Resin composition, resin film, polarizing plate and liquid crystal display panel

Abstract

To provide a resin composition having high heat resistance and ultraviolet shielding properties and low volatility in molding.SOLUTION: And a UV absorber having a 1% weight reduction temperature of 610K or higher and a maximum absorbance of 350nm or higher, and having a glass-transition temperature of 115 °C or higher. The plastic film obtained by molding the plastic composition has a transmissivity of less than 2% for light having a wave length of 370nm at an optical path length of 40 μm. Td1 / (W·η)> 5.00 * 10 - 2 (1) is satisfied, where 24sec [K] is the 1% weight reduction temperature of the UV absorber, W [wt%] is the ratio of the UV absorber to the acrylic polymer, and η [Poise] is the melt viscosity of the polymer composition at a temperature of 260 °C. and a shear rate of Td1 - 1.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition, a resin film, a polarizing plate, and a liquid crystal display panel. [Background technology]

[0002] A resin composition containing an acrylic resin and an ultraviolet absorber has excellent transparency, color tone, appearance, heat resistance, processability, and ultraviolet shielding properties, and is therefore used, for example, in polarizer protective films. Here, the polarizer protective films are attached to both sides of a polarizer to form polarizing plates, which are then placed on both sides of a liquid crystal cell to be used in liquid crystal panels.

[0003] Patent Document 1 describes a thermoplastic resin composition containing a thermoplastic acrylic resin having a ring structure in the main chain and an ultraviolet absorber having a hydroxyphenyltriazine skeleton, in which the thermoplastic acrylic resin has a ring structure content of 5 to 90%. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-52021 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the thermoplastic resin composition described in Patent Document 1 has a ring structure content of 5 to 90% in the thermoplastic acrylic resin, which requires a high molding temperature and makes the ultraviolet absorber prone to volatilization during molding, which can result in contamination of the casting roll when forming a film from the thermoplastic resin composition.

[0006] An object of the present invention is to provide a resin composition that has high heat resistance and ultraviolet shielding properties and low volatility during molding. [Means for solving the problem]

[0007] [1] A resin composition comprising an acrylic resin that does not substantially contain a ring structure in its main chain and an ultraviolet absorber having a 1% weight loss temperature of 610 K or higher and a maximum absorption wavelength of 350 nm or higher, wherein the resin composition has a glass transition temperature of 115 ° C or higher, and the transmittance of light at a wavelength of 370 nm at an optical path length of 40 μm of a film formed from the resin composition is less than 2%, and the 1% weight loss temperature of the ultraviolet absorber is Td1 [K], the ratio of the ultraviolet absorber to the acrylic resin is W [wt%], the temperature is 260 ° C, and the shear rate is 24 sec -1 When the melt viscosity of the resin composition is η [Poise], the following equation (1) is obtained: Td1 / (W·η)>5.50×10 -2 ···(1) A resin composition that satisfies the above requirements.

[0008] [2] A resin composition comprising an acrylic resin having a methyl methacrylate unit content of 98% by weight or more and a triad syndiotacticity of 54% or more, and an ultraviolet absorber having a 1% weight loss temperature of 610 K or more and a maximum absorption wavelength of 350 nm or more, wherein the resin composition is molded into a resin film having a transmittance of light of 370 nm wavelength at an optical path length of 40 μm of less than 2%, and the 1% weight loss temperature of the ultraviolet absorber is Td1 [K], the ratio of the ultraviolet absorber to the acrylic resin is W [wt%], the temperature is 260 ° C, and the shear rate is 24 sec -1 When the melt viscosity of the resin composition is η [Poise], the following equation (1) is obtained: Td1 / (W·η)>5.00×10 -2 ···(1) A resin composition that satisfies the above requirements.

[0009] [3] The resin composition according to [1] or [2], wherein the ultraviolet absorber includes 2,4,6-tris(4-butoxy-2-hydroxyphenyl)-1,3,5-triazine or 2,4,6-tris(4-butoxy-2-hydroxy-3-methylphenyl)-1,3,5-triazine.

[0010] [4] Temperature: 260°C, shear rate: 24 seconds -1 The resin composition according to any one of [1] to [3], having a melt viscosity of less than 21,000 Poise.

[0011] [5] The resin composition according to any one of [1] to [4], wherein the ratio of the ultraviolet absorber to the acrylic resin is less than 0.70% by weight.

[0012] [6] The resin composition according to any one of [1] to [5], which has a glass transition temperature of 118°C or higher.

[0013] [7] The resin composition according to any one of [1] to [6], wherein the acrylic resin has a methyl methacrylate unit content of 98% by weight or more and a triad syndiotacticity of 55% or more.

[0014] [8] The resin composition according to any one of [1] to [7], which is in the form of pellets.

[0015] [9] A resin film obtained by molding the resin composition according to any one of [1] to [8].

[0016]

[10] The resin film according to [9], which has a folding endurance of 400 times or more and a haze of less than 2.0%.

[0017]

[11] The resin film according to [9] or

[10] , which is a polarizer protective film.

[0018]

[12] A polarizing plate comprising the resin film according to

[11] .

[0019]

[13] A liquid crystal display panel comprising the polarizing plate according to

[12] . [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a resin composition that has high heat resistance and ultraviolet shielding properties and low volatility during molding. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described.

[0022] [Characteristics of the first embodiment of the resin composition] The resin composition of this embodiment includes an acrylic resin that is substantially free of a ring structure in its main chain and an ultraviolet absorber. The 1% weight loss temperature of the ultraviolet absorber is 610 K or higher, preferably 620 K or higher, and more preferably 630 K or higher. Because the 1% weight loss temperature of the ultraviolet absorber is 610 K or higher, the volatility of the resin composition of this embodiment during molding is low. The 1% weight loss temperature of the ultraviolet absorber is, for example, 660 K or lower. The maximum absorption wavelength of the ultraviolet absorber is 350 nm or higher, preferably 355 nm or higher. Because the maximum absorption wavelength of the ultraviolet absorber is 350 nm or higher, the ultraviolet shielding ability of the resin composition of this embodiment is high. The maximum absorption wavelength of the ultraviolet absorber is, for example, 365 nm or lower.

