Classifications

• • 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
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D207/00—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom
  • C07D207/02—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom
  • C07D207/44—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having three double bonds between ring members or between ring members and non-ring members
  • C07D207/444—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having three double bonds between ring members or between ring members and non-ring members having two doubly-bound oxygen atoms directly attached in positions 2 and 5
  • C07D207/448—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having three double bonds between ring members or between ring members and non-ring members having two doubly-bound oxygen atoms directly attached in positions 2 and 5 with only hydrogen atoms or radicals containing only hydrogen and carbon atoms directly attached to other ring carbon atoms, e.g. maleimide
• • 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
  • C08F220/00—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 a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/10—Esters
  • C08F220/12—Esters of monohydric alcohols or phenols
  • C08F220/14—Methyl esters, e.g. methyl (meth)acrylate
• • 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
  • C08F222/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical and containing at least one other carboxyl radical in the molecule; Salts, anhydrides, esters, amides, imides, or nitriles thereof
• • 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
  • C08L33/24—Homopolymers or copolymers of amides or imides
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L35/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical, and containing at least one other carboxyl radical in the molecule, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
  • C08L35/06—Copolymers with vinyl aromatic monomers

Definitions

• This disclosure relates to a methacrylic resin composition and an optical component.
• Methacrylic resins have excellent transparency, surface hardness, and so forth, and only display a small degree of the optical property of birefringence. For these reasons, methacrylic resins have been attracting attention in recent years as optical resins for various optical materials, and in particular for optical films, and the market for such methacrylic resins is expanding significantly.
• compositions containing a methacrylic resin having a cyclic structure-containing main chain are known to have excellent performance in terms of both heat resistance and optical properties.
• the demand for such compositions has increased rapidly, focused primarily on applications in relatively thin optical films, such as polarizer protective films and retardation films of image display devices.
• methacrylic resin-containing compositions are also being investigated with respect to applications in relatively thick molded products, such as light guide plates, display front plates, and so forth for use in displays (for example, liquid-crystal displays and automotive panel displays). These applications exploit the high heat resistance temperature and excellent optical properties of methacrylic resin-containing compositions.
• the formation of protrusions and recesses at both sides of a film by a technique referred to as knurling is a known technique for preventing the occurrence of various defects at the surface of the film during long-term storage or transport of the film as a roll-shaped product.
• knurling refers to the formation of fine protrusions and recesses that may also be referred to as embossing.
• embossing By performing knurling, roll shifting and roll looseness can be prevented, and the occurrence of various defects at the surface of a film can be inhibited by preventing film-on-film adhesion.
• the effect of inhibiting the occurrence of various defects through knurling is dependent on the height of knurling protrusions and the contact area between the knurling protrusions and a film surface wound in an overlapping manner on the knurling protrusions.
• PTL 1 discloses a method of producing an optical film having a knurled section in which the height of protrusions is 25 ⁇ m or less and is less than 20% of the height of knurling teeth.
• PTL 2 proposes a film for which, in the case of a roll-shaped product obtained by winding up an optical film, the area of a knurled section of the film and the area ratio of deformed portions per area of the knurled section are within specific ranges.
• PTL 3 proposes a method for embossing a film formed from a rubber-containing acrylic resin using an embossing die.
• the proposed method uses an acrylic resin having an elongation at rupture of 100% or more and a storage modulus, which is one type of dynamic viscoelasticity property, that is within a specific range in a temperature range of 25° C. to 50° C. higher than the heat distortion temperature.
• a resin composition composed mainly of a methacrylic resin having a cyclic structure-containing main chain is known to have a relatively low tensile elongation at break of a few percent to several tens of percent, and also has a high heat distortion temperature. This necessitates a rather high embossing temperature and makes it difficult to adopt the technique in PTL 3 as disclosed.
• PTL 4 discloses a stretched film obtained by using an acrylic resin having a cyclic structure-containing main chain and a high toughness amorphous resin (for example, a polycarbonate resin) that is not an acrylic resin having a cyclic structure-containing main chain to produce a film in a manner such that an edge section of the film is formed from the amorphous resin that is not an acrylic resin, and then performing knurling of the edge section formed from the amorphous resin that is not an acrylic resin.
• a high toughness amorphous resin for example, a polycarbonate resin
• a molded product for example, an optical film
• a molded product that is formed from a composition containing a methacrylic resin having a cyclic structure-containing main chain
• a molded product for example, an optical film
• a knurled section having excellent quality and that is compatible with an increase in production (line) speed associated with progress toward a higher production line speed, thinner film thickness, and commercialization as an elongated roll in order to expand the applications thereof.
• an objective of this disclosure is to provide a methacrylic resin composition with which a molded product having excellent surface shaping properties can be obtained and with which a decrease in quality associated with long-term storage or transport can be inhibited.
• the inventors conducted diligent investigation to achieve the objective set forth above. As a result, the inventors reached the opinion that, in order to enable stable formation of a protrusion/recess shape at the surface of a molded product, such as a film, by knurling or the like, even in a situation in which the line speed is changed, and in order to enable stable expression of a knurling effect without deformation or damage during transport or long-term storage after subsequent production of a roll-shaped product, it is important that resin properties in a temperature region below the glass transition temperature of a methacrylic resin composition that is used are taken into account in resin design.
• the inventors discovered that the stereoregularity of methacrylic acid ester monomer-derived structural units in a methacrylic resin having a cyclic structure-containing main chain is influenced not only by the polymerization temperature during radical polymerization in production of the resin, as is conventionally known, but is also strongly influenced by the type and content of a copolymerization monomer, other than a methacrylic acid ester monomer, that is used to introduce the cyclic structure, and other polymerization conditions such as the addition method of copolymerization monomers.
• the inventors discovered that the problems set forth above can be solved by controlling the stereoregularity of methacrylic acid ester monomer-derived structural units in a methacrylic resin in order to control resin properties in a temperature region below the glass transition temperature of the methacrylic resin, and by additionally controlling the amount of low molecular weight components in the resin composition, which is thought to influence release properties in knurling.
• the disclosed products were completed based on the discoveries set forth above.
• a methacrylic resin composition comprising
• a methacrylic resin including a structural unit (X) having a cyclic structure-containing main chain, the structural unit (X) being at least one selected from the group consisting of an N-substituted maleimide monomer-derived structural unit, a glutarimide-based structural unit, and a lactone ring structural unit, wherein
• the methacrylic resin composition has a Vicat softening temperature of 120° C. to 160° C.
• a ratio (S/H) of integrated intensity (S) of a syndiotactic fraction (rr) relative to integrated intensity (H) of a heterotactic fraction (mr), as determined by 1 H-NMR measurement is 1.20 to 1.50, and
• methanol-soluble content is contained in an amount of 5 mass % or less relative to 100 mass %, in total, of the methanol-soluble content and methanol-insoluble content.
• the structural unit (X) includes an N-substituted maleimide monomer-derived structural unit, and
• the N-substituted maleimide monomer-derived structural unit has a content of 5 mass % to 40 mass % relative to 100 mass % of the methacrylic resin.
• the structural unit (X) includes a lactone ring structural unit
• the lactone ring structural unit has a content of 5 mass % to 40 mass % relative to 100 mass % of the methacrylic resin.
• the optical film has an embossed section on at least part of either or both of a front surface and a rear surface.
• a methacrylic resin composition according to the present embodiment contains a methacrylic resin, and may contain other thermoplastic resins and additives as necessary.
• the methacrylic resin contained in the methacrylic resin composition according to the present embodiment includes a structural unit (X) having a cyclic structure-containing main chain and a methacrylic acid ester monomer-derived structural unit.
• the structural unit (X) is at least one selected from the group consisting of an N-substituted maleimide monomer-derived structural unit, a glutarimide-based structural unit, and a lactone ring structural unit.
• Examples of methods that may be used to produce the methacrylic resin including the structural unit (X) having a cyclic structure-containing main chain include any polymerization method from among bulk polymerization, solution polymerization, suspension polymerization, precipitation polymerization, and emulsion polymerization.
• the polymerization process in the production method according to the present embodiment may, for example, be a batch polymerization process, a semi-batch polymerization process, or a continuous polymerization process.
• monomers are preferably polymerized by radical polymerization.
• the following description relates, in particular, to each structural unit in the methacrylic resin including the structural unit (X) having a cyclic structure-containing main chain, the methacrylic resin including these structural units, and the production method of this methacrylic resin.
• the methacrylic acid ester monomer-derived structural unit is, for example, formed from a monomer selected from the following methacrylic acid esters.
• methacrylic acid esters that can be used include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, cyclopentyl methacrylate, cyclohexyl methacrylate, cyclooctyl methacrylate, tricyclodecyl methacrylate, dicyclooctyl methacrylate, tricyclododecyl methacrylate, isobornyl methacrylate, phenyl methacrylate, benzyl methacrylate, 1-phenylethyl methacrylate, 2-phenoxye
• One of these monomers may be used individually, or two or more of these monomers may be used together.
• methacrylic acid esters methyl methacrylate and benzyl methacrylate are preferable in terms of providing the resultant methacrylic resin with excellent transparency and weather resistance.
• the methacrylic resin may include just one type of methacrylic acid ester monomer-derived structural unit or may include two or more types of methacrylic acid ester monomer-derived structural units.
• the following description relates, in particular, to the structural unit (X) having a cyclic structure-containing main chain in the methacrylic resin that includes the structural unit (X), the methacrylic resin including the structural unit (X), and the production method of this methacrylic resin.
• the N-substituted maleimide monomer-derived structural unit may be formed from at least one selected from a monomer unit represented by the following formula (1) and/or a monomer unit represented by the following formula (2), and is preferably formed from both a monomer represented by the following formula (1) and a monomer represented by the following formula (2).
• R 1 represents an arylalkyl group having a carbon number of 7 to 14 or an aryl group having a carbon number of 6 to 14, and R 2 and R 3 each represent, independently of one another, a hydrogen atom, an alkyl group having a carbon number of 1 to 12, or an aryl group having a carbon number of 6 to 14.
• R 2 may include a halogen as a substituent.
• R 1 may be substituted with a substituent such as a halogen atom, an alkyl group having carbon number of 1 to 6, an alkoxy group having a carbon number of 1 to 6, a nitro group, or a benzyl group.
• a substituent such as a halogen atom, an alkyl group having carbon number of 1 to 6, an alkoxy group having a carbon number of 1 to 6, a nitro group, or a benzyl group.
• R 4 represents a hydrogen atom, a cycloalkyl group having a carbon number of 3 to 12, or an alkyl group having a carbon number of 1 to 12, and R 5 and R 6 each represent, independently of one another, a hydrogen atom, an alkyl group having a carbon number of 1 to 12, or an aryl group having a carbon number of 6 to 14.
• Examples of monomers represented by formula (1) include N-phenylmaleimide, N-benzylmaleimide, N-(2-chlorophenyl)maleimide, N-(4-chlorophenyl)maleimide, N-(4-bromophenyl)maleimide, N-(2-methylphenyl)maleimide, N-(2-ethylphenyl)maleimide, N-(2-methoxyphenyl)maleimide, N-(2-nitrophenyl)maleimide, N-(2,4,6-trimethylphenyl)maleimide, N-(4-benzylphenyl)maleimide, N-(2,4,6-tribromophenyl)maleimide, N-naphthylmaleimide, N-anthracenylmaleimide, 3-methyl-1-phenyl-1H-pyrrole-2,5-dione, 3,4-dimethyl-1-phenyl-1H-pyrrole-2,5-dione,
• N-phenylmaleimide and N-benzylmaleimide are preferable in terms of providing the resultant methacrylic resin with excellent heat resistance and optical properties such as birefringence.
• One of these monomers may be used individually, or two or more of these monomers may be used together.
• Examples of monomers represented by formula (2) include N-methylmaleimide, N-ethylmaleimide, N-n-propylmaleimide, N-isopropylmaleimide, N-n-butylmaleimide, N-isobutylmaleimide, N-s-butylmaleimide, N-t-butylmaleimide, N-n-pentylmaleimide, N-n-hexylmaleimide, N-n-heptylmaleimide, N-n-octylmaleimide, N-laurylmaleimide, N-cyclopentylmaleimide, N-cyclohexylmaleimide, 1-cyclohexyl-3-methyl-1H-pyrrole-2,5-dione, 1-cyclohexyl-3,4-dimethyl-1H-pyrrole-2,5-dione, 1-cyclohexyl-3-phenyl-1H-pyrrole-2,5-dione, and 1-cycl
• N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, and N-cyclohexylmaleimide are preferable in terms of providing the resultant methacrylic resin with excellent weather resistance, and N-cyclohexylmaleimide is particularly preferable in terms of providing excellent low water absorbency demanded of optical materials in recent years.
• One of these monomers may be used individually, or two or more of these monomers may be used together.
• the methacrylic resin according to the present embodiment is particularly preferably obtained using a monomer represented by formula (1) and a monomer represented by formula (2), in combination, in order to exhibit a high level of control on birefringence properties.
• the content (B1) of a structural unit derived from the monomer represented by formula (1) in terms of a molar ratio (B1/B2) relative to the content (B2) of a structural unit derived from the monomer represented by formula (2), is preferably greater than 0 and no greater than 15, and more preferably greater than 0 and no greater than 10.
• the methacrylic resin according to the present embodiment can display good heat resistance and good photoelastic properties while maintaining transparency, and without yellowing or loss of environmental resistance.
• the content of the N-substituted maleimide monomer-derived structural unit is not specifically limited so long as the resultant composition has a Vicat softening point (described further below) and an S/H ratio (described below) satisfying ranges according to the present embodiment.
• the content of the N-substituted maleimide monomer-derived structural unit relative to 100 mass % of the methacrylic resin is preferably 5 mass % to 40 mass %, and more preferably 5 mass % to 35 mass %.
• the content of the N-substituted maleimide monomer-derived structural unit is within any of the ranges set forth above, a more adequate enhancement effect can be achieved with respect to heat resistance of the methacrylic resin, and a more preferable enhancement effect can also be achieved with respect to weather resistance, low water absorbency, and optical properties of the methacrylic resin.
• Restricting the content of the N-substituted maleimide monomer-derived structural unit to 40 mass % or less is effective for preventing a decrease in physical properties of the methacrylic resin caused by a large amount of monomer remaining unreacted due to reduced reactivity of monomer components in the polymerization reaction.
• the methacrylic resin according to the present embodiment that includes the N-substituted maleimide monomer-derived structural unit may further include structural units derived from other monomers that are copolymerizable with the methacrylic acid ester monomer and the N-substituted maleimide monomer to the extent that the objectives of the present disclosure are not impeded.
• Examples of other copolymerizable monomers that can be used include aromatic vinyls; unsaturated nitriles; acrylic acid esters including a cyclohexyl group, a benzyl group, or an alkyl group having a carbon number of 1 to 18; glycidyl compounds; and unsaturated carboxylic acids.
• aromatic vinyls that can be used include styrene, ⁇ -methylstyrene, and divinylbenzene.
