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WO2025121272A1 - Composition de résine et son procédé de production - Google Patents

Composition de résine et son procédé de production Download PDF

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Publication number
WO2025121272A1
WO2025121272A1 PCT/JP2024/042451 JP2024042451W WO2025121272A1 WO 2025121272 A1 WO2025121272 A1 WO 2025121272A1 JP 2024042451 W JP2024042451 W JP 2024042451W WO 2025121272 A1 WO2025121272 A1 WO 2025121272A1
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WIPO (PCT)
Prior art keywords
resin
mass
polymerization
resin composition
methacrylic resin
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English (en)
Japanese (ja)
Inventor
誉士夫 古川
藍子 桂
誠 長谷川
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Kaneka Corp
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Kaneka Corp
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Publication of WO2025121272A1 publication Critical patent/WO2025121272A1/fr
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F120/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
    • C08F120/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F120/10—Esters
    • C08F120/12—Esters of monohydric alcohols or phenols
    • C08F120/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
    • C08F120/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/04—Homopolymers or copolymers of esters
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/04—Homopolymers or copolymers of esters
    • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
    • C08L33/10—Homopolymers or copolymers of methacrylic acid esters
    • C08L33/12—Homopolymers or copolymers of methyl methacrylate
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/80—Constructional details
    • H10K50/86—Arrangements for improving contrast, e.g. preventing reflection of ambient light
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/10—OLED displays

Definitions

  • the present invention relates to a resin composition and a method for producing the same.
  • Methacrylic resins are widely used in a variety of fields due to their excellent transparency, weather resistance, and processability.
  • resin films obtained by molding methacrylic resins are used for optical applications such as display devices due to their excellent optical properties.
  • Known methods for manufacturing resin films include the melt extrusion method using a T-die, and the solution casting method, in which a dope in which resin is dissolved in a solvent is cast onto the surface of a support, and then the solvent is evaporated to form a film.
  • the solution casting method has the advantage that the physical stress applied to the resin film during film formation is small, making it less likely for polymer orientation to occur, and the strength and optical properties of the resulting resin film are isotropic.
  • Another advantage of the solution casting method is that the thickness precision of the resulting resin film is extremely high.
  • methacrylic resins with high molecular weights are generally used. Using a high molecular weight methacrylic resin not only makes it suitable for the solution casting method, but also results in good mechanical properties for the resin film obtained.
  • the objective of the present invention is to provide a resin composition containing a methacrylic resin that can be used to produce molded articles that have excellent heat resistance and mechanical properties while maintaining transparency, and a method for producing the same.
  • ⁇ 1> A methacrylic resin having a triad syndiotacticity of 55% or more and a weight average molecular weight (Mw) of 500,000 or more as measured by gel permeation chromatography (GPC); and a resin composition comprising: ⁇ 2> The resin composition according to ⁇ 1>, wherein a mass ratio of the methacrylic resin to the acrylic crosslinked particles is 99.9:0.1 to 65:35. ⁇ 3> The resin composition according to ⁇ 1> or ⁇ 2>, wherein the methacrylic resin has a ratio of structural units derived from methyl methacrylate of 99.5 mass% or more.
  • ⁇ 4> The resin composition according to ⁇ 1> or ⁇ 2>, wherein the methacrylic resin has a ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) of 1.6 to 2.8.
  • Mw/Mn weight average molecular weight
  • Mn number average molecular weight
  • ⁇ 5> The resin composition according to any one of ⁇ 1> to ⁇ 4>, wherein the methacrylic resin has a ratio of terminal double bonds to structural units derived from methyl methacrylate of less than 0.02 mol %.
  • ⁇ 6> The resin composition according to any one of ⁇ 1> to ⁇ 5>, wherein the methacrylic resin includes a terminal structure represented by the following formula (1) derived from a polymerization initiator.
  • R 1 , R 2 , and R 3 each independently represent an alkyl group, a substituted alkyl group, an ester group, or an amide group. However, at least one of R 1 , R 2 , and R 3 represents an ester group or an amide group. Two of R 1 , R 2 , and R 3 may be bonded to each other to form an alicyclic structure. * represents a bond to a structural unit derived from a monomer.) ⁇ 7> The resin composition according to any one of ⁇ 1> to ⁇ 6>, wherein the acrylic crosslinked particles are a core-shell type elastomer having a core layer made of a rubber-like polymer and a shell layer made of a glassy polymer.
  • ⁇ 8> ⁇ 1> to ⁇ 7> contain the resin composition according to any one of ⁇ 1> to ⁇ 7> and a solvent
  • the dope for film production by a solution casting method includes a first solvent having a hydrogen bond parameter ⁇ H of 1 to 12 in the Hansen solubility parameters, and a second solvent having a hydrogen bond parameter ⁇ H of 14 to 24.
  • a resin film comprising the resin composition according to any one of ⁇ 1> to ⁇ 7>.
  • the resin film according to ⁇ 9> having a glass transition temperature of 120° C. or higher.
  • the resin film according to ⁇ 9> or ⁇ 10> which has a bending resistance of 2,500 or more in an MIT bending endurance test.
  • ⁇ 12> ⁇ 12> The resin film according to any one of ⁇ 9> to ⁇ 11>, having an internal haze of 0.4% or less.
  • ⁇ 13> The resin film according to any one of ⁇ 9> to ⁇ 12>, wherein the b* value is 0.3 or less.
  • ⁇ 14> The method for producing a resin composition according to any one of ⁇ 1> to ⁇ 7>, further comprising: polymerizing a monomer mixture having a methyl methacrylate content of 99.5% by mass or more in the presence of a polymerization initiator and a chain transfer agent; In the polymerization step, the polymerization temperature is set to less than 100° C.
  • a method for producing a resin composition comprising the step of producing a methacrylic resin, wherein a ratio of a total molar amount of the chain transfer agent to a total molar amount of the polymerization initiator is 3.0 or less.
  • ⁇ 16> The method for producing a resin composition according to ⁇ 14> or ⁇ 15>, wherein, in the method for producing the methacrylic resin, aqueous polymerization is performed in the polymerization step.
  • ⁇ 17> The resin film according to any one of ⁇ 9> to ⁇ 13>, wherein the resin film is an optical film.
  • ⁇ 18> The resin film according to any one of ⁇ 9> to ⁇ 13>, wherein the resin film is a polarizer protective film.
  • a polarizing plate comprising a polarizer and the resin film according to any one of ⁇ 9> to ⁇ 13> laminated together.
  • a display device comprising the polarizing plate according to ⁇ 19>.
  • the present invention provides a resin composition capable of producing a molded article having excellent heat resistance and mechanical properties while maintaining transparency, a method for producing the same, and a resin film containing the resin composition.
  • the methacrylic resin according to this embodiment has a syndiotacticity (rr) of 55% or more, preferably 56% or more, and more preferably 57% or more.
  • a syndiotacticity (rr) of 55% or more When the syndiotacticity (rr) of 55% or more, the glass transition temperature (Tg) of the methacrylic resin increases, and the heat resistance tends to improve.
  • the upper limit of the syndiotacticity (rr) is not particularly limited, but from the viewpoint of the molding temperature, and the toughness and secondary processability of the molded body, it is preferably 67% or less, more preferably 65% or less, and even more preferably 63% or less.
  • Syndiotacticity is the proportion of two chains (diads) in a chain of three consecutive structural units (triad) that are both racemo (rr). Chains (diads) of structural units in a polymer molecule that have the same configuration are called meso and those with the opposite configuration are called racemo, and are abbreviated as m and r, respectively.
  • the syndiotacticity (rr) can be calculated by measuring a 1 H-NMR spectrum in deuterated chloroform at 22° C. and 16 accumulations, measuring 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 when tetramethylsilane (TMS) is set to 0 ppm from the spectrum, and then using the formula: (X/Y) ⁇ 100.
  • the methacrylic resin according to this embodiment preferably has a glass transition temperature (Tg) of 120°C or higher, more preferably 122°C or higher, and even more preferably 124°C or higher.
  • Tg glass transition temperature
  • the glass transition temperature (Tg) in this specification is the midpoint glass transition temperature determined from a DSC curve, and is measured by the method described in the Examples below.
  • the syndiotacticity (rr) and glass transition temperature (Tg) of the methacrylic resin can be controlled by adjusting the polymerization temperature when synthesizing the methacrylic resin. For example, lowering the polymerization temperature is preferable for increasing the syndiotacticity (rr) and glass transition temperature (Tg) of the methacrylic resin.
  • the glass transition temperature (Tg) can also be controlled by adjusting the molecular weight of the methacrylic resin.
  • the methacrylic resin according to this embodiment has a weight average molecular weight (Mw) of 500,000 or more.
  • Mw weight average molecular weight
  • the weight average molecular weight (Mw) of the methacrylic resin is preferably 600,000 or more, more preferably 700,000 or more, and even more preferably 800,000 or more.
  • Mw weight average molecular weight
  • the methacrylic resin according to this embodiment preferably has a dispersity (Mw/Mn), which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), of 1.6 to 2.8, more preferably 1.7 to 2.5, even more preferably 1.7 to 2.4, and particularly preferably 1.7 to 2.3.
