Resin composition, film, polarizing plate, method for manufacturing resin composition, and method for manufacturing film

Abstract

The invention provides a resin composition capable of inhibiting pollution of a forming roller and preventing foreign matters from appearing on a film, a film, a polarizing plate, a manufacturing method of the resin composition, and a manufacturing method of the film. Provided is a resin composition which contains 0.05-10 parts by mass of a compound having 1-3 cyclic ether structures per molecule per 100 parts by mass of a polyamide resin, and which has a haze of 10% or less when made into a film having a thickness of 200 [mu] m.

Description

Technical Field

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

[0002] Polyamide resins are widely used in many fields such as electrical and electronic products, automobiles, machinery, and building materials due to their excellent mechanical properties such as rigidity and strength and heat resistance (Patent Documents 1 to 3).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-129271

[0006] Patent Document 2: Japanese Patent Application Publication No. 2013-001906

[0007] Patent Document 3: Japanese Patent Application Publication No. 2012-131977 Summary of the invention

[0008] Technical problem to be solved by the invention

[0009] As described above, polyamide resins are widely used in many fields, but the transparency of these resins is generally poor and thus they are not used for applications requiring transparency.

[0010] Under such circumstances, the inventors of the present invention studied the use of polyamide resins for transparent applications such as protective films for polarizing films. However, when the polyamide resin is formed into a film, it was found that the forming rollers were contaminated or foreign matter appeared. In the past, it was known that such roller contamination or foreign matter did not cause any problem in transparent parts and transparent films such as food packaging materials using polyamide resins, but it became a problem in applications such as sunglasses that require extremely high transparency.

[0011] The purpose of the present invention is to solve the technical problem, and its purpose is to provide a resin composition that can suppress contamination of the molding roll even when molded into a film and is less likely to have foreign matter on the film, as well as a film, a polarizing plate, a method for producing the resin composition, and a method for producing the film.

[0012] Technical means for solving technical problems

[0013] The inventors of the present invention have conducted studies based on the above-mentioned technical problems and have found that the above-mentioned technical problems can be solved by using a compound having 1 to 3 cyclic ether structures in one molecule.

[0014] Specifically, the above technical problems can be solved by the following technical means.

[0015] <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 based on 100 parts by mass of a polyamide resin, wherein the composition has a haze of 10% or less when formed into a 200 μm thick film.

[0016] <2> The resin composition according to <1>, wherein a content of the filler in the resin composition is 0 to 10% by mass.

[0017] <3> The resin composition according to <1> or <2>, wherein the polyamide resin includes an aliphatic polyamide resin.

[0018] <4> The resin composition according to any one of <1> to <3>, wherein the compound having 1 to 3 cyclic ether structures in one molecule includes an epoxy ring and / or an oxetane ring.

[0019] <5> The resin composition according to <1>, wherein the content of the filler in the resin composition is 0 to 10% by mass, 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.

[0020] <6> The resin composition according to any one of <1> to <5>, which is used for a protective film for a polarizing plate.

[0021] <7> A film formed from the resin composition according to any one of <1> to <6>.

[0022] <8> The film according to <7>, which has a thickness of 100 to 1000 μm.

[0023] <9> The film according to <7> or <8>, which is a protective film for a polarizing plate.

[0024] <10> A polarizing plate comprising a polarizing film and a protective film present on at least one surface of the polarizing film, wherein the protective film is the film according to any one of <7> to <9>.

[0025] <11> A method for producing a resin composition, comprising the step of 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 performing melt-kneading.

[0026] <12> The method for producing a resin composition according to <11>, wherein the resin composition has a haze of 10% or less when formed into a 200 μm thick film.

[0027] <13> A method for producing a film, comprising the step of 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 performing melt-kneading.

[0028] <14> The method for producing a film according to <13>, wherein the film has a haze of 10% or less.

