Methyl methacrylate block copolymer and method for preparing same

Abstract

The methyl methacrylate-based triblock copolymer of the present invention is obtained by RAFT polymerization using a RAFT agent, and by controlling the weight-average molecular weight and the methyl methacrylate block repeating unit, it can be used as a variety of materials, and can simultaneously achieve transparency and impact resistance.

Description

Technology Field

[0001] The present invention relates to a methyl methacrylate-based triblock copolymer obtained by RAFT polymerization using a new RAFT (Fragmentation Chain Transfer) agent and a method for producing the same. Background Technology

[0002] Polymethyl methacrylate (PMMA) has excellent transparency and hardness, so it is used in various fields such as transparent sheets, interior materials, automotive exterior materials, adhesives, and displays. However, PMMA has low impact resistance due to its brittle nature, which limits its use. To address this, there have been attempts to compensate for the shortcomings of PMMA by copolymerizing it with styrene, butadiene, or acrylic monomers.

[0003] In particular, to compensate for the low impact resistance of PMMA and simultaneously achieve excellent transparency, conventional PMMA is compounded with a core-shell type acrylic impact modifier manufactured by emulsion polymerization.

[0004] In the case of core-shell type acrylic impact modifiers, they are manufactured by copolymerizing styrene and butyl acrylate as the composition of the rubber layer within the particles, and by reducing the difference in refractive index with the PMMA resin, the PMMA resin composition containing the acrylic impact modifier can have high transparency.

[0005] However, conventional PMMA resin compositions containing acrylic impact modifiers have a problem in that when heated to a high temperature of 70 to 80°C, the transmittance decreases rapidly and the haze increases rapidly, making it difficult to secure the high transparency that is an advantage of PMMA resin.

[0006] Therefore, in order to solve the problem of difficulty in securing transparency in PMMA resin compositions containing the aforementioned conventional acrylic impact reinforcement, a block copolymer having excellent toughness while securing transparency was proposed by including an n-butyl acrylate (n-BA) block unit with excellent elasticity within a single molecular chain of PMMA.

[0007] Conventional block copolymers described above are manufactured using the NMP (Nitroxide-mediated polymerization) polymerization method and the anionic polymerization method. The NMP polymerization method has been commercialized by Arkema and sold under the name Nanostrength, while the anionic polymerization method has been commercialized and produced by Kuraray as a product called Kurarity.

[0008] However, the above-mentioned anionic polymerization is very difficult to perform, such as maintaining a low-temperature environment to activate the anions. In addition, the above-mentioned living polymerization (nitroxide-mediated polymerization, NMP polymerization) necessarily requires the inclusion of a small amount of styrene for stable polymerization, which causes the manufactured polymethyl methacrylate-polyacrylic block copolymer to suffer from problems of reduced physical properties, such as reduced weather resistance due to styrene.

[0009] Therefore, there is a need to manufacture a new method for producing a methyl methacrylate-based block copolymer and a block copolymer obtained therefrom to solve the above problems.

[0010] In other words, there is a need for a new method for manufacturing an acrylic block copolymer that allows for easy control of block unit content and molecular weight, as well as a simpler polymerization process, and a triblock copolymer obtained therefrom. The problem to be solved

[0011] One embodiment provides a methyl methacrylate-based block copolymer that cannot be manufactured by conventional suspension polymerization, and a methyl methacrylate-based triblock polymer using a new RAFT agent capable of acrylic block polymerization.

[0012] In one embodiment, to solve the problem of reduced transparency of the methyl methacrylate block copolymer produced by the living radical polymerization above, a methyl methacrylate-based triblock copolymer with excellent transparency is provided.

[0013] In one embodiment, a method for manufacturing a methyl methacrylate-based triblock copolymer having excellent polymerization properties even at room temperature is provided to solve the difficult polymerization process problem of the anionic polymerization described above.

[0014] As one embodiment, a methyl methacrylate-based triblock copolymer with excellent molecular weight and block unit control can be used as an acrylic molded article such as an automotive exterior material, interior / outterior material or film, or as a material such as an adhesive by further including a solvent. means of solving the problem

[0015] As one embodiment of the present invention, the methyl methacrylate-based triblock copolymer may be obtained by RAFT polymerization using a RAFT agent represented by the following chemical formula 1.

[0016] [Chemical Formula 1]

[0017]

[0018] (In the above Chemical Formula 1, R1 and R2 are independently C1-C6 alkyls, and R3 and R4 are independently hydrogen, C1-C 12 Alkyl, C1-C 12 Haloalkyl, C1-C 12 Alkoxy and C1-C 12 One or more selected from haloalkoxy, where n and m are independent integers from 1 to 5.)

[0019] As one embodiment of the present invention, in Formula 1, R1 and R2 are independently methyl or ethyl, R3 and R4 are independently hydrogen or one or more selected from C1-C6 alkyl, C1-C6 haloalkyl, C1-C6 alkoxy and C1-C6 haloalkoxy, and n and m may be independently integers from 1 to 3.

