Classifications

• • 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
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D133/00—Coating compositions based on 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 only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
  • C09D133/04—Homopolymers or copolymers of esters
  • C09D133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
  • C09D133/10—Homopolymers or copolymers of methacrylic acid esters
  • C09D133/12—Homopolymers or copolymers of methyl methacrylate
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2325/00—Characterised by the use 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 an aromatic carbocyclic ring; Derivatives of such polymers
  • C08J2325/02—Homopolymers or copolymers of hydrocarbons
  • C08J2325/04—Homopolymers or copolymers of styrene
  • C08J2325/06—Polystyrene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2325/00—Characterised by the use 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 an aromatic carbocyclic ring; Derivatives of such polymers
  • C08J2325/02—Homopolymers or copolymers of hydrocarbons
  • C08J2325/04—Homopolymers or copolymers of styrene
  • C08J2325/08—Copolymers of styrene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2333/00—Characterised by the use 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; Derivatives of such polymers
  • C08J2333/04—Characterised by the use 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; Derivatives of such polymers esters
  • C08J2333/06—Characterised by the use 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; Derivatives of such polymers esters of esters containing only carbon, hydrogen, and oxygen, the oxygen atom being present only as part of the carboxyl radical
  • C08J2333/10—Homopolymers or copolymers of methacrylic acid esters
  • C08J2333/12—Homopolymers or copolymers of methyl methacrylate

Definitions

• the present invention relates to a methacrylic copolymer essentially containing a methyl methacrylate unit, an ⁇ -methylstyrene unit and a styrene unit, and a method for producing the same.
• a methacrylic copolymer that essentially contains a methyl methacrylate unit and an ⁇ -methylstyrene unit is known as a resin material with excellent transparency.
• Patent Document 1 discloses a copolymer composed of 10 to 65% by weight of ⁇ -methylstyrene units, 10 to 40% by weight of methyl methacrylate units and 10 to 80% by weight of styrene units, and has a weight average molecular weight of range of 50000 to 400000, a Vicat softening temperature of 105 ° C. or higher, a refractive index of 1.550 to 1.580, a water absorption of 0.13% or less, and a birefringence value of 300 nm when a prism with a thickness of 10 mm is used.
• the following resin materials for optical prisms or lenses are disclosed.
• Patent Document 2 describes a method in which a weight average molecular weight range of 50,000 to 200,000, a ratio of ⁇ -methylstyrene units of 10 to 40% by weight, and a ratio of methyl methacrylate units of 40 to 40% are applied to the surface of a transparent thermoplastic. It discloses a resin molded article coated with an ⁇ -methylstyrene copolymer containing 90% by weight and 0 to 30% by weight of monomer units copolymerizable therewith.
• Patent Document 3 uses ⁇ -methylstyrene, methyl methacrylate and maleic anhydride as monomers, and uses a polyfunctional organic peroxide having a 10-hour half-life temperature of 60 to 110° C. as a polymerization initiator for all monomers.
• a method for producing an ⁇ -methylstyrene copolymer characterized by adding 0.05 to 1.0% by weight based on the amount and carrying out bulk polymerization at 100 to 150°C.
• Patent Document 4 when producing an ⁇ -methylstyrene copolymer consisting of 6 to 34% by weight of ⁇ -methylstyrene units, 0 to 50% by weight of styrene units and 94 to 16% by weight of methyl methacrylate units, it takes 10 hours and half. 6 to 40% by weight of ⁇ -methylstyrene, 0 to 50% by weight of styrene, and 94 to 16% by weight of methyl methacrylate using a polyfunctional organic peroxide having an initial temperature in the range of 60 to 110°C as a polymerization initiator. It discloses a method for producing an ⁇ -methylstyrene copolymer, characterized by adding 0.05 to 1.0 parts by weight to 100 parts by weight of a monomer and carrying out bulk polymerization at 100 to 150°C.
• Patent Document 5 discloses an ⁇ -methyl styrene unit containing 10 to 35% by weight of ⁇ -methylstyrene unit, 94 to 15% by weight of methyl methacrylate unit, and 0 to 50% by weight of a vinyl monomer copolymerizable with these monomers as structural units.
• a styrene copolymer 0.05 to 1.0 parts by weight of an organic peroxide as a polymerization initiator per 100 parts by weight of monomers and 0.01 to 0.15 parts by weight of divinylbenzene per 100 parts by weight of monomers are used. It discloses a method for producing an ⁇ -methylstyrene copolymer characterized by adding parts by weight and polymerizing at 100 to 150°C.
• Patent Document 6 states that this production method enables continuous production of an ⁇ -methylstyrene copolymer by bulk polymerization.
• An object of the present invention is to provide a novel copolymer essentially containing a methyl methacrylate unit and an ⁇ -methylstyrene unit, and a method for producing a copolymer suitable for producing the same.
• the present invention includes the following aspects.
• [1] Contains 40 to 87% by mass of methyl methacrylate units, 8 to 30% by mass of ⁇ -methylstyrene units, and 5 to 30% by mass of styrene units.
• A is the logarithm of the peak top molecular weight in the differential molecular weight distribution curve obtained by gel permeation chromatography measurement using a differential refractive index detector
• B is the gel using an absorbance detector with a detection wavelength of 254 nm. It is the logarithm of the peak top molecular weight in the differential molecular weight distribution curve obtained by permeation chromatography measurement.
• a laminate having a layer containing the methacrylic copolymer described in [1] and a layer containing another thermoplastic resin.
