Resin composition

Abstract

A resin composition according to an embodiment of the present invention comprises: a graft copolymer including a conjugated diene-based polymer, an alkyl (meth)acrylate-based monomer unit, an aromatic vinyl-based monomer unit, and a vinylcyan-based monomer unit; and a styrene-based copolymer including an alkyl (meth)acrylate-based monomer unit, an aromatic vinyl-based monomer unit, and a maleimide-based monomer unit, wherein the conjugated diene-based polymer may have a degree of crosslinking of 85% or more and a degree of swelling of 14 or less, and the graft copolymer may have a degree of swelling of 5-16.

Description

Resin composition

[0001] [Cross-reference with related applications]

[0002] This application claims the benefit of priority based on Korean Patent Application 10-2024-0130085 filed September 25, 2024, and all contents disclosed in the literature of said Korean patent applications are incorporated herein as part of this specification.

[0003]

[0004] [Technology Field]

[0005] The present invention relates to a resin composition.

[0006] Recently, there has been a demand for the development of parts that require both heat resistance and transparency, such as automotive interior and exterior components, washing machine transparent windows, vacuum cleaner dust cups, and office equipment transparent windows.

[0007]

[0008] A method utilizing polycarbonate resin as a transparent plastic material to impart transparency to a resin composition is known; however, while polycarbonate resin offers excellent transparency and room-temperature impact resistance, it suffers from poor chemical resistance and low-temperature impact resistance. Furthermore, its insufficient processability limits design freedom due to reduced moldability resulting from changes in interior and exterior designs for future electric vehicles, and it poses limitations for application to large parts due to the high occurrence of paint cracks and adhesion defects caused by poor paintability. In addition, high processing temperatures cause melting defects in the printed areas during the film insert injection molding process, leading to a high defect rate and making it difficult to apply. Furthermore, U.S. Patent No. 3,787,522 and Japanese Registered Patent No. 1988-042940 disclose a method for imparting impact resistance to transparent polymethyl methacrylate resin; however, while polymethyl methacrylate resin has excellent transparency and processability, its impact resistance is extremely poor, limiting its application to parts requiring impact resistance. Additionally, due to poor paint adhesion, it is difficult to use for automotive applications involving painting processes. European Registered Patent No. 0,703,252 discloses a method for imparting transparency to high-impact polystyrene (HIPS) resin; however, high-impact polystyrene resin has problems with poor chemical resistance and scratch resistance.

[0009] Since resin compositions manufactured by the method described above have a problem in that properties other than transparency are degraded, a method of imparting transparency and heat resistance to an acrylonitrile-butadiene-styrene (ABS) copolymer has been proposed to manufacture a resin composition that has excellent heat resistance and transparency while not degrading other properties. The ABS copolymer is manufactured by graft copolymerizing styrene and acrylonitrile onto a butadiene rubbery polymer. The ABS copolymer possesses a balanced combination of stiffness, chemical resistance, impact resistance, and processability, and has the advantages of excellent impact strength, mechanical properties, surface gloss, and secondary processing characteristics such as plating, printing, and painting, as well as the ability to produce products in various colors. However, the ABS resin itself cannot simultaneously exhibit heat resistance and transparency.

[0010] Transparent ABS resins are imparted with transparent properties by keeping the difference in refractive index between the graft thermoplastic resin and the thermoplastic resin used as a matrix within 0.005. Meanwhile, methods have been developed to manufacture ABS copolymers with excellent heat resistance by introducing monomers with excellent heat resistance, such as maleimide monomers or alkyl-substituted styrene monomers, into a part of the resin composition containing the ABS copolymer, or by adding inorganic materials. However, alkyl-substituted styrene monomers have the disadvantage of requiring a long reaction time due to their very slow polymerization rate, as well as having a low molecular weight of the produced polymer and easy thermal decomposition. Maleimide monomers have the characteristic of having a very fast polymerization rate, making it very difficult to control the reaction temperature. Furthermore, as the content of maleate monomers increases, the impact strength of the ABS copolymer decreases, and whitening occurs within the resin due to the difference in heat resistance between the matrix resin and the rubber. In the case of transparent heat-resistant ABS materials, there is a problem where the whitening phenomenon is highly visible externally.

[0011] To prevent this whitening phenomenon, Korean registered patent 10-1561328 proposed a method of using small particles to increase the overall surface area and reduce the distance between particles; however, it is difficult to overcome impact resistance in automotive materials that must use heat-resistant styrene-based resins, and even if the content of graft copolymer resin is increased to improve impact resistance, there is a problem of rapidly decreasing heat resistance. In addition, as shown in Fig. 1, it can be confirmed that a whitening phenomenon occurs when exposed to a low-temperature environment (-40℃ for 24 hours).

[0012] [Prior Art Literature]

[0013] [Patent Literature]

[0014] (Patent Document 1) US 3787522 A

[0015] (Patent Document 2) JP 1988-042940 B2

[0016] (Patent Document 3) EP 0703252 B2

[0017] (Patent Document 4) KR 10-1561328

[0018] The present invention was devised to solve the problems of the prior art described above, and aims to provide a resin composition that has excellent heat resistance, transparency, and impact resistance, and in particular does not exhibit whitening even in low-temperature environments.

[0019] (1) The present invention provides a resin composition comprising: a graft copolymer comprising a conjugated diene polymer, an alkyl (meth)acrylate monomer unit, an aromatic vinyl monomer unit, and a vinyl cyanide monomer unit; and a styrene copolymer comprising an alkyl (meth)acrylate monomer unit, an aromatic vinyl monomer unit, and a maleimide monomer unit, wherein the degree of crosslinking of the conjugated diene polymer is 85% or more and the degree of swelling is 14 or less, and the degree of swelling of the graft copolymer is 5 or more and 16 or less.

[0020] (2) The present invention provides a resin composition according to (1), wherein the graft copolymer has a refractive index of 1.515 or higher and 1.520 or lower.

[0021] (3) The present invention provides a resin composition in which, in (1) or (2), the difference in refractive index between the graft copolymer and the styrene-based copolymer is 0.1 or less.

[0022] (4) The present invention provides a resin composition in which, in any one of (1) to (3), the graft copolymer has a weight-average molecular weight of 85,000 g / mol or more and 125,000 g / mol or less.

[0023] (5) The present invention provides a resin composition in which, in any one of (1) to (4), the graft copolymer has a graft rate of 40% or more.

[0024] (6) The present invention provides a resin composition in which, in any one of (1) to (5), the graft copolymer comprises: 20% by weight or more and 70% by weight or less of a conjugated diene polymer, 25% by weight or more and 55% by weight or less of an alkyl (meth)acrylate monomer unit, 1% by weight or more and 15% by weight or less of an aromatic vinyl monomer unit, and 5% by weight or less of a vinyl cyanide monomer unit.

[0025] (7) The present invention provides a resin composition in which, in any one of (1) to (6), the styrene copolymer comprises: 50% by weight or more and 90% by weight or less of an alkyl (meth)acrylate monomer unit, 1% by weight or more and 20% by weight or less of an aromatic vinyl monomer unit, and 1% by weight or more and 20% by weight or less of a maleimide monomer unit.

[0026] (8) The present invention provides a resin composition in which, in any one of (1) to (7), the graft copolymer is included in an amount of 10% or more and 40% or less, and the styrene copolymer is included in an amount of 60% or more and 90% or less.

[0027] (9) The present invention provides a resin composition in which, in any one of (1) to (8), the haze of a 3 mm thick specimen is measured by the ASTM D1003 method, the specimen is stored in a low-temperature chamber of -40 ℃ for 24 hours, the haze is measured again, and the change in haze calculated according to the following mathematical formula 7 is 1.0 or less.

[0028] [Mathematical Formula 7]

[0029] △Haze = (Haze of specimen after cold storage) - (Haze of specimen before cold storage)

[0030] (10) The present invention provides a resin composition in which, in any one of (1) to (9) above, the heat distortion temperature measured under a stress of 18.6 kgf using a specimen with a thickness of 6.4 mm by the ASTM D648 method is 90.0 ℃ or higher.