  • Mw/Mn dispersity of the methacrylic resin
  • the fluidity of the methacrylic resin tends to improve and it tends to be easier to mold
  • the dispersity (Mw/Mn) of the methacrylic resin is 2.8 or less
  • the mechanical properties of the resulting molded article such as impact resistance, toughness, and bending resistance, tend to improve.
  • weight average molecular weight (Mw) and number average molecular weight (Mn) in this specification are values calculated using standard polystyrene as measured by gel permeation chromatography (GPC) and are measured by the method described in the examples below.
  • the weight average molecular weight (Mw) and number average molecular weight (Mn) of the methacrylic resin can be controlled by adjusting the type and amount of polymerization initiator and chain transfer agent used when synthesizing the methacrylic resin.
  • the proportion of structural units derived from methyl methacrylate is 99.5% by mass or more, and the proportion of structural units derived from monomers other than methyl methacrylate is 0.5% by mass or less.
  • the proportion of structural units derived from methyl methacrylate 99.5% by mass or more, it is possible to improve the transparency of the resin film formed from the resin composition according to this embodiment described below.
  • the content of methyl methacrylate is high, there are few impurities, which is also preferable from the viewpoint of recycling.
  • the structural units derived from methyl methacrylate are represented by the following formula.
  • Examples of monomers other than methyl methacrylate 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 ⁇ -methylstyrene; acrylamide; methacrylamide; acrylonit
  • the methacrylic resin according to this embodiment preferably has a 5% weight loss temperature of 300°C or higher, which allows it to have excellent thermal stability.
  • the methacrylic resin of this embodiment the ratio of the amount of chain transfer agent to the amount of polymerization initiator during production is adjusted to an appropriate range to reduce the proportion of terminal double bonds.
  • the methacrylic resin according to this embodiment can achieve a 5% weight loss temperature of 300°C or higher, despite having a high weight average molecular weight (Mw) of 500,000 or more.
  • the 5% weight loss temperature in this specification is the temperature determined from a thermogravimetric curve, and is measured by the method described in the Examples below.
  • the methacrylic resin according to this embodiment preferably has a ratio of terminal double bonds to structural units derived from methyl methacrylate of less than 0.02 mol%, more preferably less than 0.010 mol%, and even more preferably less than 0.006 mol%.
  • the methacrylic resin according to this embodiment can be produced by radical polymerization, as shown in the production method described later.
  • the methacrylic resin produced by radical polymerization contains terminal double bonds generated by disproportionation termination reaction during polymerization, hydrogen abstraction reaction of monomers by polymerization initiator, etc.
  • terminal double bonds affect the thermal stability of the resin, so the proportion of terminal double bonds is preferably small.
  • the proportion of terminal double bonds is controlled by the method described later, and if it can be reduced to less than 0.015 mol%, the thermal stability of the methacrylic resin tends to be greatly improved.
  • the lower limit of the proportion of terminal double bonds is preferably 0 mol%, but may be 0.0005 mol%.
  • the ratio of the terminal double bond to the structural unit derived from methyl methacrylate can be calculated from the formula: [(3 ⁇ X)/(2 ⁇ Y)] ⁇ 100 by measuring a 1 H-NMR spectrum in deuterated chloroform at 20° C. and 8,192 cumulative cycles, and measuring the sum (X) of the areas of the peaks (5.47 to 5.52 ppm and 6.21 ppm) derived from the terminal double bonds of the methacrylic resin and the area (Y) of the peaks (0.5 to 1.25 ppm) derived from the ⁇ -methyl groups of the methacrylic resin from the spectrum, as described in the Examples below.
  • the proportion of terminal double bonds in the methacrylic resin can be controlled by adjusting the amounts of polymerization initiator and chain transfer agent used when synthesizing the methacrylic resin, the polymerization temperature, the polymerization time, etc. For example, it is preferable to reduce the amount of polymerization initiator used, increase the amount of chain transfer agent used, lower the polymerization temperature, and extend the polymerization time in order to reduce the proportion of terminal double bonds.
  • the methacrylic resin according to this embodiment preferably contains a terminal structure represented by the following formula (1) derived from a polymerization initiator.
  • R 1 , R 2 , and R 3 each independently represent an alkyl group, a substituted alkyl group, an ester group, or an amide group. However, at least one of R 1 , R 2 , and R 3 represents an ester group or an amide group. Two of R 1 , R 2 , and R 3 may be bonded to each other to form an alicyclic structure. * represents a bond to a structural unit derived from a monomer.
  • alkyl group examples include linear or branched alkyl groups having 1 to 6 carbon atoms.
  • substituents that the alkyl group may have include a hydroxy group, a carboxy group, an alkoxy group, and a halogen atom.
  • ester group is a group represented by -COOR4 .
  • R4 represents an alkyl group having 1 to 6 carbon atoms, which may have a substituent such as a hydroxy group, a carboxy group, an alkoxy group, or a halogen atom.
  • amide group is a group represented by -C(O) NR5 , where R5 represents an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group, or an alkenyl group having 2 to 6 carbon atoms, which may have a substituent such as a hydroxy group, a carboxy group, an alkoxy group, or a halogen atom.
  • the terminal structure represented by the above formula (1) can be introduced into the molecule of the methacrylic resin by using a non-nitrile azo polymerization initiator represented by the following formula (2) when synthesizing the methacrylic resin.
  • R 1 , R 2 , and R 3 in the formula are the same as those in the above formula (1).
  • the thermal stability of the resulting methacrylic resin tends to be improved compared to the use of a polymerization initiator other than the non-nitrile azo polymerization initiator (e.g., a nitrile azo polymerization initiator).
  • the non-nitrile azo polymerization initiator is also preferable in that the toxicity of the initiator itself and the decomposition products tends to be low compared to the nitrile azo polymerization initiator.
  • non-nitrile azo polymerization initiator represented by the above formula (2) examples include 2,2'-azobis(dimethyl isobutyrate), 1,1'-azobis(methyl cyclohexanecarboxylate), 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], 2,2'-azobis(N-butyl-2-methylpropionamide), 2,2'-azobis(N-cyclohexyl-2-methylpropionamide), 2,2'-azobis ⁇ 2-methyl-N-[2-(1-hydroxyethyl)]propionamide ⁇ , 2,2'-azobis ⁇ 2-methyl-N-[2-(1-hydroxybutyl)]propionamide ⁇ , etc.
  • at least one selected from 2,2'-azobis(dimethyl isobutyrate) and 1,1'-azobis(methyl cyclohexanecarboxylate) is preferred.
  • the methacrylic resin according to this embodiment preferably has a residual chain transfer agent rate of 0.005% by mass or less, and more preferably is substantially 0% by mass (i.e., below the detection limit).
  • the residual chain transfer agent rate is measured by the method described in the examples below.
  • the methacrylic resin according to this embodiment is not only excellent in heat resistance and thermal stability, but is also expected to be suitable for reuse after disposal, i.e., recycling.
  • a method for recycling methacrylic resin for example, chemical recycling (a method in which decomposition oil is recovered as a decomposition product by thermal decomposition and reused as a chemical raw material or fuel) is known.
  • chemical recycling a method in which decomposition oil is recovered as a decomposition product by thermal decomposition and reused as a chemical raw material or fuel
  • a cyclic structure is introduced into the molecular structure of the methacrylic resin, or a monomer having a rigid structure is copolymerized.
  • these structures become impurities in chemical recycling, and are not preferable.
  • the methacrylic resin according to this embodiment has a high proportion of structural units derived from methyl methacrylate, and it is expected that the monomer recovered as decomposition oil will have a high yield, and it is expected to show good chemical recyclability.
  • the method for producing the methacrylic resin according to the present embodiment includes a polymerization step of polymerizing a monomer mixture having a methyl methacrylate content of 99.5% by mass or more in the presence of a polymerization initiator and a chain transfer agent, and in the polymerization step, the polymerization temperature is set to less than 100° C. until 90% or more of the resulting methacrylic resin is produced.
  • until 90% or more of the resulting methacrylic resin is produced means “until at least the conversion rate is 90%” when the polymerization reaction is carried out to a conversion rate of 100%, and means “until at least the conversion rate is 45%” when the polymerization reaction is terminated at a conversion rate of 50%, for example.
  • the polymerization temperature may be increased to 100° C. or more for the purpose of reducing the remaining monomer components and deactivating the remaining polymerization initiator.
  • a conventionally known polymerization method can be adopted, and for example, radical polymerization methods such as continuous bulk polymerization, solution polymerization, emulsion polymerization, emulsifier-free (soap-free) emulsion polymerization, and suspension polymerization can be adopted.
  • radical polymerization methods such as continuous bulk polymerization, solution polymerization, emulsion polymerization, emulsifier-free (soap-free) emulsion polymerization, and suspension polymerization can be adopted.
  • production methods involving aqueous polymerization are preferred, suspension polymerization method and emulsion polymerization method are more preferred, and suspension polymerization method is even more preferred.
  • the methacrylic resin is synthesized in an aqueous suspension obtained by mixing water, a monomer mixture, a dispersant, a polymerization initiator, a chain transfer agent, and optionally other additives.
  • the order in which the components are mixed is not particularly limited.
  • the components may be mixed simultaneously to prepare an aqueous suspension.
  • the monomer mixture and the chain transfer agent are added, and then the dispersant is added to prepare an aqueous suspension.
  • the mass ratio of the obtained methacrylic resin to water (methacrylic resin/water) is preferably 1.0/0.6 to 1.0/3.0.