[0020] As one embodiment of the present invention, the methyl methacrylate-based triblock copolymer may have a polymethyl methacrylate-polyacrylate-polymethyl methacrylate triblock structure and may include a *-SC(=S)-S-* structure in the polyacrylate-based unit.

[0021] As another embodiment of the present invention, the methyl methacrylate-based triblock copolymer may have polyacrylate-based block units selected from one or more of methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, iso-butyl acrylate, and tert-butyl acrylate.

[0022] As one embodiment of the present invention, the methyl methacrylate-based triblock copolymer may contain 5 to 50 weight% of polymethyl methacrylate block units with respect to 100 weight% of the methyl methacrylate-based triblock copolymer.

[0023] As one embodiment of the present invention, the methyl methacrylate-based triblock copolymer may have a weight-average molecular weight of 1,000 to 1,000,000 g / mol and a molecular weight distribution (PDI) of 1.1 to 5.0.

[0024] As one embodiment of the present invention, the methyl methacrylate-based triblock copolymer may have a haze of 20% or less as measured by ISO 14782.

[0025] As one embodiment of the present invention, the methyl methacrylate-based triblock copolymer may have an impact strength of 3 kJ / m² or more as measured by ISO 179-1.

[0026] One embodiment of the present invention may provide an acrylic molded article manufactured by including the methyl methacrylate-based triblock copolymer.

[0027] As one embodiment of the present invention, the acrylic molded article may be an acrylic molded article that is an automotive exterior part.

[0028] As one embodiment of the present invention, the acrylic molded article may be an interior or exterior material.

[0029] One embodiment of the present invention may provide an adhesive composition comprising the methyl methacrylate-based triblock copolymer and a solvent.

[0030] One embodiment of the present invention may provide a method for manufacturing a methyl methacrylate-based triblock copolymer comprising a first polymerization process step of polymerizing a RAFT agent represented by the following chemical formula 1, methyl methacrylate, and a radical initiator, and a second polymerization process step after the first polymerization process, comprising an acrylic monomer different from the methyl methacrylate and a radical initiator.

[0031] [Chemical Formula 1]

[0032]

[0033] (In the above Chemical Formula 1, R1 and R2 are independently C1-C6 alkyls, and R3 and R4 are independently hydrogen, C1-C 12 Alkyl, C1-C 12 Haloalkyl, C1-C 12 Alkoxy and C1-C 12 One or more selected from haloalkoxy, where n and m are independent integers from 1 to 5.)

[0034] As one embodiment of the present invention, the polymethyl methacrylate polymer obtained in the first polymerization process may have a weight-average molecular weight of 10,000 to 1,000,000 g / mol.

[0035] As one embodiment of the present invention, the acrylic monomer may be one or more selected from methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, iso-butyl acrylate and tert-butyl acrylate. Effects of the invention

[0036] As one embodiment of the present invention, the methyl methacrylate-based triblock copolymer has a haze of 20% or less as measured by ASTM D1003 and an impact strength of 5 kJ / m² as measured by ISO 179-1. By possessing this, it can be effectively used as an unpainted automotive exterior material capable of realizing aesthetic colors.

[0037] As one embodiment of the present invention, the methyl methacrylate-based triblock copolymer may have a variety of weight-average molecular weights ranging from 10,000 to 1,000,000 g / mol, and thus can be used as various materials such as acrylic molded articles, adhesives, or impact modifiers.

[0038] As one embodiment of the present invention, the method for manufacturing the methyl methacrylate-based triblock copolymer may allow for additional polymerization by having a reversible reactor present even after the completion of polymerization, so that the manufactured methyl methacrylate triblock copolymer is PDI ( Polydispersity The index) can have a narrow molecular distribution in the range of 1.1 to 2.0.

[0039] Therefore, the above-mentioned methyl methacrylate-based triblock copolymer can not only achieve excellent transparency and impact strength, but also allows for easy control of block units and molecular weight, so it can be usefully utilized in various materials such as acrylic molded articles or adhesives that do not contain core-shell acrylic impact modifiers. Brief explanation of the drawing

[0040] Figure 1 shows the results of measuring the RAFT agent prepared in Preparation Example 1 by Proton NMR (a) and Carbon NMR (b). Figure 2 shows the results of elemental analysis (a) and GC-Mass measurement (b) of the RAFT agent prepared in Preparation Example 1. Specific details for implementing the invention

[0041] Hereinafter, the methyl methacrylate-based triblock copolymer of the present invention will be described in detail. Unless otherwise defined, technical and scientific terms used herein have the meaning commonly understood by those skilled in the art to which this invention pertains, and descriptions of known functions and configurations that could unnecessarily obscure the essence of the present invention are omitted in the following description.

[0042] The singular form used in this specification is intended to include the plural form unless specifically indicated otherwise in the context.

[0043] Additionally, the numerical ranges used in this specification include lower and upper limits and all values ​​within the range, increments logically derived from the form and width of the defined range, all of which are limited values, and all possible combinations of upper and lower limits of numerical ranges defined in different forms. Unless otherwise specifically defined in this specification, values ​​outside the numerical range that may occur due to experimental error or rounding are also included in the defined numerical range.