• a reaction raw material comprising a monomer mixture containing 40 to 87% by mass of methyl methacrylate, 10 to 30% by mass of ⁇ -methylstyrene, and 3 to 30% by mass of styrene, and a radical polymerization initiator is placed in a tank. continuously fed to a type reactor, obtaining a reaction product by bulk-polymerizing the monomer mixture at a polymerization conversion rate of 30 to 60% by mass in a tank reactor; A reaction product is continuously withdrawn from a tank reactor, and a monomer mixture remaining in the withdrawn reaction product is removed from the reaction product.
• a reaction raw material comprising 100 parts by mass of a monomer mixture comprising 40 to 87% by mass of methyl methacrylate, 10 to 30% by mass of ⁇ -methylstyrene, and 3 to 30% by mass of styrene, and a radical polymerization initiator.
• the tank reactor Polymerizing the monomer mixture in a tank reactor to obtain a reaction product, continuously withdrawing the reaction product from the tank reactor, and removing the monomer mixture remaining in the withdrawn reaction product from the reaction product;
• the average concentration of the radical polymerization initiator present in the liquid in the tank reactor is I mol/L
• the average residence time of the reaction raw materials in the tank reactor is ⁇ hr
• their product I ⁇ is , the polymerization conversion rate is 30 to 60% by mass when it is more than 1.0 ⁇ 10 ⁇ 6 mol ⁇ hr/L and less than 2.0 ⁇ 10 ⁇ 5 mol ⁇ hr/L.
• the methacrylic copolymer of the present invention has high heat resistance, low saturated water absorption, and high thermal decomposition resistance.
• the molded article of the present invention is suitable as an optical member such as a polarizing plate protective film.
• continuous bulk polymerization of methyl methacrylate, ⁇ -methylstyrene, and styrene can be carried out with a short average residence time and a high polymerization conversion rate. It can be manufactured with flexibility, high flexibility or high responsiveness.
• the production method of the present invention is suitable for producing methacrylic copolymers.
• the methacrylic copolymer of the present invention includes structural units derived from methyl methacrylate (in the present application, may be referred to as "methyl methacrylate units"), structural units derived from ⁇ -methylstyrene (in the present application, “ ⁇ -methylstyrene unit”) and a structural unit derived from styrene (in the present application, it is sometimes referred to as a "styrene unit").
• the total content of structural units derived from methyl methacrylate is usually 40-87% by mass, preferably 45-87% by mass, more preferably 50-87% by mass.
• the total content of structural units derived from ⁇ -methylstyrene is usually 8-30% by mass, preferably 8-27% by mass, more preferably 8-25% by mass.
• the total content of structural units derived from styrene is usually 5-30% by mass, preferably 5-28% by mass, more preferably 5-25% by mass.
• the methacrylic copolymer of the present invention may contain other copolymerizable monomer units in a small amount of 5% by mass or less. Examples of other copolymerizable monomer units include methacrylate units other than methyl methacrylate units and acrylic ester units such as methyl acrylate units.
• the total amount of all monomer units including methyl methacrylate units, ⁇ -methylstyrene units, and styrene units is 100% by mass.
• /B is usually less than 0.05, preferably less than 0.04, and more preferably less than 0.03. This means that the methacrylic copolymer of the present invention contains structural units that absorb light with a wavelength of 254 nm at almost the same ratio regardless of the molecular weight, and that the degree of growth of the molecular chains is the compositional ratio of the copolymer.
• A is the logarithm of the peak top molecular weight in the differential molecular weight distribution curve obtained by gel permeation chromatography measurement using a differential refractive index detector
• B is the gel using an absorbance detector with a detection wavelength of 254 nm. It is the logarithm of the peak top molecular weight in the differential molecular weight distribution curve obtained by permeation chromatography measurement.
• is the absolute value of the difference between A and B.
• the molecular weight of the methacrylic copolymer was converted from the elution time of the methacrylic copolymer using a calibration curve representing the relationship between the molecular weight of standard polymethyl methacrylate and the elution time (retention time).
• the peak top molecular weight in the differential molecular weight distribution curve is the molecular weight at the point of inflection or maximum slope in the integral molecular weight distribution curve.
• the methacrylic copolymer of the present invention has a weight average molecular weight Mw of preferably 30,000 to 200,000, more preferably 40,000 to 180,000, even more preferably 50,000 to 160,000. Mw is calculated using the formula (2) from the molecular weight distribution obtained by gel permeation chromatography measurement using a differential refractive index detector.
• N is the number of polymer molecules
• M is the molecular weight
• the number average molecular weight Mn is calculated using the formula (3) from the molecular weight distribution obtained by gel permeation chromatography measurement using a differential refractive index detector.
• N is the number of polymer molecules
• M is the molecular weight
• the chromatogram consists of a chart plotting the electrical signal value (intensity Y) derived from the refractive index difference between the test solution and the reference solution against the retention time X, and the electrical signal value (intensity Y ) is plotted against retention time X.
• a standard polymethyl methacrylate is measured by gel permeation chromatography to prepare a calibration curve representing the relationship between retention time and molecular weight. The line connecting the point where the slope of the peak on the high molecular weight side changes from zero to plus and the point where the slope on the low molecular weight side of the peak changes from minus to zero is taken as the baseline.
• the melt flow rate determined by measuring the methacrylic resin composition of the present invention under conditions of 230° C. and a load of 3.8 kg is preferably 0.5 to 30 g/10 min, more preferably 1.0 to 20 g. /10 minutes, more preferably 1.5 to 15 g/10 minutes.