  • the monomer mixture preferably contains 99.5% by mass or more of methyl methacrylate.
  • Dispersants include, for example, poorly water-soluble inorganic salts such as tricalcium phosphate, magnesium pyrophosphate, hydroxyapatite, and kaolin; and water-soluble polymers such as polyvinyl alcohol, methyl cellulose, polyacrylamide, and polyvinylpyrrolidone.
  • poorly water-soluble inorganic salts such as tricalcium phosphate, magnesium pyrophosphate, hydroxyapatite, and kaolin
  • water-soluble polymers such as polyvinyl alcohol, methyl cellulose, polyacrylamide, and polyvinylpyrrolidone.
  • an anionic surfactant such as sodium ⁇ -olefin sulfonate or sodium dodecylbenzene sulfonate.
  • polymerization initiator known polymerization initiators such as azo polymerization initiators and peroxide polymerization initiators can be used.
  • azo polymerization initiators are preferred from the viewpoint of improving the thermal stability of the resulting methacrylic resin.
  • azo polymerization initiators only generate alkyl radicals, and therefore have a lower hydrogen abstraction capacity than peroxide polymerization initiators.
  • the hydrogen abstraction capacity of the polymerization initiator is high, for example, when methyl methacrylate is used as a monomer, hydrogen is abstracted from the ⁇ -methyl group of methyl methacrylate or the methyl group of the ester by the free radicals generated from the polymerization initiator, and polymerization proceeds from the newly generated radicals on the ⁇ -methyl group or the methyl group of the ester, resulting in the production of a polymer with double bonds derived from the monomer structure remaining at the end. Therefore, when a polymerization initiator with high hydrogen abstraction capacity is used, the thermal stability of the resulting methacrylic resin tends to be insufficient. Therefore, in order to obtain a methacrylic resin with high thermal stability, azo polymerization initiators are more suitable than peroxide polymerization initiators.
  • the hydrogen abstraction ability of a polymerization initiator can be measured, for example, by a radical trapping method using ⁇ -methylstyrene dimer (i.e., the ⁇ -methylstyrene dimer trapping method).
  • the methacrylic resin synthesized using a non-nitrile azo polymerization initiator has a terminal structure introduced into the molecule that is more thermally stable than the methacrylic resin synthesized using a polymerization initiator other than the non-nitrile azo polymerization initiator (for example, a nitrile azo polymerization initiator).
  • a polymerization initiator other than the non-nitrile azo polymerization initiator for example, a nitrile azo polymerization initiator.
  • non-nitrile azo polymerization initiators are more preferable.
  • non-nitrile azo polymerization initiators include those represented by the above formula (2), and from the standpoint of half-life temperature, cost, etc., at least one selected from 2,2'-azobis(isobutyric acid) dimethyl and 1,1'-azobis(cyclohexane carboxylate) is preferable.
  • the amount of polymerization initiator used is preferably 1 part by mass or less, more preferably 0.5 parts by mass or less, and even more preferably 0.1 parts by mass or less, per 100 parts by mass of the total monomer mixture.
  • the amount of polymerization initiator used is preferably 0.001 parts by mass or more per 100 parts by mass of the total monomer mixture.
  • chain transfer agents include primary alkyl mercaptan chain transfer agents such as n-butyl mercaptan, n-octyl mercaptan, n-hexadecyl mercaptan, n-dodecyl mercaptan, and n-tetradecyl mercaptan; secondary alkyl mercaptan chain transfer agents such as s-butyl mercaptan and s-dodecyl mercaptan; tertiary alkyl mercaptan chain transfer agents such as t-dodecyl mercaptan and t-tetradecyl mercaptan; thioglycolic acid esters such as 2-ethylhexyl thioglycolate, ethylene glycol dithioglycolate, trimethylolpropane tris(thioglycolate), and pentaerythritol tetraki
  • alkyl mercaptan chain transfer agents and thioglycolic acid esters are preferred from the standpoint of ease of handling, stability, and thermal stability of the resulting methacrylic resin, with n-octyl mercaptan being a more preferred alkyl mercaptan chain transfer agent and 2-ethylhexyl thioglycolate being a more preferred thioglycolic acid ester.
  • the amount of chain transfer agent used is preferably 0.03 mol% or less, more preferably 0.025 mol% or less, based on the total amount of the monomer mixture. There is no particular lower limit to the amount of chain transfer agent used, but it is preferably 0.0015 mol% or more based on the total amount of the monomer mixture.
  • the ratio of the total molar amount of the chain transfer agent to the total molar amount of the polymerization initiator is preferably 3.0 or less, more preferably 2.6 or less, and even more preferably 2.0 or less.
  • the polymerization temperature when synthesizing the methacrylic resin is set to less than 100°C from the viewpoints of controlling the syndiotacticity of the resulting methacrylic resin and productivity, and is preferably 20°C or higher and less than 100°C, more preferably 30 to 95°C, even more preferably 50 to 90°C, and particularly preferably 60 to 85°C.
  • a post-polymerization may be carried out by raising the temperature to a temperature higher than that of the first stage in order to reduce the amount of residual monomer.
  • the amount of dissolved oxygen in the polymerization raw materials is preferably 10 ppm or less, more preferably 5 ppm or less, even more preferably 4 ppm or less, and particularly preferably 2 ppm or less.
  • an inert gas such as nitrogen gas can be fed into the reaction vessel before, during, and after the temperature is raised to a predetermined polymerization temperature.
  • an inert gas such as nitrogen gas
  • the monomer mixture contains a polymerization inhibitor
  • the suspension containing the methacrylic resin obtained by suspension polymerization may be washed with an acid, water, or alkali to remove the dispersant.
  • the number of times these washing operations are performed can be selected optimally taking into consideration the work efficiency and the efficiency of removing the dispersant, and may be one or multiple times.
  • Methacrylic resin can be separated from a suspension containing the methacrylic resin by a conventionally known dehydration method.
  • the dehydration method include a method using a centrifuge and a method of removing water by suction on a porous belt or a filter membrane.
  • the hydrous methacrylic resin obtained through the above-mentioned dehydration can be dried and recovered by a conventionally known method.
  • drying methods include hot air drying, which involves blowing hot air into a tank from a hot air blower, blow heater, etc.; vacuum drying, which involves reducing the pressure inside the system and then heating it as necessary; barrel drying, which involves rotating the obtained methacrylic resin in a container to remove moisture; and spin drying, which involves drying using centrifugal force. These drying methods may be performed alone or in combination of two or more.
  • the methacrylic resin is synthesized in an emulsion of water, a monomer mixture, an emulsifier, a polymerization initiator, a chain transfer agent, and optionally other additives.
  • the monomer mixture preferably contains 99.5% by mass or more of methyl methacrylate, and more preferably contains 100% by mass.
  • emulsifiers include anionic surfactants such as alkyl sulfonates, alkyl benzene sulfonates, dialkyl sulfosuccinates, ⁇ -olefin sulfonates, naphthalene sulfonate-formaldehyde condensates, alkyl naphthalene sulfonates, N-methyl-N-acyltaurine salts, and phosphate salts (polyoxyethylene alkyl ether phosphates, etc.); nonionic surfactants; and the like.
  • the above salts include lithium salts, sodium salts, potassium salts, calcium salts, and magnesium salts.
  • These emulsifiers may be used alone or in combination of two or more. The emulsifier used in the emulsion polymerization may remain in the final methacrylic resin.
  • a suitable pH adjuster can be used to prevent hydrolysis of the monomer methyl methacrylate and the structural units derived from methyl methacrylate in the methacrylic resin obtained by polymerization.
  • pH adjusters include boric acid-potassium chloride-potassium hydroxide, potassium dihydrogen phosphate-sodium hydrogen phosphate, boric acid-potassium chloride-potassium carbonate, citric acid-potassium hydrogen citrate, potassium dihydrogen phosphate-boric acid, and sodium dihydrogen phosphate-citric acid.
  • the polymerization initiator and chain transfer agent may be the same as those in the suspension polymerization method described above.
  • the polymerization initiator may be a redox system, if necessary.
  • the ratio of the total molar amount of the chain transfer agent to the total molar amount of the polymerization initiator is set to 3.0 or less.
  • the ratio of the total molar amount of the chain transfer agent to the total molar amount of the polymerization initiator is preferably 2.6 or less, and more preferably 2.0 or less.
  • the methacrylic resin latex obtained by emulsion polymerization can be subjected to heat drying or spray drying, or to a known method of solidifying the latex by adding a water-soluble electrolyte such as a salt or an acid, and then heat treating the latex, followed by separating the resin component from the aqueous phase and drying the resulting mixture.
  • a solid or powdered methacrylic resin can be obtained.
  • the above salt is not particularly limited, but a divalent salt is preferred, and specific examples include calcium salts such as calcium chloride and calcium acetate; magnesium salts such as magnesium chloride and magnesium sulfate; and the like. Among these salts, magnesium salts such as magnesium chloride and magnesium sulfate are preferred.
  • commonly added additives such as anti-aging agents and ultraviolet absorbers may be added.
  • the form of the methacrylic resin obtained by aqueous polymerization may be a powder, a granule, or a powder-granule containing both powder and granule.
  • suspension polymerization is suitable for producing primary particles with an average particle size of about 10 to 1000 ⁇ m
  • emulsion polymerization is suitable for producing primary particles with an average particle size of about 50 to 500 nm.