[0023] In this specification and claims, acrylic resin refers to a polymer of a monomer having an acryloyl group and / or a monomer having a methacryloyl group. In this case, the acrylic resin may be either a homopolymer or a copolymer. When the acrylic resin is a copolymer, it may be a copolymer of a monomer not having an acryloyl group or a methacryloyl group. The acrylic resin may also be a mixture of two or more polymers with different monomer compositions.

[0024] The glass transition temperature of the resin composition of this embodiment is 115°C or higher, preferably 118°C or higher, more preferably 120°C or higher, even more preferably 121°C or higher, and particularly preferably 122°C or higher. Since the glass transition temperature of the resin composition of this embodiment is 115°C or higher, the heat resistance of the resin composition of this embodiment is high. The glass transition temperature of the resin composition of this embodiment is, for example, 160°C or lower. From the viewpoint of molding temperature and secondary processability of the molded article, it is preferably 135°C or lower, more preferably 130°C or lower.

[0025] The resin film obtained by molding the resin composition of this embodiment has a transmittance of less than 2%, preferably less than 1.5%, for light with a wavelength of 370 nm at an optical path length of 40 μm. Because the resin film obtained by molding the resin composition of this embodiment has a transmittance of less than 2% for light with a wavelength of 370 nm at an optical path length of 40 μm, the resin composition of this embodiment has high ultraviolet shielding properties.

[0026] The 1% weight loss temperature of the UV absorber is Td1 [K], the ratio of the UV absorber to the acrylic resin is W [wt%], the temperature is 260°C, and the shear rate is 24 sec -1 When the melt viscosity of the resin composition of this embodiment is η [Poise], it is expressed by the following formula (1): Td1 / (W·η)>5.00×10 -2 ···(1) and equation (2) Td1 / (W·η)>5.50×10 -2 ···(2) It is preferable to satisfy the formula (3). Td1 / (W·η)>6.00×10 -2 ···(3) It is more preferable to satisfy the following. Since formula (1) is satisfied, the volatility of the resin composition of this embodiment during molding is low. Here, if Td1 is large, the ultraviolet absorber is less likely to volatilize during molding of the resin composition of this embodiment. Furthermore, if W is large, the ultraviolet absorber is more likely to volatilize during molding of the resin composition of this embodiment. Furthermore, if η is large, the molding temperature of the resin composition of this embodiment needs to be increased, and the ultraviolet absorber is more likely to volatilize. Therefore, Td1 / (W·η) is an index of the resistance to volatilization of the ultraviolet absorber during molding of the resin composition of this embodiment.

[0027] (acrylic resin substantially free of ring structures in the main chain) The content of structural units containing ring structures in the acrylic resin that is substantially free of ring structures in the main chain is, for example, less than 1% by weight. Examples of ring structures include glutarimide rings, lactone rings, maleic anhydride rings, maleimide rings, and glutaric anhydride rings.

[0028] For example, the content of the glutarimide ring-containing structural unit in an acrylic resin composed of a methyl methacrylate unit and a glutarimide ring-containing structural unit can be determined as follows: 1 The H-NMR spectrum is measured. Next, the molar ratio of the methyl methacrylate units to the structural units containing glutarimide rings is determined from the peak area A derived from the O-CH3 protons of the methyl methacrylate units around 3.5 to 3.8 ppm and the peak area B derived from the N-CH3 protons of the glutarimide rings around 3.0 to 3.3 ppm. Next, the molar ratio of the methyl methacrylate units to the structural units containing glutarimide rings is converted into weight to calculate the content of the structural units containing glutarimide rings.

[0029] The acrylic resin that does not substantially contain a ring structure in the main chain is not particularly limited as long as it can make the glass transition temperature of the resin composition of this embodiment 115°C or higher, but examples include acrylic resins having a syndiotacticity of 50% or higher, expressed as a triad. The syndiotacticity of the acrylic resin expressed as a triad is preferably 55% or higher, more preferably 56% or higher, and even more preferably 57% or higher. The syndiotacticity of the acrylic resin expressed as a triad is, for example, 75% or lower, but from the viewpoints of molding temperature, toughness of the molded body, and secondary processability, it is preferably 70% or lower, and more preferably 67% or lower.

[0030] The acrylic resin substantially free of a ring structure in the main chain may be a mixture of two or more acrylic resins having different syndiotacticities in triad expression.

[0031] The syndiotacticity of acrylic resin triads is the proportion of three structural unit sequences (triads) that are rr. In addition, in two structural unit sequences (diads), those with the same configuration are called meso (m) and those with the opposite configuration are called racemo (r).

[0032] The weight-average molecular weight of the acrylic resin is preferably from 50,000 to 200,000, and more preferably from 90,000 to 150,000. When the weight-average molecular weight of the acrylic resin is 50,000 or more, the mechanical properties of a molded article of the resin composition of this embodiment are improved, and when it is 200,000 or less, the moldability of the resin composition of this embodiment is improved.

[0033] The molecular weight dispersity of the acrylic resin, i.e., the ratio of the weight average molecular weight to the number average molecular weight, is preferably 1.6 to 2.5, more preferably 1.7 to 2.2. When the molecular weight dispersity of the acrylic resin is 1.6 or more, the moldability of the resin composition of this embodiment is improved, and when it is 2.5 or less, the impact resistance, toughness, and flex resistance of an article molded from the resin composition of this embodiment are improved.

[0034] The synthesis method of the acrylic resin is not particularly limited, but examples thereof include anionic polymerization and radical polymerization. Among these, radical polymerization is preferred from an environmental perspective (see, for example, International Publication No. 2023 / 238886). Here, the glass transition temperature and syndiotacticity (triad expression) of the acrylic resin can be controlled by the polymerization temperature of the acrylic resin. For example, by lowering the polymerization temperature of the acrylic resin, the glass transition temperature and syndiotacticity of the acrylic resin can be increased. The glass transition temperature of the acrylic resin can also be controlled by the molecular weight of the acrylic resin.

[0035] The content of methyl methacrylate units in the acrylic resin is preferably 98% by weight or more, more preferably 99% by weight or more, and even more preferably 100% by weight.