[0031] (11) The present invention provides a graft copolymer comprising a conjugated diene polymer, an alkyl (meth)acrylate monomer unit, an aromatic vinyl monomer unit, and a vinyl cyanide monomer unit, wherein the degree of crosslinking of the conjugated diene polymer is 85% or more, the degree of swelling is 14 or less, and the degree of swelling of the graft copolymer is 5 or more and 16 or less.

[0032] The resin composition according to one embodiment of the present invention has excellent heat resistance, transparency, impact resistance, and low-temperature whitening properties.

[0033] Figure 1 is a transmission electron microscope (TEM) image taken after exposing a resin composition according to the prior art (Patent Document 4) to -40°C for 24 hours.

[0034] Hereinafter, the present invention will be described in more detail to aid in understanding the invention.

[0035] Terms and words used in the description and claims of the present invention should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0036] The terms used in this invention are used merely to describe exemplary embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise.

[0037] In the present invention, the term 'monomer unit' may refer to a component, structure, or the material itself derived from a monomer, and as a specific example, may refer to a repeating unit formed within a polymer by a monomer introduced during the polymerization of a polymer and participating in the polymerization reaction.

[0038] The term 'composition' as used in the present invention includes reaction products and decomposition products formed from the materials of the said composition, as well as mixtures of materials containing said composition.

[0039]

[0040] The present invention provides a resin composition.

[0041] A resin composition according to one embodiment of the present invention comprises at least a graft copolymer comprising a conjugated diene polymer, an alkyl (meth)acrylate monomer unit, an aromatic vinyl monomer unit, and a vinyl cyanide monomer unit; and a styrene copolymer comprising an alkyl (meth)acrylate monomer unit, an aromatic vinyl monomer unit, and a maleimide monomer unit, wherein the degree of crosslinking of the conjugated diene polymer is 85% or more and the degree of swelling is 14 or less, and the degree of swelling of the graft copolymer is 5 or more and 16 or less.

[0042] The inventors have discovered that by controlling the degree of swelling of the graft copolymer included in the resin composition, the degree of swelling of the conjugated diene polymer, and the degree of crosslinking to an appropriate range, it is possible to prevent low-temperature whitening caused by the difference in heat resistance between the graft copolymer and the matrix (styrene copolymer), while also securing excellent heat resistance, transparency, and impact resistance, and thus have completed the present invention.

[0043]

[0044] The following describes in detail each component constituting the resin composition.

[0045]

[0046] 1. Graft copolymer

[0047] A resin composition according to one embodiment of the present invention may be a resin composition comprising a graft copolymer dispersed in a styrene-based copolymer, which is a matrix resin.

[0048] According to one embodiment of the present invention, the graft copolymer may comprise a conjugated diene polymer, an alkyl (meth)acrylate monomer unit, an aromatic vinyl monomer unit, and a vinyl cyanide monomer unit.

[0049] According to one embodiment of the present invention, the graft copolymer may comprise an alkyl (meth)acrylate monomer unit, an aromatic vinyl monomer unit, and a vinyl cyanide monomer unit graft-polymerized onto the conjugated diene polymer. In other words, the graft copolymer may be a core-shell type graft copolymer comprising a core comprising the conjugated diene polymer and a shell comprising an alkyl (meth)acrylate monomer unit, an aromatic vinyl monomer unit, and a vinyl cyanide monomer unit graft-polymerized onto the core.

[0050]

[0051] According to one embodiment of the present invention, the graft copolymer may include a core comprising a conjugated diene polymer.

[0052] According to one embodiment of the present invention, the conjugated diene polymer is a polymer comprising conjugated diene monomer units and crosslinkable monomer units, which may be referred to as rubber, and may serve to impart impact resistance to the graft copolymer.

[0053] According to one embodiment of the present invention, the conjugated diene monomer for forming the conjugated diene monomer unit may be one or more selected from the group consisting of 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl-1,3-octadiene, isoprene, and 2-phenyl-1,3-butadiene, and more specifically, 1,3-butadiene may be used.

[0054] According to one embodiment of the present invention, the degree of crosslinking of the conjugated diene polymer may be 85% or more and 99% or less. As a specific example, the degree of crosslinking of the conjugated diene polymer may be 85.5% or more, 86% or more, 86.5% or more, 87% or more, 87.5% or more, 88% or more, 88.5% or more, 89% or more, 89.5% or more, or 90% or more, and may also be 98.5% or less, 98% or less, 97.5% or less, 97% or less, 96.5% or less, 96% or less, 95.5% or less, 95% or less, 94.5% or less, or 94% or less. If the above range is satisfied, it is possible to prevent low-temperature whitening caused by the difference in heat resistance between the graft copolymer and the styrene-based copolymer, while ensuring excellent heat resistance, transparency, and impact resistance. However, if the degree of crosslinking of the conjugated diene polymer is less than 85%, the conjugated diene polymer shrinks significantly at ultra-low temperatures of -30°C or lower, so when it returns to room temperature, voids may form inside the conjugated diene polymer, which may cause whitening.

[0055] According to one embodiment of the present invention, the degree of crosslinking of the conjugated diene polymer may refer to the weight percentage of the insoluble portion, i.e., the gel, which is not dissolved in the solvent when the solid portion of the conjugated diene polymer is immersed in a solvent (e.g., toluene). The degree of crosslinking can be calculated according to the following Equation 1 by weighing 1 g of the solid portion of the conjugated diene polymer, immersing it in 100 g of toluene in a dark room for 12 hours, filtering the toluene-insoluble portion filtered through a 100-mesh wire mesh, drying the filtered portion at 85 ℃ for 4 hours to obtain a dried portion, and measuring the weight of the obtained dried portion.

[0056]

[0057] [Mathematical Formula 1]

[0058] Degree of Crosslinking (%) = Gel Content (Weight %) = Weight of Dry Powder / Weight of Initial Solids (1g) x 100 (%)

[0059]

[0060] According to one embodiment of the present invention, the conjugated diene polymer may have a swelling degree of 7 or more and 14 or less, and specifically, as an example, may be 7.2 or more, 7.4 or more, 7.6 or more, 7.8 or more, or 8 or more, and may also be 13.8 or less, 13.6 or less, 13.4 or less, 13.2 or less, 13 or less, or 12.8 or less. When the above range is satisfied, it is possible to prevent low-temperature whitening caused by the difference in heat resistance between the graft copolymer and the styrene copolymer, while ensuring excellent heat resistance, transparency, and impact resistance.

[0061] According to one embodiment of the present invention, the degree of swelling of the conjugated diene polymer can be calculated according to the following mathematical formula 2 by weighing 1 g of the solid content of the conjugated diene polymer, immersing it in 100 g of toluene in a dark room for 12 hours, filtering it through a 100 mesh wire mesh, storing the filtered toluene-insoluble content at room temperature for 5 to 10 minutes, and then measuring the weight (weight a).

[0062]

[0063] [Mathematical Formula 2]

[0064] Degree of swelling = Weight a / Initial solid weight

[0065]

[0066] According to one embodiment of the present invention, the conjugated diene polymer may be a conjugated diene copolymer polymerized by further including a monomer copolymerizable with the conjugated diene monomer, comprising the conjugated diene monomer. As a specific example, the conjugated diene polymer may be a butadiene polymer, a butadiene-styrene copolymer, or a butadiene-acrylonitrile copolymer.

[0067]

[0068] According to one embodiment of the present invention, the conjugated diene polymer may be introduced during the production of a graft copolymer in the form of a conjugated diene polymer latex comprising a conjugated diene polymer produced by emulsion polymerization.

[0069]

[0070] According to one embodiment of the present invention, the graft copolymer may include a shell surrounding the core. The shell may include an alkyl (meth)acrylate-based monomer unit, an aromatic vinyl-based monomer unit, and a vinyl cyanide-based monomer unit graft-polymerized onto the core.