  • the powder, granule, and powder-granule may contain aggregates that are collections of the above primary particles.
  • the methacrylic resin may be purified as necessary.
  • Purification methods include, for example, dissolving the methacrylic resin in a solvent and dropping it into a poor solvent to cause precipitation; heating the methacrylic resin to volatilize and remove impurities; and the like. These methods are appropriately selected according to the application, and may be combined with each other.
  • ⁇ Acrylic Crosslinked Particles> By using a resin composition containing acrylic crosslinked particles, it is possible to obtain a resin film that is excellent in transparency and color tone, and further in mechanical strength such as bending resistance.
  • the acrylic crosslinked particles are not particularly limited, and may be either hard or soft crosslinked particles, and may be single-layered or multi-layered.
  • methacrylic acid esters such as methyl methacrylate and polyfunctional monomers having two or more non-conjugated double bonds may be used as raw materials, but as described below, they may be in the form of a core-shell type polymer.
  • a core-shell type elastomer having a core layer made of a rubber-like polymer with excellent thermal stability and a shell layer made of a glassy polymer is preferred.
  • Acrylic crosslinked particles can be formed, for example, from a multilayered polymer, a graft copolymer known as a core-shell polymer.
  • a multilayered polymer is a polymer (core-shell polymer) that has a polymer layer (shell layer) obtained by polymerizing a monomer mixture in the presence of polymer particles (core layer).
  • the average particle diameter of the core layer is preferably 125 to 400 nm. If the average particle diameter of the core layer is 125 nm or more, the strength of the resin film produced can be excellent. If it is 400 nm or less, the resin film produced has excellent transparency, appearance, and optical properties.
  • the average particle diameter of the core layer is more preferably 130 to 380 nm, and particularly preferably 200 to 260 nm.
  • the average particle diameter of the core layer of the acrylic crosslinked particles in the present invention is calculated by measuring the light scattering at a wavelength of 546 nm using a spectrophotometer in the state of the polymer latex of the core layer before the shell layer is polymerized.
  • acrylic crosslinked particles that easily swell when dissolved and dispersed in the solvent used in the dope.
  • the ease of swelling can be measured by the method described in International Publication No. WO2018/212227.
  • the acrylic crosslinked particles preferably have a gel fraction of 90% or less.
  • the gel fraction is the mass ratio of the components of the acrylic crosslinked particles that are insoluble in methyl ethyl ketone to the total amount of the acrylic crosslinked particles. If the gel fraction of the acrylic crosslinked particles is 90% or less, the acrylic crosslinked particles contain a significant amount of components that are soluble in methyl ethyl ketone, and the primary particles of the acrylic crosslinked particles tend to break apart in the dope due to the soluble components.
  • the gel fraction is more preferably 87% or less, even more preferably 85% or less, even more preferably 83% or less, and particularly preferably 80% or less.
  • the lower limit of the gel fraction there is no particular limit to the lower limit of the gel fraction, but if it is too low, mechanical properties such as the bending resistance of the resin film, cracking during slitting, and cracking during punching may decrease, so it is preferably 65% or more, more preferably 68% or more, even more preferably 70% or more, and most preferably 73% or more.
  • the gel fraction can be measured by the method described below.
  • the core layer in the acrylic crosslinked particle is composed of a rigid polymer (I) containing, as structural units, 40 to 100 mass% of methacrylic acid ester units (a-1), 60 to 0 mass% of other monomer units (a-2) having a double bond copolymerizable therewith, and 0.01 to 10 mass parts of a polyfunctional monomer unit relative to a total of 100 mass parts of the (a-1) and (a-2); and 60 to 100 mass% of acrylic acid ester units (b-1), 0 to 40 mass% of other monomer units (b-2) having a double bond copolymerizable therewith, and 0.01 to 10 mass parts of a polyfunctional monomer unit relative to a total of 100 mass parts of the (b-1) and (b-2).
  • a rigid polymer (I) containing, as structural units, 40 to 100 mass% of methacrylic acid ester units (a-1), 60 to 0 mass% of other monomer units (a-2) having a double bond copolymerizable therewith, and
  • the shell layer contains 60 to 100% by mass of methacrylic acid ester units (c-1), 40 to 0% by mass of other monomer units (c-2) having a double bond copolymerizable therewith, and a hard polymer (III) containing 0 to 10 parts by mass of a polyfunctional monomer unit as a structural unit relative to a total of 100 parts by mass of (c-1) and (c-2), and the hard polymer (III) is graft-bonded to the hard polymer (I) and/or the soft polymer (II).
  • the acrylic crosslinked particles can be obtained by the method described in International Publication No. WO2018/212227.
  • the polymer layer formed in the polymerization stages (I) to (II) corresponds to the core layer, and the polymer layer formed after the polymerization stage (III) corresponds to the shell layer.
  • (I) Polymerization Step it is preferable to obtain a rigid polymer (I) by polymerizing a monomer mixture (a) consisting of 40 to 100 mass% of a methacrylic acid ester (a-1) and 60 to 0 mass% of another monomer (a-2) having a double bond copolymerizable therewith, and 0.01 to 10 mass parts of a polyfunctional monomer and 0.1 to 4.0 mass parts of a chain transfer agent per 100 mass parts in total of (a-1) and (a-2).
  • a monomer mixture (a) consisting of 40 to 100 mass% of a methacrylic acid ester (a-1) and 60 to 0 mass% of another monomer (a-2) having a double bond copolymerizable therewith, and 0.01 to 10 mass parts of a polyfunctional monomer and 0.1 to 4.0 mass parts of a chain transfer agent per 100 mass parts in total of (a-1) and (a-2).
  • the other monomer having a copolymerizable double bond (hereinafter sometimes referred to as "copolymerizable monomer”) is preferably an acrylic acid alkyl ester having an alkyl group with 1 to 12 carbon atoms and/or an aromatic vinyl monomer.
  • the monomer mixture (a) is preferably composed of 40 to 100 mass% methacrylic acid ester, 0 to 35 mass% acrylic acid ester, 0 to 10 mass% aromatic vinyl monomer, and 0 to 15 mass% other monomers having copolymerizable double bonds, and is particularly preferably composed of 51 to 96.8 mass% methacrylic acid ester, 3.1 to 29 mass% acrylic acid ester, 0.1 to 10 mass% aromatic vinyl monomer, and 0 to 10 mass% other monomers having copolymerizable double bonds.
  • zipping depolymerization under high temperature conditions is suppressed to increase thermal stability, and the resulting acrylic crosslinked particles can be blended with methacrylic resin without impairing the optical properties such as transparency and color tone of the methacrylic resin.
  • the methacrylic acid esters include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, isobornyl methacrylate, phenyl methacrylate, and benzyl methacrylate.
  • methacrylic acid alkyl esters having an alkyl group with 1 to 4 carbon atoms are preferred, such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and t-butyl methacrylate. These may be used alone or in combination of two or more, with methyl methacrylate being particularly preferred.
  • the other monomer having a copolymerizable double bond is preferably at least one selected from the group consisting of acrylic acid esters, aromatic vinyl monomers, and copolymerizable monomers other than (meth)acrylic acid esters and aromatic vinyl monomers, and more preferably one or more monomers selected from the group consisting of acrylic acid alkyl esters having an alkyl group with 1 to 12 carbon atoms, aromatic vinyl monomers, and copolymerizable monomers other than (meth)acrylic acid esters and aromatic vinyl monomers.
  • the other monomer having a copolymerizable double bond is preferably an acrylic acid alkyl ester having an alkyl group with 1 to 12 carbon atoms and/or an aromatic vinyl monomer.
  • the amount of the multifunctional monomer used in the (I) polymerization step is preferably 0.01 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, and most preferably 0.01 to 2 parts by mass, per 100 parts by mass of the total of (a-1) and (a-2).
  • the amount of the multifunctional monomer used is 0.01 part by mass or more, the transparency of the obtained film is improved, and when it is 10 parts by mass or less, excellent mechanical properties can be imparted to the film.
  • polyfunctional monomer any of those known as crosslinking agents or crosslinkable monomers can be used.
  • crosslinkable monomer it is more preferable to use allyl methacrylate alone or in combination with another polyfunctional monomer.
  • the amount of the chain transfer agent used in the polymerization step (I) is preferably 0.1 to 4.0 parts by mass per 100 parts by mass of the total of (a-1) and (a-2).
  • the lower limit is more preferably 0.20 parts by mass, and particularly preferably 0.50 parts by mass.
  • the upper limit is more preferably 3.5 parts by mass, and particularly preferably 1.5 parts by mass.
  • the chain transfer agent has the function of increasing the amount of low-molecular-weight free polymers, so the more the chain transfer agent is used, the lower the degree of crosslinking of the core layer, the easier it is for the core layer to absorb the solvent, the higher the degree of swelling of the acrylic crosslinked particles, the easier it is for the primary particles of the acrylic crosslinked particles to break apart, and the less likely the dope will become cloudy.
  • an excessive amount of the chain transfer agent it may be difficult to obtain sufficient mechanical properties such as bending resistance of the resin film, cracking during slitting, and cracking during punching.
  • the chain transfer agent is used within the above range, it is possible to obtain acrylic crosslinked particles that are less likely to cause clouding of the dope and can impart excellent mechanical properties to the resin film.