[0036] Monomers other than methyl methacrylate that can be used when synthesizing an acrylic resin are not particularly limited, and examples thereof include alkyl acrylate esters such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; aryl acrylate esters such as phenyl acrylate; cycloalkyl acrylate esters such as cyclohexyl acrylate and norbornenyl acrylate; alkyl methacrylate esters other than methyl methacrylate such as ethyl methacrylate, propyl methacrylate, and butyl methacrylate; aryl methacrylate esters such as phenyl methacrylate; cycloalkyl methacrylate esters such as cyclohexyl methacrylate and norbornenyl methacrylate; aromatic vinyl compounds such as styrene and α-methylstyrene; acrylamide; methacrylamide; acrylonitrile; and methacrylonitrile.

[0037] [Characteristics of the Second Aspect of the Resin Composition] The resin composition of this embodiment contains an acrylic resin and an ultraviolet absorber. The 1% weight loss temperature of the ultraviolet absorber is 610 K or higher, preferably 620 K or higher, and more preferably 630 K or higher. Because the 1% weight loss temperature of the ultraviolet absorber is 610 K or higher, the volatility of the resin composition of this embodiment during molding is low. The 1% weight loss temperature of the ultraviolet absorber is, for example, 660 K or lower. The maximum absorption wavelength of the ultraviolet absorber is 350 nm or higher, preferably 355 nm or higher. Because the maximum absorption wavelength of the ultraviolet absorber is 350 nm or higher, the ultraviolet shielding ability of the resin composition of this embodiment is high. The maximum absorption wavelength of the ultraviolet absorber is, for example, 365 nm or lower.

[0038] The glass transition temperature of the resin composition of this embodiment is preferably 115°C or higher, more preferably 118°C or higher, even more preferably 120°C or higher, even more preferably 121°C or higher, and particularly preferably 122°C or higher. When the glass transition temperature of the resin composition of this embodiment is 115°C or higher, the heat resistance of the resin composition of this embodiment is increased. Note that the glass transition temperature of the resin composition of this embodiment is, for example, 160°C or lower, but from the viewpoint of molding temperature and secondary processability of the molded article, it is preferably 135°C or lower, more preferably 130°C or lower.

[0039] The resin film obtained by molding the resin composition of this embodiment has a transmittance of less than 2%, preferably less than 1.5%, for light with a wavelength of 370 nm at an optical path length of 40 μm. Because the resin film obtained by molding the resin composition of this embodiment has a transmittance of less than 2% for light with a wavelength of 370 nm at an optical path length of 40 μm, the resin composition of this embodiment has high ultraviolet shielding properties.

[0040] The 1% weight loss temperature of the UV absorber is Td1 [K], the ratio of the UV absorber to the acrylic resin is W [wt%], the temperature is 260°C, and the shear rate is 24 sec -1 When the melt viscosity of the resin composition of this embodiment is η [Poise], it is expressed by the following formula (1): Td1 / (W·η)>5.00×10 -2 ···(1) and equation (2) Td1 / (W·η)>5.50×10 -2 ···(2) It is preferable to satisfy the formula (3). Td1 / (W·η)>6.00×10 -2 ···(3) It is more preferable that the following condition is satisfied: Since the formula (1) is satisfied, the volatility of the resin composition of the present embodiment during molding is reduced.

[0041] (acrylic resin) The syndiotacticity of the acrylic resin, expressed as a triad, is preferably 54% or more, more preferably 55% or more, even more preferably 56% or more, and particularly preferably 57% or more. The syndiotacticity of the acrylic resin, expressed as a triad, is, for example, 80% or less, preferably 75% or less, more preferably 70% or less, and even more preferably 67% or less from the viewpoints of molding temperature, toughness of the molded body, and secondary processability.

[0042] The acrylic resin may be a mixture of two or more acrylic resins having different syndiotacticities in triad notation.

[0043] The syndiotacticity of acrylic resin triads is the proportion of three structural unit sequences (triads) that are rr. In addition, in two structural unit sequences (diads), those with the same configuration are called meso (m) and those with the opposite configuration are called racemo (r).

[0044] The weight-average molecular weight of the acrylic resin is preferably from 50,000 to 200,000, and more preferably from 90,000 to 150,000. When the weight-average molecular weight of the acrylic resin is 50,000 or more, the mechanical properties of a molded article of the resin composition of this embodiment are improved, and when it is 200,000 or less, the moldability of the resin composition of this embodiment is improved.

[0045] The molecular weight dispersity of the acrylic resin, i.e., the ratio of the weight average molecular weight to the number average molecular weight, is preferably 1.6 to 2.5, more preferably 1.7 to 2.2. When the molecular weight dispersity of the acrylic resin is 1.6 or more, the moldability of the resin composition of this embodiment is improved, and when it is 2.5 or less, the impact resistance, toughness, and flex resistance of an article molded from the resin composition of this embodiment are improved.

[0046] The synthesis method of the acrylic resin is not particularly limited, but examples thereof include anionic polymerization and radical polymerization. Among these, radical polymerization is preferred from an environmental perspective (see, for example, International Publication No. 2023 / 238886). Here, the glass transition temperature and syndiotacticity (triad expression) of the acrylic resin can be controlled by the polymerization temperature of the acrylic resin. For example, by lowering the polymerization temperature of the acrylic resin, the glass transition temperature and syndiotacticity of the acrylic resin can be increased. The glass transition temperature of the acrylic resin can also be controlled by the molecular weight of the acrylic resin.

[0047] The content of methyl methacrylate units in the acrylic resin is 98% by weight or more, preferably 99% by weight or more, and more preferably 100% by weight.

[0048] Monomers other than methyl methacrylate that can be used when synthesizing an acrylic resin are not particularly limited, and examples thereof include alkyl acrylate esters such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; aryl acrylate esters such as phenyl acrylate; cycloalkyl acrylate esters such as cyclohexyl acrylate and norbornenyl acrylate; alkyl methacrylate esters other than methyl methacrylate such as ethyl methacrylate, propyl methacrylate, and butyl methacrylate; aryl methacrylate esters such as phenyl methacrylate; cycloalkyl methacrylate esters such as cyclohexyl methacrylate and norbornenyl methacrylate; aromatic vinyl compounds such as styrene and α-methylstyrene; acrylamide; methacrylamide; acrylonitrile; and methacrylonitrile.