[0044] The term "comprising" in this specification is an open description having an equivalent meaning to expressions such as "comprising," "containing," "having," or "characterizing," and does not exclude elements, materials, or processes not additionally listed.

[0045] Terms in this specification, "C1-C n " may be a term meaning a carbon compound with 1 or more and n or fewer carbon atoms.

[0046] The methyl methacrylate-based triblock copolymer of the present invention may be obtained by RAFT polymerization using a RAFT represented by the following chemical formula 1.

[0047] [Chemical Formula 1]

[0048]

[0049] (In the above Chemical Formula 1, R1 and R2 are independently C1-C6 alkyls, and R3 and R4 are independently hydrogen, C1-C 12 Alkyl, C1-C 12 Haloalkyl, C1-C 12 Alkoxy and C1-C 12 One or more selected from haloalkoxy, where n and m are integers independently selected from 1 to 5.

[0050] In one embodiment, the RAFT agent may be such that R1 and R2 in Formula 1 are independently methyl or ethyl, R3 and R4 are independently hydrogen or one or more selected from C1-C6 alkyl, C1-C6 haloalkyl, C1-C6 alkoxy and C1-C6 haloalkoxy, and n and m are independently integers selected from 1 to 3.

[0051] As another embodiment, the RAFT agent may be represented by the following chemical formula 2, wherein R1 and R2 are methyl, R3 and R4 are independently hydrogen or C1-C6 alkyl, n and m may be 1.

[0052] [Chemical Formula 2]

[0053]

[0054] The RAFT agent represented by Chemical Formula 1 above can perform a RAFT polymerization reaction with methyl methacrylate and acrylate-based monomers better than other RAFT agents, and thus can polymerize the methyl methacrylate-based triblock polymer with better reactivity.

[0055] As one embodiment, the methyl methacrylate-based triblock copolymer may be characterized by having a polymethyl methacrylate-polyacrylate-polymethyl methacrylate triblock structure and including a *-SC(=S)-S-* structure in the polyacrylate-based unit.

[0056] The methyl methacrylate-based triblock copolymer having the above-mentioned triblock structure can not only maintain the excellent transparency of methyl methacrylate but also have excellent impact resistance by including polyacrylate block units, and can be preferred, especially when manufactured with acrylate monomers having long-chain alkyl groups, as it can have even better impact resistance.

[0057] In one embodiment, the methyl methacrylate-based triblock copolymer may comprise one or more polyacrylate-based block units selected from methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, iso-butyl acrylate, and tert-butyl acrylate.

[0058] As another embodiment, the methyl methacrylate-based triblock copolymer may be prepared by including one or more selected from ethyl acrylate, propyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate.

[0059] Alternatively, the methyl methacrylate-based triblock copolymer may be preferred if it is prepared by including n-butyl acrylate alone or a copolymer of n-butyl acrylate and 2-ethylhexyl acrylate, as this can simultaneously achieve excellent transparency and impact resistance, but this is not necessarily limited thereto.

[0060] The above methyl methacrylate-based triblock copolymer may have a polymethyl methacrylate-polyacrylate-SC(=S)-S-polyacrylate-polymethyl methacrylate structure. A more detailed structure will be described in the methyl methacrylate-based tricopolymer to be described later. In addition, the methyl methacrylate-based triblock copolymer having the above structure can control the molecular weight of the polyacrylate-based block unit, thereby enabling the realization of various physical properties.

[0061] In one embodiment, the methyl methacrylate-based triblock copolymer may have polymethyl methacrylate block polymer units of 70% by weight or less, 50% by weight or less, or 30% by weight or less with respect to the total weight of the methyl methacrylate-based triblock copolymer, and may have 5% by weight or more or 10% by weight or more, although this does not limit the lower limit.

[0062] Of course, the above methyl methacrylate-based triblock copolymer may contain 1 to 99 weight% of polymethyl methacrylate block units, but in order to maintain the excellent transparency of the methyl methacrylate-based triblock copolymer and to achieve excellent impact resistance, it may be preferred to contain 5 to 50 weight%, preferably 10 to 30 weight%, and more preferably 20 to 30 weight% of polymethyl methacrylate block units, but this is not necessarily limited thereto.

[0063] As one embodiment, the methyl methacrylate-based triblock copolymer may have a weight-average molecular weight of 10,000 to 1,000,000 g / mol or 10,000 to 500,000 g / mol.

[0064] Methyl methacrylate-based triblock copolymers having a weight-average molecular weight within the above range may be preferred because the weight-average molecular weight and molecular weight distribution can be controlled according to the RAFT agent content.

[0065] In one embodiment, the methyl methacrylate-based triblock copolymer may have a molecular weight distribution (PDI) of 2 or less, 1.5 or less, 1.3 or less, or 1.2 or less. Additionally, if necessary, the molecular weight distribution may be extended up to 5.0 by repeating polymerization.

[0066] That is, the methyl methacrylate-based triblock copolymer can have a portion that can be reversibly added and decomposed not disappear even after polymerization is completed, so the molecular weight distribution can be controlled to the above range, and preferably, the PDI can be manufactured narrowly by utilizing the above excellent molecular weight control, so it can be usefully used as an adhesive that achieves better stress.