  • the chain transfer agent used in the polymerization step is not particularly limited, and any chain transfer agent known in the art can be used.
  • the chain transfer agents can be used alone or in combination of two or more.
  • the chain transfer agent contains a sulfur component, so alkyl mercaptan chain transfer agents and thiophenol are preferred, and alkyl mercaptan chain transfer agents are more preferred.
  • alkyl mercaptan chain transfer agents are more preferred.
  • n-octyl mercaptan and n-dodecyl mercaptan are preferred, and n-octyl mercaptan is particularly preferred.
  • the rigid polymer (I) obtained in the polymerization step (I) of the acrylic crosslinked particles preferably has an alkylthio group derived from an alkyl mercaptan chain transfer agent, and more preferably has a primary and/or secondary alkylthio group derived from a primary and/or secondary alkyl mercaptan chain transfer agent.
  • An alkylthio group refers to a structure represented by the chemical formula RS- (R is an alkyl group), and a primary and/or secondary alkylthio group refers to the above R being a primary and/or secondary alkyl group.
  • (II) Polymerization Step it is preferable to obtain a flexible polymer (II) by polymerizing a monomer mixture (b) consisting of 60 to 100 mass % of an acrylic acid ester (b-1) and 0 to 40 mass % of another monomer (b-2) having a double bond copolymerizable therewith, and 0.1 to 5 mass parts of a polyfunctional monomer and 0 to 2.0 mass parts of a chain transfer agent per 100 mass parts in total of the (b-1) and (b-2).
  • a monomer mixture (b) consisting of 60 to 100 mass % of an acrylic acid ester (b-1) and 0 to 40 mass % of another monomer (b-2) having a double bond copolymerizable therewith, and 0.1 to 5 mass parts of a polyfunctional monomer and 0 to 2.0 mass parts of a chain transfer agent per 100 mass parts in total of the (b-1) and (b-2).
  • the other monomer having a copolymerizable double bond is preferably at least one selected from the group consisting of methacrylic acid esters and other monomers having a copolymerizable double bond.
  • an alkyl acrylate ester having an alkyl group with 1 to 12 carbon atoms is preferred, such as ethyl acrylate, n-butyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl acrylate.
  • These acrylic acid esters may be used alone or in combination of two or more.
  • n-butyl acrylate is preferred, and a combination of n-butyl acrylate and ethyl acrylate, or a combination of n-butyl acrylate and 2-ethylhexyl acrylate is also preferred.
  • the acrylic acid ester used in the (II) polymerization stage preferably contains 50 to 100% by mass of n-butyl acrylate, and particularly preferably 80 to 100% by mass.
  • the methacrylic acid ester, other monomers having a copolymerizable double bond, polyfunctional monomers, and chain transfer agents used in the (II) polymerization stage are the same as those described in the (I) polymerization stage above.
  • a chain transfer agent may or may not be used, but it is preferable not to use one.
  • (III) Polymerization Step it is preferable to obtain a rigid polymer (III) by polymerizing a monomer mixture (c) consisting of 60 to 100 mass% of a methacrylic acid ester (c-1) and 40 to 0 mass% of another monomer (c-2) having a double bond copolymerizable therewith, and 0 to 10 mass parts of a polyfunctional monomer and 0 to 6 mass parts of a chain transfer agent relative to a total of 100 mass parts of the (c-1) and (c-2).
  • a monomer mixture (c) consisting of 60 to 100 mass% of a methacrylic acid ester (c-1) and 40 to 0 mass% of another monomer (c-2) having a double bond copolymerizable therewith, and 0 to 10 mass parts of a polyfunctional monomer and 0 to 6 mass parts of a chain transfer agent relative to a total of 100 mass parts of the (c-1) and (c-2).
  • the monomer mixture (c) preferably contains an acrylic acid ester.
  • the amount of the acrylic acid ester used in the monomer mixture (c) is preferably 0 to 40% by mass, more preferably 10 to 40% by mass, and most preferably 20 to 30% by mass.
  • the acrylic crosslinked particles preferably have a structure in which the hard polymer (III) is grafted to the hard polymer (I) and/or the soft polymer (II).
  • the entire hard polymer (III) may be grafted to the hard polymer (I) and/or the soft polymer (II), or a portion of the hard polymer (III) may be grafted to the hard polymer (I) and/or the soft polymer (II), while the remainder may exist as a polymer component (free polymer) that is not grafted to either the hard polymer (I) or the soft polymer (II).
  • the polymer component that is not grafted also constitutes a part of the acrylic crosslinked particles.
  • the methacrylic acid ester, other monomer having a copolymerizable double bond, polyfunctional monomer, and chain transfer agent used in the (III) polymerization stage are the same as those described in the (I) polymerization stage.
  • a polyfunctional monomer and/or a chain transfer agent may or may not be used, but it is preferable not to use them.
  • the acrylic crosslinked particles may include a polymerization stage other than the polymerization stages (I) to (III) above.
  • a rigid polymer (IV) by polymerizing a monomer mixture (d) consisting of 40 to 100 mass% methacrylic acid ester (d-1), 0 to 60 mass% acrylic acid ester (d-2), and 0 to 5 mass% other monomer having a copolymerizable double bond (d-3), as well as 0 to 10 mass parts of a multifunctional monomer and 0 to 6 mass parts of a chain transfer agent per 100 mass parts of the total of (d-1), (d-2), and (d-3).
  • a monomer mixture (d) consisting of 40 to 100 mass% methacrylic acid ester (d-1), 0 to 60 mass% acrylic acid ester (d-2), and 0 to 5 mass% other monomer having a copolymerizable double bond (d-3), as well as 0 to 10 mass parts of a multifunctional monomer and 0 to 6 mass parts of a chain transfer agent per 100 mass parts of the total of (d-1), (d-2), and (d-3).
  • the amount of acrylic acid ester (d-2) used is preferably 0 to 55% by mass, more preferably 15 to 40% by mass, and most preferably 20 to 40% by mass.
  • the methacrylic acid esters, acrylic acid esters, other monomers having a copolymerizable double bond, polyfunctional monomers, and chain transfer agents used in the (IV) polymerization stage are the same as those described in (I) to (III) above.
  • polyfunctional monomers and/or chain transfer agents may or may not be used, but it is preferable not to use them.
  • the hard polymer (IV) may have a structure in which it is grafted to the hard polymer (I) and/or the soft polymer (II) and/or the hard polymer (III).
  • the entire hard polymer (IV) may be grafted to the hard polymer (I) and/or the soft polymer (II) and/or the hard polymer (III), or a part of the hard polymer (IV) may be grafted to the hard polymer (I) and/or the soft polymer (II) and/or the hard polymer (III), while the remainder may be present as a polymer component that is not grafted to any of the hard polymer (I), the soft polymer (II) and the hard polymer (III).
  • the polymer component that is not grafted also constitutes a part of the acrylic crosslinked particles.
  • the acrylic crosslinked particles can be produced by ordinary emulsion polymerization using a known emulsifier.
  • the polymerization initiator used in the polymerization to obtain the acrylic crosslinked particles is preferably a polymerization initiator having a 10-hour half-life temperature of 100° C. or less from the viewpoint of improving the thermal stability of the resin film.
  • the polymerization initiator is not particularly limited as long as it is a polymerization initiator having a 10-hour half-life temperature of 100° C. or less, but the 10-hour half-life temperature of the polymerization initiator is preferably 100° C. or less, more preferably 80° C. or less, and particularly preferably 75° C. or less.
  • persulfates are preferable, and examples thereof include potassium persulfate, sodium persulfate, and ammonium persulfate. Among them, potassium persulfate is particularly preferable.
  • the polymerization initiator is preferably used during polymerization in the polymerization stage (I), and more preferably during polymerization in the polymerization stage using a chain transfer agent. It is particularly preferable to use the polymerization initiator in all polymerization stages of the acrylic crosslinked particles.
  • the total amount of polymerization initiator used is preferably 0.01 to 1.0 parts by mass relative to 100 parts by mass of the total amount of the monomer mixture constituting the acrylic crosslinked particles.
  • the amount of each of the polymerization initiators used is preferably 0.01 to 1.85 parts by mass in the (I) polymerization stage, 0.01 to 0.6 parts by mass in the (II) polymerization stage, and 0.01 to 0.90 parts by mass in the (III) polymerization stage.
  • the amount of polymerization initiator used in the (I) polymerization stage is more than 1% by mass and 29% by mass or less relative to the total amount of polymerization initiator used.
  • the core layer of the acrylic crosslinked particles refers to the crosslinked polymer obtained by carrying out polymerization up to the polymerization stage (II) (therefore, the outermost layer of the core layer is the soft polymer formed in the polymerization stage (II)), and the shell layer refers to the hard polymer obtained by carrying out polymerization after the polymerization stage (II).
  • the acrylic crosslinked particle latex thus obtained is coagulated by spray drying or by adding a water-soluble electrolyte such as a salt or acid, and then heat-treated, after which the resin component is separated from the aqueous phase, appropriately washed, and dried, or by other known methods to obtain solid or powdered acrylic crosslinked particles.