• the methacrylic copolymer of the present invention preferably has a glass transition temperature Tg of 115°C or higher, more preferably 120°C or higher, and even more preferably 125°C or higher.
• Tg glass transition temperature
• the upper limit of the glass transition temperature of the methacrylic copolymer of the present invention is not particularly limited, it is preferably 140°C or lower.
• the 1% thermal weight loss temperature under a nitrogen atmosphere of the methacrylic copolymer related to the present invention is preferably above 260°C, more preferably above 265°C, and even more preferably above 270°C.
• the 1% thermal weight loss temperature can be obtained as the temperature at which the thermal weight loss is 1% with respect to the charged weight using a thermogravimetric analyzer (TGA).
• the thermal weight retention of the methacrylic copolymer related to the present invention when held at 270°C for 30 minutes is preferably over 88%, more preferably over 90%.
• Thermogravimetric retention can be measured using a thermogravimetry apparatus (TGA). A sample with an initial weight of W0 was heated to 270°C at a rate of 20°C/min in a nitrogen atmosphere, held for 30 minutes after reaching 270°C, and when reaching W1, (W1/W0) x 100 was calculated from the thermogravimetric retention ( %) can be calculated.
• TGA thermogravimetry apparatus
• the methacrylic copolymer of the present invention preferably has a saturated water absorption of less than 1.7%, more preferably less than 1.6%.
• Determination of the saturated water absorption is performed as follows. A press-molded sheet of 50 mm ⁇ 50 mm ⁇ 1.0 mm thickness made of a methacrylic copolymer is placed in a dryer at 80° C. and dried for 16 hours or longer. The dried sheet is returned to room temperature and the initial weight W 0 is weighed with an accuracy of 0.1 mg. Next, soak in distilled water at 23° C. for 24 hours, drain, wipe off moisture with a dry cloth or the like, and weigh with an accuracy of 0.1 mg within 1 minute after wiping. Again, immerse in distilled water at 23° C. for 24 hours, drain, wipe off moisture with a dry cloth or the like, and weigh with an accuracy of 0.1 mg within 1 minute after wiping. The weight when the weight change becomes less than 0.02 % of the initial weight W 0 is defined as the saturated weight W S , and the saturated water absorption As is calculated by the following equation.
• the methacrylic copolymer of the present invention is not particularly limited by its production method as long as it satisfies the above characteristic values.
• the methacrylic copolymer of the present invention can be obtained, for example, by the method for producing a methacrylic copolymer of the present invention.
• reaction raw materials are continuously supplied to a tank reactor, and a monomer mixture is polymerized in the tank reactor to produce a reaction product and continuously withdrawing the reaction product from the tank reactor, and removing the monomer mixture remaining in the withdrawn reaction product from the reaction product.
• One embodiment (manufacturing method) of the method for producing the methacrylic copolymer of the present invention is a unit containing 40 to 87% by mass of methyl methacrylate, 10 to 30% by mass of ⁇ -methylstyrene and 3 to 30% by mass of styrene.
• a reaction raw material containing a monomer mixture and a radical polymerization initiator is continuously supplied to a tank reactor, and the monomer mixture is formed into a lump at a polymerization conversion rate of 30 to 60% by mass in the tank reactor.
• the present invention comprises a monomer mixture containing 40 to 87% by mass of methyl methacrylate, 10 to 30% by mass of ⁇ -methylstyrene, and 3 to 30% by mass of styrene, and a radical polymerization initiator.
• the reaction raw material used in the production method of the present invention contains a monomer mixture and a radical polymerization initiator, preferably a monomer mixture, a chain transfer agent and a radical polymerization initiator.
• the monomer mixture contains methyl methacrylate, ⁇ -methylstyrene, and styrene.
• the amount of methyl methacrylate contained in the monomer mixture is usually 40-87% by mass, preferably 45-87% by mass, more preferably 50-87% by mass.
• the amount of ⁇ -methylstyrene contained in the monomer mixture is usually 10-30% by mass, preferably 10-27% by mass, more preferably 10-25% by mass.
• the amount of styrene contained in the monomer mixture is usually 3-30% by mass, preferably 3-28% by mass, more preferably 3-25% by mass.
• the monomer mixture is 100% by mass in total of all monomers including methyl methacrylate, ⁇ -methylstyrene, and styrene.
• the polymerization rate of ⁇ -methylstyrene which has low copolymerization reactivity with methyl methacrylate, tends to increase, and in a continuous polymerization system, a short average residence time and an appropriate initiation It is possible to easily increase the polymerization conversion rate by adjusting the amount of the agent.
• the monomer mixture preferably has b * of -1 to 2, more preferably -0.5 to 1.5.
• b * is a value measured according to the International Commission on Illumination (CIE) standard (1976) or JIS Z-8722.
• the monomer mixture removed from the reaction product is recovered and reused in the present invention. can be used. If b * of the recovered monomer mixture is increased by heat applied during recovery, it is preferable to adjust b * to the above range by purifying by an appropriate method.
• a chain transfer agent can be included in the reaction raw materials in order to adjust the molecular weight of the copolymer.
• Chain transfer agents that can be used in the present invention include n-octylmercaptan, n-dodecylmercaptan, t-dodecylmercaptan, 1,4-butanedithiol, 1,6-hexanedithiol, ethylene glycol bisthiopropionate, and butane.
• monofunctional alkylmercaptans such as n-octylmercaptan and n-dodecylmercaptan are preferred.
• These chain transfer agents can be used singly or in combination of two or more.