[0067] In one embodiment, the methyl methacrylate-based triblock copolymer may have a haze measured by ISO 14782 at 80°C of 20% or less, 15% or less, preferably 10% or less, more preferably 5% or less, 3% or less, or 2% or less, and may be 0.5% or more or 1% or more, although the lower limit is not limited.

[0068] Since the above-described methyl methacrylate-based triblock copolymer has a very low haze within the range described above even at high temperatures, it can solve the problem of haze that increases rapidly at high temperatures in conventional PMMA resin compositions containing acrylic impact modifiers, and thus can be applied to fields requiring transparency.

[0069] In one embodiment, the methyl methacrylate-based triblock copolymer may have an impact strength measured by ISO 179-1 of 3 kJ / m² or more, 5 kJ / m² or more, preferably 10 kJ / m² or more, 15 kJ / m² or more, more preferably 20 kJ / m² or more, or 25 kJ / m² or more, and may have an upper limit of 50 kJ / m² or less, 40 kJ / m² or less, or 35 kJ / m² or less.

[0070] Surprisingly, the above-mentioned methyl methacrylate-based triblock copolymer can have impact strength within the range described above even without including additional impact modifiers, so it can be usefully used for unpainted automotive exterior materials or interior materials that require high impact resistance.

[0071] In addition, since the above-mentioned methyl methacrylate-based triblock copolymer has haze and impact strength within the range described above, it can be more usefully utilized as an aesthetically pleasing unpainted automotive exterior material by further including a coloring agent.

[0072] The method for manufacturing a methyl methacrylate-based triblock copolymer according to the present invention will be described in detail below.

[0073] The method for manufacturing a methyl methacrylate-based triblock copolymer of the present invention comprises a first polymerization process step of polymerizing a RAFT agent represented by Chemical Formula 1, methyl methacrylate, and a radical initiator, and a second polymerization process step after the first polymerization process, comprising an acrylic monomer different from the methyl methacrylate and a radical initiator.

[0074] As one embodiment, the RAFT agent can be prepared by the following reaction scheme 1.

[0075] [Reaction Equation 1]

[0076]

[0077] (In the above reaction scheme 1, R1 and R2 are independently C1-C6 alkyls, and R3 and R4 are independently hydrogen, C1-C 12 Alkyl, C1-C 12 Haloalkyl, C1-C 12 Alkoxy and C1-C 12 One or more selected from haloalkoxy, where A is a halogen substituent of F, Cl, Br, or I, and n and m are independent integers from 1 to 5.

[0078] The step of manufacturing the above RAFT agent may include a step of purifying by chromatography, but is not limited thereto.

[0079] In one embodiment, the first polymerization process step may produce a first polymer represented by Formula 3, comprising methyl methacrylate, a RAFT agent, and a radical initiator.

[0080]

[0081] (In the above chemical formula 3, R1 and R2 are independently C1-C6 alkyls, and R3 and R4 are independently hydrogen, C1-C 12 Alkyl, C1-C 12 Haloalkyl, C1-C 12 Alkoxy and C1-C 12 One or more selected from haloalkoxy, and n and m are integers from 1 to 5 independently of each other.

[0082] In the above chemical formula 3, may refer to a methyl methacrylate block unit, and the molecular weight of the methyl methacrylate block unit described above can be controlled by the amount of methyl methacrylate added in the manufacturing method.

[0083] The first polymer above contains *-SC(=S)-S-*, so that it can react with another monomer in the second polymerization process step to produce a block copolymer.

[0084] In one embodiment, the first polymer produced in the first polymerization process step may have a weight-average molecular weight of 500 to 50,000 g / mol. In another embodiment, the first polymer may have a weight-average molecular weight of 10,000 to 500,000 g / mol or 10,000 to 300,000 g / mol.

[0085] In addition, each polymethyl methacrylate block unit contained in the first polymer has a *-SC(=S)-S-* structure as its center, and the left and right sides may have the same or different molecular weights, but this is not a limitation.

[0086] The first polymer can be controlled according to the RAFT agent content added in the first polymerization process step, but in order for the methyl methacrylate-based triblock copolymer prepared including it to achieve excellent transparency and rigidity and to be usefully used as an adhesive or an acrylic molded article, it may be a desirable form to have a weight-average molecular weight within the above range.

[0087] In one embodiment, the second polymerization process step may produce a methyl methacrylate-based triblock copolymer represented by the following chemical formula 4, comprising a first polymer, an acrylic monomer different from methyl methacrylate, and a radical initiator.

[0088] [Chemical Formula 4]

[0089]

[0090] (In the above Chemical Formula 4, R1, R2, R3, R4, n and m are the same as defined in the above Chemical Formula 3, and R5 and R6 are the same, C1 to C 10 It is a substituted or unsubstituted straight-chain or branched alkyl group)

[0091] The methyl methacrylate-based triblock copolymer represented by the above chemical formula 4 still contains *-SC(=O)-S-*, so it can be repolymerized later by a radical reaction.