  • a water-soluble electrolyte such as a salt or acid
  • soft means that the glass transition temperature of the polymer is less than 10°C. From the viewpoint of enhancing the impact resistance improvement effect such as crack resistance, the glass transition temperature of the soft polymer is preferably less than 0°C, and more preferably less than -20°C. Also, “hard” means that the glass transition temperature of the polymer is 10°C or higher.
  • the hard polymer constituting the shell layer of the acrylic crosslinked particles (when the shell layer is multi-layered, the layer among the multi-layered layers having the highest glass transition temperature) preferably has a glass transition temperature of 10°C or higher and 92°C or lower.
  • glass transition temperatures of "soft” and “hard” polymers are calculated using the Fox formula using values given in the Polymer Hand Book (J. Brandrup, Interscience 1989) (for example, polymethyl methacrylate is 105°C and polybutyl acrylate is -54°C).
  • the polymer (I) obtained in the polymerization stage (I) is a hard polymer
  • the polymer (II) obtained in the polymerization stage (II) is a soft polymer
  • the polymer (III) obtained in the polymerization stage (III) is a hard polymer
  • the polymer (IV) obtained in the polymerization stage (IV) is a hard polymer.
  • the acrylic crosslinked particles having such a configuration have a good balance of appearance, transparency, weather resistance, gloss, processability, thermal stability, etc. when blended with various methacrylic resins. This makes it possible to provide a film that is excellent in thermal stability, weather resistance, gloss, processability, etc., without compromising the excellent color tone, appearance, and transparency unique to the blended methacrylic resin.
  • the resin composition according to the present embodiment contains the above-described methacrylic resin according to the present embodiment and acrylic crosslinked particles.
  • the blending ratio of the methacrylic resin and the acrylic crosslinked particles varies depending on the application of the molded article, but the mass ratio of the methacrylic resin and the acrylic crosslinked particles is preferably 99.9:0.1 to 65:35, and more preferably 99:1 to 65:35.
  • the mass ratio of the methacrylic resin and the acrylic crosslinked particles is preferably 95:5 to 65:35, and more preferably 90:10 to 60:40.
  • the amount of methacrylic resin is 65 parts by mass or more relative to 100 parts by mass of the total amount of both components, methacrylic resin and acrylic crosslinked particles, the properties of the methacrylic resin can be fully exhibited, and when the amount is 95 parts by mass or less, the mechanical strength of the methacrylic resin can be sufficiently improved.
  • the resin composition may further contain known additives such as light stabilizers, ultraviolet absorbers, heat stabilizers, matting agents, light diffusing agents, colorants, dyes, pigments, antistatic agents, heat ray reflectors, lubricants, plasticizers, stabilizers, flame retardants, release agents, polymer processing aids, antioxidants, and fillers, as well as resins other than methacrylic resins.
  • known additives such as light stabilizers, ultraviolet absorbers, heat stabilizers, matting agents, light diffusing agents, colorants, dyes, pigments, antistatic agents, heat ray reflectors, lubricants, plasticizers, stabilizers, flame retardants, release agents, polymer processing aids, antioxidants, and fillers, as well as resins other than methacrylic resins.
  • resins other than methacrylic resins include styrene-based resins such as acrylonitrile styrene resin and styrene maleic anhydride resin; polycarbonate resins; polyvinyl acetal resins; cellulose acylate resins; fluorine-based resins such as polyvinylidene fluoride and polyfluorinated alkyl (meth)acrylate resins; silicone-based resins; polyolefin-based resins; polyethylene terephthalate resins; polybutylene terephthalate resins; and the like.
  • styrene-based resins such as acrylonitrile styrene resin and styrene maleic anhydride resin
  • polycarbonate resins such as acrylonitrile styrene resin and styrene maleic anhydride resin
  • polycarbonate resins such as acrylonitrile styrene resin and styrene maleic
  • the resin composition according to this embodiment may also contain inorganic fine particles having birefringence as described in Japanese Patent No. 3648201, Japanese Patent No. 4336586, etc., or a low molecular weight compound having birefringence and a molecular weight of 5,000 or less (preferably 1,000 or less) as described in Japanese Patent No. 3696649 in order to adjust the orientation birefringence of the molded product.
  • the form of the resin composition according to this embodiment is not particularly limited, and may be a powder, granules, a powder-granule mixture containing both powder and granules, or pellet-shaped.
  • the dope used for producing a resin film by a solution casting method contains the resin composition according to the present embodiment described above and a solvent.
  • the solvent preferably contains a first solvent having a hydrogen bond parameter ⁇ H of 1 to 12 in the Hansen solubility parameter and a second solvent having a hydrogen bond parameter ⁇ H of 14 to 24.
  • the dope according to the present embodiment may further contain other components such as multilayer structure polymer particles, as in the resin composition according to the present embodiment described above. Each component such as the methacrylic resin and the multilayer structure polymer particles is dissolved or dispersed in the solvent.
  • first solvent having a hydrogen bond parameter ⁇ H of 1 to 12 for example, the solvents described in International Publication No. WO2018/212227 can be used. These first solvents may be used alone or in combination of two or more. Among these first solvents, methyl ethyl ketone (5.1), chloroform (5.7), and methylene chloride (7.1) are preferred, with methylene chloride being more preferred, because they have excellent solubility for methacrylic resin and a fast evaporation rate.
  • the number in parentheses indicates the value of the hydrogen bond parameter ⁇ H.
  • Examples of second solvents with a hydrogen bond parameter ⁇ H of 14 to 24 include methanol (22.3), ethanol (19.4), isopropanol (16.4), butanol (15.8), and ethylene glycol monoethyl ether (14.3).
  • the numbers in parentheses indicate the value of the hydrogen bond parameter ⁇ H.
  • These second solvents may be used alone or in combination of two or more. Among these second solvents, methanol and ethanol are preferred, and ethanol is more preferred.
  • the proportion of the first solvent in the solvent is preferably 55 to 95% by mass, more preferably 60 to 95% by mass, and even more preferably 70 to 95% by mass.
  • the content of the methacrylic resin in the dope is not particularly limited and is determined appropriately taking into consideration the solubility of the methacrylic resin in the solvent used and the conditions under which the solution casting method is carried out.
  • the content of the methacrylic resin is preferably 5 to 50% by mass, more preferably 10 to 45% by mass, and even more preferably 15 to 40% by mass.
  • the viscosity of the dope can be adjusted appropriately by adjusting the content of methacrylic resin and other components in the dope.
  • the viscosity of the dope is measured by the method described in the examples below.
  • the dope is used to manufacture a resin film by a solution casting method.
  • the dope according to this embodiment is cast onto the surface of a support and coated in a uniform film shape with an applicator to form a dope film.
  • the dope may be cast onto the support using a pressure die.
  • the formed dope film is heated on the support to evaporate the solvent and form a resin film.
  • the conditions for evaporating the solvent can be appropriately determined depending on the boiling point of the solvent used.
  • the formed resin film is then peeled off from the support surface.
  • the obtained resin film may be subjected to a drying process, a heating process, a stretching process, etc. as appropriate.
  • the resin film according to the present embodiment includes the resin composition according to the present embodiment described above.
  • the resin film according to the present embodiment is produced, for example, by a solution casting method using the dope according to the present embodiment described above.
  • the thickness of the resin film according to this embodiment is, for example, preferably 500 ⁇ m or less, more preferably 300 ⁇ m or less, and even more preferably 200 ⁇ m or less.
  • the thickness of the resin film according to this embodiment is, for example, preferably 10 ⁇ m or more, more preferably 30 ⁇ m or more, even more preferably 50 ⁇ m or more, and particularly preferably 60 ⁇ m or more. If the thickness of the resin film is within the above range, there is an advantage that the resin film is less likely to deform when vacuum forming is performed using the resin film, and breakage is less likely to occur in the deep drawing portion. Another advantage is that a resin film with uniform optical properties and good transparency can be produced.
  • the total light transmittance of the resin film according to this embodiment is preferably 85% or more, more preferably 88% or more, and even more preferably 91% or more. If the total light transmittance is within the above range, the film is highly transparent and can be suitably used for optical applications that require light transmittance.
  • the glass transition temperature of the resin film according to this embodiment is preferably 120°C or higher, more preferably 122°C or higher, and even more preferably 124°C or higher. If the glass transition temperature is within the above range, the resin film will have sufficient heat resistance.
  • the resin film according to this embodiment preferably has a 5% weight loss temperature of 300°C or higher, and more preferably 305°C or higher. This provides excellent thermal stability.
  • the haze of the resin film according to this embodiment is preferably 2.0% or less, more preferably 1.5% or less, even more preferably 1.3% or less, and particularly preferably 1.0% or less.
  • the internal haze of the resin film is preferably 1.5% or less, more preferably 1.0% or less, even more preferably 0.5% or less, and particularly preferably 0.4% or less. If the haze and internal haze are within the above ranges, the film is highly transparent and can be suitably used for optical applications requiring light transparency.
  • the haze is composed of the haze inside the film and the haze on the film surface (external), and these are referred to as the internal haze and external haze, respectively.
  • the b* value of the resin film according to this embodiment is preferably 0.3 or less, more preferably 0.25 or less, and even more preferably 0.20 or less.
  • the yellowness index (YI) of the resin film according to this embodiment is preferably 1.2 or less, more preferably 1.0 or less, and even more preferably 0.5 or less. If the YI is within the above range, the film has high transparency and can be suitably used for optical applications that require light transmittance.