• Examples of unsaturated nitriles that can be used include acrylonitrile, methacrylonitrile, and ethacrylonitrile.
• acrylic acid esters examples include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, and butyl acrylate.
• glycidyl compounds examples include glycidyl acrylate and allyl glycidyl ether.
• unsaturated carboxylic acids examples include acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid, and half-esterified products and anhydrides thereof.
• the methacrylic resin may include just one type of structural unit derived from another copolymerizable monomer, or may include two or more types of structural units derived from other copolymerizable monomers.
• the content of structural units derived from such other copolymerizable monomers relative to 100 mass % of the methacrylic resin is preferably 0 mass % to 10 mass %, more preferably 0 mass % to 9 mass %, and even more preferably 0 mass % to 8 mass %.
• the content of structural units derived from other monomers is preferable for the content of structural units derived from other monomers to be within any of the ranges set forth above in terms that molding properties and mechanical properties of the resin can be enhanced without losing the intended effects of introducing a cyclic structure into the main chain.
• the method used to produce the methacrylic resin including the N-substituted maleimide monomer-derived structural unit in the main chain thereof may be any polymerization method from among bulk polymerization, solution polymerization, suspension polymerization, precipitation polymerization, and emulsion polymerization, is preferably suspension polymerization, bulk polymerization, or solution polymerization, and is more preferably solution polymerization.
• the polymerization process in the production method according to the present embodiment may, for example, be a batch polymerization process, a semi-batch polymerization process, or a continuous polymerization process.
• the monomers are preferably polymerized by radical polymerization.
• the following provides a specific description of production by radical polymerization using solution polymerization as one example of a method of producing the methacrylic resin including the N-substituted maleimide monomer-derived structural unit (hereinafter, also referred to as a “maleimide copolymer”).
• a so-called “semi-batch polymerization method” in which a portion of the monomers is charged into a reactor prior to the start of polymerization, a polymerization initiator is added to initiate polymerization, and then a remaining portion of the monomers is subsequently fed into the reactor can be preferably adopted in the present embodiment. Adoption of this method tends to facilitate control of the molecular weight distribution and chemical composition distribution of the resultant polymer.
• a ratio of the amount of the monomers used in initial charging (start of polymerization) and the amount of the monomers added after the start of polymerization (amount of monomers at start of polymerization:amount of monomers added after start of polymerization), in terms of mass ratio, is preferably 1:9 to 8:2, more preferably 2:8 to 7.5:2.5, and even more preferably 3:7 to 5:5.
• the mixing composition of monomers in the initial charge can be selected as appropriate in consideration of copolymerization reactivity of each of the monomers used in copolymerization, which tends to facilitate control of the chemical composition distribution of the resultant polymer.
• polymerization solvents that can be used include aromatic hydrocarbons such as toluene, xylene, ethylbenzene, and isopropylbenzene; ketones such as methyl isobutyl ketone, butyl cellosolve, methyl ethyl ketone, and cyclohexanone; and polar solvents such as dimethylformamide and 2-methylpyrrolidone.
• aromatic hydrocarbons such as toluene, xylene, ethylbenzene, and isopropylbenzene
• ketones such as methyl isobutyl ketone, butyl cellosolve, methyl ethyl ketone, and cyclohexanone
• polar solvents such as dimethylformamide and 2-methylpyrrolidone.
• an alcohol such as methanol, ethanol, or isopropanol may be used in combination as the polymerization solvent to the extent that dissolution of the polymerized product during polymerization is not impaired.
• the amount of solvent used in polymerization is preferably 10 parts by mass to 200 parts by mass.
• the amount of solvent is more preferably 25 parts by mass to 200 parts by mass, further preferably 50 parts by mass to 200 parts by mass, and even more preferably 50 parts by mass to 150 parts by mass.
• the polymerization temperature is preferably 50° C. to 200° C., and more preferably 60° C. to 180° C. from a viewpoint of productivity. Moreover, from a viewpoint of stereoregularity of methyl methacrylate monomer-derived structural units, the polymerization temperature is preferably 70° C. to 130° C., and more preferably 80° C. to 120° C.
• the polymerization time is preferably 0.5 hours to 10 hours, and more preferably 1 hour to 8 hours from a viewpoint of productivity and so forth.
• polymerization may be performed with addition of a polymerization initiator and/or a chain transfer agent as necessary.
• the polymerization initiator may be any initiator commonly used in radical polymerization and examples thereof include organic peroxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxy isopropyl carbonate, t-amyl peroxy-2-ethylhexanoate, t-amyl peroxyisononanoate, and 1,1-di(t-butylperoxy)cyclohexane; and azo compounds such as 2,2′-azobis(isobutyronitrile), 1,1′-azobis(cyclohexanecarbonitrile), 2,2′-azobis(2,4-dimethylvaleronitrile), and dimethyl-2,2′-azobisisobutyrate.
• organic peroxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide
• One of these polymerization initiators may be used individually, or two or more of these polymerization initiators may be used together.
• the additive amount of the polymerization initiator when the total amount of monomers used in polymerization is taken to be 100 parts by mass may be 0.01 parts by mass to 1 part by mass, and is preferably 0.05 parts by mass to 0.5 parts by mass.
• These polymerization initiators may be added at any stage so long as the polymerization reaction is in progress.
• the type of initiator, amount of initiator, polymerization temperature, and so forth are appropriately selected such that the total amount of radicals generated by the polymerization initiator as a proportion relative to the total amount of unreacted monomer remaining in the reaction system is constantly no greater than a certain value.
• Adoption of this method can suppress the amount of oligomer or low molecular weight product produced in a latter stage of polymerization and enables improvement of polymerization stability by inhibiting overheating during polymerization.
• the chain transfer agent may be a chain transfer agent that is commonly used in radical polymerization and examples thereof include mercaptan compounds such as n-butyl mercaptan, n-octyl mercaptan, n-decyl mercaptan, n-dodecyl mercaptan, and 2-ethylhexyl thioglycolate; halogen compounds such as carbon tetrachloride, methylene chloride, and bromoform; and unsaturated hydrocarbon compounds such as ⁇ -methylstyrene dimer, ⁇ -terpinene, dipentene, and terpinolene.
• mercaptan compounds such as n-butyl mercaptan, n-octyl mercaptan, n-decyl mercaptan, n-dodecyl mercaptan, and 2-ethylhexyl thioglycolate
• One of these chain transfer agents may be used individually, or two or more of these chain transfer agents may be used together.
• chain transfer agents may be added at any stage, without any specific limitations, so long as the polymerization reaction is in progress.
• the additive amount of the chain transfer agent when the total amount of monomers used in polymerization is taken to be 100 parts by mass may be 0.01 parts by mass to 1 part by mass, and is preferably 0.05 parts by mass to 0.5 parts by mass.
• the concentration of dissolved oxygen is preferably 10 ppm or less.
• the concentration of dissolved oxygen can be measured, for example, using a dissolved oxygen (DO) meter B-505 (produced by Iijima Electronics Corporation).
• the method by which the concentration of dissolved oxygen is reduced may be selected as appropriate from methods such as a method in which an inert gas is bubbled into the polymerization solution; a method in which an operation of pressurizing the inside of a vessel containing the polymerization solution to approximately 0.2 MPa with an inert gas and then releasing the pressure is repeated prior to polymerization; and a method in which an inert gas is passed through a vessel containing the polymerization solution.
• a polymerized product is collected from the polymerization solution obtained through solution polymerization.
• methods that can be adopted include a method in which the polymerization solution is added into an excess of a poor solvent in which the polymerized product obtained through polymerization does not dissolve, such as a hydrocarbon solvent or an alcohol solvent, treatment (emulsifying dispersion) is subsequently performed using a homogenizer, and unreacted monomers are separated from the polymerization solution by pre-treatment such as liquid-liquid extraction or solid-liquid extraction; and a method in which the polymerization solvent and unreacted monomers are separated by a step referred to as a devolatilization step to collect the polymerized product.
• a poor solvent in which the polymerized product obtained through polymerization does not dissolve such as a hydrocarbon solvent or an alcohol solvent
• treatment emulsifying dispersion
• unreacted monomers are separated from the polymerization solution by pre-treatment such as liquid-liquid extraction or solid-liquid extraction
• a devolatilization step
• the devolatilization step is a step in which volatile content such as the polymerization solvent, residual monomers, and reaction by-products are removed under heated vacuum conditions.
• Examples of devices that can be used in the devolatilization step include devolatilization devices comprising a tubular heat exchanger and a devolatilization tank; thin film evaporators such as WIPRENE and EXEVA produced by Kobelco Eco-Solutions Co., Ltd., and Kontro and Diagonal-Blade Kontro produced by Hitachi, Ltd.; and vented extruders having sufficient residence time and surface area for displaying devolatilization capability.
• devolatilization devices comprising a tubular heat exchanger and a devolatilization tank
• thin film evaporators such as WIPRENE and EXEVA produced by Kobelco Eco-Solutions Co., Ltd., and Kontro and Diagonal-Blade Kontro produced by Hitachi, Ltd.
• vented extruders having sufficient residence time and surface area for displaying devolatilization capability.
• the treatment temperature in the devolatilization device is preferably 150° C. to 350° C., more preferably 170° C. to 300° C., and even more preferably 200° C. to 280° C.
• a temperature of 150° C. or higher is effective for preventing an excessive amount of residual volatile content.
• a temperature of 350° C. or lower reduces the risk of coloring or decomposition of the resultant methacrylic resin.
• the degree of vacuum in the devolatilization device may be 10 Torr to 500 Torr and, within this range, is preferably 10 Torr to 300 Torr.
• the degree of vacuum is 500 Torr or less, volatile content has a lower tendency to remain, and when the degree of vacuum is 10 Torr or more, industrial implementation is easier.
• the treatment time is selected as appropriate depending on the amount of residual volatile content and is preferably as short as possible in order to inhibit coloring or decomposition of the resultant methacrylic resin.
• the polymerized product collected through the devolatilization step is pelletized through a step referred to as a pelletization step.
• molten resin is extruded from a porous die as strands and is then pelletized by cold cutting, hot cutting in air, strand cutting in water, or under water cutting.
• the devolatilization step and the pelletization step may be combined.
• a composition is produced after mixing two or more types of methacrylic resins that include at least a structure derived from a monomer represented by formula (1) and a structure derived from a monomer represented by formula (2) as a framework, but differ in terms of weight average molecular weight and stereoregularity.
• the stereoregularity of a methacrylic resin is expressed by a ratio (S/H) of the integrated intensity (S) of a syndiotactic fraction (rr) relative to the integrated intensity (H) of a heterotactic fraction (mr) among methacrylic acid ester monomer-derived structural units of the methacrylic resin, as determined by 1 H-NMR measurement.
• the weight average molecular weight (Mw) of each of the methacrylic resins may be freely selected from a range of 70,000 to 800,000.
• the weight average molecular weight thereof is preferably 70,000 to 150,000, and more preferably 100,000 to 150,000.
• S/H ratio thereof used as an indicator of stereoregularity is preferably 1.10 to 1.40, and more preferably 1.15 to 1.35.
• the weight average molecular weight thereof is preferably 220,000 to 800,000, and more preferably 220,000 to 600,000.
• the S/H ratio thereof used as an indicator of stereoregularity is preferably 1.30 to 1.50, and more preferably 1.35 to 1.50.
• the mixing ratio of the low molecular weight component and the high molecular weight component is not specifically limited and can be appropriately selected from a range of 5 parts by mass to 95 parts by mass of the low molecular weight component and 95 parts by mass to 5 parts by mass of the high molecular weight component.
• a glutarimide-based structural unit according to the present embodiment is represented by the following general formula (3).
• R 7 and R 8 are each, independently of one another, hydrogen or a methyl group, and R 9 is hydrogen, a methyl group, a butyl group, or a cyclohexyl group, and more preferable that R 7 is a methyl group, R 8 is hydrogen, and R 9 is a methyl group.
• the methacrylic resin may include a single type of glutarimide-based structural unit or may include two or more types of glutarimide-based structural units.
• the content of the glutarimide-based structural unit is not specifically limited so long as the preferable ranges for the Vicat softening point (described below) and S/H ratio (described below) of a composition according to the present embodiment are satisfied.
• the content of the glutarimide-based structural unit relative to 100 mass % of the methacrylic resin is preferably 5 mass % to 70 mass %, and more preferably 5 mass % to 60 mass %.
• the content of the glutarimide-based structural unit is within any of the ranges set forth above in terms that a resin having good molding properties, heat resistance, and optical properties can be obtained.
• the methacrylic resin including the glutarimide-based structural unit may further include an aromatic vinyl monomer unit as necessary.
• aromatic vinyl monomers examples include, but are not specifically limited to, styrene and a-methylstyrene.
• the aromatic vinyl monomer is preferably styrene.
• the content of the aromatic vinyl unit in the methacrylic resin including the glutarimide-based structural unit is not specifically limited. However, the content of the aromatic vinyl unit relative to 100 mass % of the methacrylic resin is preferably 0 mass % to 10 mass %, more preferably 0 mass % to 9 mass %, and even more preferably 0 mass % to 8 mass %.
• the content of the aromatic vinyl unit prefferably be in any of the ranges set forth above in terms that both heat resistance and excellent photoelastic properties can be obtained.
• the methacrylic resin including the glutarimide-based structural unit in the main chain thereof may, for example, be a methacrylic resin including a glutarimide-based structural unit described in JP 2006-249202 A, JP 2007-009182 A, JP 2007-009191 A, JP 2011-186482 A, or WO 2012/114718 A1, and may be formed by a method described in the same publication.
• a lactone ring structural unit according to the present embodiment is preferably a six-membered ring since this provides excellent cyclic structure stability.
• the lactone ring structural unit that is a six-membered ring is, for example, particularly preferably a structure represented by the following general formula (4).
• R 10 , R 11 , and R 12 are each, independently of one another, a hydrogen atom or an organic residue having a carbon number of 1 to 20.
• Examples of the organic residue include saturated aliphatic hydrocarbon groups (alkyl groups, etc.) having a carbon number of 1 to 20 such as a methyl group, an ethyl group, and a propyl group; unsaturated aliphatic hydrocarbon groups (alkenyl groups, etc.) having a carbon number of 2 to 20 such as an ethenyl group and a propenyl group; aromatic hydrocarbon groups (aryl groups, etc.) having a carbon number of 6 to 20 such as a phenyl group and a naphthyl group; and groups in which at least one hydrogen atom of any of these saturated aliphatic hydrocarbon groups, unsaturated aliphatic hydrocarbon groups, and aromatic hydrocarbon groups is substituted with at least one group selected from the group consisting of a hydroxy group, a carboxyl group, an ether group, and an ester group.
• saturated aliphatic hydrocarbon groups alkyl groups, etc.