[0071] According to one embodiment of the present invention, the alkyl (meth)acrylate-based monomer unit is intended to impart transparency to the graft copolymer and improve compatibility with the styrene-based copolymer. The alkyl (meth)acrylate-based monomer for forming the alkyl (meth)acrylate-based monomer unit may be an alkyl (meth)acrylate-based monomer having 1 to 12 carbon atoms. As a specific example, the alkyl (meth)acrylate-based monomer may be one or more selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, and lauryl (meth)acrylate, and as a more specific example, it may be methyl methacrylate. Here, (meth)acrylate means including both methacrylate and acrylate.

[0072] According to one embodiment of the present invention, the aromatic vinyl monomer unit is intended to improve mechanical properties and compatibility with a styrene copolymer, and may be one or more selected from the group consisting of styrene, α-methylstyrene, α-ethylstyrene, and p-methylstyrene, and may be styrene as a specific example.

[0073] According to one embodiment of the present invention, the graft copolymer may comprise a vinyl cyanide monomer unit graft-polymerized onto the conjugated diene-based polymer. The vinyl cyanide monomer unit is intended to improve mechanical properties and compatibility with the styrene-based copolymer, and may be one or more selected from the group consisting of acrylonitrile, methacrylonitrile, and ethacrylonitrile, and as a specific example, it may be acrylonitrile.

[0074]

[0075] According to one embodiment of the present invention, the graft copolymer may have the content of the conjugated diene polymer and each monomer unit adjusted in order to improve mechanical properties, heat resistance, and transparency. As a specific example, the graft copolymer may comprise 20% to 70% by weight of a conjugated diene polymer, 25% to 55% by weight of an alkyl (meth)acrylate monomer unit, 1% to 15% by weight of an aromatic vinyl monomer unit, 0.0% to 3% by weight of a crosslinkable monomer unit, and 0% to 5% by weight of a vinyl cyanide monomer unit.

[0076] According to one embodiment of the present invention, the graft copolymer may comprise 20% to 70% by weight of a conjugated diene polymer. As a specific example, the graft copolymer may comprise 20% or more by weight, 25% or more by weight, 30% or more by weight, 35% or more by weight, 40% or more by weight, 45% or more by weight, or 50% or more by weight of a conjugated diene polymer, and may also comprise 70% or less by weight, 65% or less by weight, 60% or less by weight, 55% or less by weight, or 50% or less by weight. Within this range, the impact strength of the resin composition is secured, and the graft polymerization is carried out smoothly, resulting in superior mechanical properties.

[0077] According to one embodiment of the present invention, the graft copolymer may comprise 25% to 55% by weight of alkyl (meth)acrylate-based monomer units. As a specific example, the graft copolymer may comprise 25% or more, 30% or more, or 35% or more by weight of alkyl (meth)acrylate-based monomer units, and may also comprise 55% or less, 50% or less, 45% or less, 40% or less, or 35% or less by weight. Within this range, the transparency of the resin composition is excellent, and the compatibility between the graft copolymer and the styrene-based copolymer is excellent, resulting in superior mechanical properties.

[0078] According to one embodiment of the present invention, the graft copolymer may further include crosslinkable monomer units in an amount of 3 weight% or less. As a specific example, the graft copolymer may include aromatic vinyl monomer units in an amount of 0.1 weight% or more, 0.2 weight% or more, 0.4 weight% or more, 0.6 weight% or more, 0.8 weight% or more, 1 weight% or more, or 1.5 weight% or more, and may also include 2.8 weight% or less, 2.6 weight% or less, 2.4 weight% or less, 2.2 weight% or less, or 2 weight% or less, and within this range, the impact strength of the resin composition is excellent and low-temperature whitening can be prevented.

[0079] According to one embodiment of the present invention, the crosslinkable monomer for forming the crosslinkable monomer unit is a comonomer that facilitates polymerization during conjugated diene-based polymerization, and may be one or more selected from the group consisting of divinylbenzene, 3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, allyl acrylate, allyl methacrylate, trimethylolpropane triacrylate, tetraethylene glycol diacrylate, and tetraethylene glycol dimethacrylate, and a specific example may be divinylbenzene.

[0080] According to one embodiment of the present invention, the graft copolymer may comprise 1% to 15% by weight of aromatic vinyl monomer units. As a specific example, the graft copolymer may comprise 1% or more by weight, 5% or more by weight, 6% or more by weight, 7% or more by weight, 8% or more by weight, 9% or more by weight, or 10% or more by weight of aromatic vinyl monomer units, and may also comprise 15% or less by weight, 14% or less by weight, 13% or less by weight, or 12% or less by weight. Within this range, the transparency of the resin composition is excellent, and the compatibility between the graft copolymer and the styrene copolymer is excellent, resulting in superior mechanical properties.

[0081] In the present invention, the graft copolymer may comprise 0% to 5% by weight of vinyl cyanide monomer units. As a specific example, the graft copolymer may comprise 0.0% or more, 0.1% or more, 0.5% or more, 1% or more, 1.5% or more, or 2.0% or more of vinyl cyanide monomer units, and may also comprise 5.0% or less, 4.5% or less, 4.0% or less, 3.5% or less, 3.0% or less, or 2.5% or less. Within this range, the transparency and color of the resin composition are excellent, the content of coagulated material due to reduced latex stability is minimized, and the compatibility between the graft copolymer and the styrene copolymer is excellent, resulting in superior mechanical properties.

[0082]

[0083] According to one embodiment of the present invention, the graft copolymer may have a swelling degree of 5 or more and 16 or less. As a specific example, the graft copolymer may have a swelling degree of 5.5 or more, 6 or more, 6.5 or more, 7 or more, 7.5 or more, 8 or more, 8.5 or more, 9 or more, or 9.5 or more, and may also have a swelling degree of 15.9 or less, 15.8 or less, 15.7 or less, 15.6 or less, or 15.5 or less. When the above range is satisfied, it is possible to prevent low-temperature whitening caused by the difference in heat resistance between the graft copolymer and the styrene-based copolymer, while ensuring excellent heat resistance, transparency, and impact resistance.

[0084] According to one embodiment of the present invention, the degree of swelling of the graft copolymer can be calculated according to the following mathematical formula 3 by immersing a certain amount of the graft copolymer in acetone to extract the insoluble part and vacuum drying it, and then immersing the insoluble part of the dried graft copolymer in 100 ml of toluene for 48 hours and filtering it through a 100 mesh wire mesh, measuring the weight of the toluene-insoluble part (weight c) and the weight of the toluene-insoluble part vacuum dried (weight d).

[0085] [Mathematical Formula 3]

[0086] Swelling degree = Weight of toluene-insoluble matter (weight c) / Weight after vacuum drying (weight d)

[0087]

[0088] According to one embodiment of the present invention, the graft copolymer may have a refractive index of 1.515 or higher and 1.520 or lower. As a specific example, the graft copolymer may have a refractive index of 1.515 or higher, 1.516 or higher, 1.517 or higher, or 1.518 or higher, and may also have a refractive index of 1.520 or lower, 1.519 or lower, or 1.518 or lower, and within this range, the transparency of the resin composition may be particularly excellent. The refractive index may be calculated according to the following Equation 4 from the content of each component added during the manufacture of the graft copolymer. Additionally, the refractive index may be the refractive index measured using an Abbe refractometer. The refractive index may be controlled according to the polymer and each monomer component and content added during the polymerization of the graft copolymer. Specifically, in order to ensure the transparency of the graft copolymer, it is necessary to control the refractive index of the conjugated diene polymer and the refractive index of the remaining components to a similar degree, and the mixing ratio of each monomer accordingly may be important. For example, the refractive indices according to each polymer and monomer component introduced during the manufacture of the graft copolymer may be approximately 1,3-butadiene 1.518, methyl methacrylate 1.49, styrene 1.59, and acrylonitrile 1.52.