  • the resin film according to this embodiment preferably has excellent mechanical properties, for example, high bending resistance.
  • the MIT bending resistance test and the clamshell bending resistance test are known methods for evaluating bending resistance.
  • the resin film according to this embodiment preferably has a bending number of 2500 or more times in the MIT bending resistance test, and more preferably has a bending number of 3000 or more times in the MIT bending resistance test. If the number of bending times until breakage is within the above range, the bending resistance of the resin film is sufficient.
  • the number of bending times in the MIT bending resistance test is measured by the method described in the examples below.
  • the resin film according to this embodiment can be suitably used as an optical film such as a polarizer protective film.
  • the optical anisotropy is small.
  • the optical anisotropy in the thickness direction as well as the optical anisotropy in the in-plane direction (length direction, width direction) of the resin film is small.
  • the absolute values of the in-plane phase difference and the thickness direction phase difference are both small.
  • the absolute value of the in-plane phase difference is preferably 20 nm or less, and more preferably 15 nm or less.
  • the absolute value of the thickness direction phase difference is preferably 50 nm or less, more preferably 20 nm or less, and even more preferably 15 nm or less.
  • the phase difference is an index value calculated based on birefringence.
  • the in-plane phase difference (Re) and thickness direction phase difference (Rth) can be calculated by the following formulas. In an ideal resin film that is completely optically isotropic in three dimensional directions, the in-plane phase difference Re and thickness direction phase difference Rth are both 0.
  • nx, ny, and nz represent the refractive index in the respective axial directions, where the in-plane stretching direction (the orientation direction of the polymer chain) is the X axis, the direction perpendicular to the X axis is the Y axis, and the thickness direction of the resin film is the Z axis.
  • d represents the thickness of the resin film
  • nx-ny represents the orientation birefringence.
  • the MD direction of the film is the X axis, but in the case of a stretched film, the stretching direction is the X axis.
  • the resin film according to this embodiment has an orientation birefringence value of preferably -5.0x10 -4 to 5.0x10 -4 , more preferably -4.0x10 -4 to 4.0x10 -4 , and even more preferably -3.8x10 -4 to 3.8x10 -4 . If the orientation birefringence is within the above range, there is a tendency that stable optical properties can be obtained without birefringence occurring during molding processing.
  • the resin film according to the present embodiment may be further stretched, which can improve the mechanical strength of the resin film and the thickness accuracy of the resin film.
  • an unstretched resin film is first formed from the dope according to this embodiment, and then uniaxial or biaxial stretching is performed.
  • a stretching operation is appropriately performed as the film formation and solvent degassing processes progress. This makes it possible to produce a stretched film (uniaxially or biaxially stretched film). Stretching during film formation and stretching after film formation may be appropriately combined.
  • the stretching ratio of the stretched film is not particularly limited and is appropriately determined depending on the mechanical strength, surface properties, thickness accuracy, etc. of the stretched film to be produced. Although it also depends on the stretching temperature, the stretching ratio is generally preferably selected in the range of 1.1 to 5 times, more preferably in the range of 1.3 to 4 times, and even more preferably in the range of 1.5 to 3 times. If the stretching ratio is within the above range, it tends to be possible to significantly improve the mechanical properties of the film, such as the elongation rate, tear propagation strength, and fatigue resistance.
  • the resin film according to the present embodiment can be used for various applications such as transportation equipment, solar cell components, civil engineering and construction components, daily necessities, electrical and electronic devices, optical components, and medical supplies.
  • the resin film according to the present embodiment has excellent heat resistance and optical properties, and can be suitably used for optical applications.
  • optical applications include optical films such as front panels (cover windows) of various display devices, diffusion plates, polarizer protective films, polarizing plate protective films, retardation films, light diffusion films, and optically isotropic films.
  • the resin film according to this embodiment can be suitably used as a polarizer protective film or a front panel (cover window) of a display device.
  • a functional coating layer such as a primer layer or a hard coat layer may be formed on at least one main surface of the resin film as necessary.
  • the resin film according to this embodiment is used as a polarizer protective film, the resin film according to this embodiment is laminated with a polarizer to form a polarizing plate.
  • the polarizer is not particularly limited, and any conventionally known polarizer can be used. This polarizing plate is used in display devices such as liquid crystal display devices and organic EL display devices.
  • Average particle size of acrylic crosslinked particles The average particle size was measured in the form of latex using a Hitachi High-Technologies Corporation U-5100 ratio beam spectrophotometer as a measuring device, and was determined using light scattering at a wavelength of 546 nm.
  • the mixture was dried under the same conditions as above to recover the dried free polymer and the dried methanol soluble component.
  • the weight average molecular weight (Mw), number average molecular weight (Mn), and the ratio of weight average molecular weight to number average molecular weight (Mw/Mn), which is an index of molecular weight distribution, of the methacrylic resin were calculated by a standard polystyrene conversion method using gel permeation chromatography (GPC). Specifically, the analysis was performed using a sample solution prepared by dissolving 40 mg of methacrylic resin in 2 mL of chloroform with the following apparatus and conditions.
  • Terminal double bond amount As a pretreatment, the methacrylic resin was dissolved in methylene chloride, and the solution was dropped into methanol to precipitate and purify the resin. The precipitated resin was collected by suction filtration, dried, and subjected to analysis. A solution was prepared by dissolving 20 mg of the dried methacrylic resin in 0.6 to 0.7 mL of deuterated chloroform, and 1 H-NMR was measured using a nuclear magnetic resonance device (AVANCE NEO 700 MHz, manufactured by Bruker).
  • AVANCE NEO 700 MHz manufactured by Bruker
  • the measurement temperature was 20°C, the number of accumulations was 8,192, and the measurement was performed while erasing the methoxy group-derived peak of the methacrylic resin (3.60 ppm, the value when the chemical shift of the solvent peak was 7.26 ppm) using the Excitation Sculpting (ES) method, which is a type of solvent elimination method.
  • ES Excitation Sculpting
  • Residual rate of chain transfer agent The residual rate of the chain transfer agent in the methacrylic resin was quantified using a gas chromatograph (Agilent Technologies, 7890B).
  • DB-1 (Agilent Technologies, film thickness 0.8 ⁇ m ⁇ inner diameter 0.20 mm ⁇ length 30 m) was used as the analytical column, the inlet temperature was 150 ° C., and the detector temperature was 320 ° C.
  • the column temperature was raised from 35 ° C. to 210 ° C. at a heating rate of 30 ° C. / min, then raised from 210 ° C. to 260 ° C. at a heating rate of 10 ° C. / min, and further raised from 260 ° C. to 320 ° C.
  • Dope Viscosity Methacrylic resin was dissolved in a mixed solvent consisting of 93% by mass of methylene chloride and 7% by mass of ethanol to prepare dopes with solid content (SC) of 10% by mass (Examples 1 and 2), 12% by mass (Example 3), or 25% by mass (Comparative Examples 1 and 2).
  • the dope viscosity was measured using a B-type viscometer (BMII, manufactured by Toki Sangyo Co., Ltd.). The temperature of the measurement sample was adjusted to 23° C., and the indicated value was read at 30 rpm (12 rpm for Examples 1 and 3) using a No. 2 rotor.
  • the glass transition temperature of the resin film was measured by the following method.
  • the resin was heat-treated using a thermogravimetric analyzer (STA7200, Hitachi High-Tech Science Co., Ltd.) for the purpose of removing residual monomers and decomposition products of the polymerization initiator in the methacrylic resin.
  • the resin was heat-treated under the conditions of increasing the temperature from 40°C to 190°C at a rate of 10°C/min under a nitrogen flow of 200mL/min, and maintaining the temperature at 190°C for 2.0 to 2.5 minutes.
  • the glass transition temperature (Tg) of the methacrylic resin after the heat treatment was measured using a differential scanning calorimeter (DSC; DSC7000X, Hitachi High-Tech Science Co., Ltd.). First, under a nitrogen flow rate of 40 mL/min, the sample was heated a first time from 40° C. to 160° C. at a heating rate of 10° C./min, cooled to 40° C., and then heated a second time from 40° C. to 160° C. at a heating rate of 10° C./min, under conditions of a DSC measurement.
  • DSC differential scanning calorimeter
  • the midpoint glass transition temperature (the temperature at the point where the curve of the stepwise change of the glass transition intersects with a straight line equidistant in the vertical direction from both the straight line obtained by extrapolating the baseline before the inflection point to the high temperature side and the straight line obtained by extrapolating the baseline after the inflection point to the low temperature side) was read from the DSC curve measured during the second heating.
  • the 5% weight loss temperature (Td5) of the resin film and the acrylic crosslinked particle powder was measured using a thermogravimetric analyzer (STA7200, manufactured by Hitachi High-Tech Science Co., Ltd.). First, the first heating was performed from 40°C to 190°C at a heating rate of 10°C/min under a nitrogen flow of 200mL/min, then cooled to 40°C, and then the second heating was performed from 40°C to 500°C at a heating rate of 10°C/min. The temperature at which the weight of the sample decreased to 95% of the weight at the start of the second heating, as determined from the thermogravimetric (TG) curve measured during the second heating, was taken as the 5% weight loss temperature (Td5).