• the amount of the chain transfer agent to be used is preferably 0 to 1 part by mass, more preferably 0.0001 to 0.8 part by mass and even more preferably 0.001 to 0.8 part by mass, based on 100 parts by mass of the monomer mixture. 6 parts by weight, more preferably 0.002 to 0.4 parts by weight.
• radical polymerization initiator used in the present invention generates reactive radicals.
• radical polymerization initiators include t-hexylperoxyisopropyl monocarbonate, t-hexylperoxy 2-ethylhexanoate, 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate, t-butyl peroxypivalate, t-hexyl peroxypivalate, t-butyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, 1,1,3,3-tetramethylbutylper oxyneodecanoate, 1,1-bis(t-hexylperoxy)cyclohexane, benzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, lauroyl peroxide, 2,2′-azobis(2-methyl propionitrile), 2,2′-azobis(2-methylbutyronitrile), dimethyl
• radical polymerization initiators can be used singly or in combination of two or more.
• the amount of the radical polymerization initiator to be used is preferably set so as to satisfy the average concentration of the radical polymerization initiator present in the liquid in the tank reactor, which will be described later.
• the method of preparing the reaction raw materials is not particularly limited. It is preferable to prepare the reaction raw materials immediately before supplying them to the tank reactor. Moreover, it is preferable to prepare the reaction raw materials in an inert atmosphere such as nitrogen gas. For example, it is preferable to continuously supply each component constituting the reaction raw material from a tank storing the reaction raw material through a pipe to the mixer, and mix the components in the mixer to obtain the reaction raw material.
• a radical polymerization initiator can be dissolved in methyl methacrylate and prepared as a solution.
• the mixer can be equipped with a dynamic stirrer or a static stirrer. Then, the obtained reaction raw material is continuously supplied to the tank reactor.
• the monomer mixture can be prepared before being mixed with the chain transfer agent and/or radical polymerization initiator.
• a radical polymerization initiator is dissolved in methyl methacrylate to form a polymerization initiator solution, which is then mixed with a monomer or a mixture of a monomer and a chain transfer agent in a predetermined ratio. is preferred.
• the polymerization initiator solution may preferably have a dissolved oxygen content of greater than 3 ppm, more preferably greater than 5 ppm, and even more preferably greater than 10 ppm.
• Preparation of the monomer mixture or reactants may be carried out in the presence of oxygen.
• the as-prepared monomer mixture or reactant may preferably have a dissolved oxygen content of greater than 3 ppm, more preferably greater than 5 ppm, and even more preferably greater than 10 ppm.
• the dissolved oxygen content of the reaction raw material immediately before being supplied to the tank reactor is preferably 10 ppm or less, more preferably 5 ppm or less, still more preferably 4 ppm or less, and most preferably 3 ppm or less.
• the amount of dissolved oxygen in the reactants immediately prior to feeding can be adjusted by purging the reactants immediately after preparation with nitrogen to expel oxygen.
• the tank-type reactor used in the present invention is capable of simultaneously carrying out the supply of reaction raw materials, the polymerization reaction of the monomer mixture, and the withdrawal of the reaction product.
• the tank reactor usually includes a stirring means for stirring the liquid in the tank reactor, a feed port for supplying reaction raw materials to the tank reactor, and a reaction product withdrawn from the tank reactor. An exit is provided for The amount of reaction raw materials supplied to the tank reactor and the amount of reaction products withdrawn from the tank reactor are balanced so that the amount of liquid in the tank reactor is substantially constant.
• the amount of liquid in the tank reactor (volume V) is preferably 1/4 or more, more preferably 1/4 to 3/4, more preferably 1/3 to the volume of the tank reactor. 2/3.
• the tank reactor used in the present invention preferably has a plurality of supply ports for supplying reaction raw materials. Then, the reaction raw materials are continuously supplied from at least two supply ports simultaneously or alternately, preferably simultaneously.
• the supply port may be installed on the top surface of the tank reactor, may be installed on the side surface of the tank reactor, may be installed on the bottom surface of the tank reactor, or may be installed on the top surface of the tank reactor. It may be installed on at least two of the surface, side surface and bottom surface.
• the plurality of supply ports are arranged at mutually symmetrical positions.
• the height of the supply port may be higher than the liquid level in the tank reactor, or may be lower than the liquid level in the tank reactor.
• the shape of the supply port may be the shape of the cut end of the circular pipe itself, or may be a shape such that the reaction raw material is widely dispersed over the liquid surface in the tank reactor.
• stirring means examples include a Maxblend stirrer, a lattice blade stirrer, a propeller stirrer, a screw stirrer, a helical ribbon stirrer, and a paddle stirrer.
• the Maxblend stirrer is preferred from the viewpoint of uniform mixing.
• the temperature in the tank reactor that is, the temperature of the liquid in the tank reactor is preferably 120 to 150°C, more preferably 124 to 145°C.
• the temperature of the liquid can be controlled by an external heat exchange control method such as a jacket or a heat transfer tube, or by a self heat exchange control method in which a tube through which reaction raw materials or reaction products flow is arranged in the reactor. .
• the average residence time of the reactants in the tank reactor is preferably 1.5 to 5 hours, more preferably 2 to 4.5 hours, still more preferably 2.5 to 4 hours. From the viewpoint of making it easier to control the polymerization reaction and the molecular weight while suppressing the necessary amount of the polymerization initiator, and improving the productivity by bringing the reaction to a steady state in a relatively short time.
• the average residence time of the reaction raw materials in the tank reactor is preferably within the above range.
• the average residence time can be adjusted by adjusting the capacity of the tank reactor and the feed amount of the reactants.