• unsaturated aliphatic hydrocarbon groups alkeny
• the lactone ring structure may be formed, for example, by copolymerizing an acrylic acid-based monomer having a hydroxy group and a methacrylic acid ester monomer such as methyl methacrylate to introduce a hydroxy group and an ester group or carboxyl group into the molecular chain, and then causing dealcoholization (esterification) or dehydration condensation (hereinafter, also referred to as a “cyclocondensation reaction”) between the hydroxy group and the ester group or carboxyl group.
• a methacrylic acid ester monomer such as methyl methacrylate
• acrylic acid-based monomers having a hydroxy group examples include 2-(hydroxymethyl)acrylic acid, 2-(hydroxyethyl)acrylic acid, alkyl 2-(hydroxymethyl)acrylates (for example, methyl 2-(hydroxymethyl)acrylate, ethyl 2-(hydroxymethyl)acrylate, isopropyl 2-(hydroxymethyl)acrylate, n-butyl 2-(hydroxymethyl)acrylate, and t-butyl 2-(hydroxymethyl)acrylate) and alkyl 2-(hydroxyethyl)acrylates.
• alkyl 2-(hydroxymethyl)acrylates for example, methyl 2-(hydroxymethyl)acrylate, ethyl 2-(hydroxymethyl)acrylate, isopropyl 2-(hydroxymethyl)acrylate, n-butyl 2-(hydroxymethyl)acrylate, and t-butyl 2-(hydroxymethyl)acrylate
• alkyl 2-(hydroxymethyl)acrylates for example, methyl 2-(hydroxymethyl)acrylate, ethyl 2-(hydroxymethyl)acrylate, isopropyl 2-(
• 2-(hydroxymethyl)acrylic acid and alkyl 2-(hydroxymethyl)acrylates that are monomers having a hydroxyallyl moiety are preferable, and methyl 2-(hydroxymethyl)acrylate and ethyl 2-(hydroxymethyl)acrylate are particularly preferable.
• the content of the lactone ring structural unit in the methacrylic resin including the lactone ring structural unit in the main chain thereof so long as the ranges for the Vicat softening point (described below) and the S/H ratio (described below) that are preferable for a composition according to the present embodiment are satisfied.
• the content of the lactone ring structural unit relative to 100 mass % of the methacrylic resin is preferably 5 mass % to 40 mass %, and more preferably 5 mass % to 35 mass %.
• the content of the lactone ring structure in the methacrylic resin can be determined by a method described in the previously mentioned patent literature.
• the methacrylic resin including the lactone ring structural unit may include constitutional units derived from other monomers that are copolymerizable with the above-described methacrylic acid ester monomer and acrylic acid-based monomer having a hydroxy group.
• Examples of such other copolymerizable monomers include monomers having a polymerizable double bond such as styrene, vinyltoluene, ⁇ -methylstyrene, ⁇ -hydroxymethylstyrene, ⁇ -hydroxyethylstyrene, acrylonitrile, methacrylonitrile, methallyl alcohol, allyl alcohol, ethylene, propylene, 4-methyl-1-pentene, vinyl acetate, 2-hydroxymethyl-1-butene, methyl vinyl ketone, N-vinylpyrrolidone, and N-vinylcarbazole.
• monomers having a polymerizable double bond such as styrene, vinyltoluene, ⁇ -methylstyrene, ⁇ -hydroxymethylstyrene, ⁇ -hydroxyethylstyrene, acrylonitrile, methacrylonitrile, methallyl alcohol, allyl alcohol, ethylene, propylene, 4-methyl
• substitutional units may be included, or two or more of these other monomers may be included.
• the content of structural units derived from such other copolymerizable monomers relative to 100 mass % of the methacrylic resin is preferably 0 mass % to 10 mass %, more preferably 0 mass % to 9 mass %, and even more preferably 0 mass % to 8 mass %.
• the methacrylic resin according to the present embodiment may include one type of structural unit or two or more types of structural units derived from the other copolymerizable monomers described above.
• the methacrylic resin including the lactone ring structural unit in the main chain thereof can be formed, for example, by a method described in JP 2001-151814 A, JP 2004-168882 A, JP 2005-146084 A, JP 2006-96960 A, JP 2006-171464 A, JP 2007-63541 A, JP 2007-297620 A, or JP 2010-180305 A.
• the method used to produce the methacrylic resin including the lactone ring structural unit is a method in which a lactone ring structure is formed by a cyclization reaction after polymerization.
• a lactone ring structure is formed by a cyclization reaction after polymerization.
• monomers are polymerized by radical polymerization through a solution polymerization method that uses a solvent.
• the polymerization process may, for example, be a batch polymerization process, a semi-batch polymerization process, or a continuous polymerization process.
• a so-called “semi-batch polymerization method” in which a portion of the monomers is charged into a reactor prior to the start of polymerization, a polymerization initiator is added to initiate polymerization, and a remaining portion of the monomers is subsequently fed into the reactor can be preferably adopted in the present embodiment. Adoption of this method tends to facilitate control of the molecular weight distribution and chemical composition distribution of the resultant polymer.
• a ratio of the amount of the monomers used in initial charging (start of polymerization) and the amount of the monomers added after the start of polymerization (amount of monomers at start of polymerization:amount of monomers added after start of polymerization), in terms of mass ratio, is preferably 1:9 to 8:2, more preferably 2:8 to 7.5:2.5, and even more preferably 3:7 to 5:5.
• the mixing composition of monomers in the initial charge can be selected as appropriate in consideration of copolymerization reactivity of each of the monomers used in copolymerization, which tends to facilitate control of the chemical composition distribution of the resultant polymer.
• solvent used in polymerization examples include aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; and ketones such as methyl ethyl ketone and methyl isobutyl ketone.
• One of these solvents may be used individually, or two or more of these solvents may be used together.
• the amount of solvent used in polymerization is, for example, preferably 50 parts by mass to 200 parts by mass, and more preferably 100 parts by mass to 200 parts by mass.
• polymerization is preferably performed such that the concentration of produced polymer in the reaction mixture obtained after polymerization is 50 mass % or less, and this concentration is preferably controlled to 50 mass % or less by adding polymerization solvent to the reaction mixture as appropriate.
• the method by which the polymerization solvent is added to the reaction mixture as appropriate is not specifically limited and may, for example, be through continuous addition of the polymerization solvent or intermittent addition of the polymerization solvent.
• the polymerization solvent that is added may be a single type of solvent, or may be a mixed solvent of two or more types of solvents.
• the polymerization temperature is preferably 50° C. to 200° C., and more preferably 60° C. to 180° C. from a viewpoint of productivity. Moreover, from a viewpoint of stereoregularity of methyl methacrylate monomer-derived structural units, the polymerization temperature is preferably 70° C. to 130° C., and more preferably 80° C. to 120° C.
• the polymerization time is preferably 0.5 hours to 10 hours, and more preferably 1 hour to 8 hours from a viewpoint of productivity and so forth.
• polymerization may be performed with addition of a polymerization initiator and/or a chain transfer agent as necessary.
• the polymerization initiator may be, but is not specifically limited to, any of the polymerization initiators disclosed in relation to the production method of the methacrylic resin including the N-substituted maleimide monomer-derived structural unit.
• One of these polymerization initiators may be used individually, or two or more of these polymerization initiators may be used together.
• the amount of polymerization initiator that is used can be set as appropriate depending on the combination of monomers, reaction conditions, and so forth, without any specific limitations. However, when the total amount of monomer used in polymerization is taken to be 100 parts by mass, the amount of polymerization initiator may be 0.05 parts by mass to 1 part by mass.
• These polymerization initiators may be added at any stage so long as the polymerization reaction is in progress.
• the type of initiator, amount of initiator, polymerization temperature, and so forth are appropriately selected such that the total amount of radicals generated by the polymerization initiator as a proportion relative to the total amount of unreacted monomer remaining in the reaction system is constantly no greater than a certain value.
• Adoption of this method can suppress production of oligomer or low molecular weight component in a latter stage of polymerization and enables improvement of polymerization stability by inhibiting overheating during polymerization.
• the chain transfer agent may be any chain transfer agent that is commonly used in radical polymerization and examples thereof include the chain transfer agents disclosed in relation to the production method of the methacrylic resin including the N-substituted maleimide monomer-derived structural unit.
• One of these chain transfer agents may be used individually, or two or more of these chain transfer agents may be used together.
• chain transfer agents may be added at any stage, without any specific limitations, so long as the polymerization reaction is in progress.
• the amount of chain transfer agent that is used is preferably 0.05 parts by mass to 1 part by mass.
• the methacrylic resin according to the present embodiment that includes the lactone ring structural unit can be obtained by performing a cyclization reaction after completion of the polymerization reaction. Therefore, the polymerization reaction liquid is preferably subjected to the lactone cyclization reaction in a solvent-containing state without removing the polymerization solvent therefrom.
• the copolymer obtained through polymerization is heat treated to cause a cyclocondensation reaction between a hydroxy group and an ester group present in the molecular chain of the copolymer and thereby form a lactone ring structure.
• Heat treatment for formation of the lactone ring structure may be performed, for example, using a reaction apparatus including a vacuum device or devolatilization device for removal of alcohol that may be produced as a by-product of cyclocondensation, or an extruder including a devolatilization device.
• the heat treatment may be performed in the presence of a cyclocondensation catalyst to promote the cyclocondensation reaction.
• cyclocondensation catalysts that can be used include monoalkyl, dialkyl, and trialkyl esters of phosphorus acid such as methyl phosphite, ethyl phosphite, phenyl phosphite, dimethyl phosphite, diethyl phosphite, diphenyl phosphite, trimethyl phosphite, and triethyl phosphite; and monoalkyl, dialkyl, and trialkyl esters of phosphoric acid such as methyl phosphate, ethyl phosphate, 2-ethylhexyl phosphate, octyl phosphate, isodecyl phosphate, lauryl phosphate, stearyl phosphate, isostearyl phosphate, dimethyl phosphate, diethyl phosphate, di-2-ethylhexyl phosphate, diisodecyl
• One of these cyclocondensation catalysts may be used individually, or two or more of these cyclocondensation catalysts may be used together.
• the amount of cyclocondensation catalyst that is used is not specifically limited, the amount of the cyclocondensation catalyst relative to 100 parts by mass of the methacrylic resin is, for example, preferably 0.01 parts by mass to 3 parts by mass, and more preferably 0.05 parts by mass to 1 part by mass.
• Using 0.01 parts by mass or more of a catalyst is effective for improving the rate of the cyclocondensation reaction, whereas using 3 parts by mass or less of a catalyst is effective for preventing coloring of the resultant polymer and polymer crosslinking that then makes melt molding difficult.
• the timing of addition of the cyclocondensation catalyst is not specifically limited.
• the cyclocondensation catalyst may be added in an initial stage of the cyclocondensation reaction, may be added partway through the reaction, or may be added both in the initial stage and partway through the reaction.
• devolatilization is preferably carried out concurrently with the reaction.
• a devolatilization device comprising a heat exchanger and a devolatilization tank, a vented extruder, or an apparatus in which a devolatilization device and an extruder are arranged in series, and more preferable to use a vented twin-screw extruder.
• the vented twin-screw extruder is preferably a vented extruder equipped with a plurality of vent ports.
• the reaction treatment temperature is preferably 150° C. to 350° C., and more preferably 200° C. to 300° C.
• a reaction treatment temperature of 150° C. or higher is effective for preventing inadequate cyclocondensation reaction and excessive residual volatile content, whereas a reaction treatment temperature of 350° C. or lower is effective for inhibiting coloring or decomposition of the resultant polymer.
• the degree of vacuum therein is preferably 10 Torr to 500 Torr, and more preferably 10 Torr to 300 Torr. Volatile content has a low tendency to remain when the degree of vacuum is 500 Torr or less, whereas industrial implementation is relatively simple when the degree of vacuum is 10 Torr or more.
• an alkaline earth metal and/or amphoteric metal salt of an organic acid is preferably added in pelletization to deactivate residual cyclocondensation catalyst.
• alkaline earth metal and/or amphoteric metal salt of an organic acid examples include calcium acetyl acetate, calcium stearate, zinc acetate, zinc octanoate, and zinc 2-ethylhexanoate.
• the methacrylic resin is melted and extruded as strands from an extruder equipped with a porous die, and is then pelletized by cold cutting, hot cutting in air, strand cutting in water, or under water cutting.
• the composition is produced after mixing two or more types of methacrylic resins that include at least a structure derived from a monomer represented by the previously shown formula (4) as a framework, but differ in terms of weight average molecular weight and stereoregularity.
• the stereoregularity of a methacrylic resin is expressed by a ratio (S/H) of the integrated intensity (S) of a syndiotactic fraction (rr) relative to the integrated intensity (H) of a heterotactic fraction (mr) among methacrylic acid ester monomer-derived structural units of the methacrylic resin, as determined by 1 H-NMR measurement.
• the weight average molecular weight (Mw) of each of the methacrylic resins may be freely selected from a range of 70,000 to 800,000.
• the weight average molecular weight thereof is preferably 70,000 to 150,000, and more preferably 100,000 to 150,000.
• S/H ratio thereof used as an indicator of stereoregularity is preferably 1.10 to 1.40.
• the weight average molecular weight thereof is preferably 200,000 to 800,000, and more preferably 220,000 to 600,000.
• S/H ratio thereof used as an indicator of stereoregularity is preferably 1.30 to 1.50.
• the mixing ratio of the low molecular weight component and the high molecular weight component is not specifically limited and can be appropriately selected from a range of 5 parts by mass to 95 parts by mass of the low molecular weight component and 95 parts by mass to 5 parts by mass of the high molecular weight component.
• a methacrylic resin according to the present embodiment preferably includes at least one cyclic structural unit selected from the group consisting of an N-substituted maleimide monomer-derived structural unit, a glutarimide-based structural unit, and a lactone ring structural unit.
• the methacrylic resin includes an N-substituted maleimide monomer-derived structural unit in terms that a high degree of control of optical properties such as the photoelastic coefficient can be easily achieved without blending with another thermoplastic resin.
• thermoplastic resin may be compounded in production of the methacrylic resin composition according to the present embodiment with the aim of adjusting birefringence or improving flexibility, so long as the objectives of the present embodiment are not impeded.
• thermoplastic resins examples include polyacrylates such as polybutyl acrylate; aromatic vinyl resins such as styrene polymers (for example, polystyrene, styrene-methyl methacrylate copolymer, styrene-butyl acrylate copolymer, styrene-acrylonitrile copolymer, and acrylonitrile-butadiene-styrene block copolymer); acrylic rubber particles having a 3 or 4 layer structure described in JP S59-202213 A, JP S63-27516 A, JP S51-129449 A, and JP S52-56150 A; rubbery polymers disclosed in JP S60-17406 B and JP H8-245854 A; and methacrylic rubber-containing graft copolymer particles obtained by multi-step polymerization described in WO 2014-002491 A1.
• polyacrylates such as polybutyl acrylate
• aromatic vinyl resins such as styren
• thermoplastic resins from a viewpoint of obtaining good optical properties and mechanical properties, it is preferable to use a styrene-acrylonitrile copolymer or rubber-containing graft copolymer particles having a grafted portion in a surface layer thereof with a chemical composition that is compatible with the methacrylic resin including the structural unit (X) having a cyclic structure-containing main chain.