[0049] The acrylic resin is substantially free of ring structures in the main chain. The content of structural units containing ring structures in the acrylic resin is, for example, less than 1% by weight. Examples of ring structures include glutarimide rings, lactone rings, maleic anhydride rings, maleimide rings, and glutaric anhydride rings.

[0050] For example, the content of the glutarimide ring-containing structural unit in an acrylic resin composed of a methyl methacrylate unit and a glutarimide ring-containing structural unit can be determined as follows: 1 The H-NMR spectrum is measured. Next, the molar ratio of the methyl methacrylate units to the structural units containing glutarimide rings is determined from the peak area A derived from the O-CH3 protons of the methyl methacrylate units around 3.5 to 3.8 ppm and the peak area B derived from the N-CH3 protons of the glutarimide rings around 3.0 to 3.3 ppm. Next, the molar ratio of the methyl methacrylate units to the structural units containing glutarimide rings is converted into weight to calculate the content of the structural units containing glutarimide rings.

[0051] [Features common to the first and second aspects of the resin composition] The temperature of the resin composition of this embodiment is 260°C, and the shear rate is 24 sec -1 The melt viscosity of the resin composition of this embodiment is preferably less than 21,000 Poise, more preferably less than 19,500 Poise, and even more preferably less than 18,000 Poise at a temperature of 260°C and a shear rate of 24 sec -1 When the melt viscosity at 260°C is less than 21,000 Poise, the molding temperature of the resin composition of this embodiment can be lowered, and the volatility of the resin composition during molding is reduced. -1 The melt viscosity at is, for example, 16,500 Poise or more.

[0052] The ratio of the UV absorber to the acrylic resin in the resin composition of this embodiment is preferably less than 0.70 wt%, more preferably less than 0.65 wt%. If the ratio of the UV absorber to the acrylic resin in the resin composition of this embodiment is less than 0.70 wt%, the volatility of the resin composition during molding of this embodiment will be low. Note that the ratio of the UV absorber to the acrylic resin in the resin composition of this embodiment is, for example, 0.50 wt% or more.

[0053] The form of the resin composition of the present embodiment is not particularly limited, but may be, for example, pellets.

[0054] (ultraviolet absorber) The ultraviolet absorber preferably contains 2,4,6-tris(4-butoxy-2-hydroxyphenyl)-1,3,5-triazine or 2,4,6-tris(4-butoxy-2-hydroxy-3-methylphenyl)-1,3,5-triazine, which reduces the volatility of the resin composition of this embodiment during molding.

[0055] The content of 2,4,6-tris(4-butoxy-2-hydroxyphenyl)-1,3,5-triazine or 2,4,6-tris(4-butoxy-2-hydroxy-3-methylphenyl)-1,3,5-triazine in the ultraviolet absorber is preferably 30% by weight or more. When the content of 2,4,6-tris(4-butoxy-2-hydroxyphenyl)-1,3,5-triazine or 2,4,6-tris(4-butoxy-2-hydroxy-3-methylphenyl)-1,3,5-triazine in the ultraviolet absorber is 30% by weight or more, the volatility of the resin composition of this embodiment during molding is low.

[0056] The ultraviolet absorber may further contain a compound other than 2,4,6-tris(4-butoxy-2-hydroxyphenyl)-1,3,5-triazine or 2,4,6-tris(4-butoxy-2-hydroxy-3-methylphenyl)-1,3,5-triazine (hereinafter referred to as "other compounds"). Examples of the other compounds include, but are not limited to, hydroxyphenyltriazine-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and benzophenone-based ultraviolet absorbers, and two or more of these may be used in combination. Examples of hydroxyphenyltriazine-based ultraviolet absorbers include 2,4,6-tris(4-hexyloxy-2-hydroxy-3-methylphenyl)-1,3,5-triazine and 2,4-bis[4-(2-ethylhexyloxy)-2-hydroxyphenyl]-6-(4-methoxyphenyl)-1,3,5-triazine. Among these, 2,4,6-tris(4-hexyloxy-2-hydroxy-3-methylphenyl)-1,3,5-triazine is preferred because it reduces the volatility of the resin composition of this embodiment when molded.

[0057] (Other resins) The resin composition of this embodiment may contain an acrylic resin having a ring structure in the main chain as long as the object of the present invention is not impaired, but preferably does not contain an acrylic resin having a ring structure in the main chain. The content of the acrylic resin having a ring structure in the main chain in the resin composition of this embodiment is, for example, less than 1% by weight. Examples of acrylic resins having a ring structure in the main chain include acrylic resins having one or more rings selected from the group consisting of glutarimide rings, lactone rings, maleic anhydride rings, maleimide rings, and glutaric anhydride rings in the main chain.

[0058] The resin composition of this embodiment may further contain a resin other than an acrylic resin, such as a styrene resin (e.g., acrylonitrile-styrene resin, styrene-maleic anhydride resin), a fluororesin (e.g., polycarbonate, polyvinyl acetal, cellulose acylate, polyvinylidene fluoride, polyfluorinated alkyl (meth)acrylate), a silicone resin, a polyolefin, polyethylene terephthalate, polybutylene terephthalate, or a polyimide.

[0059] (antioxidant) The resin composition of this embodiment may further contain an antioxidant. This enhances the oxidative degradation resistance of the resin composition of this embodiment. Examples of antioxidants include phosphorus-based antioxidants, hindered phenol-based antioxidants, and thioether-based antioxidants. The content of the antioxidant in the resin composition of this embodiment is, for example, 0.1 wt % or more and 2.0 wt % or less.

[0060] (Anti-blocking agent) The resin composition of this embodiment may further contain an antiblocking agent. This increases the blocking resistance of the resin composition of this embodiment. Examples of antiblocking agents include crosslinked acrylic particles and inorganic particles (e.g., silica particles). The volume average particle size of the antiblocking agent is, for example, 0.1 μm or more and 2.5 μm or less. The content of the antiblocking agent in the resin composition of this embodiment is, for example, 1.0 wt % or less.

[0061] (Other additives) The resin composition of the present embodiment may further contain additives such as a light stabilizer, a heat stabilizer, a matting agent, a light diffusing agent, a colorant, a dye, a pigment, an antistatic agent, a heat ray reflecting material, a lubricant, a plasticizer, a stabilizer, a flame retardant, a release agent, a polymer processing aid, a toughness improver, and a filler.