• the average concentration of the radical polymerization initiator present in the liquid in the tank reactor is preferably 1.0 ⁇ 10 ⁇ 6 mol/L or more and 2.0 ⁇ 10 ⁇ 5 mol/L or less.
• organic solvents are not used in bulk polymerization, but organic solvents can optionally be included in the reaction raw materials when adjusting the viscosity of the liquid in the tank reactor.
• organic solvent aromatic hydrocarbons such as benzene, toluene and ethylbenzene are preferred. These solvents can be used singly or in combination of two or more.
• the amount used is preferably 30 parts by mass or less, more preferably 10 parts by mass or less, and still more preferably 0 parts by mass with respect to 100 parts by mass of the monomer mixture.
• the amount of water contained in the liquid in the tank reactor is preferably 1000 ppm or less, more preferably 700 ppm or less, and even more preferably 280 ppm or less.
• Methods for reducing the amount of water contained in the liquid in the tank reactor include, for example, pretreatment of the reaction raw materials in an adsorption dehydration tower, etc., and adding an inert gas to the gas phase of the tank reactor. is introduced, part of the water vapor is accompanied by an inert gas, condensed by a brine-cooled condenser, and discharged out of the system.
• bulk polymerization is carried out until the polymerization conversion reaches 30 to 60% by mass, preferably 35 to 55% by mass, more preferably 35 to 50% by mass, more preferably 35% by mass. It is carried out until it becomes ⁇ 45% by mass.
• the polymerization conversion rate can be calculated from the content of the copolymer or monomer mixture present in the reaction product discharged from the tank reactor as a value for the content in the reaction raw materials.
• Bulk polymerization in a tank reactor is preferably carried out in an inert gas atmosphere such as nitrogen gas.
• An additional reactor may be connected to the rear stage of the tank reactor.
• An additional reactor that can be connected to the latter stage may be of tank type or tubular type.
• Bulk polymerization continues in additional reactors. Bulk polymerization in the additional reactor is carried out until the polymerization conversion is 30 to 60% by weight, preferably 35 to 55% by weight, more preferably 35 to 50% by weight, more preferably 35 to 50% by weight. You may carry out until it becomes 45 mass %.
• the polymerization conversion rate can be calculated from the content of the copolymer or monomer mixture present in the reaction product withdrawn from the additional reactor as a value for the content in the reaction raw material.
• Bulk polymerization in the additional reactor is preferably carried out in an inert gas atmosphere such as nitrogen gas.
• the incorporation rate of ⁇ -methylstyrene calculated from the following formula can be more than 50%, preferably more than 52%, more preferably more than 54%.
• ⁇ -Methylstyrene uptake rate (%) ( ⁇ -methylstyrene weight in methacrylic copolymer/ ⁇ -methylstyrene styrene weight in monomer mixture) ⁇ 100
• the production method of the present invention has a step of removing the monomer mixture from the reaction product. Optionally, solvent is also removed in this step. This step isolates the copolymer.
• the removal method is not particularly limited, but a heating devolatilization method is preferred. Examples of the heat devolatilization method include the equilibrium flash evaporation method and the adiabatic flash evaporation method, and the adiabatic flash evaporation method is preferred.
• the temperature at which the adiabatic flash evaporation method is carried out is preferably 180-300°C, more preferably 190-280°C, even more preferably 200-280°C.
• the temperature at which the adiabatic flash evaporation method is carried out is too low, devolatilization will take a long time and the devolatilization will be inadequate, which may cause appearance defects such as silver on the molded product.
• the temperature for carrying out the adiabatic flash evaporation method is too high, the copolymer tends to be colored due to oxidation, burning, decomposition, or the like, or depolymerization reaction of the copolymer tends to occur.
• Adiabatic flash evaporation may be carried out in multiple stages.
• the vapor of the flash-evaporated monomer mixture can be used to heat the reaction product flowing through the heat transfer tube, and the heated reaction product can be supplied into a low-pressure flash tank and flash-evaporated.
• the reaction product can be pressurized by a pump or the like.
• the copolymer obtained by removing the monomer mixture from the reaction product can be made into pellets, granules, etc. according to known methods in order to facilitate handling as a molding material.
• the amount of the monomer mixture contained in the copolymer after removing the monomer mixture is preferably 1% by mass or less, more preferably 0.5% by mass or less. It is preferable to use a vented extruder for removing the monomer mixture, forming the isolated copolymer into a molding material, and/or compounding the additives described below.
• the methacrylic copolymer of the present invention or the copolymer obtained by the production method of the present invention can be subjected to a polymer reaction by a known method.
• polymer reactions include imidization reactions described in JP-A-2010-254742 and JP-A-2010-261025, and grafting reactions described in JP-A-2012-201831.
• the methacrylic copolymer of the present invention can optionally be blended with various additives to form a resin composition.
• the amount of the additive compounded is preferably 0.5% by mass or less, more preferably 0.2% by mass or less, relative to the resin composition. If the amount of the additive is too large, the molded product may have poor appearance such as silver streaks.
• the production method of the present invention may further include a step of adding various additives to obtain a resin composition.
• the amount of additive contained in the resin composition is preferably 0.5% by mass or less, more preferably 0.2% by mass or less, relative to the copolymer. If the amount of the additive contained in the resin composition is too large, the molded article may have poor appearance such as silver.
• the additive may be added to the reaction raw material, the reaction product, or the copolymer.
• Additives include antioxidants, heat deterioration inhibitors, ultraviolet absorbers, light stabilizers, lubricants, release agents, polymer processing aids, antistatic agents, flame retardants, dyes and pigments, light diffusing agents, and organic pigments. , matting agents, impact modifiers, phosphors, and the like.