• the average particle diameter of acrylic rubber particles, methacrylic rubber-containing graft copolymer particles, or a rubbery polymer such as described above is preferably 0.03 ⁇ m to 1 ⁇ m, and more preferably 0.05 ⁇ m to 0.5 ⁇ m from a viewpoint of improving impact strength, optical properties, and so forth of a film obtained using the methacrylic resin composition according to the present embodiment.
• the content of other thermoplastic resins relative to 100 parts by mass of the methacrylic resin is preferably 0 parts by mass to 50 parts by mass, and more preferably 0 parts by mass to 25 parts by mass.
• ultraviolet absorbers Although no specific limitations are placed on ultraviolet absorbers that can be used, an ultraviolet absorber having a maximum absorption wavelength in a range of 280 nm to 380 nm is preferable.
• ultraviolet absorbers that can be used include benzotriazole compounds, benzotriazine compounds, benzophenone compounds, oxybenzophenone compounds, benzoate compounds, phenolic compounds, oxazole compounds, cyanoacrylate compounds, and benzoxazinone compounds.
• One of these ultraviolet absorbers may be used individually, or two or more of these ultraviolet absorbers may be used together. By using two types of ultraviolet absorbers having different structures, ultraviolet light can be absorbed over a wider wavelength region.
• benzotriazole compounds examples include 2,2′-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol], 2-(3,5-di-tert-butyl-2-hydroxyphenyl)-5-chlorobenzotriazole, 2-(2H-benzotriazol-2-yl)-p-cresol, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2-benzotriazol-2-yl-4,6-di-tert-butylphenol, 2-[5-chloro(2H)-benzotriazol-2-yl]-4-methyl-6-t-butylphenol, 2-(2H-benzotriazol-2-yl)-4,6-di-t-butylphenol, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-t
• benzotriazole compounds having a molecular weight of 400 or more are preferable.
• benzotriazole compounds that are commercially available products include Kemisorb® 2792 (Kemisorb is a registered trademark in Japan, other countries, or both; produced by Chemipro Kasei Kaisha, Ltd.), ADK STAB® LA31 (ADK STAB is a registered trademark in Japan, other countries, or both; produced by Adeka Corporation), and TINUVIN® 234 (TINUVIN is a registered trademark in Japan, other countries, or both; produced by BASF).
• benzotriazine compounds examples include 2-mono(hydroxyphenyl)-1,3,5-triazine compounds, 2,4-bis(hydroxyphenyl)-1,3,5-triazine compounds, and 2,4,6-tris(hydroxyphenyl)-1,3,5-triazine compounds.
• Kemisorb 102 produced by Chemipro Kasei Kaisha, Ltd.
• LA-F70 produced by Adeka Corporation
• LA-46 produced by Adeka Corporation
• TINUVIN 405 produced by BASF
• TINUVIN 460 produced by BASF
• TINUVIN 479 produced by BASF
• TINUVIN 1577FF produced by BASF
• an ultraviolet absorber having a 2,4-bis(2,4-dimethylphenyl)-6-[2-hydroxy-4-(3-alkyloxy-2-hydroxypropyloxy)-5- ⁇ -cumylphenyl]-s-triazine framework (“alkyloxy” refers to a long chain alkyloxy group such as an octyloxy, nonyloxy, or decyloxy group) is more preferable in terms of having high acrylic resin compatibility and excellent ultraviolet absorption properties.
• the ultraviolet absorber is preferably a benzotriazole compound having a molecular weight of 400 or more or a benzotriazine compound, and from a viewpoint of inhibiting decomposition of the ultraviolet absorber under heating during extrusion, the ultraviolet absorber is particularly preferably a benzotriazine compound.
• the melting point (Tm) of the ultraviolet absorber is preferably 80° C. or higher, more preferably 100° C. or higher, further preferably 130° C. or higher, and even more preferably 160° C. or higher.
• the weight reduction rate of the ultraviolet absorber under heating from 23° C. to 260° C. at a rate of 20° C./min is preferably 50% or less, more preferably 30% or less, further preferably 15% or less, even more preferably 10% or less, and particularly preferably 5% or less.
• the amount of the ultraviolet absorber is not specifically limited so long as the disclosed effects can be displayed without impairing heat resistance, damp heat resistance, thermal stability, and molding properties, but relative to 100 parts by mass of the methacrylic resin, is preferably 0.1 parts by mass to 5 parts by mass, more preferably 0.2 parts by mass to 4 parts by mass, further preferably 0.25 parts by mass to 3 parts by mass, and even more preferably 0.3 parts by mass to 3 parts by mass.
• the amount of the ultraviolet absorber is within any of the ranges set forth above, an excellent balance of ultraviolet absorption performance, film molding properties, thin film compatibility, and so forth can be obtained.
• At least one antioxidant selected from hindered phenol antioxidants, phosphoric antioxidants, sulfuric antioxidants, and the like is preferably added to the methacrylic resin composition according to the present embodiment so that the properties of the methacrylic resin according to the present embodiment are expressed.
• One of these antioxidants may be used, or two or more of these antioxidants may be used in combination.
• hindered phenol antioxidants that can be used include, but are not specifically limited to, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 3,3′,3′′,5,5′,5′′-hexa-tert-butyl-a,a′,a′′-(mesitylene-2,4,6-triyl)tri-p-cresol, 4,6-bis(octylthiomethyl)-o-cresol, 4,6-bis(dodecylthiomethyl)-o-cresol, ethylenebis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-to
• hindered phenol antioxidants may be used as these hindered phenol antioxidants.
• examples of such commercially available hindered phenol antioxidants include, but are not specifically limited to, Irganox® 1010 (Irganox is a registered trademark in Japan, other countries, or both; pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]; produced by BASF), Irganox 1076 (octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate; produced by BASF), Irganox 1330 (3,3′,3′′,5,5′,5′′-hexa-t-butyl-a,a′,a′′-(mesitylene-2,4,6-triyl)tri-p-cresol; produced by BASF), Irganox 3114 (1,3,5-tris(3,5-di-t-but
• Irganox 1010 Irganox 1010
• Irganox 1076 ADK STAB AO-60
• ADK STAB AO-80 ADK STAB AO-80
• Sumilizer GS Sumilizer GS, and the like are preferable in terms of thermal stability imparting effect with respect to the resin.
• One of these hindered phenol antioxidants may be used individually, or two or more of these hindered phenol antioxidants may be used together.
• phosphoric antioxidants examples include those classified as phosphites and phosphonites.
• phosphites that can be used as phosphoric antioxidants include, but are not specifically limited to, tris(2,4-di-t-butylphenyl) phosphite, tris(2,6-di-t-butylphenyl) phosphite, tris(2,4-di-t-butyl-5-methylphenyl) phosphite, bis(2,4-di-t-butyl-6-methylphenyl)ethyl phosphite, 2,2′-methylenebis(4,6-di-t-butylphenyl)octyl phosphite, bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, and cyclic neopentanetetraylbis(2,6-di-t-butyl-4-methylphenyl) phosphite.
• phosphoric antioxidants examples of which include Irgafos 168 (tris(2,4-di-t-butylphenyl) phosphite; produced by BASF), Irgafos 12 (tris[2-[[2,4,8,10-tetra-t-butyldibenzo[d,f][1,3,2]dioxaphosphepin-6-yl]oxy]ethyl]amine; produced by BASF), Irgafos 38 (bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite; produced by BASF), ADK STAB HP-10 (2,2′-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite; produced by Adeka Corporation), ADK STAB PEP24G (cyclic neopentanetetraylbis(2,4-di-ter
• Examples of phosphonites that can be used as phosphoric antioxidants include tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenylenediphosphonite and tetrakis(2,4-di-tert-butyl-5-methylphenyl)-4,4′-biphenylenediphosphonite.
• phosphonites may be used as the phosphoric antioxidant, examples of which include Hostanox® P-EPQ (Hostanox is a registered trademark in Japan, other countries, or both; tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenylenediphosphonite; produced by Clariant Co., Ltd.) and GSY P101 (tetrakis(2,4-di-t-butyl-5-methylphenyl)-4,4′-biphenylenediphosphonite; produced by Sakai Chemical Industry Co., Ltd.).
• Hostanox® P-EPQ Hostanox is a registered trademark in Japan, other countries, or both
• GSY P101 tetrakis(2,4-di-t-butyl-5-methylphenyl)-4,4′-biphenylenediphosphonite; produced by Sakai Chemical Industry Co., Ltd.
• ADK STAB PEP-36 ADK STAB PEP-36A
• Sumilizer GP Sumilizer GP
• GSY P101 GSY P101
• One of these phosphoric antioxidants may be used individually, or two or more of these phosphoric antioxidants may be used together.
• sulfuric antioxidants that can be used include, but are not specifically limited to, 2,4-bis(dodecylthiomethyl)-6-methylphenol (Irganox 1726 produced by BASF), Irganox 1520L (produced by BASF), 2,2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]propan-1,3-diyl bis[3-(dodecylthio)propionate] (ADK STAB AO-4125 produced by Adeka Corporation), 2,2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]propan-1,3-diyl bis[3-(dodecylthio)propionate] (KEMINOX® PLS (KEMINOX is a registered trademark in Japan, other countries, or both) produced by Chemipro Kasei Kaisha, Ltd.), and di(tridecyl)-3,3′-thiodipropionate
• ADK STAB AO-4125 ADK STAB AO-4125
• KEMINOX PLS KEMINOX PLS, and the like are preferable in terms of thermal stability imparting effect with respect to the resin.
• One of these sulfuric antioxidants may be used individually, or two or more of these sulfuric antioxidants may be used together.
• the content of the antioxidant can be any amount that enables an effect of thermal stability improvement, excessively high antioxidant content may lead to problems such as bleed-out during processing. Accordingly, the content of the antioxidant relative to 100 parts by mass of the methacrylic resin is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, further preferably 1 part by mass or less, even more preferably 0.8 parts by mass or less, even further preferably 0.01 parts by mass to 0.8 parts by mass, and particularly preferably 0.01 parts by mass to 0.5 parts by mass.
• the methacrylic resin composition according to the present embodiment may contain other additives to the extent that the effects according to the present embodiment are not significantly lost.
• additives examples include, but are not specifically limited to, inorganic fillers; pigments such as iron oxide; lubricants and release agents such as stearic acid, behenic acid, zinc stearate, calcium stearate, magnesium stearate, and ethylene bis stearamide; softeners and plasticizers such as paraffinic process oils, naphthenic process oils, aromatic process oils, paraffin, organic polysiloxanes, and mineral oils; higher alcohols such as cetyl alcohol and stearyl alcohol; release agents such as glycerin higher fatty acid esters (for example, stearic acid monoglyceride and stearic acid diglyceride); flame retardants; antistatic agents; reinforcers such as organic fiber, glass fiber, carbon fiber, and metal whisker; colorants; other additives; and mixtures of any of the preceding examples.
• inorganic fillers examples include, but are not specifically limited to, inorganic fillers; pigments such as iron oxide; lubricants and release agents such as
• the weight average molecular weight (Mw) of the methacrylic resin composition according to the present embodiment determined as a polymethyl methacrylate equivalent molecular weight through measurement by gel permeation chromatography (GPC) using a differential refractive index detector is preferably 120,000 to 200,000, more preferably 120,000 to 170,000, and even more preferably 120,000 to 150,000.
• a weight average molecular weight (Mw) in any of the ranges set forth above is preferable in terms that an excellent balance of mechanical strength and molding properties can be achieved.
• the Vicat softening temperature (Tvicat) of the methacrylic resin composition according to the present embodiment is 120° C. to 160° C., preferably 120° C. to 150° C., and more preferably 120° C. to 140° C.
• the Vicat softening temperature (Tvicat) can be determined through measurement of a specimen of 4 mm in thickness in accordance with ISO 306.
• the Vicat softening temperature is carried out by determining the temperature at which deformation of the resin due to heat starts to occur.
• the Vicat softening temperature is defined as the temperature of the specimen at which a needle having a needle tip area of 1 mm 2 sinks to a depth of 1 mm within the specimen, the Vicat softening temperature is normally taken to be the temperature of a heat transfer medium that is used in measurement.
• This indicator is influenced not only by the glass transition temperature and melting point of the resin, but also by the molecular weight and molecular weight distribution of the resin. Moreover, this indicator is expected to be strongly influenced by the glass transition temperature distribution with respect to softening behavior of the resin, and is considered to be a useful indicator when the resin is heated and softened for secondary processing (inclusive of surface shaping processing by heating that is a subject of the present disclosure).
• the Vicat softening temperature of the methacrylic resin composition being 120° C. or higher, the heat resistance required in recent years for lens molded products and film molded product optical films for liquid-crystal displays can be easily obtained.
• the Vicat softening temperature of a methacrylic resin composition is higher than 160° C., it is necessary to adopt a rather high temperature during melt processing, which may lead to thermal decomposition of resin and the like, and thus it may be difficult to obtain a good quality product by melt processing.
• the stereoregularity of methacrylic acid ester monomer-derived structural units is expressed by a ratio (S/H) of the integrated intensity (S) of a syndiotactic fraction (rr) relative to the integrated intensity (H) of a heterotactic fraction (mr) among methacrylic acid ester monomer-derived structural units, as determined by 1 H-NMR measurement.
• the S/H ratio is 1.20 to 1.50, preferably 1.25 to 1.50, and more preferably 1.30 to 1.40.
• An S/H ratio that is within any of the ranges set forth above is preferable in terms that shape replicability is possible even when the conveyance speed in a surface shaping step of knurling or the like is increased, such as in mass production, and in terms that durable protrusions and recesses can be shaped.
• surface shaping properties of a molded product by knurling or the like can be improved by mixing two or more types of methacrylic resins that each have a cyclic structure-containing main chain, but differ in terms of weight average molecular weight and stereoregularity.
• the stereoregularity of methacrylic acid ester monomer-derived structural units in a methacrylic resin having a cyclic structure-containing main chain and a methacrylic resin composition containing this methacrylic resin can be measured by calculating the proportions of triad tacticities by 1 H-NMR measurement.
• the triad tacticities can be measured by the following method.
• a sample is dissolved in chloroform and is then measured by 1 H-NMR measurement using, for example, a 400 MHz NMR spectrometer (for example, an NMR spectrometer produced by Bruker Corporation).
• the integrated values for peaks near ⁇ 1.2 ppm, ⁇ 1.0 ppm, and ⁇ 0.8 ppm are respectively taken to be the proportions of isotactic triads, heterotactic triads, and syndiotactic triads.
• the triad tacticities can be obtained by a method described in the subsequent EXAMPLES section.
• the amount of methanol-soluble content in the methacrylic resin composition according to the present embodiment as a proportion relative to 100 mass %, in total, of methanol-soluble content and methanol-insoluble content, is 5 mass % or less, preferably 4.5 mass % or less, more preferably 4 mass % or less, further preferably 3.5 mass % or less, preferably 3 mass % or less, and more preferably 2.5 mass % or less.