[0062] (Method of producing resin composition) The resin composition of this embodiment can be produced by a known method. An example of the method for producing the resin composition of this embodiment will be described below.

[0063] First, an ultraviolet absorber is added to an acrylic resin using a twin-screw extruder equipped with a die at the outlet, and the mixture is kneaded. Next, the strands extruded from the die are cooled in a water tank and then pelletized using a pelletizer to obtain the resin composition of the present embodiment.

[0064] (resin film) The resin film of this embodiment is obtained by molding the resin composition of this embodiment.

[0065] The resin film of the present embodiment preferably has a folding endurance of 400 times or more, and more preferably 500 times or more. When the resin film of the present embodiment has a folding endurance of 400 times or more, the resin film of the present embodiment has high flex resistance.

[0066] The haze of the resin film of this embodiment is preferably less than 2.0%, more preferably less than 1.0%. When the haze of the resin film of this embodiment is less than 2.0%, the transparency of the resin film of this embodiment is maintained. The haze of the resin film of this embodiment is, for example, 0.1% or more.

[0067] The internal haze of the resin film of this embodiment is preferably less than 0.5%, more preferably less than 0.1%. When the internal haze of the resin film of this embodiment is less than 0.5%, the transparency of the resin film of this embodiment is maintained. The internal haze of the resin film of this embodiment is, for example, 0.01% or more.

[0068] The thickness of the resin film of this embodiment is preferably 10 μm or more and 500 μm or less, more preferably 20 μm or more and 300 μm or less, and even more preferably 30 μm or more and 100 μm or less. When the thickness of the resin film of this embodiment is 10 μm or more, the ultraviolet ray shielding property of the resin film of this embodiment is improved, and when it is 500 μm or less, the bending resistance of the resin film of this embodiment is improved.

[0069] (Application) The resin film of this embodiment can be applied to, for example, transportation equipment, solar cell components, civil engineering and construction components, daily necessities, electrical and electronic devices, optical components, and medical supplies, but is preferably used as a polarizer protective film. In this case, the resin film of this embodiment is attached to a polarizer to form a polarizing plate. The polarizing plate can be applied to, for example, a liquid crystal display panel or an organic EL display panel.

[0070] (Method of manufacturing resin film) The resin film of this embodiment can be produced by a known method, and an example of the method for producing the resin film of this embodiment will be described below.

[0071] First, the resin composition of the present embodiment is melted using a twin-screw extruder equipped with a T-die at the outlet, and the sheet extruded from the T-die is cooled with a cooling roll to obtain a raw film. Next, the raw film is biaxially stretched to obtain the resin film of the present embodiment. At this time, the biaxial stretching may be simultaneous biaxial stretching or sequential biaxial stretching.

[0072] The temperature when biaxially stretching the raw film is preferably (Tg + 5)°C or higher (Tg + 30)°C or lower, more preferably (Tg + 6)°C or higher (Tg + 25)°C or lower, and even more preferably (Tg + 7)°C or higher (Tg + 20)°C or lower, where Tg is the glass transition temperature of the resin composition of this embodiment. The areal stretching ratio when biaxially stretching the raw film is not particularly limited, but is, for example, 2 times or higher and 10 times or lower. The stretching speed when biaxially stretching the raw film is not particularly limited, but is, for example, 1.1 times / min or higher and 100 times / min or lower. When sequentially biaxially stretching the raw film, the stretching speed in the first stage and the stretching speed in the second stage may be the same or different. In sequential biaxial stretching, the first stage stretching is usually stretching in the longitudinal direction (MD), and the second stage stretching is stretching in the transverse direction (TD).

[0073] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the above-described embodiments may be modified as appropriate within the scope of the spirit of the present invention. [Example]

[0074] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0075] (polymerization conversion rate) The polymerization conversion rate [%] was calculated by the weight ratio of the solid content of the polymerization solution to the weight of the charged monomers using a gravimetric method. The solid content of the polymerization solution was calculated by drying the polymerization solution in an oven set at 150°C for 30 minutes.

[0076] (Syndiotacticity rr in triplicate display) Using a 400MHz nuclear magnetic resonance spectrometer AVANCEIII (manufactured by Bruker), the acrylic resin was measured in a deuterated chloroform solution at 22°C with 16 cycles of accumulation. 1The H-NMR spectrum was measured. Next, the area (X) of the region from 0.60 to 0.95 ppm and the area (Y) of the region from 0.60 to 1.25 ppm were measured when tetramethylsilane (TMS) was set to 0 ppm, and then the area was calculated using the formula (X / Y)×100 The syndiotacticity rr of the triad was calculated by the following formula.

[0077] (Weight average molecular weight Mw and molecular weight dispersity Mw / Mn) The weight-average molecular weight Mw and molecular weight dispersity Mw / Mn of the acrylic resin were calculated using a high-speed GPC system HLC-8220GPC (manufactured by Tosoh Corporation) in terms of standard polystyrene. Specifically, the analysis was carried out under the following conditions using a sample solution prepared by dissolving 4 mg of acrylic resin in 2 mL of chloroform. Detector: RI detector Solvent: Chloroform Guard column: KF-G 4A (manufactured by Resonac) Analytical column: KF-806M and KF-806L (both manufactured by Resonac) connected in series Measurement temperature: 40℃ Standard material: Standard polystyrene (manufactured by Tosoh)

[0078] (1% weight loss temperature Td1) Using a STA7200 thermogravimetric differential thermal analyzer (Hitachi High-Tech Science), 10 mg of UV absorber was heated from 40°C at a rate of 5°C / min in a nitrogen atmosphere, and the temperature Td1 [K] at which the weight decreased by 1% was determined. When two or more UV absorbers were used, the temperature at which the weight decreased by 1% of the UV absorbers mixed at a predetermined ratio was used as Td1.

[0079] (Ratio of UV absorber to acrylic resin W) The ratio W [wt %] of the UV absorber to the acrylic resin in the resin composition was calculated. When two or more UV absorbers were used, the ratio W [wt %] was the total amount of UV absorbers to the acrylic resin in the resin composition.