• Antioxidants have the effect of preventing the oxidative deterioration of resins by themselves in the presence of oxygen.
• examples thereof include phosphorus antioxidants, hindered phenol antioxidants, thioether antioxidants, and the like. These antioxidants can be used singly or in combination of two or more.
• phosphorus antioxidants or hindered phenol antioxidants are preferable, and combined use of phosphorus antioxidants and hindered phenol antioxidants is more preferable. preferable.
• the ratio is not particularly limited, but the mass ratio of phosphorus-based antioxidant/hindered phenol-based antioxidant is preferably 1/5. to 2/1, more preferably 1/2 to 1/1.
• Phosphorus-based antioxidants include 2,2-methylenebis(4,6-di-t-butylphenyl)octylphosphite (manufactured by ADEKA; trade name: ADEKA STAB HP-10), tris(2,4-di-t- Butylphenyl)phosphite (manufactured by BASF; trade name: IRUGAFOS168) and the like are preferred.
• Hindered phenol-based antioxidants include pentaerythrityl-tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] (manufactured by BASF; trade name IRGANOX1010), octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl)propionate (manufactured by BASF; trade name IRGANOX1076) and the like are preferred.
• Thermal degradation inhibitors can prevent thermal degradation of resins by scavenging polymer radicals that are generated when exposed to high heat under virtually oxygen-free conditions.
• heat deterioration inhibitor examples include 2-t-butyl-6-(3′-t-butyl-5′-methyl-hydroxybenzyl)-4-methylphenyl acrylate (manufactured by Sumitomo Chemical; trade name Sumilizer GM), 2,4-di-t-amyl-6-(3′,5′-di-t-amyl-2′-hydroxy- ⁇ -methylbenzyl)phenyl acrylate (manufactured by Sumitomo Chemical; trade name Sumilizer GS), 4 -t-butyl-2-(5-t-butyl-2-oxo-3H-benzofuran-3-yl)phenyl-3,5-di-t-butyl-4-hydroxybenzoate (manufactured by Chitec Technology; product name Levonox 501), 5,7-di-t-butyl-3-(3,4-dimethylphenyl)-3H-benzofuran-2-one, 5,7-di-t-but
• a UV absorber is a compound that has the ability to absorb UV rays.
• a UV absorber is a compound that is said to have the function of mainly converting light energy into heat energy.
• ultraviolet absorbers examples include benzophenones, benzotriazoles, triazines, benzoates, salicylates, cyanoacrylates, oxalic acid anilides, malonic acid esters, and formamidines. These can be used individually by 1 type or in combination of 2 or more types.
• benzotriazoles and ultraviolet absorbers having a maximum molar extinction coefficient ⁇ max of 1200 dm 3 ⁇ mol ⁇ 1 cm ⁇ 1 or less at a wavelength of 380 to 450 nm are preferred.
• Benzotriazoles are highly effective in suppressing deterioration of optical properties such as coloration due to exposure to ultraviolet rays, so they are used as ultraviolet absorbers when applying the resin composition of the present invention to applications requiring the above properties. preferable.
• a light stabilizer is a compound that is said to have the function of scavenging radicals that are mainly generated by light oxidation.
• Suitable light stabilizers include hindered amines such as compounds having a 2,2,6,6-tetraalkylpiperidine skeleton.
• a mold release agent is a compound that has the function of facilitating the release of the molded product from the mold.
• release agents include higher alcohols such as cetyl alcohol and stearyl alcohol; and glycerin higher fatty acid esters such as stearic acid monoglyceride and stearic acid diglyceride.
• the ratio is not particularly limited, but the higher alcohol/glycerin fatty acid monoester mass ratio is preferably 2.5/1 to 3.5/1, and more. It is preferably 2.8/1 to 3.2/1.
• a polymer processing aid is a compound that exerts an effect on thickness accuracy and thinning when molding the resin composition of the present invention.
• Polymeric processing aids are typically polymer particles having a particle size of 0.05 to 0.5 ⁇ m, which can be produced by emulsion polymerization methods.
• the polymer particles may be monolayer particles composed of a polymer having a single composition ratio and a single intrinsic viscosity, or may be multilayer particles composed of two or more polymers having different composition ratios or intrinsic viscosities. may Among these, particles having a two-layer structure having an inner layer of a polymer layer having a low intrinsic viscosity and an outer layer of a polymer layer having a high intrinsic viscosity of 5 dl/g or more are preferred.
• the polymer processing aid preferably has a limiting viscosity of 3 to 6 dl/g. From the viewpoint of obtaining a resin composition having an effect of improving moldability and high melt fluidity, it is preferable to use a polymer processing aid having an intrinsic viscosity within the above range.
• the resin composition of the present invention may contain an impact modifier.
• impact modifiers include core-shell type modifiers containing acrylic rubber or diene rubber as a core layer component; modifiers containing a plurality of rubber particles, and the like.
• organic pigment a compound that has the function of converting ultraviolet rays, which are considered harmful to resins, into visible light is preferably used.
• light diffusing agents and matting agents examples include glass microparticles, polysiloxane crosslinked microparticles, crosslinked polymer microparticles, talc, calcium carbonate, barium sulfate, and the like.
• Examples of phosphors include fluorescent pigments, fluorescent dyes, fluorescent white dyes, fluorescent brighteners, and fluorescent bleaching agents.