[0089] [Mathematical Formula 4]

[0090] Refractive Index (RI) = ∑Wti*RIi

[0091] - Wti = Weight fraction (%) of each component in the graft copolymer

[0092] - RIi = Refractive index of the homopolymer of each component of the graft copolymer

[0093] According to one embodiment of the present invention, the graft copolymer may have a weight-average molecular weight of 85,000 g / mol or more and 125,000 g / mol or less. The weight-average molecular weight of the graft copolymer may be the weight-average molecular weight of the shell in a core-shell type graft copolymer, and as a specific example, may be the weight-average molecular weight of a free polymer containing each monomer unit included in the shell in a state not grafted to the conjugated diene polymer which is the core, and this may be measured by gel permeation chromatography after separating the graft copolymer into sol / gel and then diluting the obtained sol in tetrahydrofuran. As a specific example, the weight-average molecular weight of the graft copolymer may be 85,000 g / mol or more, 86,000 g / mol or more, 87,000 g / mol or more, 88,000 g / mol or more, 89,000 g / mol or more, 90,000 g / mol or more, 91,000 g / mol or more, 92,000 g / mol or more, 93,000 g / mol or more, 94,000 g / mol or more, 100,000 g / mol or more, 100,500 g / mol or more, 101,000 g / mol or more, 101,500 g / mol or more, or 102,000 g / mol or more, and may also be 125,000 g / mol or less, 120,000 g / mol or less, 115,000 g / mol or less, or It can be 110,000 g / mol or less, and within this range, the mechanical properties of the resin composition are excellent, and compatibility with styrene-based copolymers is even better.

[0094] According to one embodiment of the present invention, the graft copolymer may have a molecular weight distribution of 2.7 or less. Here, the molecular weight distribution may be the ratio of the weight-average molecular weight to the number-average molecular weight, meaning 'weight-average molecular weight (Mw) / number-average molecular weight (Mn)'. The molecular weight distribution of the graft copolymer may be 2.7 or less, 2.6 or less, 2.5 or less, 2.4 or less, or 2.3 or less, and may also be 1.0 or more, 1.5 or more, 2.0 or more, or 2.1 or more, and within this range, the mechanical properties of the resin composition are excellent, and compatibility with the styrene-based copolymer is even better.

[0095] According to one embodiment of the present invention, the weight-average molecular weight, molecular weight distribution, and transparency of the resin of the graft copolymer can be controlled according to the water solubility characteristics of the molecular weight regulator, particularly when polymerizing a graft copolymer using MMA. When the water solubility is 1 mg or more per 1 L at 50°C, it is highly effective for MMA-based products with a fast reaction rate. The molecular weight regulator may be a mercaptan-type molecular weight regulator, and specifically, it may be one or more selected from the group consisting of 1-butyl mercaptan, n-decyl mercaptan, n-hexyl mercaptan, and n-octyl mercaptan, and more specifically, n-octyl mercaptan. Molecular weight regulators with a water solubility of less than 1 mg per 1 L are difficult to participate in the reaction immediately upon addition, and especially in polymerization environments where a large amount of MMA is used, the transfer reaction rate is particularly reduced, making it difficult to raise the graft rate to a certain level.

[0096] According to one embodiment of the present invention, the graft copolymer may have a graft rate of 40% or more. The graft rate of the graft copolymer may be calculated according to the following Equation 5 after adding a certain amount of dried copolymer powder of the graft copolymer latex to acetone, dissolving the liberated graft copolymer by vibrating it with a vibrator (product name: SI-600R, manufacturer: Lab. companion) for 24 hours, centrifuging it at 14,000 rpm for 1 hour with a centrifuge, and drying it at 140°C for 2 hours with a vacuum dryer (product name: DRV320DB, manufacturer: ADVANTEC) to obtain an insoluble fraction. As a specific example, the graft rate of the above graft copolymer may be 40% or more, 41% or more, 42% or more, 43% or more, 44% or more, 44% or more, or 45% or more, and may also be 80% or less, 75% or less, or 70% or less, and within this range, the mechanical properties of the resin composition are excellent and the compatibility with the styrene-based copolymer is even better.

[0097] [Mathematical Formula 5]

[0098] Graft rate (%) = [(Y - (X*R)) / (X*R)] * 100

[0099] Y: Weight of insoluble matter

[0100] X: Weight of graft copolymer added when obtaining insoluble matter

[0101] R: Fraction of conjugated diene polymer in the graft copolymer added when obtaining the insoluble fraction

[0102]

[0103] 2. Styrene-based copolymer

[0104] According to one embodiment of the present invention, the styrene copolymer may be the matrix resin of the resin composition, and although it is referred to as a styrene copolymer in the present invention in accordance with the name used to refer to a conventional matrix resin, it may also be referred to as an acrylic copolymer in terms of the ratio between the monomers described below. The styrene copolymer may be a non-graft copolymer comprising alkyl (meth)acrylate monomer units, aromatic vinyl monomer units, and maleimide monomer units, and as a specific example, it may further include vinyl cyanide monomer units as needed.

[0105] According to one embodiment of the present invention, the alkyl (meth)acrylate monomer unit for forming the alkyl (meth)acrylate monomer unit of the styrene-based copolymer, the aromatic vinyl monomer for forming the aromatic vinyl monomer unit, and the vinyl cyanide monomer for forming the vinyl cyanide monomer unit may each be selected from monomers of the same type as the alkyl (meth)acrylate monomer, aromatic vinyl monomer, maleimide monomer, and vinyl cyanide monomer of the graft copolymer described above, and may be the same or different from each monomer of the graft copolymer.

[0106] According to one embodiment of the present invention, the maleimide monomer unit of the styrene-based copolymer is intended to impart heat resistance to the styrene-based copolymer, and the maleimide monomer for forming the maleimide monomer unit is N-phenylmaleimide, maleimide, N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-isobutylmaleimide, Nt-butylmaleimide, N-cyclohexylmaleimide, N-chloromaleimide, N-methylphenylmaleimide, N-bromophenylmaleimide, N-naphthylmaleimide, N-laurylmaleimide, N-hydroxyphenylpalimide, N-methoxyphenylmaleimide, N-carboxyphenylmaleimide, N-nitrophenylmaleimide, and It may be one or more selected from the group consisting of N-benzylmaleimide, and a specific example may be N-phenylmaleimide.

[0107] According to one embodiment of the present invention, the styrene-based copolymer may have a refractive index of 1.515 or higher and 1.520 or lower. As a specific example, the styrene-based copolymer may have a refractive index of 1.515 or higher, 1.516 or higher, 1.517 or higher, or 1.518 or higher, and may also have a refractive index of 1.520 or lower, 1.519 or lower, or 1.518 or lower, and within this range, the transparency of the resin composition may be particularly excellent. The refractive index may be calculated according to the following Equation 6 from the content of each component added during the manufacture of the styrene-based copolymer. Additionally, the refractive index may be the refractive index measured using an Abbe refractometer. The refractive index may be controlled according to the polymer and each monomer component and content added during the polymerization of the styrene-based copolymer. For example, the refractive indices according to each monomer component added during the manufacture of the above styrene-based copolymer may be about 1.49 for methyl methacrylate, about 1.63 for N-phenylmaleimide, about 1.59 for styrene, and about 1.52 for acrylonitrile.

[0108] [Mathematical Formula 6]

[0109] Refractive Index (RI) = ∑Wti*RIi

[0110] - Wti = Weight fraction (%) of each component in styrene copolymer

[0111] - RIi = Refractive index of the homopolymer of each component of the styrene-based copolymer

[0112] According to one embodiment of the present invention, the styrene-based copolymer may have a weight-average molecular weight of 80,000 g / mol or more and 160,000 g / mol or less. The weight-average molecular weight of the styrene-based copolymer may be measured by gel permeation chromatography after dilution with tetrahydrofuran. As a specific example, the weight-average molecular weight of the styrene-based copolymer may be 80,000 g / mol or more, 85,000 g / mol or more, 90,000 g / mol or more, 95,000 g / mol or more, or 100,000 g / mol or more, and may also be 160,000 g / mol or less, 155,000 g / mol or less, 150,000 g / mol or less, or 140,000 g / mol or less, and within this range, the mechanical properties of the resin composition are excellent and the compatibility with the graft copolymer is even better.