[0092] The above polymethyl methacrylate block unit and polyacrylate block unit may be in a polymerization ratio of 1:1 to 1:5, preferably 1:1 to 1:3, and more preferably 1:1 to 1:2.

[0093] Methyl methacrylate block copolymers having a block unit molar ratio within the above range may be preferred as they can achieve excellent transparency while having excellent impact strength, but this is not necessarily a limitation.

[0094] In one embodiment, the radical initiator for the first and second polymerization process steps may be used without limitation as a peroxide-based, azo-based, or redox catalyst capable of initiating a polymerization reaction, for example, AIBN (Azobisisobutyronitrile), but is not necessarily limited to any that is recognizable by a person skilled in the art.

[0095] In one embodiment, the first polymerization process step and the second polymerization process step may be polymerized under an organic solvent, and may include one or more selected from tetrahydrofuran, ethylacetic acid, ether, hexane, chloroform, and dichloromethane as long as the methyl methacrylate and acrylate monomers are soluble, although this is not limited thereto; specifically, it may be tetrahydrofuran alone or may include the same.

[0096] The following describes in detail an article manufactured including the above-mentioned methyl methacrylate-based triblock copolymer.

[0097] The above methyl methacrylate-based triblock copolymer can be applied in various fields because, even after the polymerization reaction is completed, *-SS(=O)-S-* remains as shown in Chemical Formula 3 and allows for additional reactions to proceed, thereby enabling control of the weight-average molecular weight as well as control of the PDI.

[0098] The acrylic molded article of the present invention can be manufactured by including a methyl methacrylate-based triblock copolymer.

[0099] The above-mentioned molded product can be manufactured by extrusion, injection, or casting, and can be in the form of a film, sheet, rod, pipe, or various other structures. It can be used without limitation as long as it is a material requiring excellent transparency and impact resistance.

[0100] In one embodiment, when used as an acrylic molded article, the molecular weight is not limited as long as it is molded, but for example, the methyl methacrylate-based triblock copolymer may be used with a weight-average molecular weight of 10,000 g / mol or more, 50,000 g / mol or more, 100,000 g / mol or more, 200,000 g / mol or more, 300,000 g / mol or more, 500,000 g / mol or more, and up to 1,000,000 g / mol or less, or may be 10,000 to 500,000 g / mol, 30,000 to 300,000, or 50,000 to 200,000 g / mol, but is not limited as long as it can be manufactured as an acrylic molded article.

[0101] The above methyl methacrylate-based triblock copolymer may have a high-temperature haze of 20% or less, preferably 10% or less, and more preferably 5% or less as measured by ISO 14782, and may be applicable to various fields by achieving an impact strength of 5 kJ / m² or more, 10 kJ / m² or more, or 20 kJ / m² or more as measured by ISO 179-1.

[0102] As one embodiment, the acrylic molded product may be an automotive exterior part.

[0103] The above acrylic molded product exhibits excellent transparency, so automotive exterior parts manufactured using it can not only achieve excellent colorability but also exhibit superior impact resistance compared to PMMA resin, making them more useful.

[0104] In one embodiment, the acrylic molded article may be an interior or exterior material. The interior or exterior material may achieve excellent transparency and enable more elegant colors.

[0105] In one embodiment, the acrylic molded article may further include one or more additives selected from lubricants, heat stabilizers, colorants, UV stabilizers, fillers, impact modifiers, plasticizers, and antioxidants.

[0106] The adhesive composition of the present invention may include the methyl methrylate-based block copolymer and the solvent.

[0107] As one embodiment, the methyl methacrylate-based block copolymer included in the adhesive composition may have a weight-average molecular weight of 1,000 to 50,000 g / mol, and specifically, 5,000 to 100,000 g / mol.

[0108] As another embodiment, the methyl methacrylate-based block copolymer may have a PDI of 1.1 to 2, preferably 1.1 to 1.5.

[0109] The methyl methacrylate-based block tricopolymer having the above weight average molecular weight can be dissolved in an organic solvent and have a viscosity suitable for use as an adhesive. In addition, the above methyl methacrylate-based triblock copolymer can have a narrow PDI, so an adhesive composition containing it can achieve superior adhesive performance.

[0110] The solvent included in the above adhesive composition may be used without limitation as long as it is capable of dissolving methyl methacrylate.

[0111] The methyl methacrylate-based triblock copolymer according to the present invention will be described in more detail through the following examples. However, the following examples are merely references for the detailed description of the present invention and are not limited thereto, and the present invention may be implemented in various forms. Furthermore, unless otherwise defined, all technical and scientific terms have the same meaning as generally understood by one of the art to which the present invention pertains. Additionally, the terms used in the description of the present invention are merely for the purpose of effectively describing specific examples and are not intended to limit the present invention.

[0113] [measurement method]

[0114] 1. High temperature haze

[0115] Haze was measured in accordance with ISO 14782 at a high temperature of 80°C. The methyl methacrylate-based triblock copolymer prepared in the following examples and comparative examples was injection-molded to a thickness of 3.0 mm, and the haze was measured using the measurement sample.