[0080] (Maximum absorption wavelength λmax) Using a UV-visible spectrophotometer V-560 (manufactured by JASCO Corporation), the UV-visible absorption spectrum of a solution prepared by dissolving the UV absorber in a chloroform solution at a concentration of 10 mg / L was measured, and the maximum absorption wavelength λmax was determined.

[0081] (Melt viscosity η) Using a Capillograph 1D (manufactured by Toyo Seiki Seisakusho), the temperature was 260°C and the shear rate was 24 seconds. -1 The melt viscosity η [Poise] of the resin composition was measured under the following conditions: A capillary die with a length of 10 mm and a hole diameter of 1 mm was used, and the resin composition was dried at 90°C for 9 hours or more in advance.

[0082] (glass transition temperature Tg) The glass transition temperature of the resin composition was measured using a differential scanning calorimeter DSC7000X (Hitachi High-Tech Science). Specifically, the sample was first heated from 40°C to 160°C at a heating rate of 10°C / min under a nitrogen flow rate of 40 mL / min, cooled to 40°C, and then heated from 40°C to 160°C at a heating rate of 10°C / min. Next, the glass transition temperature Tg (midpoint glass transition temperature) was read from the DSC curve measured during the second heating run. Here, the midpoint glass transition temperature is the temperature at the point where the stepwise change in the glass transition of the DSC curve intersects with a line equidistant along the vertical axis from both a line extrapolating the baseline before the inflection point of the DSC curve to the higher temperature side and a line extrapolating the baseline after the inflection point of the DSC curve to the lower temperature side.

[0083] (Transmittance of light with a wavelength of 370 nm) The ultraviolet-visible absorption spectrum of the 40 μm thick resin film was measured using an ultraviolet-visible spectrophotometer V-560 (manufactured by JASCO Corporation), and the transmittance of light with a wavelength of 370 nm was determined.

[0084] (Volatility during molding) A 2 cm square resin film was placed in a glass dish, and a 5 cm square glass plate was placed on top of it. The dish was then placed on a hot plate set to a predetermined temperature and heated for 1 hour. At this time, the temperature of the hot plate was set at a shear rate of 365 sec in accordance with the method for measuring the melt viscosity η described above. -1 The temperature was set to be the temperature at which the melt viscosity of the resin composition became 3,000 Poise under the conditions described above. Specifically, the melt viscosity of the resin composition was measured at least three times at intervals of 10°C, and then an exponential approximation curve was drawn, and the temperature at which the melt viscosity of the resin composition became 3,000 Poise was determined based on the approximation curve by interpolation and extrapolation.

[0085] After heating, the glass plate with the volatiles attached was collected in a glass bottle, 10 g of chloroform was added, and the bottle was capped. The whole was then slowly shaken to dissolve the volatiles into the chloroform. The absorbance Abs of the volatile eluate at a wavelength of 380 nm was then measured using a UV-visible spectrophotometer V-560 (manufactured by JASCO). The higher the Abs of the volatile eluate, the more the UV absorber had volatilized from the resin film, impairing the UV absorption performance required for the resin film.

[0086] (Hayes) The haze of the resin film was measured using a haze meter NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS7136:2000.

[0087] (internal haze) The internal haze of the resin film was measured using a haze meter NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS7136:2000. Specifically, to cancel the influence of surface scattering of the resin film, glycerin was dropped onto the front and back of the resin film, and then the film was sandwiched between glass plates. The interface between the resin film and the glass plates was filled with glycerin, and the haze was measured. Next, the internal haze of the resin film was calculated by subtracting the haze of the glass plate, which had been measured previously.

[0088] (folding durability) The resin film was cut into 15 mm wide strips to prepare test pieces. The fold endurance of the resin film was measured under the following conditions using an MIT folding fatigue tester, Model D (manufactured by Toyo Seiki Co., Ltd.). The folding endurance of the resin film was measured in the MD and TD directions of the resin film, and the arithmetic average was calculated. Load: 1.96N Bending angle: 135° Bending speed: 175 times / min Bending clamp curvature radius: 0.38 mm

[0089] (dimensional change rate) Using a cutter, the resin film was cut into a size of 90 mm x 90 mm to prepare a test specimen. Next, holes were punched with a 1 mm diameter punch at locations 20 mm inward from the four corners of the test specimen diagonally, and the hole spacing was measured using a three-dimensional measuring instrument MF201 (manufactured by Mitutoyo). Next, the test specimen was left to stand for 120 hours in an environmental testing device LH-20 (manufactured by Nagano Science) set at 85 ° C and 85% RH, and the hole spacing was measured again. Next, the shrinkage rate of the test specimen was calculated from the difference in hole spacing before and after leaving it at 85 ° C and 85% RH, and the dimensional change rate of the resin film was evaluated.

[0090] (Production of acrylic resin A) A 4L glass reactor equipped with an H-shaped impeller stirrer was charged with 150 parts by weight of deionized water, 0.20 parts by weight of tribasic calcium phosphate (as a dispersant), 0.0075 parts by weight of sodium α-olefin sulfonate, and 0.30 parts by weight of sodium chloride. Next, under a nitrogen atmosphere, 100 parts by weight of methyl methacrylate (MMA), 0.289 parts by weight of n-octyl mercaptan (as a chain transfer agent), and 0.074 parts by weight of 2,2'-azobis(isobutyrate) dimethyl V-601 (Fujifilm Wako Pure Chemical Industries, Ltd.) (as a polymerization initiator) were added to the reactor while stirring at 250 rpm. The liquid temperature in the reactor was then raised to 70°C to initiate polymerization. Two hours after the start of polymerization, 0.10 parts by weight of tribasic calcium phosphate was added to the polymerization solution. An exothermic peak associated with the gel effect was observed 4 hours and 20 minutes after the start of polymerization. Seven hours after the start of polymerization, the temperature was raised to 95°C. Seven hours after the start of polymerization, the polymerization conversion rate was 93%. Two hours after the temperature reached 95°C, the reactor was cooled to room temperature to terminate the polymerization, yielding an acrylic resin dispersion. At this time, the polymerization conversion rate was 99%. The acrylic resin dispersion was then washed with 1N hydrochloric acid in an amount 0.1 times the weight of the charged monomer, followed by washing with water to remove the dispersant. The washed acrylic resin was then dehydrated and dried to yield acrylic resin A in the form of beads. Acrylic resin A had an MMA unit content of 100% by weight, an rr of 57%, an Mw of 105,500, and an Mw / Mn of 1.96.