• additives may be added at the reaction raw material stage, may be added at the reaction product stage, or may be added at the methacrylic copolymer or resin composition stage obtained after devolatilization. may
• the resin composition of the present invention may contain a methacrylic resin.
• the content of the methacrylic copolymer of the present invention in the resin composition is 20 to 100% by mass, preferably 25 to 100% by mass, more preferably 30 to 100% by mass.
• the resin composition of the present invention has an excellent balance between heat resistance and low water absorption when the content of the methacrylic copolymer of the present invention is in the range of 20 to 100% by mass.
• the ratio of structural units derived from methacrylic acid ester is 80% by mass or more, preferably 90% by mass or more, more preferably 95% by mass or more, and still more preferably 99% by mass or more.
• Methacrylates include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, s-butyl methacrylate, t-butyl methacrylate, amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, pentadecyl methacrylate, dodecyl methacrylate; phenyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate, 2-hydroxyethyl methacrylate, methacrylic acid 2 - ethoxyethyl, glycidyl methacrylate, allyl methacrylate; cyclohexyl methacrylate, norbornenyl methacrylate, isoborn
• Methacrylic acid esters can be used alone or in combination of two or more.
• the methacrylic resin may contain structural units derived from monomers other than the methacrylic acid ester. Acrylic acid esters are preferred as such other monomers.
• the content of structural units derived from an acrylic acid ester in the methacrylic resin is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and most preferably 1.0% by mass or less.
• Such acrylic esters include methyl acrylate (hereinafter referred to as "MA"), ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, dodecyl acrylate, stearyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, cyclohexyl acrylate , 2-methoxyethyl acrylate, 3-methoxybutyl acrylate, trifluoromethyl acrylate, trifluoroethyl acrylate, pentafluoroethyl acrylate, glycidyl acrylate, allyl acrylate, phenyl
• the methacrylic resin is obtained by polymerizing the above methacrylic acid ester and other optional monomers.
• the plurality of types of monomers are generally mixed to prepare a monomer mixture, which is then subjected to polymerization.
• the polymerization method is not particularly limited, but from the viewpoint of productivity, radical polymerization is preferably carried out by methods such as bulk polymerization, suspension polymerization, solution polymerization and emulsion polymerization.
• the weight average molecular weight (hereinafter referred to as "Mw") of the methacrylic resin is preferably 40,000 to 400,000, more preferably 45,000 to 200,000, even more preferably 50,000 to 150,000.
• Mw weight average molecular weight
• the resin composition of the present invention has excellent mechanical strength. Workability can be improved.
• the resin composition of the present invention preferably has a total light transmittance of 90.0% or more, more preferably 90.5% or more at a molded article having a thickness of 3 mm, measured by the method specified in JISK7361-1. Preferably it is 91.0% or more. When the total light transmittance is 90.0% or more, the molded article has excellent transparency.
• the resin composition of the present invention has a molded product with a haze (cloudiness) measured by the method specified in JIS-K7136, preferably 3.0% or less, more preferably 2.5% or less, and even more preferably 2.0% or less. .0% or less.
• the resin composition "having a haze (cloudiness) of X% or less in the molded article measured by the method specified in JIS-K7136" means a A square test piece is prepared, and the haze (cloudiness) of the test piece is measured by the method specified in JIS-K7136, and it means a resin composition that is X% or less.
• the methacrylic copolymer of the present invention, its resin composition, or the copolymer obtained by the production method of the present invention, or its resin composition can be prepared by injection molding, compression molding, extrusion molding, vacuum molding, and the like.
• Various molded articles can be obtained by molding (melting and heating molding) by the molding method.
• the molded article of the present invention includes, for example, signboard parts; display parts; lighting parts; interior parts; Optical parts such as light guide films, Fresnel lenses, lenticular lenses, front panels of various displays, diffuser plates; traffic-related parts; polarizer protective films, polarizing plate protective films, retardation films, automotive interior surface materials, mobile phones surface materials, film members such as marking films; members for home electric appliances; and the like.
• Weight average molecular weight Mw, molecular weight distribution Mw/Mn A value corresponding to the molecular weight of standard polymethyl methacrylate from the chromatogram measured by GPC (gel permeation chromatography) was taken as the molecular weight of the copolymer.
• each unit composition in the copolymer For the ⁇ -methylstyrene-methyl methacrylate copolymer, the proton ratio between the phenyl group of the ⁇ -methylstyrene unit and the methoxy group of the methyl methacrylate unit was determined by 1 H-NMR, and the ⁇ -methylstyrene unit ⁇ MSt, ⁇ MSt, The methyl methacrylate unit MMA was calculated.
• the carbon ratio of the phenyl group of the ⁇ -methylstyrene unit, the carbonyl group of the methyl methacrylate unit, and the phenyl group of the styrene unit was obtained by 13 C-NMR.
• ⁇ -Methylstyrene unit ⁇ MSt, methyl methacrylate unit MMA, and styrene unit St were calculated.
• Glass transition temperature Tg Glass transition temperature Tg
• DSC-50 product number
• thermogravimetry device Shiadzu Corporation, TGA-50
• the temperature was raised to 500 ° C. at 10 ° C./min under a nitrogen atmosphere, and the temperature at the time of 1% weight loss was the 1% thermal weight loss temperature.
• thermogravimetric retention rate (Thermal weight retention rate) Using a thermogravimetry device (Shimadzu Corporation, TGA-50), a sample with an initial weight of W0 was heated to 270 ° C. at 20 ° C./min in a nitrogen atmosphere, and held for 30 minutes after reaching 270 ° C., and reached W1. When it reaches, the thermogravimetric retention rate (%) can be calculated from (W1/W0) ⁇ 100.