[0029] Effects of the Invention

[0030] The present invention can provide a resin composition which can suppress contamination of a molding roll even when molded into a film and in which foreign matter is less likely to appear in the film, a film, a polarizing plate, a method for producing the resin composition, and a method for producing the film. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram showing the layer structure of the polarizing plate of this embodiment. DETAILED DESCRIPTION

[0032] A mode for carrying out the present invention (hereinafter referred to as "this embodiment") will be described in detail below. However, the following this embodiment is an example for explaining the present invention, and the present invention is not limited to this embodiment.

[0033] In the present specification, the use of "to" means that the numerical values ​​described before and after it are included as the lower limit and the upper limit.

[0034] In this specification, various physical property values ​​and characteristic values ​​are values ​​at 23°C unless otherwise specified.

[0035] 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 JP-A-2018-165298, and the content is incorporated into this specification.

[0036] The "film" and "sheet" in this specification refer to a substantially flat shaped body whose thickness is thinner than its length and width, respectively. Furthermore, the "film" and "sheet" in this specification may be a single layer or a multilayer.

[0037] When the standard measurement methods and the like shown in this specification differ by year, unless otherwise specified, the standards as of January 1, 2022 are used.

[0038] The resin composition of the present embodiment is characterized in that it contains 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 the haze when formed into a 200 μm thick film is 10% or less. By setting such a structure, contamination of the molding roll can be suppressed, and foreign matter is less likely to appear in the film.

[0039] It is speculated that the cause of the above-mentioned roller contamination is due to diamines or aminocarboxylic acids from the raw materials contained in the polyamide resin, or dimers or trimers of the raw material monomers. In addition, it is speculated that the cause of the above-mentioned roller contamination is also due to a small amount of decomposition products generated when the resin composition is extruded in a film form. For this reason, a compound having 1 to 3 cyclic ether structures in one molecule (hereinafter sometimes referred to as "cyclic ether compound") is added to the polyamide resin. Such a cyclic ether compound reacts with diamines or aminocarboxylic acids as raw material monomers, dimers or trimers of raw material monomers, or decomposition products generated when the resin composition is extruded in a film form. As a result, it is speculated that the diamines from the raw materials can be effectively suppressed from seeping out of the film, and roller contamination can be suppressed. In addition, when the cyclic ether compound contains multiple cyclic ether structures, the cyclic ether compound reacts with the above-mentioned diamines, etc. to generate foreign matter in the film. In the present embodiment, it is speculated that the generation of foreign matter can be suppressed by making the number of cyclic ether structures in the cyclic ether compound 3 or less.

[0040] This embodiment is described below.

[0041] <Polyamide resin>

[0042] The resin composition of the present embodiment contains a polyamide resin. The polyamide resin used in the present embodiment is not particularly limited unless it deviates from the gist of the present invention, but an amorphous polyamide resin is preferred from the viewpoint of transparency.

[0043] Here, the amorphous polyamide resin is a polyamide resin without a clear melting point, specifically, a crystalline melting enthalpy ΔHm is 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 accordance with JIS K7121 and K7122 during the temperature rise, more specifically, according to the contents described in paragraph 0101 of the specification of Japanese Patent No. 7021725.

[0044] The polyamide resin used in the present embodiment can be a semi-aromatic polyamide resin, or an aliphatic polyamide resin, preferably an aliphatic polyamide resin, and more preferably an alicyclic polyamide resin. Aliphatic polyamide resin refers to a polyamide resin in which preferably 90% by mass or more, more preferably 95% by mass or more, and further preferably 98% by mass or more of its raw monomers are aliphatic monomers. Alicyclic polyamide refers to a polyamide resin comprising alicyclic monomer units in an aliphatic polyamide resin, preferably a polyamide resin in which 10% by mass or more (more preferably 30% by mass or more, and preferably less than 100% by mass, less than 70% by mass, less than 60% by mass, less than 50% by mass) of all monomer units constituting the polyamide resin are alicyclic monomer units.

[0045] Examples of the polyamide resin include a polyamide resin in which the main component of the raw material monomer (e.g., 50% by mass or more, preferably 90% by mass or more) is synthesized from diamine and dicarboxylic acid, a polyamide resin in which the main component of the raw material monomer is synthesized from aminocarboxylic acid, and a polyamide resin in which the main component of the raw material monomer is synthesized from diamine, dicarboxylic acid, and aminocarboxylic acid. The polyamide resin used in this embodiment is particularly 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 monomer. In this embodiment, for a resin composition using such a polyamide resin, roller contamination can be particularly effectively suppressed.

