a commercially available product may be used. Examples of commercially available products include D-1000 (manufactured by NOF Corporation) and D-2000 (manufactured by NOF Corporation).

[0037] The content of polyalkylene glycol (B) in the resin composition of this embodiment is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, and even more preferably 0.2% by mass or more, based on 100% by mass of the resin composition. Depending on the application, it may be 0.4% by mass or more, and preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 2% by mass or less, even more preferably 1% by mass or less, and even more preferably 0.5% by mass or less. Depending on the application, it may be 0.3 parts by mass or less. By setting the content at or above the lower limit, roll contamination during molding tends to be effectively suppressed. Furthermore, by setting the content at or below the upper limit, it tends to be more effectively suppressed deterioration in glass transition temperature and toughness. Note that in the resin composition of this embodiment, the total amount of polyamide resin (A) and polyalkylene glycol (B) does not exceed 100% by mass. The resin composition of this embodiment may contain only one type of polyalkylene glycol (B), or may contain two or more types. When two or more kinds are contained, the total amount is preferably within the above range. In addition, it is preferable that the resin composition of this embodiment does not substantially contain polyalkylene glycols other than polyalkylene glycol (B) (for example, having a number average molecular weight of less than 100 or more than 3500). Specifically, the content of polyalkylene glycols other than polyalkylene glycol (B) contained in the resin composition of this embodiment is preferably less than 10 parts by mass, more preferably less than 5 parts by mass, even more preferably less than 3 parts by mass, even more preferably less than 1 part by mass, and even more preferably less than 0.1 parts by mass, relative to 100 parts by mass of polyalkylene glycol (B).

[0038] <Other Components> The resin composition of this embodiment may or may not contain components other than the polyamide resin (A) and the polyalkylene glycol (B). Examples of other components include release agents, ultraviolet absorbers, antioxidants, heat stabilizers, flame retardants, flame retardant aids, colorants, antistatic agents, fluorescent brighteners, antifogging agents, flow improvers, plasticizers, dispersants, antibacterial agents, antiblocking agents, impact improvers, sliding improvers, hue improvers, acid trapping agents, and the like. In addition, the resin composition of this embodiment may contain additives described in paragraphs 0047 to 0103 of WO 2021 / 241471, additives described in paragraphs 0041 to 0056 of JP 2023-61203 A, and additives described in paragraphs 0017 to 0021 of WO 2024 / 029515, within the scope of the present invention, and the contents of these additives are incorporated herein.

[0039] When other components are contained, the total content thereof is preferably 0.001 to 3 mass% of the resin composition, more preferably less than 2 mass%, even more preferably less than 1 mass%, even more preferably less than 0.5 mass%, even more preferably less than 0.1 mass%, and may even be less than 0.01 mass%. Only one type of other component may be contained, or two or more types may be contained. When two or more types of other components are contained, the total amount is preferably in the above range.

[0040] <Physical Properties of Resin Composition> The resin composition of this embodiment preferably has excellent transparency. Specifically, the resin composition of this embodiment, when molded into a 300 μm thick film, preferably has a total light transmittance of 80% or more, more preferably 85% or more, and even more preferably 90% or more. The upper limit of the total light transmittance is preferably 100%, but the required performance is met even if it is 99% or less. Furthermore, the resin composition of this embodiment, when molded into a 300 μm thick film, preferably has a haze of 3.0% or less, more preferably 2.0% or less, even more preferably 1.5% or less, even more preferably 1.0% or less, even more preferably 0.7% or less, even more preferably 0.5% or less, even more preferably 0.4% or less, and even more preferably 0.3% or less, 0.28% or less, or 0.25% or less. The lower limit of the haze is preferably 0%, but the required performance is met even if it is 0.001% or more. The total light transmittance and haze are measured according to the description in the examples below.

[0041] <Method for Producing Resin Composition> Any method can be used as a method for producing the resin composition of this embodiment. For example, the resin composition can be obtained by mixing the polyamide resin (A) and the polyalkylene glycol (B) and melt-kneading them. More specifically, the polyamide resin (A), the polyalkylene glycol (B), and other components that are added as needed are mixed using a mixing means such as a V-type blender to prepare a lump blend, which is then melt-kneaded in a vented extruder and pelletized.

[0042] <Film> The film of this embodiment is formed from the resin composition of this embodiment. The thickness of the film of this embodiment is preferably 10 μm or more, more preferably 50 μm or more, and even more preferably 100 μm or more, and is preferably 1000 μm or less, more preferably 800 μm or less, even more preferably 700 μm or less, even more preferably 600 μm or less, and even more preferably 500 μm or less.

[0043] The film of this embodiment preferably has excellent transparency. Specifically, the film of this embodiment preferably has a total light transmittance of 80% or more, more preferably 85% or more, and even more preferably 90% or more. The upper limit of the total light transmittance of the film is preferably 100%, but the required performance is met even if it is 99% or less. Furthermore, the film of this embodiment preferably has a haze of 3.0% or less, more preferably 2.0% or less, even more preferably 1.5% or less, even more preferably 1.0% or less, even more preferably 0.7% or less, even more preferably 0.5% or less, even more preferably 0.4% or less, and even more preferably 0.3% or less, 0.28% or less, or 0.25% or less. The lower limit of the haze of the film is preferably 0%, but the required performance is met even if it is 0.001% or more. The total light transmittance and haze are measured according to the description in the examples below.