[0117] 2. Impact resistance measurement

[0118] Impact strength tests were performed using notched specimens in accordance with ISO 179-1. Specimens were manufactured with dimensions of 80±2 x 10±0.2 x 4±0.2 (unit: mm), and the dimensions of the specimens (thickness h, width b, and length l) were specified such that h≤b≤l. A notch 2 mm deep was made in the width direction of the specimen, and the impact strength was measured by striking the opposite side of the notch. The average value of a total of 8 specimens was used to calculate the impact strength according to the formula below, and the result was expressed in units of kJ / m².

[0119] Impact Strength (kJ / m²) = (Sample Absorbed Energy (J) / Sample Thickness × Specimen Width (m²) × 10 3

[0121] 3. GPC Measurement

[0122] The prepared methyl methacrylate-based triblock copolymer was dissolved in tetrahydrofuran and measured using gel permeation chromatography (GPC).

[0123] The weight-average molecular weight was measured using a Waters gel permeation chromatography (GPC) system. The system consists of a mobile phase pump (M515 Pump), a column heater (ALLCOLHTRB), a detector (2414 RI Detector), and an injector (2695 EB Automatic Injector). A Waters Styragel HR was used as the analytical column, and American Polymer Standard Corporation STD polymethyl methacrylate (PMMA) was used as the standard. HPLC-grade tetrahydrofuran (THF) was used as the mobile phase solvent, and measurements were performed under conditions of a column heater temperature of 40°C and a mobile phase solvent flow rate of 1.0 mL / min. The copolymer prepared for sample analysis was dissolved in the mobile phase solvent tetrahydrofuran (THF) and injected into the GPC system to measure the weight-average molecular weight.

[0125] [Preparation Example 1]

[0126]

[0127] 30 ml of deionized water was added to the flask, and 3 g of sodium hydrosulfide hydrate was added and dissolved. The flask was then placed in an ice bath and cooled to 0 ℃. After cooling was complete, 3 g of α-bromorophenyl acetic acid was slowly added in several portions. After adding the ingredients, the mixture was stirred at room temperature for 12 hours, then heated to 95 ℃ and maintained for 3 hours. Subsequently, the flask was placed in an ice bath to cool, and 1 ml of 30% sulfuric acid solution was added to complete the first reaction. Afterward, extraction was performed three times using diether ether and deionized water, and the solvent in the diether ether layer was evaporated and concentrated to complete the synthesis of the first-step intermediate.

[0128]

[0129] Subsequently, 3g of the first step intermediate was dissolved in 50ml of methanol (MeOH) in a 100ml round-bottom flask (RBF), 2ml of concentrated sulfuric acid solution was added, and the reaction was carried out at 60°C under reflux for 12 hours. After the reaction was complete, the methanol was removed using a rotary evaporator, and 150ml of diethyl ether was added to dissolve it. After performing extraction three times using Na2CO3 solution and diethyl ether, the solvent was evaporated from the diethyl ether layer to synthesize the second intermediate.

[0130]

[0131] Finally, 3g of the second-step product was dissolved in 10ml of THF and placed in a Round Bottom Flask (RBF). 1.2g of trimethylamine was added, and the mixture was stirred to form a suspension. Subsequently, 2g of carbon disulfide (CS2) was added and stirred for 10 minutes, followed by the addition of 3g of α-bromorophenyl acetate. When a precipitate formed, the mixture was stirred for 5 minutes, filtered, and washed twice with 20ml of acetone. The solvent was removed from the filtered solution using a rotary evaporator, purified by chromatography with a petroleum ether / EA mixed solvent, and the final RAFT agent was obtained through cooling and recrystallization. The structure of the newly synthesized RAFT agent was measured using Proton NMR and Carbon NMR and is shown in Figure 1 below, while elemental analysis and GC-Mass analysis were performed and are shown in Figure 2 below.

[0133] [Example 1]

[0134]

[0135] 4.93 g (49.2 mmol) of methyl methacrylate, 0.1 g (0.246 mmol) of the RAFT agent from Preparation Example 1, 0.008 g (0.0492 mmol) of AIBN, and 50 mL of toluene were placed in a 100 mL Schlenk flask and dissolved uniformly. After removing oxygen from the polymer solution through three freeze-pump-thaw cycles, the reaction was carried out at 70°C for 12 hours. After the reaction, the polymerization solution was precipitated in methanol and dried in a vacuum oven at room temperature for one day to obtain PMMA macro-CTA.

[0136]

[0137] Subsequently, the synthesis process of the triblock copolymer was carried out in the same manner as the experimental procedure mentioned above. The synthesized PMMA macro-CTA (2 g, 0.111 mmol), n-butyl acrylate (11.393 g, 88.89 mmol), AIBN (0.0036 g, 0.0222 mmol), and 50 ml of toluene were placed in a 100 mL Schlenk flask and dissolved uniformly. After removing oxygen from the polymer solution through three freeze-pump-thaw cycles, the reaction was carried out at 70°C for 8 hours. After the reaction, the polymerization solution was precipitated in methanol and dried in a vacuum oven at room temperature for one day to obtain the methyl methacrylate-based triblock copolymer.