[0046] 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, and alicyclic diamines having 6 to 25 carbon atoms are preferred.

[0047] 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, and preferably 18 or less, more preferably 16 or less, further preferably 14 or less, further preferably 12 or less, further 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.

[0048] 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 further 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.

[0049] 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.

[0050] 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 preferably 22 or less, more preferably 20 or less, and further 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, and dodecanedioic acid, among which adipic acid and sebacic acid are preferred, and sebacic acid is more preferred.

[0051] The carbon number of the alicyclic dicarboxylic acid having 6 to 25 carbon atoms is preferably 6 or more and preferably 18 or less, more preferably 16 or less, further preferably 14 or less, further preferably 12 or less, further 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.

[0052] As the aminocarboxylic acid unit, an aminocarboxylic acid unit having 4 to 20 carbon atoms can be exemplified. The aminocarboxylic acid is preferably composed 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, and preferably 18 or less, more preferably 16 or less, further preferably 14 or less, and further preferably 13 or less. As a specific example of the aminocarboxylic acid, 11-aminoundecanoic acid can be exemplified.

[0053] As an example of the polyamide resin used in the present embodiment, polyamide 11 can be exemplified.

[0054] As another example of the polyamide resin used in the present embodiment, the alicyclic diamine units having 6 to 25 carbon atoms and the linear aliphatic dicarboxylic acid units having 4 to 20 carbon atoms preferably account for 90% by mass or more of all monomer units, more preferably 95% by mass or more, and may account for 100% by mass.

[0055] As a specific example of the polyamide resin used in the present embodiment, a polyamide resin obtained from 4,4′-methylenebis(2-methylcyclohexylamine) and sebacic acid can be exemplified.

[0056] As a specific example of the polyamide resin used in the present embodiment, a polyamide resin obtained by 1,3-bisaminomethylcyclohexane and / or 1,4-bisaminomethylcyclohexane and adipic acid can also be exemplified. In addition, as another example of the polyamide resin used in the present embodiment, a polyamide resin obtained by 1,3-bisaminomethylcyclohexane and / or 1,4-bisaminomethylcyclohexane and adipic acid, 1,4-cyclohexanedicarboxylic acid (preferably, the molar ratio of adipic acid to 1,4-cyclohexanedicarboxylic acid is 85 to 95:15 to 5) can be exemplified. A portion of the above polyamide resin can be substituted by other monomers (diamine, dicarboxylic acid, aminocarboxylic acid, lactam, etc.).

[0057] The polyamide resin used in the present embodiment may be a commercially available product. Examples of commercially available products include "Trogamid CX7323" produced by Daicel-Evonik Corporation, "Grilamid TR90" produced by Ems-Chemie, "Rilsan (registered trademark) Clear G350", "Rilsan Clear G850", "Rilsan Clear G820" produced by Arkema, and "Rilsan Clear G850" is particularly preferred.

[0058] As the polyamide resin, in addition to the above-mentioned resins, the contents described in paragraphs 0169 to 0220 of International Publication No. 2021 / 140927 may also be referred to, and the contents are incorporated into the present specification.

[0059] The content of the polyamide resin (preferably amorphous polyamide resin) in the resin combination of the present embodiment is preferably more than 95 mass % in the resin combination, more preferably more than 96 mass %, further preferably more than 97 mass %, more preferably more than 98 mass %, more preferably more than 99 mass %. By being set to more than the above-mentioned lower limit, there is a trend that chemical resistance further improves. And the upper limit of the content of the polyamide resin (preferably amorphous polyamide resin) in the resin combination of the present embodiment is preferably the amount that the total amount of polyamide resin and cyclic ether compound reaches 100 mass %.

[0060] The resin composition of the present embodiment may contain only one polyamide resin (preferably amorphous polyamide resin) or two or more polyamide resins. When two or more polyamide resins are contained, the total amount is preferably within the above range.