[0091] Example 1 (Production of Resin Composition) A mixture of 100 parts by weight of acrylic resin A and 0.55 parts by weight of the ultraviolet absorber 2,4,6-tris(4-butoxy-2-hydroxyphenyl)-1,3,5-triazine (hereinafter referred to as UVA-1) was hand-blended and extruded at 255°C using a 15 mm diameter, L / D=45, intermeshing co-rotating twin-screw extruder (KZW15TWIN-45MG, manufactured by Technovel) equipped with a die at the outlet. The extruded strand was then cooled in a water bath, pelletized in a pelletizer, and dried at 90°C for 4 hours to obtain a pelletized resin composition. The resin composition had a Tg of 120°C, an η of 17,870 Poise, a λmax of 363 nm, and a Td1 / (W·η) of 6.24×10. -2 [K / (wt%·Poise)].

[0092] (Manufacturing of resin films) The resin composition was extruded at an extrusion temperature of 255°C using a 15mm diameter, L / D=45 intermeshing co-rotating twin-screw extruder KZW15TWIN-45MG (manufactured by Technovel) equipped with a T-die at the outlet. The screw torque was 8.0 amperes. The sheet extruded from the T-die was then cooled with a cooling roll to obtain a raw film having a width of 160 mm and a thickness of 160 μm. A 100 mm x 100 mm piece was then cut from the raw film so that two sides were parallel to the extrusion direction. The piece was then placed in a pantograph-type biaxial stretching device and simultaneously biaxially stretched at a stretching temperature of 135°C and a stretching speed of 100 mm / min so that the stretch ratio in the directions parallel and perpendicular to the extrusion direction was 2x. The stretched piece was then removed to room temperature and cooled to obtain a resin film having a thickness of 40 μm.

[0093] Example 2 A resin film was obtained in the same manner as in Example 1, except that in (Production of Resin Composition), 0.20 parts by weight of UVA-1 and 0.40 parts by weight of the ultraviolet absorber 2,4,6-tris(4-hexyloxy-2-hydroxy-3-methylphenyl)-1,3,5-triazine (hereinafter referred to as UVA-2) were hand-blended with 100 parts by weight of acrylic resin A. The resin composition had a Tg of 120°C, an η of 17,870 Poise, a λmax of 359 nm, and a Td1 / (W·η) of 5.94×10 -2 [K / (wt%·Poise)].

[0094] Example 3 A resin film was obtained in the same manner as in Example 1, except that in (Production of resin composition), Parapet HR-S (manufactured by Kuraray) (hereinafter referred to as acrylic resin B) was used instead of acrylic resin A, and in (Production of resin film), the extrusion temperature was adjusted to 257°C so that the screw torque was 8.0 amperes, and the stretching temperature was changed to 131°C. The resin composition had a Tg of 116°C, an η of 19,470 Poise, a λmax of 363 nm, and a Td1 / (W·η) of 5.72×10 -2 Acrylic resin B had an MMA unit content of 98% by weight or more, rr of 51%, Mw of 122,000, and Mw / Mn of 1.89.

[0095] (Production of acrylic resin C) A 40 mm diameter, L / D=90 intermeshing co-rotating twin-screw extruder equipped with a die at the outlet was used. The temperature of each temperature-controlled zone was set to 250-280°C, and the screw speed was set to 85 rpm. Methyl methacrylate resin was melted and filled using a kneading block. Next, 1.8 wt% monomethylamine (manufactured by Mitsubishi Gas Chemical Company) was injected through the nozzle relative to the methyl methacrylate resin to imidize the methyl methacrylate resin. The strand extruded from the die was then cooled in a water bath and pelletized using a pelletizer to obtain pellets of acrylic resin C. Acrylic resin C had an Mw of 107,000 and an Mw / Mn ratio of 1.98.

[0096] (Comparative Example 1) A resin film was obtained in the same manner as in Example 1, except that in (Production of Resin Composition), a mixture prepared by hand-blending 100 parts by weight of acrylic resin C with 0.55 parts by weight of UVA-1 was used, and in (Production of Resin Film), the extrusion temperature was adjusted to 260°C so that the screw torque was 8.0 amperes, and the stretching temperature was changed to 137°C. The resin composition had a Tg of 122°C, an η of 20,690 Poise, a λmax of 363 nm, and a Td1 / (W η) of 5.39 × 10 -2 [K / (wt%·Poise)].

[0097] (Comparative Example 2) A resin film was obtained in the same manner as in Comparative Example 1, except that in (Production of Resin Composition), 2.40 parts by weight of the ultraviolet absorber 2,4-bis(4-butoxy-2-hydroxyphenyl)-6-(2,4-dibutoxyphenyl)-1,3,5-triazine (hereinafter referred to as UVA-3) was hand-blended with 100 parts by weight of acrylic resin C. The resin composition had a Tg of 122°C, an η of 20,690 Poise, a λmax of 348 nm, and a Td1 / (W·η) of 1.25×10 -2 [K / (wt%·Poise)].

[0098] Table 1 shows the properties of acrylic resins A to C.

[0099] [Table 1]

[0100] Table 2 shows the evaluation results of the resin composition and the resin film.

[0101] [Table 2]

[0102] Table 2 shows that the resin compositions of Examples 1 to 3 have high heat resistance and UV shielding properties and low volatility during molding. The resin compositions of Examples 1 to 3 contain an acrylic resin that does not substantially contain a ring structure in the main chain, and have a melt viscosity of 3,000 Poise at a temperature of 272 to 276°C, and a Td1 / (W·η) of 5.72×10 -2 ~6.24×10 -2 In contrast, the resin composition of Comparative Example 1 contains acrylic resin C having a ring structure in the main chain, and the temperature at which the melt viscosity reaches 3,000 Poise is 280°C, so the molding temperature must be high and the volatility during molding is high. Furthermore, the resin composition of Comparative Example 2 contains acrylic resin C having a ring structure in the main chain, and the temperature at which the melt viscosity reaches 3,000 Poise is 280°C, and Td1 / (W·η) is 1.32×10 -2 [K / wt% / Poise], so high molding temperatures are required and volatility during molding is high.