[0138] Afterwards, the methyl methacrylate-based triblock copolymer was measured using the above measurement method and is shown in Table 1 below.

[0140] [Example 2]

[0141] In Example 1 above, a methyl methacrylate-based triblock copolymer was obtained in the same way except that PMMA macro-CTA (1 g, 0.0555 mmol) was added.

[0142] Afterwards, the methyl methacrylate-based triblock copolymer was measured using the above measurement method and is shown in Table 1 below.

[0144] [Example 3]

[0145] In Example 1 above, a methyl methacrylate-based triblock copolymer was obtained in the same way except that PMMA macro-CTA (4 g, 0.444 mmol) was added.

[0146] Afterwards, the methyl methacrylate-based triblock copolymer was measured using the above measurement method and is shown in Table 1 below.

[0148] [Example 4]

[0149] In Example 1 above, a methyl methacrylate-based triblock copolymer was obtained in the same way except that PMMA macro-CTA (8 g, 0.888 mmol) was added.

[0150] Afterwards, the methyl methacrylate-based triblock copolymer was measured using the above measurement method and is shown in Table 1 below.

[0152] [Example 5]

[0153] In Example 1 above, a methyl methacrylate-based triblock copolymer was obtained in the same way except that PMMA macro-CTA (11 g, 0.0.6105 mmol) was added.

[0154] Afterwards, the methyl methacrylate-based triblock copolymer was measured using the above measurement method and is shown in Table 1 below.

[0156] [Comparative Example 1]

[0157] 11.393 g of n-butyl acrylate (BA), 2 g of methyl acrylate (MA), 1.5 g of ethyl acetate, and 100 g of ethyl acetate were placed in a flask equipped with a stirring device, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, and the contents of the flask were heated to 80°C while introducing nitrogen gas into the flask. Then, 0.05 g of 2,2'-azobisisobutyronitrile was added to the flask under stirring, and heating and cooling were performed for 1 hour to maintain the temperature of the contents of the flask at 80°C. Subsequently, heating and cooling were performed for 10 hours to maintain the temperature of the contents of the flask at 80°C, and finally, a copolymer solution containing copolymer (RA1) was prepared by diluting with ethyl acetate. Afterward, the final solution was concentrated and vacuum dried at 70°C for 15 hours to obtain the copolymer.

[0158] Afterwards, the obtained copolymer was measured using the above measurement method and is shown in Table 1 below.

[0160] [Comparative Example 2]

[0161] LiCl was pre-burned under vacuum and added to a glass reactor purged with nitrogen. Tetrohydrofuran and 1,1-Diphenylethylene were added to the glass reactor via a capillary tube or syringe. Subsequently, sec-butyllithium was added, with 5 times the molar amount of LiCl and 3 times the molar amount of 1,1-Diphenylethylene added relative to the sec-butyllithium. Then, NiBr2-(PPh3)2 was added dropwise to the glass reactor until the red color persisted, followed by the addition of diethyl meso-2,5-dibromoadifate, and then MMA.

[0162] Subsequently, the glass reactor was lowered to -78°C, and n-butyl acrylate was slowly added dropwise to carry out a cationic polymerization reaction for 1 hour. After the polymerization was completed, the solution was quenched in degassed methanol, the final solution was concentrated, and then vacuum dried at 70°C for 15 hours to obtain the copolymer.

[0163] Afterwards, the obtained copolymer was measured using the above measurement method and is shown in Table 1 below.

[0165] [Comparative Example 3]

[0166] For 100 parts by weight of polymethyl methacrylate resin (LXMMA, HP202), 30 parts by weight of acrylic impact modifier (LXMMA, PR 700) were mixed for 10 minutes using a Banbury mixer, and then a resin composition was prepared by kneading at a cylinder temperature of 230°C using a twin-screw extruder (32Φ, L / D=36, SM PLATEK) and pelletizing.

[0167] Afterwards, the obtained resin composition was measured using the above measurement method and is shown in Table 1 below.

[0169] Weight-average molecular weight (g / mol) PDI Haze (%) Impact resistance (kJ / ㎡) Example 1 96,000 1.3 2 25 Example 2 93,000 1.4 2 20 Example 3 100,000 1.3 2 20 Example 4 98,000 1.2 2 15 Example 5 105,000 1.3 2 10 Comparative Example 1 120,600 2.0 1 2 Comparative Example 2 110,600 2.0 1 2 Comparative Example 3 10,000 - 30 5

[0170] In Table 1 above, Examples 1 to 5 are methyl methacrylate triblock copolymers prepared with different PMMA macro-CTA contents. Looking at Examples 3 to 5, it was confirmed that impact strength is controlled as the PMMA macro-CTA content increases.

[0171] In contrast, as shown in Table 1 above, it was confirmed that the copolymer of Comparative Example 1, being a random copolymer of MMA and n-BA, has a much lower high-temperature haze than Examples 1 to 5 prepared from RAFT materials, but has a much lower impact strength.