• the proportion of methanol-soluble content is 5 mass % or less in terms that even when the conveyance speed in a surface shaping step of knurling or the like is increased, such as in mass production, excellent release properties and shape replicability can be achieved and durable protrusions and recesses can be shaped.
• the methanol-soluble content and methanol-insoluble content refer to components obtained by dissolving the methacrylic resin composition in chloroform, dripping the resultant solution into an excess of methanol to cause re-precipitation, separating a filtrate and a filtration residue, and then drying the obtained filtrate and filtration residue.
• the methanol-soluble content and the methanol-insoluble content can be obtained by a method described in the subsequent EXAMPLES section.
• Examples of methods that can be used to adjust the amount of methanol-soluble content to within any of the ranges set forth above include, but are not specifically limited to, a method in which production of oligomer or low-molecular weight product is suppressed by controlling the addition method of monomers and the addition method of polymerization initiator in polymerization.
• the methanol-soluble content of the methacrylic resin composition according to the present embodiment may include, for example, unreacted monomer components, oligomer components such as dimers and trimers of these monomers, and low-molecular weight components that have a weight average molecular weight of approximately 1,000 to 15,000 and have a chemical composition such as to be soluble in normal temperature methanol.
• the glass transition temperature (Tg) of the methacrylic resin composition according to the present embodiment is preferably higher than 120° C. and no higher than 160° C.
• the glass transition temperature (Tg) of the methacrylic resin composition is higher than 120° C., the heat resistance required in recent years for optical components such as lens molded products, film molded products for liquid-crystal displays, and optical films can be more easily obtained.
• Tg glass transition temperature
• the glass transition temperature (Tg) can be measured in accordance with JIS-K7121.
• the glass transition temperature (Tg) (° C.) may be measured as follows. First, specimens are obtained by cutting approximately 10 mg from a sample at four points (four locations) after the sample has been conditioned (left for 1 week at 23° C.) in a standard state (23° C., 65% RH). A DSC curve is then plotted using a differential scanning calorimeter (Diamond DSC produced by PerkinElmer Japan) under a nitrogen gas flow rate of 25 mL/min while heating the specimen from room temperature (23° C.) to 200° C. at 10° C./min (primary heating), holding the specimen at 200° C. for 5 minutes to completely melt the specimen, cooling the specimen from 200° C. to 40° C.
• Tg glass transition temperature
• Tg glass transition temperature
• the absolute value of the photoelastic coefficient C R of the methacrylic resin composition according to the present embodiment including the structural unit (X) having a cyclic structure-containing main chain is preferably 3.0 ⁇ 10 ⁇ 12 Pa ⁇ 1 or less, more preferably 2.0 ⁇ 10 ⁇ 12 Pa ⁇ 1 or less, and even more preferably 1.0 ⁇ 10 ⁇ 12 Pa ⁇ 1 or less.
• the photoelastic coefficient is described in various documents (for example, refer to Review of Chemistry, No. 39, 1998 (published by Japan Scientific Societies Press)) and is defined by the following formulae (i-a) and (i-b).
• C R represents the photoelastic coefficient
• ⁇ R represents tensile stress
• represents the absolute value of birefringence
• nx represents the refractive index of the tension direction
• ny represents the refractive index of an in-plane direction that is perpendicular to the tension direction.
• the absolute value of the photoelastic coefficient C R of the methacrylic resin composition according to the present embodiment is 3.0 ⁇ 10 ⁇ 12 P ⁇ 1 or less, in a situation in which the methacrylic resin composition is formed into a film and used in a liquid-crystal display, it is possible to inhibit or prevent phase difference irregularity, reduced contrast at the periphery of the display screen, and light leakage.
• the photoelastic coefficient C R can, more specifically, be determined by a method described in the subsequent EXAMPLES section.
• the methacrylic resin composition is preferably produced by also using, for example, a filtration device such as a sintered filter, pleated filter, or leaf disk-type polymer filter having a filtration precision of 1.5 ⁇ m to 20 ⁇ m in one or more steps selected from a polymerization reaction step, a liquid-liquid separation step, a liquid-solid separation step, a devolatilization step, a pelletization step, and a molding step in order to reduce the amounts of contaminants.
• a filtration device such as a sintered filter, pleated filter, or leaf disk-type polymer filter having a filtration precision of 1.5 ⁇ m to 20 ⁇ m in one or more steps selected from a polymerization reaction step, a liquid-liquid separation step, a liquid-solid separation step, a devolatilization step, a pelletization step, and a molding step in order to reduce the amounts of contaminants.
• production of the methacrylic resin composition is preferably carried out after reducing the amount of oxygen and moisture as much as possible.
• the dissolved oxygen concentration in a polymerization solution in solution polymerization is preferably less than 300 ppm in the polymerization step, and in a production method in which an extruder or the like is used, the oxygen concentration inside the extruder is preferably less than 1 volume %, and more preferably less than 0.8 volume %.
• the amount of moisture in the methacrylic resin is adjusted to preferably 1,000 mass ppm or less, and more preferably 500 mass ppm or less.
• pelletized methacrylic resin used as a raw material is sufficiently dried in advance by heating under vacuum or in dehumidified air to remove as much moisture as possible.
• an inert gas such as nitrogen gas
• an inert gas is caused to flow inside the extruder and that production is carried out using a vented extruder while performing vacuum venting.
• the drying temperature is preferably 40° C. to 120° C., and more preferably 70° C. to 100° C.
• the degree of vacuum can be selected as appropriate without any specific limitations.
• Molten methacrylic resin that has been melt-kneaded is then melt-extruded from a porous die using the extruder and is pelletized.
• the pelletization method used during this process may be, for example, hot cutting in air, water ring-type hot cutting, cold cutting, strand cutting in water, under water cutting, or the like.
• strand cutting in water is generally more preferable in terms of productivity and pelletizer cost.
• the pelletization is more preferably performed under implementable conditions in which the temperature of the molten resin is as low as possible, the residence time from an outlet of the porous die to the surface of cooling water is as short as possible, and the temperature of the cooling water is as high as possible.
• the temperature of the molten resin is preferably 240° C. to 300° C., and more preferably 250° C. to 290° C.
• the residence time from the outlet of the porous die to the surface of the cooling water is preferably 5 seconds or less, and more preferably 3 seconds or less
• the temperature of the cooling water is preferably 30° C. to 80° C., and more preferably 40° C. to 60° C.
• the present embodiment it is preferable in the present embodiment to use two or more types of methacrylic resins that each have the same type of cyclic structure in the main chain thereof, but differ in terms of weight average molecular weight, Vicat softening point, and S/H ratio, and to select the proportion of structural units derived from each monomer, the weight average molecular weight, the Vicat softening point, and the S/H ratio of each methacrylic resin, and the mixing ratio of these methacrylic resins as appropriate, so long as the properties stipulated in the present embodiment are satisfied.
• a situation in which the S/H ratio of a high molecular weight component is greater than the S/H ratio of a low molecular weight component is preferable in terms of enabling stable formation of a protrusion/recess shape at the surface of a film or other molded product by knurling or the like.
• the method by which two or more types of methacrylic resins are mixed is not specifically limited and examples thereof include a method in which a solution containing two or more types of polymerized products is mixed in liquid-phase and subjected to post-treatment, and a method in which mixing is performed using a melt-kneader, such as an extruder, after pelletization.
• a method in which a solution containing two or more types of polymerized products is mixed in liquid-phase and subjected to post-treatment is preferable when a methacrylic resin having a high molecular weight is used.
• the resin composition according to the present embodiment may be used to form a molded product by a commonly known method such as injection molding, sheet molding, blow molding, injection blow molding, inflation film molding, T-die film molding, press molding, extrusion molding, foam molding, or cast molding, and with further use of a molding method for secondary processing such as pressure molding or vacuum molding.
• sheet molding, inflation film molding, T-die film molding, and extrusion molding are suitable for forming a sheet or film to obtain an optical sheet or optical film.
• the following provides a description of a method of producing a pre-stretching film (unstretched film) and a stretched film using the methacrylic resin composition according to the present embodiment.
• the method involves, for example, supplying raw material resin into a single-screw or twin-screw extruder, melt-kneading the raw material resin, subsequently extruding a sheet using a T-die, guiding the sheet on a casting roll, and solidifying the sheet.
• longitudinal uniaxial stretching may be performed by stretching in the directional of mechanical flow using a pair of rolls having different circumferential speeds
• transverse uniaxial stretching may be performed by stretching in a perpendicular direction (TD direction) relative to the direction of mechanical flow
• biaxial stretching may be performed by sequential biaxial stretching using roll stretching and tenter stretching, simultaneous biaxial stretching by tenter stretching, biaxial stretching by tubular stretching, inflation stretching, tenter method sequential biaxial stretching, or the like.
• sequential biaxial stretching comprising roll stretching and tenter stretching is preferable as this enables the greatest expression of the features of the methacrylic resin composition according to the present embodiment.
• the final stretching ratio can be determined in consideration of the heat shrinkage rate of the resultant molded/stretched product.
• the stretching ratio in at least one direction is preferably 0.1% to 400%, more preferably 10% to 400%, and even more preferably 50% to 350%.
• folding strength tends to be insufficient
• the stretching ratio is greater than any of the upper limits set forth above, a film cannot be continuously and stably produced because breaking or rupturing frequently occurs during the film production process.
• the stretching temperature is preferably Tvicat ⁇ 30° C. to Tvicat+50° C.
• Tvicat Vicat softening temperature refers to a value for the resin composition used in production of the film.
• the lower limit for the stretching temperature is preferably Tvicat ⁇ 20° C. or higher, more preferably Tvicat ⁇ 10° C. or higher, further preferably Tvicat or higher, even more preferably Tvicat+5° C. or higher, and particularly preferably Tvicat+7° C. or higher.
• the upper limit for the stretching temperature is preferably Tvicat+45° C. or lower, and more preferably Tvicat+40° C. or lower.
• the film is preferably subjected to heat treatment (annealing) or the like after stretching treatment to stabilize optical isotropy and mechanical properties of the film.
• the heat treatment conditions are not specifically limited and may be selected as appropriate in the same manner as for the conditions of heat treatment performed with respect to conventional and commonly known stretched films.
• the heat treatment may be performed with a temperature of preferably Tvicat ⁇ 30° C. to Tvicat+30° C., more preferably Tvicat ⁇ 30° C. to Tvicat+20° C., and even more preferably Tvicat ⁇ 15° C. to Tvicat+10° C., for a time of preferably 1 second to 10 minutes, and more preferably 5 seconds to 4 minutes, and with a tension of preferably 0.1 kg/m to 20 kg/m.
• the thickness of the optical film is not specifically limited, the thickness may be, for example, 1 ⁇ m to 250 ⁇ m, and is preferably 10 ⁇ m to 100 ⁇ m.
• the molded product according to the present embodiment preferably includes an embossed section on at least part of either or both of a front surface and a rear surface.
• the embossed section may be provided just in proximity to a film edge.
• the shape of protrusions in the embossed section may be selected as appropriate depending on the objective and application, and may be a circular shape, a polygonal shape such as square shape, diamond shape, or trapezoidal shape, or the like.
• the shaped design may differ depending on the thickness of the molded product on which the embossed section is formed.
• the density of protrusions in the embossed section is preferably 50 per cm 2 to 200 per cm 2 , but is not specifically limited to this range.
• the height of the protrusions in the embossed section is preferably 6 ⁇ m to 16 ⁇ m, and particularly preferably 8 ⁇ m to 14 ⁇ m. Also note that the protrusions may each have the same height or may have different heights. The height of the protrusions can be measured by a method described in the subsequent EXAMPLES section.
• examples include light guide plates, diffuser plates, quarter-wave plates, half-wave plates, polarizer protective films, viewing angle compensation films, liquid-crystal optical compensation films and other retardation films, display front plates, display base plates, lenses, touch panels, optical waveguides, and the like used in displays such as liquid-crystal displays, plasma displays, organic EL displays, field emission displays, and rear projection televisions. Use in transparent base plates and the like of solar cells is also appropriate.
• Examples of molded product applications include household goods, OA equipment, AV equipment, battery fittings, lighting equipment, automobile component applications for tail lamps, meter covers, head lamps, light guide rods, lenses, and so forth, housing applications, sanitary applications as a sanitary ware alternative or the like, and light guide plates, diffuser plates, polarizing plate protective films, quarter-wave plates, half-wave plates, viewing angle control films, liquid-crystal optical compensation film and other retardation films, display front plates, display base plates, lenses, touch panels, and the like used in displays such as liquid-crystal displays, plasma displays, organic EL displays, field emission displays, and rear projection televisions. Use in transparent base plates and the like of solar cells is also appropriate.
• Other possible applications include those in the fields of optical communication systems, optical switching systems, and optical measurement systems for waveguides, lenses, optical fibers, optical fiber coating materials, LED lenses, lens covers, and so forth. Moreover, use as a modifier for another resin is also possible.
• optical components are preferable (particularly optical components having an embossed section on at least part of either or both of a front surface and a rear surface), and optical films are more preferable (particularly optical films having an embossed section on at least part of either or both of a front surface and a rear surface).
• the methacrylic resin composition according to the present embodiment and the optical component according to the present embodiment in a situation in which, with regards to production of a molded product for use in the optical field (particularly an optical film) that is subjected to surface shaping treatment, there is progress toward higher line speed, smaller film thickness, and commercialization as an elongated roll, it is still possible to inhibit a decrease in film quality associated with long-term storage or transport. Therefore, according to the present embodiment, it is possible to provide a methacrylic resin composition that can be used to produce an optical film or other molded product for use in the optical field that has excellent surface shaping properties, and to provide an optical component such as an optical film.
• the weight average molecular weight (Mw) and number average molecular weight (Mn) of methacrylic resins produced in the following production examples and methacrylic resin compositions produced in the following examples and comparative examples were measured using the following device and conditions.
• Standard samples for calibration curve Following 10 types of polymethyl methacrylate (PMMA Calibration Kit M-M-10 produced by Polymer Laboratories Ltd.) of differing molecular weight each having a known monodisperse weight peak molecular weight
• the RI detection intensity was measured with respect to the elution time of the methacrylic resin or methacrylic resin composition under the conditions set forth above.
• the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the methacrylic resins and methacrylic resin compositions were determined based on calibration curves obtained through measurement of the calibration curve standard samples, and then Mw/Mn was calculated using the determined values.
• the Vicat softening temperature (° C.) of methacrylic resin compositions obtained in the following examples and comparative examples was measured in accordance with ISO 306 under the following conditions.
• Specimen shape Length 80 mm, width 10 mm, thickness 4 mm
• Heating rate 50° C./hr
• the Vicat softening temperature (° C.) was taken to be the temperature at which a needle-shaped indenter of 1 mm in diameter penetrated to a depth of 1 mm.