[0061] <Compounds having 1 to 3 cyclic ether structures in one molecule>

[0062] 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) relative to 100 parts by mass of the polyamide resin. By containing the cyclic ether compound, the diamine as a raw material monomer, the dimer or trimer of the raw material monomer, or the decomposition product, etc. remaining in the polyamide resin reacts, and when the resin composition is formed into a film, it is possible to effectively suppress the diamine and the like from adhering to the roller and causing roller contamination.

[0063] In the present embodiment, the number of cyclic ether structures in the cyclic ether compound is preferably one or two.

[0064] Furthermore, in the present embodiment, the cyclic ether compound preferably includes an oxirane ring and / or an oxetane ring.

[0065] The molecular weight of the cyclic ether compound is preferably 180 or more, and preferably 1000 or less, and more preferably 800 or less. By setting it to be above the above lower limit, the volatilization of the cyclic ether compound itself can be more effectively suppressed. In addition, by setting it to be below the above upper limit, the mass per unit cyclic ether structure can be reduced, and the amount of the cyclic ether compound used to suppress roller contamination can be reduced. As a result, the heat resistance (glass transition temperature) of the obtained film can be improved. In the present 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 molecular weights of the cyclic ether compounds multiplied by the mass fraction.

[0066] The cyclic ether compound used in the present embodiment preferably has constituent elements consisting only of carbon atoms, hydrogen atoms, and oxygen atoms. By setting such a constitution, it is possible to more effectively suppress roller contamination and suppress the generation of foreign matter.

[0067] The cyclic ether compound used in this embodiment preferably has 3 or less aromatic rings in one molecule, and more preferably contains no aromatic rings. Due to the small number of aromatic rings, there is a tendency to improve compatibility with polyamide resins (especially aliphatic polyamide resins), and there is a tendency to be able to more effectively exert the effects of the present invention.

[0068] The cyclic ether compound used in the present embodiment preferably contains an epoxy ring and / or an oxetane ring, and the constituent elements are composed only of carbon atoms, hydrogen atoms, and oxygen atoms, and the molecular weight is 180 to 1000, and the number of aromatic rings in one molecule is 3 or less (preferably 1 or 2). By setting such a structure, it is possible to more effectively suppress roller contamination and the generation of foreign matter. The cyclic ether compound used in the present embodiment is particularly preferably (molecular weight of a compound having 1 to 3 cyclic ether structures in one molecule / number of cyclic ether structures) < 250.

[0069] The cyclic ether compound used in the present embodiment may or may not have a group reactive with an amino group other than the cyclic ether structure.

[0070] An example of the cyclic ether compound used in the present embodiment is a compound having no group reactive with an amino group other than a cyclic ether structure.

[0071] Another example of the cyclic ether compound used in the present embodiment is a compound having no allyl group.

[0072] The cyclic ether compound used in the present embodiment is also preferably a compound having 1 or 2 functional groups reactive with an amino group, wherein at least one of the functional groups reactive with an amino group in the compound is an epoxy group or an oxetanyl group.

[0073] By setting it as the above-mentioned structure, there is a tendency that the effect of the present invention can be more effectively exerted.

[0074] The content of the cyclic ether compound in the resin composition of the present embodiment is 0.05 mass parts or more, preferably 0.08 mass parts or more, more preferably 0.1 mass parts or more, further preferably 0.2 mass parts or more, further preferably 0.3 mass parts or more, and further preferably 0.4 mass parts or more relative to 100 mass parts of polyamide resin. By setting it to above the above lower limit, there is a trend that roller contamination can be more effectively suppressed. In addition, the upper limit of the content of the above cyclic ether compound is 10 mass parts or less, preferably 8 mass parts or less, more preferably 5 mass parts or less, further preferably 3 mass parts or less, and then less than 2 mass parts, and can also be less than 1.5 mass parts. By setting it to below the above upper limit, the glass transition temperature of the resin composition or film can be effectively suppressed. In particular, even if it is matched with less than 2 mass parts in a small amount, roller contamination can be suppressed, which is very valuable from this point of view.