[0044] <Rolled Body> The film of the present embodiment can be wound around a core material to form a rolled body.

[0045] <Polarizing Sheet> A film formed from the resin composition of this embodiment or a film of this embodiment is preferably used as a protective film for a polarizing sheet (a film that protects a polarizing film). In this embodiment, the polarizing sheet preferably includes the film of this embodiment and a polarizing film, and is a sheet in which the polarizing film and the protective film are laminated in this order. That is, the film of this embodiment is preferably used as at least one of the protective films for a polarizing sheet. The protective film is usually attached to the polarizing film via an adhesive. In this embodiment, one of the protective films of the polarizing sheet may be the film of this embodiment or another protective film. When one of the protective films of the polarizing sheet is the film of this embodiment, the other protective film of the polarizing sheet may be a known protective film for a polarizing sheet, or may be the film of this embodiment. Known polarizing films can be used, and examples thereof include polyvinyl alcohol (PVA) films adsorbed or impregnated with iodine or a dichroic organic dye. Known adhesives can be used to attach the film of this embodiment or other protective films to the polarizing film, and examples thereof include acrylic adhesives, urethane adhesives, epoxy adhesives, silicone adhesives, and polyvinyl alcohol adhesives. Among these, urethane adhesives are preferred. The thickness of the adhesive is usually 1 μm or more and usually 30 μm or less. The polarizing sheet of this embodiment may further include a masking film or the like on the outer side of the film of this embodiment and other protective films.

[0046] In this embodiment, the polarizing sheet of this embodiment is preferably used in a heat-bent product that has been subjected to heat bending. When the film of this embodiment is used in a polarizing sheet or heat-bent product, the film of this embodiment may be provided on either side of the polarizing film, or may be provided on both sides. In a first embodiment, the film of this embodiment is disposed so that it is located on the convex side of the polarizing film after heat bending, for example, on the side of protective film 4 in FIG. 1 . In a second embodiment, the film of this embodiment is disposed so that it is located on the concave side of the polarizing film after heat bending, for example, on the side of protective film 3 in FIG. 1 . In a third embodiment, the film of this embodiment is disposed on both sides of the polarizing film, for example, both protective films 3 and 4 in FIG. 1 are films of this embodiment. Note that in FIG. 1 , the lens 1, the polarizing film 2, and the protective films 3 and 4 are bent, but it goes without saying that a polarizing sheet that has not been bent is also included in this embodiment. The film of this embodiment and other protective films used in the polarizing sheet of this embodiment may or may not be stretched. In the first embodiment, stretching is preferred. In the second embodiment, it is preferable that the protective film is not stretched. In the third embodiment, it is preferable that the protective film disposed so as to be located on the side of protective film 4 in Fig. 1 is stretched, and it is preferable that the protective film disposed so as to be located on the side of protective film 3 in Fig. 1 is not stretched.

[0047] In this embodiment, the polarizing sheet is preferably used as a polarizing sheet for use in liquid crystal display devices, polarizing lenses (sunglasses, ski goggles, prescription eyeglass lenses, camera viewfinder lenses), covers for various instruments, glass for automobiles, glass for trains, polarizing sheets for in-vehicle display panels and electronic device housings, etc., in-vehicle inner mirrors, silver mirrors for helmets, etc., and is particularly preferably used as sunglasses.

[0048] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be changed as appropriate 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.

[0049] 1. Raw materials A1: G850, manufactured by Arkema, a polyamide resin synthesized from bis(4-amino-3-methylcyclohexyl)methane, sebacic acid, and aminoundecanoic acid (the proportion of aminoundecanoic acid is 17 mol% relative to 100 mol% of the raw material monomers), an amorphous polyamide resin A2: XE4205, manufactured by EMS, a polyamide resin synthesized from bis(4-amino-3-methylcyclohexyl)methane and sebacic acid, an amorphous polyamide resin

[0050] B1: FUJIFILM Wako Pure Chemical Industries, Ltd., polyethylene glycol, number average molecular weight: 1000 B2: D-1000, manufactured by NOF Corporation, polypropylene glycol, number average molecular weight: 1000 B3: D-2000, manufactured by NOF Corporation, polypropylene glycol, number average molecular weight: 2000 B4: D-4000, manufactured by NOF Corporation, polypropylene glycol, number average molecular weight: 4000 B5: PB-700, manufactured by NOF Corporation, copolymer of butylene glycol units and propylene glycol units (propylene glycol units account for less than 50 mol% of all units), number average molecular weight: 700

[0051] 2. Examples 1 to 6 and Comparative Examples 1 to 4 <Production of Resin Pellets> Each component was blended in a tumbler to obtain the composition shown in Tables 1 and 2 below (contents in Tables 1 and 2 are shown in parts by mass), and the blend was introduced into the base of a twin-screw extruder (TEX30α, manufactured by The Japan Steel Works, Ltd.) and melt-kneaded at a cylinder temperature of 280°C to produce pellets for the Examples and Comparative Examples.