• the obtained results were used to draw a base line in a chemical shift ( ⁇ ) range of 0 ppm to 3 ppm, and then integrated values were determined in a range of 0.65 ppm to 0.90 ppm for a syndiotactic chain fraction (rr), in a range of 0.98 ppm to 1.07 ppm for a heterotactic chain fraction (mr), and in a range of 1.16 ppm to 1.25 ppm for an isotactic chain fraction (mm).
• the ratio (S/H) of the integrated intensity (S) of the syndiotactic fraction (rr) relative to the integrated intensity (H) of the heterotactic fraction (mr) was calculated as an indicator of stereoregularity.
• the filtration residue was vacuum dried for 16 hours at 60° C. and the dried product was taken to be methanol-insoluble content. Additionally, solvent was removed from the filtrate using a rotary evaporator with a bath temperature of 40° C. and a degree of vacuum that was gradually reduced from an initial setting of 390 Torr to a final level of 30 Torr. Soluble content remaining in the rotary evaporator flask was collected and taken to be methanol-soluble content.
• the mass of the methanol-insoluble content and the mass of the methanol-soluble content were weighed and then the amount of the methanol-soluble content was calculated as a proportion (mass %; proportion of methanol-soluble content) relative to the total amount (100 mass %) of the methanol-soluble content and the methanol-insoluble content.
• Each of the methacrylic resin compositions obtained in the examples and comparative examples was formed into a pressed film using a vacuum compression molding machine to obtain a measurement sample.
• the sample was prepared by using a vacuum compression molding machine (SFV-30 produced by Shinto Metal Industries Corporation) to pre-heat the resin composition for 10 minutes at 260° C. under vacuum (approximately 10 kPa) and subsequently compress the resin composition for 5 minutes at 260° C. and approximately 10 MPa, and by then releasing the vacuum and press pressure and transferring the resin composition to a compression molding machine for cooling in which the resin composition was cooled and solidified.
• the resultant pressed film was cured for at least 24 hours in a constant temperature and constant humidity chamber adjusted to a temperature of 23° C. and a humidity of 60%, and then a measurement specimen (thickness: approximately 150 ⁇ m, width: 6 mm) was cut out therefrom.
• the photoelastic coefficient C R (Pa ⁇ 1 ) was measured using a birefringence measurement device that is described in detail in Polymer Engineering and Science 1999, 39, 2349-2357.
• the film-shaped specimen was set in a film tensing device (produced by Imoto Machinery Co., Ltd.) set up in the same constant temperature and constant humidity chamber such that the chuck separation was 50 mm.
• a birefringence measurement device (RETS-100 produced by Ostuka Electronics Co., Ltd.) was set up such that a laser light path of the device was positioned in a central portion of the film.
• the birefringence of the specimen was measured while applying tensile stress with a strain rate of 50%/min (chuck separation: 50 mm, chuck movement speed: 5 mm/min).
• the photoelastic coefficient (C R ) (Pa ⁇ 1 ) was calculated by making a least squares approximation of the relationship between the absolute value (
• nx refractive index of tension direction
• ny refractive index of in-plane direction perpendicular to tension direction
• a film was produced from each methacrylic resin composition obtained in the following examples and comparative examples using a 50 mm ⁇ single-screw extruder equipped with a filter for resin filtration (leaf filter produced by Nagase & Co., Ltd.) and a T-die of 480 mm in width at the tip of the extruder.
• an unstretched film of 250 ⁇ m in thickness was obtained with film production conditions of an extruder temperature setting of 260° C., a T-die temperature setting of 255° C., a discharge rate of 8 kg/hr, and a cooling roll temperature setting of the Vicat softening temperature ⁇ 10° C.
• a roll stretching device including, in this order, a pair of pre-heating rolls, a pair of stretching rolls, an infrared heater disposed between the stretching rolls, and a pair of conveying rolls.
• the temperature of each of the rolls was set as follows using the Vicat softening temperature of the resin composition being evaluated as a reference.
• Pre-heating roll temperature Vicat softening temperature+10° C.
• Low-speed stretching roll temperature Vicat softening temperature+30° C.
• High-speed stretching roll temperature Vicat softening temperature+10° C.
• Conveying roll temperature Vicat softening temperature ⁇ 10° C.
• the distance between the low-speed stretching roll and the high-speed stretching roll was 200 mm.
• the circumferential speed difference of the high/low-speed stretching rolls under these temperature conditions was set as 2.5 times.
• the longitudinal stretching described above was followed by transverse stretching of the longitudinally stretched film using a tenter-type transverse stretching device including, in order from a film inlet side thereof, a pre-heating section, a transverse stretching section, and a heat treatment section.
• the temperatures of the sections inside the tenter-type device were set as follows using the Vicat softening temperature of the resin composition being evaluated as a reference.
• Pre-heating section Vicat softening temperature (° C.)
• Transverse stretching section Vicat softening temperature+10° C.
• Heat treatment section Vicat softening temperature (° C.)
• the stretched film was released from the clips and was supplied into a trimming device equipped with a shear cutter. Both edge sections of the film were severed to obtain a biaxially stretched film having an average thickness of 40 ⁇ m. A rolled product was then obtained by winding 1000 m in length of the obtained film around a core made of 6 inch ABS.
• the obtained biaxially stretched film was subjected to knurling under the following conditions.
• the knurling was performed using an apparatus including a pre-heating roll for pre-heating the film prior to knurling, and also including a knurling roll and a support roll for nipping the film to perform knurling thereon.
• the knurling was performed under the following conditions using an emboss roll.
• Pre-heating roll temperature 100° C.
• Knurling roll temperature Vicat softening temperature+30° C. (made of metal; induction heating roll used)
• Support roll temperature 60° C. (made of metal; induction heating roll used)
• Knurling position 15 mm to 25 mm from film edge
• Protrusion/recess density Approximately 100 per cm 2
• a thickness meter produced by Mitutoyo Corporation was used to measure the difference between the vertex of a protrusion of the knurling pattern and a section of the film that had not been subjected to knurling. Measurements were made at 3 points in the width direction of the section subjected to knurling and then, with respect to the point yielding the largest value, measurements were made at 10 points at 1 cm intervals in the length direction, and the average value for these points was taken to be the knurling thickness ( ⁇ m).
• the number of protrusions was measured using a microscope produced by Keyence Corporation. Shape replicability was then evaluated by the following standard.
• Processability was evaluated based on the occurrence or absence of continuous processing malfunction and cracking that are associated with fusion or adhesion to a knurled section of film during knurling. The occurrence or absence of cracking was confirmed by inspecting the processed film by eye.
• Evaluation was performed in the same way as under knurling conditions 1 with the exception that the conveyance (line) speed of the film subjected to knurling was changed to 60 m/min.
• Evaluation was performed in the same way as under knurling conditions 1 with the exception that the knurling roll temperature during knurling was changed to the Vicat softening temperature+60° C.
• the rolled product obtained under knurling conditions 1 set forth above was stored for 2 weeks under conditions of a temperature of 40° C. and humidity of 80% RH. Thereafter, 100 m of film was unrolled from the rolled product, and film-on-film sticking was inspected to make a three-grade classification based on the sticking state.
• a mixed monomer solution was prepared by measuring out 146.0 kg of methyl methacrylate (hereinafter, denoted as “MMA”), 4.0 kg of N-phenylmaleimide (hereinafter, denoted as “phMI”), 32.5 kg of N-cyclohexylmaleimide (hereinafter, denoted as “chMI”), 0.21 kg of n-octyl mercaptan as a chain transfer agent, and 147.0 kg of methyl isobutyl ketone (hereinafter, denoted as “MIBK”), adding these materials into a 1.25 m 3 reactor equipped with a stirring blade and a temperature controller functioning through use of a jacket, and then stirring these materials.
• MMA methyl methacrylate
• phMI N-phenylmaleimide
• chMI N-cyclohexylmaleimide
• MIBK methyl isobutyl ketone
• a mixed monomer solution for subsequent addition was prepared by measuring out 260.4 kg of MMA, 7.5 kg of phMI, 71.3 kg of chMI, and 273.0 kg of MIBK, adding these materials into a first tank, and then stirring these materials. In addition, 58.0 kg of MMA was measured out in a second tank.
• the reactor, the first tank, and the second tank were each subjected to 30 minutes of nitrogen bubbling at a rate of 10 L/min to remove dissolved oxygen.
• the solution temperature inside the reactor during polymerization was controlled to 110 ⁇ 2° C. through temperature adjustment using the jacket.
• the mixed monomer solution for subsequent addition was added from the first tank at an addition rate of 306 kg/hr.
• Irganox 1010 was added to the polymerization solution under stirring in an amount of 0.1 parts by mass per 100 parts by mass of polymer contained in the solution.
• the polymerization solution was fed into a concentrating device comprising a tubular heat exchanger and a vaporization tank that had been pre-heated to 170° C., and the concentration of polymer contained in the solution was raised to 70 mass %.
• the resultant polymerization solution was fed into a thin film evaporator having a heat transfer area of 0.2 m 2 and was subjected to devolatilization.
• the devolatilization was carried out with an evaporator internal temperature of 280° C., a feed rate of 30 L/hr, a rotational speed of 400 rpm, and a degree of vacuum of 30 Torr.
• the polymerized product subjected to devolatilization was then pressurized using a gear pump, extruded from a strand die, cooled by water, and subsequently pelletized to obtain a composition (1-1) containing a methacrylic resin polymerized product having a cyclic structure-containing main chain.
• composition (1-1) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 80.3 mass %, 1.9 mass %, and 17.8 mass %, respectively. Moreover, the weight average molecular weight (Mw) was 246,000 and the S/H ratio used as an indicator of stereoregularity was 1.42.
• a mixed monomer solution was prepared by measuring out 146.0 kg of MMA, 28.5 kg of phMI, 8.0 kg of chMI, 0.85 kg of n-octyl mercaptan as a chain transfer agent, and 147.0 kg of toluene (hereinafter, denoted as “ToL”), adding these materials into a 1.25 m 3 reactor equipped with a stirring blade and a temperature controller functioning through use of a jacket, and then stirring these materials.
• ToL toluene
• a mixed monomer solution for subsequent addition was prepared by measuring out 271.4 kg of MMA, 52.9 kg of phMI, 14.9 kg of chMI, and 273.0 kg of ToL, adding these materials into a first tank, and then stirring these materials. In addition, 58.0 kg of MMA was measured out in a second tank.
• the reactor, the first tank, and the second tank were each subjected to 30 minutes of nitrogen bubbling at a rate of 10 L/min to remove dissolved oxygen.
• the solution temperature inside the reactor during polymerization was controlled to 110 ⁇ 2° C. through temperature adjustment using the jacket.
• the mixed monomer solution for subsequent addition was added from the first tank at an addition rate of 306 kg/hr.
• Irganox 1010 was added to the polymerization solution under stirring in an amount of 0.1 parts by mass per 100 parts by mass of polymer contained in the solution.
• the polymerization solution was fed into a concentrating device comprising a tubular heat exchanger and a vaporization tank that had been pre-heated to 170° C., and the concentration of polymer contained in the solution was raised to 70 mass %.
• the resultant polymerization solution was fed into a thin film evaporator having a heat transfer area of 0.2 m 2 and was subjected to devolatilization.
• the devolatilization was carried out with an evaporator internal temperature of 280° C., a feed rate of 30 L/hr, a rotational speed of 400 rpm, and a degree of vacuum of 30 Torr.
• the polymerized product subjected to devolatilization was then pressurized using a gear pump, extruded from a strand die, cooled by water, and subsequently pelletized to obtain a composition (1-2) containing a methacrylic resin polymerized product having a cyclic structure-containing main chain.
• the chemical composition of the obtained pelletized composition (1-2) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 82.0 mass %, 14.1 mass %, and 3.9 mass %, respectively. Moreover, the weight average molecular weight (Mw) was 102,000 and the S/H ratio used as an indicator of stereoregularity was 1.26.
• a mixed monomer solution was prepared by measuring out 146.0 kg of MMA, 4.6 kg of phMI, 32.0 kg of chMI, 0.21 kg of n-octyl mercaptan as a chain transfer agent, and 147.0 kg of ToL, adding these materials into a 1.25 m 3 reactor equipped with a stirring blade and a temperature controller functioning through use of a jacket, and then stirring these materials.
• a mixed monomer solution (1) for subsequent addition was prepared by measuring out 271.2 kg of MMA, 37.1 kg of phMI, 30.9 kg of chMI, and 265.0 kg of ToL, adding these materials into a first tank, and then stirring these materials. In addition, 58.0 kg of MMA was prepared in a second tank.
• the reactor, the first tank, and the second tank were each subjected to 30 minutes of nitrogen bubbling at a rate of 10 L/min to remove dissolved oxygen.
• the solution temperature inside the reactor during polymerization was controlled to 110 ⁇ 2° C. through temperature adjustment using the jacket.
• the mixed monomer solution (1) for subsequent addition was added from the first tank at an addition rate of 306 kg/hr.
• Irganox 1010 was added to the polymerization solution under stirring in an amount of 0.1 parts by mass per 100 parts by mass of polymer contained in the solution.
• the polymerization solution was fed into a concentrating device comprising a tubular heat exchanger and a vaporization tank that had been pre-heated to 170° C., and the concentration of polymer contained in the solution was raised to 70 mass %.
• the resultant polymerization solution was fed into a thin film evaporator having a heat transfer area of 0.2 m 2 and was subjected to devolatilization.
• the devolatilization was carried out with an evaporator internal temperature of 280° C., a feed rate of 30 L/hr, a rotational speed of 400 rpm, and a degree of vacuum of 30 Torr.
• the polymerized product subjected to devolatilization was then pressurized using a gear pump, extruded from a strand die, cooled by water, and subsequently pelletized to obtain a methacrylic resin polymerized product (1-3) having a cyclic structure-containing main chain.
• the chemical composition of the obtained pelletized polymerized product (1-3) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 81.1 mass %, 8.1 mass %, and 10.8 mass %, respectively. Moreover, the weight average molecular weight (Mw) was 142,000 and the S/H ratio used as an indicator of stereoregularity was 1.24.
• a mixed monomer solution was prepared by measuring out 163.0 kg of MMA, 8.1 kg of phMI, 11.6 kg of chMI, 0.85 kg of n-octyl mercaptan as a chain transfer agent, and 147.0 kg of ToL, adding these materials into a 1.25 m 3 reactor equipped with a stirring blade and a temperature controller functioning through use of a jacket, and then stirring these materials.
• a mixed monomer solution for subsequent addition was prepared by measuring out 302.6 kg of MMA, 15.1 kg of phMI, 21.5 kg of chMI, and 273.0 kg of ToL, adding these materials into a first tank, and then stirring these materials. In addition, 58.0 kg of MMA was measured out in a second tank.
• the reactor, the first tank, and the second tank were each subjected to 30 minutes of nitrogen bubbling at a rate of 10 L/min to remove dissolved oxygen.
• the solution temperature inside the reactor during polymerization was controlled to 110 ⁇ 2° C. through temperature adjustment using the jacket.