• Example 1 73.31 parts by mass of purified methyl methacrylate, 12.50 parts by mass of ⁇ -methylstyrene, 14.19 parts by mass of styrene and an n-octylmercaptan concentration of 500 ppm were mixed in an autoclave equipped with a stirrer and a sampling tube. . 2,2′-azobis(2-methylpropionitrile) and n-octylmercaptan (n-OM) were mixed to a concentration of 400 ppm and 500 ppm, respectively, to obtain a reaction raw material. Nitrogen gas was blown into the reactants to remove dissolved oxygen to 3 ppm.
• the inside of a continuous flow tank reactor equipped with a brine-cooled condenser was purged with nitrogen gas.
• the reaction raw material is continuously supplied to the tank reactor at a constant flow rate so that the average residence time ⁇ is 150 minutes, and bulk polymerization is performed at a temperature of 130 ° C.
• the reaction product is discharged from the tank reactor. were extracted continuously.
• the pressure in the tank reactor was adjusted by a pressure regulating valve connected to the brine cooling condenser.
• the average concentration I of the radical polymerization initiator present in the liquid in the tank reactor was 6.76 ⁇ 10 ⁇ 6 mol/L.
• I ⁇ is 1.57 ⁇ 10 ⁇ 5 mol ⁇ hr/L.
• the polymerization conversion rate was 37%, the weight average molecular weight (Mw) of the obtained methacrylic copolymer was 136000, the molecular weight distribution (Mw/Mn) was 2.00, and (AB)/A was It was 5.7 ⁇ 10 ⁇ 6 .
• the obtained methacrylic copolymer pellets were pressed and measured to have a saturated water absorption of 0.87%.
• the obtained methacrylic copolymer was purified to remove unreacted monomers, and then analyzed.
• the resulting methacrylic copolymer had a methyl methacrylate unit mass fraction (MMA) of 67.5% by mass, an ⁇ -methylstyrene unit mass fraction ( ⁇ MSt) of 15.1% by mass, and a styrene unit mass fraction of The mass fraction (St) was 17.4% by mass, the glass transition temperature was 123°C, the 1% heat weight loss temperature was 276°C, the heat weight retention was 91%, and the melt flow rate was 0.80 g/10 minutes. rice field.
• MMA methyl methacrylate unit mass fraction
• ⁇ MSt ⁇ -methylstyrene unit mass fraction
• St styrene unit mass fraction
• Example 2 Methacrylic copolymerization was carried out in the same manner as in Example 1, except that the monomer mixture charged into the autoclave was 59.13 parts by mass of methyl methacrylate, 12.50 parts by mass of ⁇ -methylstyrene, and 28.37 parts by mass of styrene. A coalescence was obtained and analyzed.
• Example 3 Example 1 except that the monomer mixture charged into the autoclave was 59.97 parts by mass of methyl methacrylate, 18.75 parts by mass of ⁇ -methylstyrene, and 21.28 parts by mass of styrene, and the polymerization temperature was 140 ° C. A methacrylic copolymer was obtained and analyzed in the same manner.
• Example 4 Methacrylic copolymerization was carried out in the same manner as in Example 3, except that the monomer mixture charged into the autoclave was 77.50 parts by mass of methyl methacrylate, 17.50 parts by mass of ⁇ -methylstyrene, and 5.00 parts by mass of styrene. A coalescence was obtained and analyzed.
• Example 5 Methacrylic copolymerization was carried out in the same manner as in Example 3, except that the monomer mixture charged into the autoclave was 65.00 parts by mass of methyl methacrylate, 28.00 parts by mass of ⁇ -methylstyrene, and 7.00 parts by mass of styrene. A coalescence was obtained and analyzed.
• Comparative example 1 75.00 parts by mass of methyl methacrylate and 25.00 parts by mass of ⁇ -methylstyrene were used as the monomer mixture to be introduced into the autoclave, and the concentration of n-octylmercaptan was 400 ppm, 2,2′-azobis(2-methylpropionitrile ) concentration was 600 ppm, n-octyl mercaptan (n-OM) was 400 ppm, and the average residence time ⁇ was 200 minutes. .
• Comparative example 2 91.50 parts by mass of methyl methacrylate and 8.50 parts by mass of styrene are added to the autoclave, and 11.1 parts by mass of toluene is added to 100 parts by mass of the monomer mixture, and n-octyl Methacrylic methacrylate in the same manner as in Example 1 except that the mercaptan concentration was 2500 ppm, the 2,2'-azobis(2-methylpropionitrile) concentration was 222 ppm, the polymerization temperature was 110 ° C., and the average residence time ⁇ was 120 minutes. A system copolymer was obtained and analyzed.
• Example 5 (Comparative Example 5) The procedure of Example 4 was repeated except that the polymerization temperature was 90° C., but the polymerization rate was as low as 15% and no methacrylic copolymer was obtained.
• Example 4 achieves a polymerization rate equal to or higher than Comparative Example 1 with a shorter average residence time, and the obtained methacrylic copolymer has a higher 1% thermal weight loss temperature. Moreover, it exhibits a higher glass transition temperature and a lower water absorption rate than the methacrylic copolymer obtained in Comparative Example 2.
• Examples 1 to 5 reach the same polymerization rate with a lower concentration of 2,2′-azobis(2-methylpropionitrile) than Comparative Examples 3 and 4, and the initiator end with poor thermal decomposition resistance exhibit a high 1% thermogravimetric loss temperature.

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