[0113] In the present invention, the content of each monomer unit of the styrene copolymer can be controlled to improve the mechanical properties of the resin composition, as well as to improve heat resistance, transparency, and processability. As a specific example, the styrene copolymer may comprise 50% to 90% by weight of alkyl (meth)acrylate monomer units, 1% to 20% by weight of aromatic vinyl monomer units, 1% to 20% by weight of maleimide monomer units, and 0% to 5% by weight of vinyl cyanide monomer units.

[0114] In the present invention, the styrene-based copolymer may comprise 50% to 90% by weight of alkyl (meth)acrylate monomer units. As a specific example, the styrene-based copolymer may comprise 50% or more by weight, 55% or more by weight, 60% or more by weight, 65% or more by weight, 70% or more by weight, or 75% or more by weight of alkyl (meth)acrylate monomer units, and may also comprise 90% or less by weight, 85% or less by weight, or 80% or less by weight. Within this range, the transparency of the resin composition is excellent, and the compatibility between the graft copolymer and the styrene-based copolymer is excellent, resulting in superior mechanical properties.

[0115] According to one embodiment of the present invention, the styrene-based copolymer may comprise 1% to 20% by weight of aromatic vinyl monomer units. As a specific example, the styrene-based copolymer may comprise 1% or more by weight, 2% or more by weight, 3% or more by weight, 4% or more by weight, 5% or more by weight, or 9% or more by weight of aromatic vinyl monomer units, and may also comprise 20% or less by weight, 19% or less by weight, 18% or less by weight, 17% or less by weight, 16% or less by weight, or 15% or less by weight. Within this range, the transparency of the resin composition is excellent, and the compatibility between the graft copolymer and the styrene-based copolymer is excellent, resulting in superior mechanical properties.

[0116] According to one embodiment of the present invention, the styrene-based copolymer may comprise 1% to 20% by weight of maleimide monomer units. As a specific example, the styrene-based copolymer may comprise 1% or more by weight, 2% or more by weight, 3% or more by weight, 4% or more by weight, 5% or more by weight, 6% or more by weight, 7% or more by weight, or 7.5% or more by weight of maleimide monomer units, and may also comprise 20% or less by weight, 19% or less by weight, 18% or less by weight, 17% or less by weight, or 15% or less by weight. Within this range, the heat resistance and transparency of the resin composition are excellent, and the compatibility between the graft copolymer and the styrene-based copolymer is excellent, resulting in superior mechanical properties.

[0117] According to one embodiment of the present invention, the styrene-based copolymer may comprise 0% to 5% by weight of vinyl cyanide monomer units. As a specific example, the styrene-based copolymer may comprise 0.0% or more, 0.1% or more, 0.5% or more, 1% or more, 1.5% or more, or 2.0% or more of vinyl cyanide monomer units, and may also comprise 5.0% or less, 4.5% or less, 4.0% or less, 3.5% or less, or 3.0% or less. Within this range, the transparency and color of the resin composition are excellent, the content of coagulated material due to reduced latex stability is minimized, and the compatibility between the graft copolymer and the styrene-based copolymer is excellent, resulting in superior mechanical properties.

[0118]

[0119] 3. Other additives

[0120] According to one embodiment of the present invention, the resin composition may further include other additives. The additives may be one or more selected from the group consisting of lubricants, antioxidants, light stabilizers, hydrolysis stabilizers, release agents, pigments, antistatic agents, conductivity imparters, electromagnetic shielding agents, magnetizing agents, mineral fillers, crosslinking agents, antibacterial agents, processing aids, metal deactivators, flame suppressants, anti-friction and anti-wear agents, and coupling agents.

[0121] The above additives may be used without limitation as long as they are used in the technical field of the present invention, and a person skilled in the art may select the additives included in the present invention according to the purpose.

[0122]

[0123] 4. Resin composition

[0124] According to one embodiment of the present invention, the resin composition may comprise 10% by weight or more and 40% by weight or less of a graft copolymer and 60% by weight or more and 90% by weight or less of a styrene-based copolymer. As a specific example, the resin composition may comprise 10% by weight or more, 15% by weight or more, 20% by weight or more, 25% by weight or more, or 30% by weight or more of a graft copolymer, and may also comprise 40% by weight or less, 35% by weight or less, or 30% by weight or less, and may comprise the styrene-based copolymer as the remainder of the components other than the graft copolymer.

[0125] According to one embodiment of the present invention, the resin composition may comprise, based on the total content of the graft copolymer and the styrene copolymer, 10% to 40% by weight of a conjugated diene polymer, 40% to 75% by weight of an alkyl (meth)acrylate monomer unit, 5% to 15% by weight of a maleimide monomer unit, 5% to 15% by weight of an aromatic vinyl monomer unit, 0.0% to 3% by weight of a crosslinkable monomer unit, and 0% to 5% by weight of a vinyl cyanide monomer unit. When the graft copolymer and the styrene copolymer are mixed and kneaded within the resin composition, even if the graft copolymer and the styrene copolymer each contain monomer units formed from the same type of monomer, it is not easy to distinguish them individually. The content of the conjugated diene polymer and each monomer unit above refers to the content of the polymer and monomer units in the resin composition containing the graft copolymer and the styrene copolymer, not the content of the polymer and monomer units in the graft copolymer and the styrene copolymer.

[0126] According to one embodiment of the present invention, the resin composition may comprise 10% to 40% by weight of a conjugated diene polymer. As a specific example, the resin composition may comprise 10% or more by weight, 11% or more by weight, 12% or more by weight, 13% or more by weight, 14% or more by weight, or 15% or more by weight of a conjugated diene polymer, and may also comprise 40% or less by weight, 35% or less by weight, 30% or less by weight, 25% or less by weight, or 20% or less by weight, and within this range, while securing the impact strength and mechanical properties of the resin composition, transparency and processability are further improved.

[0127] According to one embodiment of the present invention, the resin composition may comprise 40% to 75% by weight of alkyl (meth)acrylate-based monomer units. As a specific example, the graft copolymer may comprise 40% or more, 45% or more, 50% or more, 55% or more, or 60% or more of alkyl (meth)acrylate-based monomer units, and may also comprise 75% or less, 70% or less, or 65% or less by weight, and within this range, the transparency and mechanical properties of the resin composition are even better.

[0128] According to one embodiment of the present invention, the resin composition may comprise 5% to 15% by weight of maleimide-based monomer units. As a specific example, the resin composition may comprise 5% or more by weight, 6% or more by weight, 7% or more by weight, 8% or more by weight, or 9% or more by weight of maleimide-based monomer units, and may also comprise 15% or less by weight, 14% or less by weight, 13% or less by weight, 12% or less by weight, 11% or less by weight, or 10% or less by weight, and within this range, the heat resistance and transparency of the resin composition are excellent.

[0129] According to one embodiment of the present invention, the resin composition may comprise 5% to 15% by weight of aromatic vinyl monomer units. As a specific example, the resin composition may comprise 5% or more by weight, 6% or more by weight, 7% or more by weight, 8% or more by weight, or 9% or more by weight of aromatic vinyl monomer units, and may also comprise 15% or less by weight, 14% or less by weight, 13% or less by weight, 12% or less by weight, 11% or less by weight, or 10% or less by weight, and within this range, the transparency of the resin composition is excellent and the mechanical properties are excellent.

[0130] According to one embodiment of the present invention, the resin composition may contain 3 weight% or less of crosslinkable monomer units. As a specific example, the graft copolymer may contain 0.1 weight% or more, 0.2 weight% or more, 0.4 weight% or more, 0.6 weight% or more, 0.8 weight% or more, 1 weight% or more, or 1.5 weight% or more of crosslinkable monomer units, and may also contain 2.8 weight% or less, 2.6 weight% or less, 2.4 weight% or less, 2.2 weight% or less, or 2 weight% or less, and within this range, the impact strength of the resin composition is excellent and low-temperature whitening can be prevented.

[0131] According to one embodiment of the present invention, the resin composition may comprise 0% to 5% by weight of vinyl cyanide monomer units. As a specific example, the graft copolymer may comprise 0.0% or more, 0.1% or more, 0.5% or more, 1% or more, 1.5% or more, or 2.0% or more of vinyl cyanide monomer units, and may also comprise 5.0% or less, 4.5% or less, 4.0% or less, 3.5% or less, 3.0% or less, or 2.5% or less, and within this range, the transparency and color of the resin composition are excellent.