• the mixed monomer solution for subsequent addition was added from the first tank at an addition rate of 306 kg/hr.
• Irganox 1010 was added to the polymerization solution under stirring in an amount of 0.1 parts by mass per 100 parts by mass of polymer contained in the solution.
• the polymerization solution was fed into a concentrating device comprising a tubular heat exchanger and a vaporization tank that had been pre-heated to 170° C., and the concentration of polymer contained in the solution was raised to 70 mass %.
• the resultant polymerization solution was fed into a thin film evaporator having a heat transfer area of 0.2 m 2 and was subjected to devolatilization.
• the devolatilization was carried out with an evaporator internal temperature of 280° C., a feed rate of 30 L/hr, a rotational speed of 400 rpm, and a degree of vacuum of 30 Torr.
• the polymerized product subjected to devolatilization was then pressurized using a gear pump, extruded from a strand die, cooled by water, and subsequently pelletized to obtain a composition (1-4) containing a methacrylic resin polymerized product having a cyclic structure-containing main chain.
• composition (1-4) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 90.3 mass %, 4.0 mass %, and 5.7 mass %, respectively.
• weight average molecular weight (Mw) was 95,000 and the S/H ratio used as an indicator of stereoregularity was 1.35.
• a mixed monomer solution was prepared by measuring out 108.1 kg of MMA, 32.1 kg of phMI, 42.4 kg of chMI, 0.78 kg of n-octyl mercaptan as a chain transfer agent, and 147.0 kg of ToL, adding these materials into a 1.25 m 3 reactor equipped with a stirring blade and a temperature controller functioning through use of a jacket, and then stirring these materials
• a mixed monomer solution for subsequent addition was prepared by measuring out 201 kg of MMA, 59.5 kg of phMI, 78.8 kg of chMI, and 273.0 kg of ToL, adding these materials into a first tank, and then stirring these materials. In addition, 58.0 kg of MMA was measured out in a second tank.
• the reactor, the first tank, and the second tank were each subjected to 30 minutes of nitrogen bubbling at a rate of 10 L/min to remove dissolved oxygen.
• the solution temperature inside the reactor during polymerization was controlled to 110 ⁇ 2° C. through temperature adjustment using the jacket.
• the mixed monomer solution for subsequent addition was added from the first tank at an addition rate of 306 kg/hr.
• Irganox 1010 was added to the polymerization solution under stirring in an amount of 0.1 parts by mass per 100 parts by mass of polymer contained in the solution.
• the polymerization solution was fed into a concentrating device comprising a tubular heat exchanger and a vaporization tank that had been pre-heated to 170° C., and the concentration of polymer contained in the solution was raised to 70 mass %.
• the resultant polymerization solution was fed into a thin film evaporator having a heat transfer area of 0.2 m 2 and was subjected to devolatilization.
• the devolatilization was carried out with an evaporator internal temperature of 280° C., a feed rate of 30 L/hr, a rotational speed of 400 rpm, and a degree of vacuum of 30 Torr.
• the polymerized product subjected to devolatilization was then pressurized using a gear pump, extruded from a strand die, cooled by water, and subsequently pelletized to obtain a methacrylic resin composition (1-5) having a cyclic structure-containing main chain.
• the chemical composition of the obtained composition (1-5) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 63.3 mass %, 15.8 mass %, and 20.9 mass %, respectively. Moreover, the weight average molecular weight (Mw) was 99,000 and the S/H ratio used as an indicator of stereoregularity was 1.15.
• a mixed monomer solution was prepared by measuring out 146.0 kg of MMA, 28.5 kg of phMI, 8.0 kg of chMI, 0.15 kg of n-octyl mercaptan as a chain transfer agent, and 147.0 kg of MIBK, adding these materials into a 1.25 m 3 reactor equipped with a stirring blade and a temperature controller functioning through use of a jacket, and then stirring these materials.
• a mixed monomer solution for subsequent addition was prepared by measuring out 271.4 kg of MMA, 52.9 kg of phMI, 14.9 kg of chMI, and 273.0 kg of MIBK, adding these materials into a first tank, and then stirring these materials. In addition, 58.0 kg of MMA was measured out in a second tank.
• the reactor, the first tank, and the second tank were each subjected to 30 minutes of nitrogen bubbling at a rate of 10 L/min to remove dissolved oxygen.
• the solution temperature inside the reactor during polymerization was controlled to 110 ⁇ 2° C. through temperature adjustment using the jacket.
• the mixed monomer solution for subsequent addition was added from the first tank at an addition rate of 306 kg/hr.
• Irganox 1010 was added to the polymerization solution under stirring in an amount of 0.1 parts by mass per 100 parts by mass of polymer contained in the solution.
• the polymerization solution was fed into a concentrating device comprising a tubular heat exchanger and a vaporization tank that had been pre-heated to 170° C., and the concentration of polymer contained in the solution was raised to 70 mass %.
• the resultant polymerization solution was fed into a thin film evaporator having a heat transfer area of 0.2 m 2 and was subjected to devolatilization.
• the devolatilization was carried out with an evaporator internal temperature of 280° C., a feed rate of 30 L/hr, a rotational speed of 400 rpm, and a degree of vacuum of 30 Torr.
• the polymerized product subjected to devolatilization was then pressurized using a gear pump, extruded from a strand die, cooled by water, and subsequently pelletized to obtain a composition (1-6) containing a methacrylic resin polymerized product having a cyclic structure-containing main chain.
• the chemical composition of the obtained pelletized composition (1-6) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 82.0 mass %, 14.1 mass %, and 3.9 mass %, respectively. Moreover, the weight average molecular weight (Mw) was 226,000 and the S/H ratio used as an indicator of stereoregularity was 1.26.
• a mixed monomer solution was prepared by measuring out 146.0 kg of MMA, 14.6 kg of phMI, 22.0 kg of chMI, 0.17 kg of n-octyl mercaptan as a chain transfer agent, and 147.0 kg of m-xylene (hereinafter, denoted as “mXy”), adding these materials into a 1.25 m 3 reactor equipped with a stirring blade and a temperature controller functioning through use of a jacket, and then stirring these materials.
• mXy m-xylene
• a mixed monomer solution for subsequent addition was prepared by measuring out 271.2 kg of MMA, 27.1 kg of phMI, 40.9 kg of chMI, and 273.0 kg of mXy, adding these materials into a first tank, and then stirring these materials. In addition, 58.0 kg of MMA was measured out in a second tank.
• the reactor, the first tank, and the second tank were each subjected to 30 minutes of nitrogen bubbling at a rate of 10 L/min to remove dissolved oxygen.
• the solution temperature in the reactor was raised to 100° C. by blowing steam into the jacket, and then the contents of the reactor were stirred at 50 rpm while adding a polymerization initiator solution containing 0.35 kg of t-butylperoxy isopropyl monocarbonate dissolved in 4.65 kg of mXy at a rate of 2 kg/hr to initiate polymerization.
• the solution temperature inside the reactor during polymerization was controlled to 110 ⁇ 2° C. through temperature adjustment using the jacket.
• the addition rate of the initiator solution was reduced to 1 kg/hr and the mixed monomer solution for subsequent addition was added from the first tank over 2 hours at 306.2 kg/hr.
• the entire amount of MMA in the second tank was added over 30 minutes at a rate of 116 kg/hr.
• the addition rate of the initiator solution was reduced to 0.5 kg/hr once 3.5 hours had passed from the start of polymerization, 0.25 kg/hr once 4.5 hours had passed from the start of polymerization, and 0.125 kg/hr once 6 hours had passed from the start of polymerization, and addition was stopped once 7 hours had passed from the start of polymerization.
• a polymerization solution containing a methacrylic resin having a cyclic structure-containing main chain was obtained once 10 hours had passed from the start of polymerization.
• Irganox 1010 was added to the polymerization solution under stirring in an amount of 0.1 parts by mass per 100 parts by mass of polymer contained in the solution.
• the resultant polymerization solution was fed into a concentrating device comprising a tubular heat exchanger and a vaporization tank that had been pre-heated to 170° C., and the concentration of polymer contained in the solution was raised to 70 mass %.
• the resultant polymerization solution was fed into a thin film evaporator having a heat transfer area of 0.2 m 2 and was subjected to devolatilization.
• the devolatilization was carried out with an evaporator internal temperature of 280° C., a feed rate of 30 L/hr, a rotational speed of 400 rpm, and a degree of vacuum of 30 Torr.
• the polymerized product subjected to devolatilization was then pressurized using a gear pump, extruded from a strand die, cooled by water, and subsequently pelletized to obtain a composition (2) containing a methacrylic resin polymerized product having a cyclic structure-containing main chain.
• the chemical composition of the obtained pelletized composition (2) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 81.3 mass %, 7.9 mass %, and 10.8 mass %, respectively. Moreover, the weight average molecular weight (Mw) was 157,000 and the S/H ratio used as an indicator of stereoregularity was 1.25.
• a mixed monomer solution was prepared by measuring out 450.7 kg of MMA, 39.8 kg of phMI, 59.7 kg of chMI, 0.41 kg of n-octyl mercaptan as a chain transfer agent, and 450 kg of mXy, adding these materials into a 1.25 m 3 reactor that had been purged with nitrogen in advance, and then stirring these materials.
• the mixed monomer solution was subjected to 6 hours of nitrogen bubbling at a rate of 100 mL/min to remove dissolved oxygen, and then the temperature of the mixed monomer solution was raised to 110° C.
• a polymerization initiator solution containing 0.30 kg of t-butylperoxy isopropyl monocarbonate as a polymerization initiator dissolved in 3.85 kg of mXy was subsequently added at a rate of 1 kg/hr to perform polymerization.
• a polymerization solution containing a methacrylic resin having a cyclic structure-containing main chain was obtained once 10 hours had passed from the start of polymerization.
• Irganox 1010 was added to the polymerization solution under stirring in an amount of 0.1 parts by mass per 100 parts by mass of polymer contained in the solution.
• the polymerization solution was then subjected to concentration, devolatilization, and pelletization in the same way as in Production Example 1-1 to obtain a pelletized composition (3) containing a methacrylic resin polymerized product including N-substituted maleimide structural units.
• the chemical composition of the obtained composition (3) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 81.3 mass %, 7.9 mass %, and 10.8 mass %, respectively. Moreover, the weight average molecular weight (Mw) was 155,000 and the S/H ratio used as an indicator of stereoregularity was 1.25.
• a raw material solution was prepared by charging 149.6 kg of MMA, 37.4 kg of methyl 2-(hydroxymethyl)acrylate, 0.04 kg of tris(2,4-di-t-butylphenyl) phosphite, 149.0 kg of MIBK, and 25 g of n-dodecyl mercaptan into a 1 m 3 reactor that was equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen gas supply tube, and that had been internally purged with nitrogen in advance. The reactor was stirred and the internal temperature of the reactor was raised to 100° C. while passing nitrogen therethrough.
• a polymerization initiator solution was separately prepared by mixing 0.56 kg of t-amyl peroxyisononanoate as a polymerization initiator and 3.6 kg of MIBK.
• the initiator solution was added as in (1) to (6) of the following addition profile to initiate polymerization.
• the internal temperature during the polymerization reaction was controlled to 105° C. to 110° C.
• the resultant polymer solution was subsequently heated to 240° C. in a heater comprising a multi-tube heat exchanger and was then introduced into a vented twin-screw extruder equipped with one rear vent and four front vents so as to continue the cyclization reaction while performing devolatilization.
• the conditions in the twin-screw extruder were a feed rate of the resultant copolymer solution of 15 kg/hr in terms of resin, a barrel temperature of 260° C., a rotational speed of 100 rpm, and a degree of vacuum of 10 Torr to 300 Torr.
• a catalyst deactivator (zinc 2-ethylhexanoate; produced by Nihon Kagaku Sangyo Co., Ltd.; product name: NIKKA OCTHIX Zn 18%) and Irganox 1010 were fed from two side feeds provided in a downstream half of the twin-screw extruder.
• the deactivator and Irganox 1010 were added with respective feed rates of 30 g/hr and 15 g/hr, as toluene solutions, for the same time as the feed time of the resin.
• the cyclized polymerized product subjected to cyclization and devolatilization treatment by the twin-screw extruder was extruded from a strand die, cooled by water, and then pelletized to obtain a composition (4-1) containing a methacrylic resin polymerized product.
• the chemical composition of the obtained composition (4-1) comprised lactone ring structural units in a proportion of 28.3 mass %.
• the content of lactone ring structural units was determined by a method described in JP 2007-297620 A.
• the obtained composition (4-1) had a weight average molecular weight (Mw) of 209,000 and an S/H ratio, used as an indicator of stereoregularity, of 1.40.
• a raw material solution was prepared by charging 136.6 kg of MMA, 37.4 kg of methyl 2-(hydroxymethyl)acrylate, 13.0 kg of styrene, 0.04 kg of tris(2,4-di-t-butylphenyl) phosphite, 149.0 kg of ToL, and 125 g of n-dodecyl mercaptan into a 1 m 3 reactor that was equipped with a stirrer, a temperature sensor, a cooling tube, and nitrogen gas supply tube, and that had been internally purged with nitrogen in advance. The reactor was stirred and the internal temperature of the reactor was raised to 100° C. while passing nitrogen therethrough.
• a solution for separate addition was separately prepared by mixing 0.56 kg of t-amyl peroxyisononanoate as a polymerization initiator and 6.5 kg of styrene.
• the internal temperature during the polymerization reaction was controlled to 105° C. to 110° C.
• the resultant polymer solution was subsequently heated to 240° C. in a heater comprising a multi-tube heat exchanger and was then introduced into a vented twin-screw extruder equipped with one rear vent and four front vents so as to continue the cyclization reaction while performing devolatilization.
• the conditions in the twin-screw extruder were a feed rate of the resultant copolymer solution of 15 kg/hr in terms of resin, a barrel temperature of 260° C., a rotational speed of 100 rpm, and a degree of vacuum of 10 Torr to 300 Torr.
• a catalyst deactivator (zinc 2-ethylhexanoate; produced by Nihon Kagaku Sangyo Co., Ltd.; product name: NIKKA OCTHIX Zn 18%) and Irganox 1010 were fed from two side feeds provided in a downstream half of the twin-screw extruder.
• the deactivator and Irganox 1010 were added with respective feed rates of 30 g/hr and 15 g/hr, as toluene solutions, for the same time as the feed time of the resin.
• the cyclized polymerized product subjected to cyclization and devolatilization treatment by the twin-screw extruder was extruded from a strand die, cooled by water, and then pelletized to obtain a composition (4-2) containing a methacrylic resin polymerized product.
• the chemical composition of the obtained composition (4-2) comprised lactone ring structural units in a proportion of 28.3 mass % and styrene monomer-derived structural units in a proportion of 6.8 mass %.
• the content of lactone ring structural units was determined by the method described in JP 2007-297620 A.
• the obtained composition (4-2) had a weight average molecular weight (Mw) of 109,000 and an S/H ratio, used as an indicator of stereoregularity, of 1.26.