[0075] The resin composition of the present embodiment may contain only one cyclic ether compound or two or more cyclic ether compounds. When two or more cyclic ether compounds are contained, the total amount is preferably within the above range.

[0076] In addition, the resin composition of the present embodiment preferably does not substantially contain a compound having 4 or more cyclic ether structures in one molecule. Substantially free means that the content of the compound having 4 or more cyclic ether structures in one molecule is less than 10% by mass of the content of the compound having 1 to 3 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.

[0077] <Other ingredients>

[0078] The resin composition of the present embodiment may further contain, in addition to the above components, a light stabilizer, a heat stabilizer, an antioxidant, an infrared absorber, a hydrolysis resistance improver, an ultraviolet absorber, an antistatic agent, an anti-coloring agent, an anti-gelling agent, a light-adjusting dye, and the like.

[0079] In the case of containing components other than the polyamide resin and the cyclic ether compound in the resin composition of the present embodiment, the total content is preferably 0.001% by mass or more of the resin composition, and preferably 20% by mass or less, more preferably 10% by mass or less, further preferably 5% by mass or less, further preferably 3% by mass or less, further preferably 1% by mass or less, more preferably less than 0.2% by mass, further preferably less than 0.1% by mass. By setting such a configuration, there is a tendency that the effect of the present invention can be more effectively exerted.

[0080] These components may be used alone or in combination of two or more.

[0081] In addition, the content of the filler in the resin composition is preferably 0 to 10% by mass, more preferably 0 to 5% by mass, further preferably 0 to 3% by mass, further preferably 0 to 1% by mass, further preferably 0 to 0.1% by mass, further preferably 0 to 0.01% by mass, further preferably substantially free of fillers. Substantially free of fillers means, for example, that the content is 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 1% by mass or less of the content of the cyclic ether compound contained in the resin composition.

[0082] In the resin composition of the present embodiment, it is preferred that the total amount of the polyamide resin and the cyclic ether compound accounts for 99% by mass or more of the resin composition.

[0083] The resin composition of the present embodiment is preferably a thermoplastic resin composition.

[0084] The resin composition of the present embodiment preferably contains substantially no solvent. Substantially no 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 further preferably 1% by mass or less.

[0085] <Haze>

[0086] The resin composition of the present embodiment has high transparency. Specifically, the haze when the resin composition is made into a 200 μm thick film is 10% or less. Such haze can be achieved by using a polyamide resin with high transparency, setting the content of filler in the resin composition to 10% by mass or less, etc. The haze when the above-mentioned resin composition is made into a 200 μm thick film is preferably 5% or less, more preferably 3% or less, further preferably 1.1% or less, further preferably 0.8% or less, and further preferably 0.6% or less. The haze of polyamide resin films for packaging materials and the like is usually more than 10%, while the haze of the resin composition of the present embodiment is exceptionally low.

[0087] <Method for producing resin composition>

[0088] As a method for producing the resin composition of the present embodiment, any method can be adopted.

[0089] 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 performing melt kneading. More specifically, a method can be cited in which a polyamide resin and a compound having 1 to 3 cyclic ether structures in one molecule, as well as other components as required, are mixed using a mixing means such as a V-blender to prepare a batch blended product, and then melt kneading is performed using an extruder with a vent to prepare pellets.

[0090] <Film>

[0091] The film of the present embodiment is formed from the resin composition of the present embodiment.

[0092] The thickness of the film of the present embodiment is preferably 100 μm or more, more preferably 120 μm or more, further preferably 140 μm or more, further preferably 160 μm or more, further preferably 180 μm or more. Furthermore, the thickness of the film of the present embodiment is preferably 1000 μm or less, more preferably 900 μm or less, further preferably 800 μm or less, further preferably 600 μm or less, further preferably 500 μm or less, and may be 300 μm or less.

[0093] The film of the present embodiment preferably has excellent transparency. Specifically, the haze is preferably 10% or less, more preferably 5% or less, further preferably 3% or less, further preferably 1.1% or less, further preferably 0.8% or less, further preferably 0.6% or less. The haze of polyamide resin films for packaging materials and the like usually exceeds 10%, but the haze of the film of the present embodiment is exceptionally low.