[0172] In addition, as shown in Table 1 above, Comparative Example 2 is a block copolymer prepared by cationic polymerization, and it was confirmed that it has a very low molecular weight and a wider PDI than the example. In addition, it was confirmed that the polymerization process is very difficult because the method of preparing the block copolymer of Comparative Example 2 involves polymerization in an ultra-low temperature environment of -70 ℃.

[0173] In Table 1 above, it was confirmed that Comparative Example 3, as a general impact-resistant PMMA resin, has higher haze at high temperatures and relatively lower impact resistance than Examples 1 to 5.

[0174] Accordingly, the methyl methacrylate-based triblock copolymer of the present invention can be applied to various materials as it allows for easy control of PDI, and it was confirmed that by controlling the PMMA block unit, it not only maintains transparency but also possesses excellent impact resistance.

[0175] As described above, the present invention has been explained by specific details, limited embodiments, and comparative examples; however, these are provided merely to aid in a more comprehensive understanding of the invention, and the invention is not limited to the above embodiments. Those skilled in the art can make various modifications and variations from this description.

[0176] Accordingly, the scope of the present invention is not limited to the described embodiments, and all things equivalent to or having equivalent variations to the claims set forth below, as well as the claims set forth below, shall be considered to fall within the scope of the concept of the present invention.

Claims

Claim 1 Methyl methacrylate-based triblock copolymer obtained by RAFT polymerization using a RAFT agent represented by the following chemical formula 1: [Chemical Formula 1] In the above Chemical Formula 1, R1 and R2 are independently C1-C6 alkyls, and R3 and R4 are independently hydrogen, C1-C 12 Alkyl, C1-C 12 Haloalkyl, C1-C 12 Alkoxy and C1-C 12 One or more selected from haloalkoxy, and n and m are integers from 1 to 5 independently of each other. Claim 2 A methyl methacrylate-based triblock copolymer, wherein in Formula 1, R1 and R2 are independently methyl or ethyl, R3 and R4 are independently hydrogen or one or more selected from C1-C6 alkyl, C1-C6 haloalkyl, C1-C6 alkoxy and C1-C6 haloalkoxy, and n and m are independently integers from 1 to 3. Claim 3 A methyl methacrylate-based triblock copolymer according to claim 1, characterized in that the methyl methacrylate-based triblock copolymer has a polymethyl methacrylate-polyacrylate-polymethyl methacrylate triblock structure and includes a *-SC(=S)-S-* structure in the polyacrylate-based unit. Claim 4 In claim 3, the methyl methacrylate-based triblock copolymer is a methyl methacrylate-based triblock copolymer in which the polyacrylate-based block unit is one or more selected from methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, iso-butyl acrylate, and tert-butyl acrylate. Claim 5 In claim 1, the methyl methacrylate-based triblock copolymer is a methyl methacrylate-based triblock copolymer containing 5 to 50 weight% of polymethyl methacrylate block units with respect to 100 weight% of the methyl methacrylate-based triblock copolymer. Claim 6 In claim 1, the methyl methacrylate-based triblock copolymer has a weight-average molecular weight of 1,000 to 1,000,000 g / mol and a molecular weight distribution (PDI) of 1.1 to 5.

0. Claim 7 In claim 1, the methyl methacrylate-based triblock copolymer is a methyl methacrylate-based triblock copolymer having a haze of 20% or less as measured by ISO 14782. Claim 8 In claim 1, the methyl methacrylate-based triblock copolymer is a methyl methacrylate-based triblock copolymer having an impact strength of 3 kJ / m² or more as measured by ISO 179-1. Claim 9 An acrylic molded article manufactured by including a methyl methacrylate-based triblock copolymer selected from any one of claims 1 to 8. Claim 10 In claim 9, the acrylic molded product is an acrylic molded product that is an automotive exterior part. Claim 11 In claim 9, the acrylic molded product is an acrylic molded product that is an interior or exterior material. Claim 12 An adhesive composition comprising a methyl methacrylate-based triblock copolymer and a solvent selected from any one of claims 1 to 8. Claim 13 A method for preparing a methyl methacrylate-based triblock copolymer comprising: a first polymerization process step comprising a RAFT agent represented by the following chemical formula 1, methyl methacrylate, and a radical initiator; and a second polymerization process step comprising, after the first polymerization process, an acrylic monomer different from the methyl methacrylate and a radical initiator; [Chemical Formula 1] In the above Chemical Formula 1, R1 and R2 are independently C1-C6 alkyls, and R3 and R4 are independently hydrogen, C1-C 12 Alkyl, C1-C 12 Haloalkyl, C1-C 12 Alkoxy and C1-C 12 One or more selected from haloalkoxy, and n and m are integers from 1 to 5 independently of each other. Claim 14 In claim 13, the method for producing a methyl methacrylate-based triblock copolymer having a weight-average molecular weight of 10,000 to 1,000,000 g / mol, wherein the polymethyl methacrylate polymer obtained in the first polymerization process is a methyl methacrylate-based triblock copolymer. Claim 15 A method for preparing a methyl methacrylate-based triblock copolymer, wherein the acrylic monomer is one or more selected from methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, iso-butyl acrylate, and tert-butyl acrylate.

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