• a composition (4-3) containing a methacrylic resin polymerized product was produced in the same way as in Production Example 4-2 with the exception that the method in Production Example 4-2 was changed to a method in which n-dodecyl mercaptan was not used and in which the initiator solution was added for 2 hours at an addition rate of 3.58 kg/hr.
• the chemical composition of the obtained composition (4-3) comprised lactone ring structural units in a proportion of 28.3 mass % and styrene monomer-derived structural units in a proportion of 6.5 mass %.
• the content of lactone ring structural units was determined by the method described in JP 2007-297620 A.
• the obtained composition (4-3) had a weight average molecular weight (Mw) of 142,000 and an S/H ratio, used as an indicator of stereoregularity, of 1.28.
• a mixed liquid was prepared by charging 2 kg of water, 65 g of tricalcium phosphate, 39 g of calcium carbonate, and 0.39 g of sodium lauryl sulfate to a vessel having a stirrer equipped with four pitched-paddle blades, and then mixing these materials.
• the polymerization reaction solution was then passed through a sieve having a 1.68 mm mesh to remove aggregates, moisture was separated by filtration, and the resultant slurry was dehydrated to obtain a bead-shaped polymer.
• the bead-shaped polymer was washed with water and was then dehydrated in the same manner as above.
• the bead-shaped polymer was then washed through repeated washing with deionized water and dehydration to obtain a particulate methacrylic resin (5) having a cyclic structure-containing main chain.
• the chemical composition of the obtained polymerized product (5) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 81.3 mass %, 7.9 mass %, and 10.8 mass %, respectively.
• the weight average molecular weight was 185,000
• the Vicat softening temperature was 131° C.
• the S/H ratio used as an indicator of stereoregularity was 1.95.
• composition (1-1) obtained in Production Example 1-1 and the composition (1-2) obtained in Production Example 1-2 were vacuum dried for 5 hours at 90° C., cooled to 30° C. in a nitrogen atmosphere, and then used in preparation of a composition.
• a tumbler-type mixer that had been purged with nitrogen in advance was used to prepare a mixture from 50 parts by mass of the composition (1-1), 50 parts by mass of the composition (1-2), and 0.1 parts by mass of ADK STAB PEP 36 as an antioxidant.
• the resultant mixture was fed into and melt-kneaded by a 58 mm ⁇ vented twin-screw extruder with use of dehumidified air adjusted to a dew point of ⁇ 30° C. and a temperature of 80° C.
• a nitrogen supply line was provided in a lower part of a raw material hopper for the twin-screw extruder, and nitrogen was introduced into the extruder during the above operation.
• the oxygen concentration at the bottom of the raw material hopper was measured to be approximately 1 volume %.
• Operation was performed under conditions of a temperature setting for a lower part of the extruder and a die of 270° C., a rotational speed of 200 rpm, a degree of vacuum in a vent part of 200 Torr, and a discharge rate of 20 kg/hr.
• the melt-kneaded resin composition was extruded through a porous die as strands and was introduced into a cooling bath filled with cooling water that had been pre-heated to 50° C.
• the resin composition was cooled and solidified, and was cut using a cutter to obtain a pelletized composition.
• the chemical composition of the obtained pelletized composition (1) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 81.2 mass %, 8.0 mass %, and 10.8 mass %, respectively.
• the weight average molecular weight was 143,000, the Vicat softening temperature was 130° C., and the S/H ratio used as an indicator of stereoregularity was 1.34.
• a composition (2) was prepared in the same way as in Example 1 with the exception that the methacrylic resin compositions used in Example 1 were changed to 50 parts by mass of the composition (1-1) obtained in Production Example 1-1 and 50 parts by mass of the composition (1-4) obtained in Production Example 1-4.
• the chemical composition of the obtained pelletized composition (2) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 85.2 mass %, 3.0 mass %, and 11.8 mass %, respectively.
• the weight average molecular weight was 140,000, the Vicat softening temperature was 120° C., and the S/H ratio used as an indicator of stereoregularity was 1.39.
• a composition (3) was prepared in the same way as in Example 1 with the exception that the methacrylic resin compositions used in Example 1 were changed to 50 parts by mass of the composition (1-1) obtained in Production Example 1-1 and 50 parts by mass of the composition (1-5) obtained in Production Example 1-5.
• the chemical composition of the obtained pelletized composition (3) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 71.8 mass %, 8.9 mass %, and 19.3 mass %, respectively.
• the weight average molecular weight was 137,000, the Vicat softening temperature was 138° C., and the S/H ratio used as an indicator of stereoregularity was 1.29.
• a composition (4) was prepared in the same way as in Example 1 with the exception that the methacrylic resin compositions used in Example 1 were changed to 70 parts by mass of the composition (1-1) obtained in Production Example 1-1 and 30 parts by mass of the composition (1-2) obtained in Production Example 1-2.
• the chemical composition of the obtained pelletized composition (4) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 81.5 mass %, 10.4 mass %, and 8.1 mass %, respectively.
• the weight average molecular weight was 168,000, the Vicat softening temperature was 133° C., and the S/H ratio used as an indicator of stereoregularity was 1.37.
• a composition (5) was prepared in the same way as in Example 1 with the exception that the methacrylic resin compositions used in Example 1 were changed to 30 parts by mass of the composition (1-1) obtained in Production Example 1-1 and 70 parts by mass of the composition (1-2) obtained in Production Example 1-2.
• the chemical composition of the obtained pelletized composition (5) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 80.8 mass %, 5.6 mass %, and 13.6 mass %, respectively.
• the weight average molecular weight was 122,000, the Vicat softening temperature was 127° C., and the S/H ratio used as an indicator of stereoregularity was 1.31.
• a composition (6) was prepared in the same way as in Example 1 with the exception that the methacrylic resin compositions used in Example 1 were changed to 50 parts by mass of the composition (4-1) obtained in Production Example 4-1 and 50 parts by mass of the composition (4-2) obtained in Production Example 4-2.
• the chemical composition of the obtained pelletized composition (6) comprised lactone ring structural units in a proportion of 28.3 mass % and styrene monomer-derived structural units in a proportion of 3.4 mass %.
• the weight average molecular weight was 148,000, the Vicat softening temperature was 124° C., and the S/H ratio used as an indicator of stereoregularity was 1.33.
• a composition (7) was prepared in the same way as in Example 1 with the exception that the methacrylic resin compositions used in Example 1 were changed to 100 parts by mass of the polymerized product (1-3) obtained in Production Example 1-3.
• the chemical composition of the obtained pelletized composition (7) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 81.3 mass %, 7.9 mass %, and 10.8 mass %, respectively.
• the weight average molecular weight was 131,000, the Vicat softening temperature was 129° C., and the S/H ratio used as an indicator of stereoregularity was 1.24.
• a composition (8) was prepared in the same way as in Example 1 with the exception that the methacrylic resin compositions used in Example 1 were changed to 60 parts by mass of the composition (2) obtained in Production Example 2 and 40 parts by mass of the polymerized product (5) obtained in Production Example 5. It was confirmed that the chemical composition of the obtained pelletized composition (8) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 81.3 mass %, 7.9 mass %, and 10.8 mass %, respectively.
• the weight average molecular weight was 151,000, the Vicat softening temperature was 131° C., and the S/H ratio used as an indicator of stereoregularity was 1.49.
• a composition (9) was prepared in the same way as in Example 1 with the exception that the methacrylic resin compositions used in Example 1 were changed to 50 parts by mass of the composition (1-1) obtained in Production Example 1-1 and 50 parts by mass of the composition (6) obtained in Production Example 1-6. It was confirmed that the chemical composition of the obtained pelletized composition (9) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 81.3 mass %, 7.9 mass %, and 10.8 mass %, respectively.
• the weight average molecular weight was 212,000, the Vicat softening temperature was 130° C., and the S/H ratio used as an indicator of stereoregularity was 1.34.
• An unstretched sheet of 1.5 mm in thickness was produced using the pelletized composition (4) obtained in Example 4.
• the unstretched sheet was produced using a 50 mm ⁇ single-screw extruder having a gear pump and a T-die with a lip opening of 2.5 mm and a width of 480 mm positioned at the tip of the extruder, and with production conditions of an extruder temperature setting of 270° C., a T-die temperature setting of 265° C., and a discharge rate of 8 kg/hr.
• the unstretched sheet was then longitudinally stretched with a stretching ratio of 2 times using a roll stretching device.
• the roll temperature was set as the Vicat softening temperature+10° C.
• the longitudinal stretching was followed by transverse stretching with a stretching ratio of 2 times using a tenter-type transverse stretching device with the stretching temperature set to the Vicat softening temperature+10° C.
• a sequentially biaxially stretched sheet of 35 ⁇ m in thickness was obtained.
• the photoelastic coefficient of the biaxially stretched sheet was 1.0 ⁇ 10 12 Pa ⁇ 1 .
• the obtained biaxially stretched sheet was subjected to surface shaping by press molding using the following mold.
• Pattern protrusion width 0.5 ⁇ m
• Pattern protrusion height 1 ⁇ m
• Mold release temperature Release of mold clamping pressure after cooling to 130° C.
• Cooling temperature 50° C.
• the obtained surface-shaped sheet was observed under an optical microscope. Through this observation, it was confirmed that the cross-sectional area of recesses of the surface-shaped sheet as a percentage relative to the cross-sectional area of protrusions of the mold was 92%, which is a good result. This result demonstrates that excellent surface shaping properties can be obtained even in the case of a sheet-shaped molded product that is relatively thick.
• a composition (CE1) was prepared in the same way as in Example 1 with the exception that the methacrylic resin compositions used in Example 1 were changed to 100 parts by mass of the composition (2) obtained in Production Example 2.
• the chemical composition of the obtained pelletized composition (CE1) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 81.3 mass %, 7.9 mass %, and 10.8 mass %, respectively.
• the weight average molecular weight was 141,000, the Vicat softening temperature was 129° C., and the S/H ratio used as an indicator of stereoregularity was 1.19.
• a composition (CE2) was prepared in the same way as in Example 1 with the exception that the methacrylic resin compositions used in Example 1 were changed to 100 parts by mass of the composition (3) obtained in Production Example 3.
• the chemical composition of the obtained pelletized composition (CE2) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 81.3 mass %, 7.9 mass %, and 10.8 mass %, respectively.
• the weight average molecular weight was 140,000, the Vicat softening temperature was 128° C., and the S/H ratio used as an indicator of stereoregularity was 1.15.
• a composition (CE3) was prepared in the same way as in Example 3 with the exception that the methacrylic resin compositions used in Example 3 were changed to 100 parts by mass of the composition (4-3) obtained in Production Example 4-3.
• the chemical composition of the obtained pelletized composition (CE3) comprised lactone ring structural units in a proportion of 28.3 mass % and styrene monomer-derived structural units in a proportion of 6.5 mass %.
• the weight average molecular weight was 135,000, the Vicat softening temperature was 121° C., and the S/H ratio used as an indicator of stereoregularity was 1.28.
• a methyl methacrylate-maleic anhydride-styrene copolymer (copolymer A) was obtained by a method described in JP S63-1964 B.
• methyl methacrylate-maleic anhydride-styrene copolymer was formed from 74 mass % of methyl methacrylate, 10 mass % of maleic anhydride, and 16 mass % of styrene, and had a weight average molecular weight of 121,000.
• a resin composition was prepared in the same way as in Example 1 with the exception that the copolymer A obtained as set forth above was used instead of the methacrylic resin obtained in Production Examples 1-1 and 1-2.
• the weight average molecular weight was 117,000, the Vicat softening temperature was 122° C., and the S/H ratio used as an indicator of stereoregularity was 1.96.
• a composition (9) was prepared in the same way as in Example 1 with the exception that the methacrylic resin compositions used in Example 1 were changed to 55 parts by mass of the composition (2) obtained in Production Example 2 and 45 parts by mass of the polymerized product (5) obtained in Production Example 5. It was confirmed that the chemical composition of the obtained pelletized composition (9) comprised structural units derived from the monomers MMA, phMI, and chMI in proportions of 81.3 mass %, 7.9 mass %, and 10.8 mass %, respectively.
• the weight average molecular weight was 160,000, the Vicat softening temperature was 131° C., and the S/H ratio used as an indicator of stereoregularity was 1.56.
• a surface shaping test was performed on a sheet-shaped molded product in the same way as in Example 10 with the exception that the methacrylic resin composition that was used was changed to the composition (CE2) obtained in Comparative Example 2.
• Example 1 Production 50 Production 50 143,000 130 1.34 1.8 0.2 ⁇ 10 ⁇ 12 Example Example 1-1 1-2 Example 2 Production 50 Production 50 140,000 120 1.39 2.0 0.4 ⁇ 10 ⁇ 12 Example Example 1-1 1-4 Example 3 Production 50 Production 50 137,000 138 1.29 2.5 0.4 ⁇ 10 ⁇ 12 Example Example 1-1 1-5 Example 4 Production 70 Production 30 168,000 133 1.37 1.7 0.3 ⁇ 10 ⁇ 12 Example Example 1-1 1-2 Example 5 Production 30 Production 70 122,000 127 1.31 2.1 0.3 ⁇ 10 ⁇ 12 Example Example 1-1 1-2 Example 6 Production 50 Production 50 148,000 124 1.33 4.2 1.5 ⁇ 10 ⁇ 12 Example Example 4-1 4-2 Example 7 Production 100 131,000 129 1.24 2.2 0.2 ⁇ 10 ⁇ 12 Example 1-3 Example 8 Production 60 Production 40 151,000 131 1.49 3.6 0.3 ⁇ 10 ⁇ 12 Example 2 Example 5* Example 9 Production 50 Production 50 212,000 130 1.34 1.6 0.2 ⁇ 10 ⁇ 12 Example Example 1-1 1-6 Comparative Production 100 14
• the methacrylic resin composition according to the present embodiment has excellent transparency, and good heat resistance and weather resistance, and the birefringence thereof is controlled to a high degree. Therefore, the methacrylic resin composition according to the present embodiment is suitable for use as an optical material in, for example, polarizing plate protective films, retardation plates (for example, quarter-wave plates and half-wave plates), liquid-crystal optical compensation films (for example, viewing angle control films), display front plates, display base plates, lenses, and the like used in displays such as liquid-crystal displays, plasma displays, organic EL displays, field emission displays, and rear projection televisions.
• polarizing plate protective films retardation plates (for example, quarter-wave plates and half-wave plates), liquid-crystal optical compensation films (for example, viewing angle control films), display front plates, display base plates, lenses, and the like used in displays such as liquid-crystal displays, plasma displays, organic EL displays, field emission displays, and rear projection televisions.
• the methacrylic resin composition according to the present embodiment is also suitable for use as an optical material in transparent base plates of solar cells, transparent conductive base plates of touch panels and the like, and may also be used in the fields of optical communication systems, optical switching systems, and optical measurement systems for waveguides, lenses, lens arrays, optical fibers, optical fiber coating materials, LED lenses, lens covers, and so forth.

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