  • TG thermogravimetric
  • Retention heat stability The retention heat stability of the resin film was evaluated using a thermogravimetric analyzer (STA7200, manufactured by Hitachi High-Tech Science Co., Ltd.). First, the sample was heated from 40°C to 190°C at a heating rate of 10°C/min under a nitrogen flow of 200mL/min, and then heat-treated under the condition of holding at 190°C for 2.0 to 2.5 minutes. Next, the sample was cooled to 40°C, and then heated from 40°C to 280°C at a heating rate of 10°C/min, and the mass change was recorded under the condition of holding at 280°C for 30 minutes.
  • STA7200 thermogravimetric analyzer
  • the mass when the sample temperature reached 280°C was X0
  • the mass when held at 280°C for 15 minutes was X15 .
  • the retention heat stability was evaluated from the mass loss rate calculated by the formula: [( X0 - X15 )/ X0 ]x100.
  • Yellowness index (YI) The yellowness index (YI) of the stretched resin film was measured using a spectrophotometer (SC-P, manufactured by Suga Test Instruments Co., Ltd.) in accordance with JIS K7373. The obtained results were converted into a film thickness equivalent to 40 ⁇ m.
  • MIT flexural resistance test The stretched resin film was cut into a strip of 15 mm width to prepare a test piece.
  • the test piece was set in a MIT soft fatigue resistance tester model D manufactured by Toyo Seiki Co., Ltd. in a direction in which a crease was formed perpendicular to the stretching direction.
  • the test was performed with a test load of 1.96 N, a speed of 175 times/min, a bending clamp curvature radius R of 0.38 mm, and a bending angle of 135° to the left and right, and the number of reciprocal bendings at which the test piece broke was obtained. Five measurements were performed, and the arithmetic average value was taken as the MIT reciprocal bending number.
  • MMA methyl methacrylate
  • n-OM n-octyl mercaptan
  • V-601 2,2'-azobis(isobutyrate)dimethyl
  • the inside temperature was set to 80°C, and 26% of (I) shown in Table 1 was added to the polymerization machine in one go, followed by adding 0.06 parts by mass of sodium formaldehyde sulfoxylate, 0.006 parts by mass of 2-sodium ethylenediaminetetraacetate, 0.001 parts by mass of ferrous sulfate, and 0.02 parts by mass of t-butyl hydroperoxide, and 15 minutes later, 0.03 parts by mass of t-butyl hydroperoxide was added, and polymerization was continued for another 15 minutes.
  • (I) shown in Table 1 was added to the polymerization machine in one go, followed by adding 0.06 parts by mass of sodium formaldehyde sulfoxylate, 0.006 parts by mass of 2-sodium ethylenediaminetetraacetate, 0.001 parts by mass of ferrous sulfate, and 0.02 parts by mass of t-butyl hydroperoxide, and 15 minutes later, 0.03 parts by mass of
  • Example 1 93% by mass of methylene chloride was put into a screw tube container, and while stirring with a magnetic stirrer, 10 parts by mass of the powder of the acrylic crosslinked particles (1) was gradually added, and the resulting dispersion of the acrylic crosslinked particles was dispersed for 10 minutes at 8000 rpm using a homogenizer (Ultra Turrax T25, manufactured by IKA Co., Ltd.), and then 7% by mass of ethanol was added to the dispersion. Then, while stirring, 90 parts by mass of methacrylic resin (resin A) was gradually added, and the mixture was stirred until completely dissolved, to prepare a resin dope with a solid content of 12%.
  • a homogenizer Ultra Turrax T25, manufactured by IKA Co., Ltd.
  • the above dope was cast on a glass substrate and coated with an applicator to form a uniform film. At that time, the clearance was adjusted so that the thickness after drying was about 80 ⁇ m. After coating, the dope film was dried in an oven at 40 ° C for 1 hour, and then the obtained resin film was peeled off from the glass substrate. The surface that was attached to the glass substrate was designated as surface B, and the other surface was designated as surface A. Thereafter, the resin film was fixed on a stainless steel frame and dried in an oven at 140 ° C for 2 hours to remove the remaining solvent, and a resin film was obtained. Furthermore, the obtained resin film was subjected to width-fixed uniaxial stretching at 145 ° C. The stretching ratio was set to 2 times, and a stretched resin film (stretched film) was obtained. Table 2 shows each physical property.
  • Example 2 A resin film and a stretched film were obtained in the same manner as in Example 1, except that 20 parts by mass of the acrylic crosslinked particles (1) and 80 parts by mass of the methacrylic resin (resin A) were used instead of 10 parts by mass of the acrylic crosslinked particles (1) and 90 parts by mass of the methacrylic resin (resin A) in Example 1.
  • the physical properties are shown in Table 2.
  • Example 3 A resin film and a stretched film were obtained in the same manner as in Example 1, except that 20 parts by mass of acrylic crosslinked particles (2) and 80 parts by mass of methacrylic resin (resin A) were used instead of 10 parts by mass of acrylic crosslinked particles (1) and 90 parts by mass of methacrylic resin (resin A) in Example 1.
  • the physical properties are shown in Table 2.
  • the resin film was fixed on a stainless steel frame and dried in an oven at 140 ° C for 2 hours to remove the remaining solvent, and a resin film was obtained. Furthermore, the obtained resin film was subjected to width-fixed uniaxial stretching at 145 ° C. The stretching ratio was set to 2 times, and a stretched resin film (stretched film) was obtained. Table 2 shows each physical property. Compared with Examples 1 to 3, the number of MIT round-trip bending was small, and the bending resistance was low.
  • the physical properties are shown in Table 2. Compared with Examples 1 to 3, the glass transition temperature was low, the heat resistance was insufficient, and the number of MIT reciprocating bending cycles was very small, resulting in very low bending resistance.
  • Example 3 A resin film and a stretched film were obtained in the same manner as in Example 1, except that 20 parts by mass of acrylic crosslinked particles (1) and 80 parts by mass of methacrylic resin (resin B) were used instead of 10 parts by mass of acrylic crosslinked particles (1) and 90 parts by mass of methacrylic resin (resin A) in Example 1.
  • the physical properties are shown in Table 2. Compared with Examples 1 to 3, the glass transition temperature was low and heat resistance was insufficient, the number of MIT reciprocating folds was small and bending resistance was low, and the total light transmittance was below 90%, resulting in low transparency.
  • Example 4 A resin film and a stretched film were obtained in the same manner as in Example 1, except that 20 parts by mass of acrylic crosslinked particles (1) and 80 parts by mass of methacrylic resin (resin C) (Parapet HR-S, manufactured by Kuraray Co., Ltd.) were used instead of 10 parts by mass of acrylic crosslinked particles (1) and 90 parts by mass of methacrylic resin (resin A) in Example 1.
  • the physical properties are shown in Table 2. Compared with Examples 1 to 3, the glass transition temperature was low, the heat resistance was insufficient, and the total light transmittance was below 91%, resulting in low transparency.

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Abstract

L'invention concerne une composition de résine contenant : une résine méthacrylique ayant une syndiotacticité de triade de 55 % ou plus et un poids moléculaire moyen en poids (Mw) de 500 000 ou plus telle que mesurée par chromatographie par perméation de gel (CPG) ; et des particules réticulées acryliques. L'invention concerne également un procédé de production de la composition de résine, un dopant pour produire un film contenant la composition de résine, un film de résine contenant la composition de résine, et une plaque de polarisation et un dispositif d'affichage utilisant le film de résine.
PCT/JP2024/042451 2023-12-06 2024-12-02 Composition de résine et son procédé de production Pending WO2025121272A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016080124A1 (fr) * 2014-11-19 2016-05-26 株式会社クラレ Film acrylique
JP2016188314A (ja) * 2015-03-30 2016-11-04 株式会社日本触媒 樹脂組成物、該樹脂組成物で形成されたフィルム、該フィルムを備えた偏光板及び該偏光板を備えた画像表示装置
JP2016188313A (ja) * 2015-03-30 2016-11-04 株式会社日本触媒 アクリル樹脂組成物、該樹脂組成物で形成されたフィルム、該フィルムを備えた偏光板及び該偏光板を備えた画像表示装置
JP2018002863A (ja) * 2016-06-30 2018-01-11 株式会社クラレ 耐衝撃性改良剤、熱可塑性樹脂組成物およびフィルム
WO2023238886A1 (fr) * 2022-06-07 2023-12-14 株式会社カネカ Résine méthacrylique ainsi que procédé de fabrication de celle-ci, composition de résine, dopant, et film de résine

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016080124A1 (fr) * 2014-11-19 2016-05-26 株式会社クラレ Film acrylique
JP2016188314A (ja) * 2015-03-30 2016-11-04 株式会社日本触媒 樹脂組成物、該樹脂組成物で形成されたフィルム、該フィルムを備えた偏光板及び該偏光板を備えた画像表示装置
JP2016188313A (ja) * 2015-03-30 2016-11-04 株式会社日本触媒 アクリル樹脂組成物、該樹脂組成物で形成されたフィルム、該フィルムを備えた偏光板及び該偏光板を備えた画像表示装置
JP2018002863A (ja) * 2016-06-30 2018-01-11 株式会社クラレ 耐衝撃性改良剤、熱可塑性樹脂組成物およびフィルム
WO2023238886A1 (fr) * 2022-06-07 2023-12-14 株式会社カネカ Résine méthacrylique ainsi que procédé de fabrication de celle-ci, composition de résine, dopant, et film de résine

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