[0094] The film of the present embodiment is usually a product produced by extrusion molding, that is, an extrusion molded product. In addition, the film of the present embodiment is usually molded using a roll.

[0095] The film of the present embodiment is preferably a continuous film, for example. The continuous film refers to a film having a length of, for example, 10 m or more (preferably 10000 m or less). The continuous film can be wound on a roll to form a roll.

[0096] The film of this embodiment can be used for applications requiring high transparency. Specifically, it is preferably used as a protective film for polarizers, more preferably used as a protective film for polarizers, and particularly preferably used for sunglasses and goggles.

[0097] That is, in the present embodiment, there can be exemplified a polarizing plate including a polarizing film and a protective film present on at least one surface of the polarizing film, wherein the protective film is the film of the present embodiment.

[0098] Figure 1 1 is a schematic diagram showing the layer structure of the polarizing plate of the present embodiment, wherein 1 is a polarizing film, 2 is a protective film (film of the present embodiment), and 3 is an adhesive layer for bonding the polarizing film and the protective film.

[0099] As the polarizing film, a polyvinyl alcohol resin film is preferably used. As the polyvinyl alcohol resin, polyvinyl alcohol (PVA) and its derivatives, or polyvinyl formal, polyvinyl acetal, poly (ethylene-vinyl acetate) copolymer saponification products as analogs thereof can be listed, preferably PVA. The weight average molecular weight of the PVA film is preferably 50,000 or more, more preferably 150,000 or more, and preferably 350,000 or less, more preferably 300,000 or less.

[0100] The polarizing film is preferably a film 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 preferably 8 times or less, more preferably 6.5 times or less.

[0101] 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.

[0102] When the film of this embodiment is attached to both sides of the polarizing film, an adhesive can be used. As the adhesive, polyvinyl alcohol resin-based materials, acrylic resin-based materials, polyurethane resin-based materials, polyester resin-based materials, melamine resin-based materials, epoxy resin-based materials, silicone-based materials, etc. can be used, preferably polyurethane resin-based materials.

[0103] The polarizing plate of the present embodiment is not limited to the above range. For example, other ingredients such as light stabilizers, heat stabilizers, antioxidants, infrared absorbers, hydrolysis resistance improvers, ultraviolet absorbers, antistatic agents, anti-coloring agents, anti-gelling agents, dimming dyes, etc. can be appropriately dissolved in the adhesive layer containing the adhesive for bonding the film of the present embodiment as a polarizing film and a protective film.

[0104] Regarding the manufacture and use of polarizing plates, in addition to the above contents, reference may be made to the contents described in International Publication No. 2019 / 054295 and International Publication No. 2014 / 115705, which are incorporated into this specification.

[0105] <Method for producing film>

[0106] The method for producing a film of the present embodiment includes the step of 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 performing melt kneading. The obtained film preferably satisfies the above-mentioned film of the present embodiment.

[0107] More specifically, the film can be produced by extruding the molten resin composition in a sheet form and conveying it on a roll. It is preferred that the resin composition satisfies the above-mentioned requirements of the resin composition of this embodiment.

[0108] Example

[0109] The present invention is described in more detail below by enumerating examples. As long as it does not depart from the gist of the present invention, the materials, usage, ratio, processing content, processing sequence, etc. shown in the following examples can be appropriately changed. Therefore, the scope of the present invention is not limited to the specific examples shown below.

[0110] When the measuring instruments used in the examples are difficult to obtain due to model discontinuation or the like, other instruments having equivalent performance may be used for measurement.

[0111] 1. Raw materials

[0112] The following materials were used as raw materials.

[0113] A1: Rilsan Clear G850, a polyamide resin made from 4,4'-methylenebis(2-methylcyclohexylamine) and sebacic acid, produced by Arkema

[0114] B1: OXT-221, manufactured by Toagosei Co., Ltd.

[0115]

[0116] B2: 2021P, manufactured by Daicel Co., Ltd.