[0103] Example 4 A resin film was obtained in the same manner as in Example 2, except that in (Production of resin composition), Parapet SP-01 (manufactured by Kuraray) (hereinafter referred to as acrylic resin D) was used instead of acrylic resin A, and in (Production of resin film), the extrusion temperature was adjusted to 270°C so that the screw torque was 8.0 amperes, and the stretching temperature was changed to 143°C. The resin composition had a Tg of 128°C, an η of 20,950 Poise, a λmax of 359 nm, and a Td1 / (W·η) of 5.07×10 -2 Acrylic resin D had an MMA unit content of 98% by weight or more, rr of 74%, Mw of 97,400, and Mw / Mn of 1.09.

[0104] (Comparative Example 3) A resin film was obtained in the same manner as in Example 1, except that in (Production of resin composition), Parapet EH (manufactured by Kuraray) (hereinafter referred to as acrylic resin E) was used instead of acrylic resin A, and in (Production of resin film), the extrusion temperature was adjusted to 275°C so that the screw torque was 8.0 amperes, and the stretching temperature was changed to 126°C. The resin composition had a Tg of 111°C, an η of 22,930 Poise, a λmax of 363 nm, and a Td1 / (W·η) of 4.86×10 -2 The acrylic resin E had an MMA unit content of 98% by weight or more, an rr of 53%, an Mw of 159,800, and an Mw / Mn of 2.02.

[0105] Comparative Example 4 A resin film was obtained in the same manner as in Example 1, except that in (Production of Resin Composition), acrylic resin B was used instead of acrylic resin A, 2.40 parts by weight of ultraviolet absorber (UVA-3) was hand-blended with 100 parts by weight of acrylic resin B, and in (Production of Resin Film), the extrusion temperature was adjusted to 257°C so that the screw torque was 8.0 amperes, and the stretching temperature was changed to 131°C. The resin composition had a Tg of 116°C, an η of 19,470 Poise, a λmax of 363 nm, and a Td1 / (W·η) of 1.32×10 -2 [K / (wt%·Poise)].

[0106] Table 3 shows the properties of acrylic resins A, B, D, and E.

[0107] [Table 3]

[0108] Table 4 shows the evaluation results of the resin compositions and resin films.

[0109] [Table 4]

[0110] Table 4 shows that the resin compositions of Examples 1, 2, and 4 have high heat resistance and UV shielding properties, and low volatility during molding. The resin compositions of Examples 1, 2, and 4 contain an acrylic resin with an rr of 57 to 74%, and the temperature at which the melt viscosity of the resin composition reaches 3,000 Poise is 272 to 280°C, and Td1 / (W·η) is 5.07×10 -2 ~6.24×10 -2 In contrast, the resin composition of Comparative Example 3 contains acrylic resin E with an rr of 53%, and the temperature at which the melt viscosity reaches 3,000 Poise is 283°C, and Td1 / (W·η) is 4.86×10 -2 [K / wt% / Poise], a high molding temperature is required, and volatility during molding is high. Furthermore, the resin composition of Comparative Example 4 contains acrylic resin B with rr of 51%, and Td1 / (W·η) is 1.32×10 -2 [K / weight% / Poise], so it is highly volatile during molding.

Claims

1. an acrylic resin that is substantially free of a ring structure in its main chain; and an ultraviolet absorber having a 1% weight loss temperature of 610 K or higher and a maximum absorption wavelength of 350 nm or higher, The glass transition temperature is 115°C or higher, a resin film obtained by molding the resin composition has a transmittance of less than 2% for light with a wavelength of 370 nm at an optical path length of 40 μm; The 1% weight loss temperature of the ultraviolet absorber is Td1 [K], the ratio of the ultraviolet absorber to the acrylic resin is W [wt%], the temperature is 260°C, and the shear rate is 24 sec －１ When the melt viscosity of the resin composition in the above formula (1) is η [Poise], Td1 / (W・h)>5.00×10 －２ ・・・(1) A resin composition that satisfies the above requirements.

2. an acrylic resin having a methyl methacrylate unit content of 98% by weight or more and a triad syndiotacticity of 54% or more; and an ultraviolet absorber having a 1% weight loss temperature of 610 K or higher and a maximum absorption wavelength of 350 nm or higher, a resin film obtained by molding the resin composition has a transmittance of less than 2% for light with a wavelength of 370 nm at an optical path length of 40 μm; The 1% weight loss temperature of the ultraviolet absorber is Td1 [K], the ratio of the ultraviolet absorber to the acrylic resin is W [wt%], the temperature is 260°C, and the shear rate is 24 sec －１ When the melt viscosity of the resin composition in the above formula (1) is η [Poise], Td1 / (W・h)>5.00×10 －２ ・・・(1) A resin composition that satisfies the above requirements.

3. The resin composition according to claim 1 or 2, wherein the ultraviolet absorber comprises 2,4,6-tris(4-butoxy-2-hydroxyphenyl)-1,3,5-triazine or 2,4,6-tris(4-butoxy-2-hydroxy-3-methylphenyl)-1,3,5-triazine.

4. Temperature: 260°C, shear rate: 24 sec －１ The resin composition according to claim 1 or 2, having a melt viscosity of less than 21,000 Poise at 1000 K.

5. The resin composition according to claim 1 or 2, wherein the ratio of the ultraviolet absorber to the acrylic resin is less than 0.70% by weight.

6. The resin composition according to claim 1 or 2, which has a glass transition temperature of 118°C or higher.

7. The resin composition according to claim 1 or 2, wherein the acrylic resin has a content of methyl methacrylate units of 98% by weight or more and a syndiotacticity expressed in triads of 55% or more.

8. The resin composition according to claim 1 or 2, which is in the form of pellets.

9. A resin film obtained by molding the resin composition according to claim 1 or 2.

10. The folding resistance is 400 times or more, The resin film according to claim 9, having a haze of less than 2.0%.

11. The resin film according to claim 9 , which is a polarizer protective film.

12. A polarizing plate comprising the resin film according to claim 11.

13. A liquid crystal display panel comprising the polarizing plate according to claim 12.

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