[0132] According to one embodiment of the present invention, the difference in refractive index between the graft copolymer and the styrene-based copolymer included in the resin composition may be 0.1 or less, or 0.01 or less, and is preferably 0. If the above conditions are satisfied, the transparency of the resin composition can be further improved.

[0133]

[0134] As described above, a resin composition according to one embodiment of the present invention can have excellent heat resistance, transparency, and impact resistance, as well as excellent low-temperature whitening properties, by controlling the degree of swelling of the graft copolymer and the degree of swelling and crosslinking of the conjugated diene polymer to an appropriate range.

[0135] In the present invention, the resin composition may have a notched izod impact strength measured at room temperature (23°C) by making a notch in a 1 / 4 inch thick specimen according to the ASTM D256 method, which is 5.0 kgf·cm / cm or more, 5.5 kgf·cm / cm or more, 6.0 kgf·cm / cm or more, 6.5 kgf·cm / cm or more, 7.0 kgf·cm / cm or more, 7.5 kgf·cm / cm or more, 8.0 kgf·cm / cm or more, or 8.5 kgf·cm / cm or more, and may also be 20.0 kgf·cm / cm or less, 18.0 kgf·cm / cm or less, or 15.0 kgf·cm / cm or less.

[0136] In the present invention, the resin composition may have a heat distortion temperature of 90.0 ℃ or higher, measured under a stress of 18.6 kgf using a specimen with a thickness of 6.4 mm according to the ASTM D648 method. As a specific example, the resin composition may have a heat distortion temperature of 90.0 ℃ or higher, 91.0 ℃ or higher, 92.0 ℃ or higher, 93.0 ℃ or higher, 94.0 ℃ or higher, 95.0 ℃ or higher, 95.7 ℃ or higher, 96.0 ℃ or higher, 97.0 ℃ or higher, 98.0 ℃ or higher, 99.0 ℃ or higher, or 100.0 ℃ or higher, and may also have a heat distortion temperature of 110.0 ℃ or lower, 108.0 ℃ or lower, or 105.0 ℃ or lower.

[0137] In the present invention, the resin composition may have a Vicat softening temperature of 100.0 ℃ or higher as measured by the ASTM D1525 method. As a specific example, the resin composition may have a Vicat softening temperature of 100.0 ℃ or higher, 101.0 ℃ or higher, 102.0 ℃ or higher, 103.0 ℃ or higher, 104.0 ℃ or higher, 105.0 ℃ or higher, 106.0 ℃ or higher, 106.3 ℃ or higher, 107.0 ℃ or higher, 108.0 ℃ or higher, 109.0 ℃ or higher, or 110.0 ℃ or higher, and may also have a temperature of 120.0 ℃ or lower, 118.0 ℃ or lower, or 115.0 ℃ or lower.

[0138] In the present invention, the resin composition may have a haze change amount of 1.0 or less calculated according to the following Equation 7, after measuring the haze on a 3 mm thick specimen by the ASTM D1003 method, storing the specimen in a low-temperature chamber of -40 ℃ for 24 hours, and then measuring the haze again. As a specific example, the resin composition may have a haze change amount of 1.0 or less, 0.8 or less, 0.6 or less, or 0.5 or less, and may also be 0.0 or 0.1 or more.

[0139] [Mathematical Formula 7]

[0140] △Haze = (Haze of specimen after cold storage) - (Haze of specimen before cold storage).

[0141]

[0142] Hereinafter, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0143]

[0144] Preparation Example 1: Preparation of Graft Copolymer A

[0145] A polymerization reaction was carried out by continuously introducing 50 parts by weight (based on solid content) of conjugated diene polymer latex [emulsion polymerization, gel content 90 wt%, swelling degree 9.5, average particle size 320 nm], 100 parts by weight of ion-exchanged water, 1.0 parts by weight of sodium oleate, 34 parts by weight of methyl methacrylate, 13 parts by weight of styrene, 3 parts by weight of acrylonitrile, 0.1 parts by weight of n-octyl mercaptan, 0.03 parts by weight of ethylenediaminetetraacetic acid, 0.1 parts by weight of sodium formaldehyde sulfoxylate, 0.0015 parts by weight of ferrous sulfide, and 0.2 parts by weight of t-butylhydroperoxide into a nitrogen-substituted polymerization reactor at 65°C for 3 hours. Subsequently, the internal temperature of the reactor was raised to 70 ℃, aged for 1 hour and 30 minutes, and the reaction was terminated to produce a graft copolymer latex containing the graft copolymer. Afterward, the graft copolymer latex was coagulated with an aqueous sulfuric acid solution, washed, dehydrated, and dried to obtain powdered graft copolymer A. The refractive index of the obtained graft copolymer A was 1.518, the weight-average molecular weight was 115,000 g / mol, the graft rate was 41.7%, the coagulated content was 0.05 wt%, and the degree of swelling was 11.

[0146]

[0147] Preparation Example 2: Preparation of Graft Copolymer B

[0148] A polymerization reaction was carried out by continuously introducing 50 parts by weight (based on solid content) of conjugated diene polymer latex [emulsion polymerization, gel content 85 wt%, swelling degree 12.8, average particle size 320 nm], 100 parts by weight of ion-exchanged water, 1.0 parts by weight of sodium oleate, 34 parts by weight of methyl methacrylate, 13 parts by weight of styrene, 3 parts by weight of acrylonitrile, 0.1 parts by weight of n-octyl mercaptan, 0.03 parts by weight of ethylenediaminetetraacetic acid, 0.1 parts by weight of sodium formaldehyde sulfoxylate, 0.0015 parts by weight of ferrous sulfide, and 0.2 parts by weight of t-butyl hydroperoxide into a nitrogen-substituted polymerization reactor at 65°C for 3 hours. Next, the internal temperature of the reactor was raised to 70 ℃, aged for 1 hour and 30 minutes, and the reaction was terminated to produce a graft copolymer latex containing the graft copolymer. Subsequently, the graft copolymer latex was coagulated with an aqueous sulfuric acid solution, washed, dehydrated, and dried to obtain powdered graft copolymer B. The refractive index of the obtained graft copolymer B was 1.518, the weight-average molecular weight was 110,700 g / mol, the graft rate was 42.3%, the coagulated content was 0.06 wt%, and the degree of swelling was 15.

[0149]

[0150] Preparation Example 3: Preparation of Graft Copolymer C

[0151] A polymerization reaction was carried out by continuously introducing 50 parts by weight (based on solid content) of conjugated diene polymer latex [emulsion polymerization, gel content 95 wt%, swelling degree 8, average particle size 320 nm], 100 parts by weight of ion-exchanged water, 1.0 parts by weight of sodium oleate, 34 parts by weight of methyl methacrylate, 13 parts by weight of styrene, 3 parts by weight of acrylonitrile, 0.05 parts by weight of n-octyl mercaptan, 0.03 parts by weight of ethylenediaminetetraacetic acid, 0.1 parts by weight of sodium formaldehyde sulfoxylate, 0.0015 parts by weight of ferrous sulfide, and 0.2 parts by weight of t-butylhydroperoxide into a nitrogen-substituted polymerization reactor at 65°C for 3 hours. Subsequently, the internal temperature of the reactor was raised to 70 °C, aged for 1 hour and 30 minutes, and the reaction was terminated to produce a graft copolymer latex containing the graft copolymer. Afterward, the graft copolymer latex was coagulated with an aqueous sulfuric acid solution, washed, dehydrated, and dried to obtain powdered graft copolymer C. The refractive index of the obtained graft copolymer C was 1.518, the weight-average molecular weight was 125,000 g / mol, the graft rate was 44.5%, the coagulated content was 0.06 wt%, and the degree of swelling was 9.5.