[0052] <Film Production> The pellets obtained above were extruded into a molten state using a T-die melt extruder consisting of a vented twin-screw extruder (manufactured by Toshiba Machine Co., Ltd., "TEM-26DS") with a screw nominal diameter of 28 mm and a screw L / D of 40 at a discharge rate of 15 kg / h and a screw rotation speed of 250 rpm. The pellets were then pressed between a first roll and a second roll, and then cooled and solidified to produce a film. The cylinder temperature and die temperature were 280°C, and the first roll and second roll temperatures were 120°C. A film with a thickness of 300 μm was obtained. Details of the first and second rolls used are as follows: First roll: UM roll manufactured by Toshiba Machine Co., Ltd., dimensions: outer diameter 180 mm x roll width 400 mm Second roll: rigid metal roll (surface: chrome-treated) manufactured by Toshiba Machine Co., Ltd., dimensions: outer diameter 180 mm x roll width 400 mm

[0053] <Roll Contamination> After consuming 30 kg of raw material when using Polyamide A1 or 90 kg of raw material when using Polyamide A2 to produce a film, the roll was visually evaluated as follows. The evaluation was carried out by five experts and judged by majority vote. A: No roll contamination was observed, or some roll contamination was observed but was at a practically acceptable level. B: Roll contamination occurred and was beyond the practically acceptable level.

[0054] <Measurement of Haze and Total Light Transmittance> Using a haze meter, the haze (%) and total light transmittance (%) of the 300 μm thick film obtained above were measured under conditions of a D65 light source and a 10° field of view. The haze meter used was "HM-150" manufactured by Murakami Color Research Laboratory Co., Ltd.

[0055]

[0056]

[0057] As is clear from the results in Tables 1 and 2, in the present invention, roll contamination was effectively suppressed and films with excellent transparency were obtained. In contrast, when no polyalkylene glycol (B) was contained (Comparative Examples 1 and 2), or when a polyalkylene glycol was contained but a polyalkylene glycol other than the polyalkylene glycol (B) specified in the present invention was used (Comparative Examples 3 and 4), the haze was high and the total light transmittance was reduced (Comparative Example 3), and roll contamination occurred (Comparative Examples 1, 2, and 4).

[0058] 1 Lens 2 Polarizing film 3 Protective film 4 Protective film

Claims

1. A resin composition comprising a polyamide resin containing alicyclic diamine units and aliphatic dicarboxylic acid units having 7 to 20 carbon atoms, and a polyalkylene glycol, wherein the polyalkylene glycol contains ethylene glycol units and / or propylene glycol units in a total proportion of 50 mol % or more of all units, and has a number average molecular weight of 100 to 3,500.

2. The resin composition according to claim 1, wherein the aliphatic dicarboxylic acid units having 7 to 20 carbon atoms include sebacic acid units and / or dodecanedioic acid units.

3. The resin composition according to claim 1 or 2, wherein the alicyclic diamine constituting the alicyclic diamine unit contains two substituted or unsubstituted cyclohexane rings.

4. The resin composition according to claim 1 or 2, wherein the alicyclic diamine unit includes a unit represented by formula (PA-1). (In formula (PA-1), R １ are each independently an alkyl group having 1 to 5 carbon atoms, and each n1 is independently an integer of 0 to 3. * is a bonding site with another unit or a terminal group.

5. A resin composition according to any one of claims 1 to 4, wherein the content of the polyamide resin contained in the resin composition is 90 mass% or more.

6. The resin composition according to any one of claims 1 to 5, wherein the content of polyalkylene glycol contained in the resin composition is 0.01 to 5 mass %.

7. The resin composition according to any one of claims 1 to 6, wherein the aliphatic dicarboxylic acid units having 7 to 20 carbon atoms include sebacic acid units and / or dodecanedioic acid units, the alicyclic diamine units include units represented by formula (PA-1), the content of the polyamide resin contained in the resin composition is 90 mass% or more, and the content of polyalkylene glycol contained in the resin composition is 0.01 to 5 mass% (with the proviso that the total amount of the polyamide resin and the polyalkylene glycol does not exceed 100 mass%). (In formula (PA-1), R １ are each independently an alkyl group having 1 to 5 carbon atoms, and each n1 is independently an integer of 0 to 3. * is a bonding site with another unit or a terminal group.

8. The resin composition according to any one of claims 1 to 7, wherein the polyamide resin is an amorphous resin.

9. The resin composition according to any one of claims 1 to 8, wherein the haze of the resin composition when molded into a film having a thickness of 300 µm is 3.0% or less.

10. The resin composition according to any one of claims 1 to 9, wherein the resin composition has a total light transmittance of 80% or more when molded into a film having a thickness of 300 μm.

11. The resin composition according to any one of claims 1 to 10, which is used as a protective film for a polarizing sheet.

12. A film formed from the resin composition according to any one of claims 1 to 11.

13. A polarizing sheet comprising the film according to claim 12 and a polarizing film.

14. Sunglasses comprising the polarizing sheet according to claim 13.

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