[0117]

[0118] B3: OXT-121, manufactured by Daicel Co., Ltd.

[0119]

[0120] B4: OXT-212, manufactured by Toagosei Co., Ltd.

[0121]

[0122] n is a mixture of 1 to 3.

[0123] B5: EPOGOSEY PT, produced by Yokkaichi Gosei Co., Ltd.

[0124]

[0125] A mixture wherein n is 1 to 25.

[0126] B6: TETRAD-X, manufactured by Mitsubishi Gas Chemical Co., Ltd.

[0127]

[0128] 2. Examples 1 to 5, Comparative Examples 1 and 2

[0129] <Film production>

[0130] The polyamide resin film was produced according to the following method.

[0131] The components described in Table 1 were weighed according to the addition amounts described in Table 1 (indicated by mass parts in Table 1). After that, after mixing by drum for 15 minutes, the mixture was extruded in a molten state under the conditions of discharge rate of 8 kg / h and screw speed of 100 rpm using a T-die melt extruder consisting of a twin-screw segmented extruder with a drum diameter of 25 mm and a screw L / D of 30 (manufactured by Toyo Seiki Co., Ltd., "2D30W2"), and cooled and solidified only by the first roll of a film-sheet drawing device (manufactured by Toyo Seiki Co., Ltd., "FT3W20") to produce a polyamide resin film. The temperature of the barrel and die head was 290°C and the roll temperature was 130°C.

[0132] The roll speed of the first roll was changed to adjust the thickness of the film finally obtained to 200 μm.

[0133] <Roller contamination>

[0134] Regarding roll contamination, 20 minutes after the start of drawing the resin by the film-sheet drawing device, the presence or absence of roll contamination on the first roll was visually confirmed. The evaluation was performed as follows.

[0135] A: No roller contamination was confirmed

[0136] B: Contamination of the roller (foreign matter) confirmed

[0137] The obtained film was visually checked for the presence of foreign matter under a fluorescent light, and five professionals evaluated the film and the majority vote was taken.

[0138] A: No foreign matter was found

[0139] B: Foreign matter confirmed<Haze>

[0140] The haze (unit: %) of the film obtained above was measured using a haze meter under the conditions of a D65 light source and a 10° viewing field.

[0141] As the haze meter, "HM-150" manufactured by Murakami Color Research Laboratory Co., Ltd. was used.

[0142] [Table 1]

[0143]

[0144] In the above Table 1, the unit of each component is parts by mass. When a film formed from the resin composition of the present embodiment was produced, no roll contamination was observed, and the obtained film had no foreign matter. In addition, the film formed from the resin composition of the present embodiment had excellent transparency.

[0145] Description of Reference Numerals

[0146] 1: polarizing film; 2: protective film; 3: adhesive layer.

Claims

1. A resin composition, characterized in that The polyamide resin contains 0.05 to 10 parts by mass of a compound having 1 to 3 cyclic ether structures in one molecule, based on 100 parts by mass of the polyamide resin. The haze when formed into a 200 μm thick film was 10% or less.

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

3. The resin composition according to claim 1 or 2, characterized in that The polyamide resin contains an aliphatic polyamide resin.

4. The resin composition according to any one of claims 1 to 3, characterized in that The compound having 1 to 3 cyclic ether structures in one molecule includes an epoxy ring and / or an oxetane ring.

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

6. The resin composition according to any one of claims 1 to 5, characterized in that The resin composition is used for a protective film of a polarizer.

7. A film, characterized in that The present invention is formed from the resin composition according to any one of claims 1 to 6.

8. The film according to claim 7, characterized in that The thickness is 100 to 1000 μm.

9. The film according to claim 7 or 8, characterized in that It is a protective film for polarizing plates.

10. A polarizing plate, characterized in that: A polarizing film and a protective film present on at least one surface of the polarizing film. The protective film is the film according to any one of claims 7 to 9.

11. A method for producing a resin composition, characterized in that: The method comprises the steps of 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 performing 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 200 μm thick film.

13. A method for producing a film, characterized in that: The method comprises the steps of 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 performing melt kneading.

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

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