[0152]

[0153] Preparation Example 4: Preparation of Graft Copolymer D

[0154] A polymerization reaction was carried out by continuously introducing 50 parts by weight (based on solid content) of conjugated diene polymer latex [emulsion polymerization, gel content 80 wt%, swelling degree 18, average particle size 320 nm], 100 parts by weight of ion-exchanged water, 1.0 parts by weight of sodium oleate, 34 parts by weight of methyl methacrylate, 13 parts by weight of styrene, 3 parts by weight of acrylonitrile, 0.12 parts by weight of n-octyl mercaptan, 0.03 parts by weight of ethylenediaminetetraacetic acid, 0.1 parts by weight of sodium formaldehyde sulfoxylate, 0.0015 parts by weight of ferrous sulfide, and 0.2 parts by weight of t-butylhydroperoxide into a nitrogen-substituted polymerization reactor at 65°C for 3 hours. Subsequently, the internal temperature of the reactor was raised to 70 ℃, aged for 1 hour and 30 minutes, and the reaction was terminated to produce a graft copolymer latex containing the graft copolymer. Afterward, the graft copolymer latex was coagulated with an aqueous sulfuric acid solution, washed, dehydrated, and dried to obtain powdered graft copolymer D. The refractive index of the obtained graft copolymer D was 1.518, the weight-average molecular weight was 103,500 g / mol, the graft rate was 40.5%, the coagulated content was 0.08 wt%, and the degree of swelling was 17.

[0155]

[0156] Preparation Example 5: Preparation of Graft Copolymer E

[0157] A polymerization reaction was carried out by continuously introducing 50 parts by weight (based on solid content) of conjugated diene polymer latex [emulsion polymerization, gel content 80 wt%, swelling degree 14, average particle size 320 nm], 100 parts by weight of ion-exchanged water, 1.0 parts by weight of sodium oleate, 34 parts by weight of methyl methacrylate, 13 parts by weight of styrene, 3 parts by weight of acrylonitrile, 0.1 parts by weight of n-octyl mercaptan, 0.03 parts by weight of ethylenediaminetetraacetic acid, 0.1 parts by weight of sodium formaldehyde sulfoxylate, 0.0015 parts by weight of ferrous sulfide, and 0.2 parts by weight of t-butyl hydroperoxide into a nitrogen-substituted polymerization reactor at 65°C for 3 hours. Subsequently, the internal temperature of the reactor was raised to 70 °C, and after aging for 1 hour and 30 minutes, the reaction was terminated to produce a graft copolymer latex containing the graft copolymer. Afterward, the graft copolymer latex was coagulated with an aqueous sulfuric acid solution, washed, dehydrated, and dried to obtain powdered graft copolymer E. The refractive index of the obtained graft copolymer E was 1.518, the weight-average molecular weight was 112,200 g / mol, the graft rate was 42.1%, the coagulated material content was 0.05 wt%, and the degree of swelling was 15.

[0158]

[0159] Preparation Example 6: Preparation of Graft Copolymer F

[0160] A polymerization reaction was carried out by continuously introducing 50 parts by weight (based on solid content) of conjugated diene polymer latex [emulsion polymerization, gel content 80 wt%, swelling degree 13, average particle size 320 nm], 100 parts by weight of ion-exchanged water, 1.0 parts by weight of sodium oleate, 34 parts by weight of methyl methacrylate, 13 parts by weight of styrene, 3 parts by weight of acrylonitrile, 0.1 parts by weight of n-octyl mercaptan, 0.03 parts by weight of ethylenediaminetetraacetic acid, 0.1 parts by weight of sodium formaldehyde sulfoxylate, 0.0015 parts by weight of ferrous sulfide, and 0.2 parts by weight of t-butylhydroperoxide into a nitrogen-substituted polymerization reactor at 65°C for 3 hours. Subsequently, the internal temperature of the reactor was raised to 70 °C, and after aging for 1 hour and 30 minutes, the reaction was terminated to produce a graft copolymer latex containing the graft copolymer. Afterward, the graft copolymer latex was coagulated with an aqueous sulfuric acid solution, washed, dehydrated, and dried to obtain powdered graft copolymer F. The refractive index of the obtained graft copolymer F was 1.518, the weight-average molecular weight was 108,700 g / mol, the graft rate was 41.1%, the coagulated material content was 0.06 wt%, and the degree of swelling was 16.

[0161]

[0162] Preparation Example 7: Preparation of Styrene-based Copolymer A

[0163] 77 parts by weight of methyl methacrylate, 10 parts by weight of styrene, 3 parts by weight of N-phenyl maleimide, 64 parts by weight of ion-exchanged water, 0.02 parts by weight of 1,1-di(t-butylperoxy)cyclohexane, 0.02 parts by weight of dicumyl peroxide, and 1.3 parts by weight of tricalcium phosphate were added all at once to a polymerization reactor equipped with a stirrer, the stirring speed of the reactor was set to 500 rpm, and the temperature of the reactor was raised to 90 ℃ to start polymerization. Subsequently, from the point where the polymerization conversion rate reached 5% until the point where the polymerization conversion rate reached 60%, 86 parts by weight of ion-exchanged water were continuously added to the reactor at a constant rate. In addition, from the point where the polymerization conversion rate reached 5% until the point where the polymerization conversion rate reached 70%, 10 parts by weight of N-phenyl maleimide were continuously added to the reactor at a constant rate while polymerization was carried out. At this time, the continuous input of ion-exchanged water was performed for 100 minutes, and the continuous input of N-phenylmaleimide was performed for 150 minutes. After the continuous input of both ion-exchanged water and N-phenylmaleimide was completed, polymerization was carried out for 90 minutes while maintaining the temperature of the reactor at 90 ℃, polymerization was carried out while increasing the temperature of the reactor to 120 ℃ for 20 minutes, and polymerization was carried out for 100 minutes while maintaining the temperature of the reactor at 120 ℃, after which the polymerization was terminated. Formic acid was added to the obtained polymerization slurry to adjust the acid value of the slurry to 2.5, and after removing the dispersant, the slurry was washed, dehydrated, and dried to obtain bead-shaped styrene-based copolymer A.

[0164]

[0165] Preparation Example 8: Preparation of Styrene-based Copolymer B

[0166] 79 parts by weight of methyl methacrylate, 4 parts by weight of styrene, 3 parts by weight of N-phenyl maleimide, 64 parts by weight of ion-exchanged water, 0.02 parts by weight of 1,1-di(t-butylperoxy)cyclohexane, 0.02 parts by weight of dicumyl peroxide, and 1.3 parts by weight of tricalcium phosphate were added all at once to a polymerization reactor equipped with a stirrer, the stirring speed of the reactor was set to 500 rpm, and the temperature of the reactor was raised to 90 ℃ to start polymerization. Subsequently, from the point where the polymerization conversion rate reached 5% until the point where the polymerization conversion rate reached 60%, 86 parts by weight of ion-exchanged water were continuously added to the reactor at a constant rate. In addition, from the point where the polymerization conversion rate reached 5% until the point where the polymerization conversion rate reached 70%, 7 parts by weight of N-phenyl maleimide were continuously added to the reactor at a constant rate while polymerization was carried out. At this time, the continuous input of ion-exchanged water was performed for 100 minutes, and the continuous input of N-phenylmaleimide was performed for 150 minutes. After the continuous input of both ion-exchanged water and N-phenylmaleimide was completed, polymerization was carried out for 90 minutes while maintaining the temperature of the reactor at 90 ℃, polymerization was carried out while increasing the temperature of the reactor to 120 ℃ for 20 minutes, and polymerization was carried out for 100 minutes while maintaining the temperature of the reactor at 120 ℃, after which the polymerization was terminated. Formic acid was added to the obtained polymerization slurry to adjust the acid value of the slurry to 2.5, and after removing the dispersant, the slurry was washed, dehydrated, and dried to obtain bead-shaped styrene-based copolymer B.

[0167]

[0168] Preparation Example 9: Preparation of Styrene-based Copolymer C

[0169] 75 parts by weight of methyl methacrylate, 17.5 parts by weight of styrene, 2 parts by weight of N-phenyl maleimide, 64 parts by weight of ion-exchanged water, 0.02 parts by weight of 1,1-di(t-butylperoxy)cyclohexane, 0.02 parts by weight of dicumyl peroxide, and 1.3 parts by weight of tricalcium phosphate were added all at once to a polymerization reactor equipped with a stirrer, the stirring speed of the reactor was set to 500 rpm, and the temperature of the reactor was raised to 90 ℃ to start polymerization. Subsequently, from the point where the polymerization conversion rate reached 5% until the point where the polymerization conversion rate reached 60%, 86 parts by weight of ion-exchanged water were continuously added to the reactor at a constant rate. In addition, from the point where the polymerization conversion rate reached 5% until the point where the polymerization conversion rate reached 70%, 5.5 parts by weight of N-phenyl maleimide were continuously added to the reactor at a constant rate while polymerization was carried out. At this time, the continuous input of ion-exchanged water was performed for 100 minutes, and the continuous input of N-phenylmaleimide was performed for 150 minutes. After the continuous input of both ion-exchanged water and N-phenylmaleimide was completed, polymerization was carried out for 90 minutes while maintaining the temperature of the reactor at 90 ℃, polymerization was carried out while increasing the temperature of the reactor to 120 ℃ for 20 minutes, and polymerization was carried out for 100 minutes while maintaining the temperature of the reactor at 120 ℃, after which the polymerization was terminated. Formic acid was added to the obtained polymerization slurry to adjust the acid value of the slurry to 2.5, and after removing the dispersant, the styrene-based copolymer C in the form of beads was obtained by washing, dehydrating, and drying.

[0170]

[0171] Preparation Example 10: Preparation of Styrene-based Copolymer D

[0172] A mixture of 64 parts by weight of methyl methacrylate, 26 parts by weight of styrene, 7 parts by weight of acrylonitrile, 3 parts by weight of methacrylic acid, 30 parts by weight of ethylbenzene, and 0.15 parts by weight of t-dodecyl mercaptan was continuously fed into a continuous polymerization reactor and polymerized for an average residence time of 3 hours. At this time, the temperature of the reactor was maintained at 148 ℃. The polymerization solution continuously discharged from the reactor was heated in a preheating tank, and unreacted monomers were volatilized in a volatilization tank. Then, while maintaining the temperature of the polymerization solution at 210 ℃, styrene-based copolymer D in pellet form was obtained using a polymer transfer pump extruder.

[0173]

[0174] Examples and Comparative Examples

[0175] Each of the graft copolymers prepared in Preparation Examples 1 to 5 and the styrene-based copolymers prepared in Preparation Examples 6 to 9 were mixed in the amounts listed in Tables 1 and 2 below, and extruded using a twin-screw extrusion mixer at a cylinder temperature of 250°C to prepare a transparent resin composition in the form of pellets (Examples 1 to 5 and Comparative Examples 1 to 6).

[0176]

[0177] Experimental Example 1 - Measurement of Physical Properties of Conjugated Diene Polymers

[0178] * Degree of crosslinking (%): 1 g of solids from each of the conjugated diene polymer latexes used in Preparation Examples 1 to 5 were weighed, immersed in 100 g of toluene in a dark room for 12 hours, and the toluene-insoluble matter filtered through a 100-mesh wire mesh was dried at 85°C for 4 hours to obtain a dried substance, and the weight of the obtained dried substance was measured. The degree of crosslinking was calculated according to the following Equation 1, and the calculated values ​​of the degree of crosslinking of the conjugated diene polymer are listed in Tables 1 and 2 below.

[0179]

[0180] [Mathematical Formula 1]

[0181] Degree of Crosslinking (%) = Gel Content (Weight %) = Weight of Dry Powder / Weight of Initial Solids (1g) x 100 (%)

[0182]

[0183] * Swelling degree: 1 g of solid content was weighed from each of the conjugated diene polymer latex used in Preparation Examples 1 to 5, immersed in 100 g of toluene in a dark room for 12 hours, and filtered through a 100 mesh wire mesh. The weight (weight a) of the filtered toluene-insoluble content was measured after storage at room temperature for 5 to 10 minutes, and the swelling degree was calculated according to the following Equation 2. The calculated swelling degree values ​​of the conjugated diene polymer are listed in Tables 1 and 2 below.

[0184]

[0185] [Mathematical Formula 2]

[0186] Degree of swelling = Weight a / Weight of initial solids

[0187]

[0188] * Particle size distribution (%): 1 g of conjugated diene latex was diluted in 100 g of distilled water and measured using a CHDF apparatus (Capillary HydroDynaminc Fractionation, Matec Applied Science, Model 4000).

[0189]

[0190] Experimental Example 2 - Measurement of Physical Properties of Graft Copolymer

[0191] * Swelling degree: A certain amount of the dried copolymer powder of the graft copolymer latex prepared in Preparation Examples 1 to 5 was immersed in acetone to extract the insoluble matter and vacuum dried. The weight of the toluene-insoluble matter (weight c) and the weight of the toluene-insoluble matter (weight d) were measured when the dried insoluble matter of the graft copolymer was immersed in 100 ml of toluene for 48 hours and filtered through a 100-mesh wire mesh, and the swelling degree of the graft copolymer was calculated according to the following Equation 3. The calculated swelling degree values ​​of the graft copolymer are listed in Tables 1 and 2 below.

[0192]

[0193] [Mathematical Formula 3]

[0194] Swelling degree = Weight of toluene-insoluble matter (weight c) / Weight after vacuum drying (weight d)

[0195]

[0196] * Refractive index: Calculated according to the following mathematical formula 4 from the content of each component added during the preparation of each graft copolymer in Preparation Examples 1 to 5 above.

[0197] [Mathematical Formula 4]

[0198] Refractive Index (RI) = ∑Wti*RIi

[0199] - Wti = Weight fraction (%) of each component in the graft copolymer

[0200] - RIi = Refractive index of the homopolymer of each component of the graft copolymer

[0201]

[0202] * Weight-average molecular weight: Each graft copolymer powder prepared in the above preparation example was added to acetone and stirred for 24 hours. Then, a centrifuge was used to separate the rubber component (insoluble matter) that does not dissolve in acetone and the copolymer component (soluble matter) that dissolves in acetone. The weight-average molecular weight, number-average molecular weight, and molecular weight distribution of the separated acetone-soluble matter were measured using Gel Permeation Chromatography (GPC). At this time, a combination of two PLgel Olexis columns and one PLgel mixed-C column from Polymer Laboratories was used. Additionally, all newly replaced columns were of the mixed-bed type, and polystyrene was used as the GPC standard material.

[0203] - Solvent: Tetrahydrofuran (Stabilized with BHT)

[0204] - Flow rate: 1.0 ml / min

[0205] - Sample concentration: 2.0 mg / ml

[0206] - Infusion volume: 100 µl

[0207] - Column temperature: 30 ℃

[0208] - Detector: Waters 2414 Refractive Index Detector

[0209] - Data processing: Empower 3

[0210]

[0211] * Graft rate (%): A certain amount of dried copolymer powder of each graft copolymer latex prepared in Preparation Examples 1 to 5 was added to acetone and vibrated for 24 hours with a vibrator (product name: SI-600R, manufacturer: Lab. companion) to dissolve the liberated graft copolymer, centrifuged at 14,000 rpm for 1 hour with a centrifuge, and dried at 140 ℃ for 2 hours with a vacuum dryer (product name: DRV320DB, manufacturer: ADVANTEC) to obtain the insoluble matter, and then calculated according to the following mathematical formula 5.

[0212] [Mathematical Formula 5]

[0213] Graft rate (%) = [(Y - (X*R)) / (X*R)] * 100

[0214] Y: Weight of insoluble matter

[0215] X: Weight of graft copolymer added when obtaining insoluble matter

[0216] R: Fraction of conjugated diene polymer in the graft copolymer added when obtaining the insoluble fraction

[0217]

[0218] * Coagulated content (weight%): Each graft copolymer latex prepared in Preparation Examples 1 to 5 was filtered through a 100 mesh structure, and the material that did not pass through the structure was dried in a hot air dryer at 80°C for 6 hours to measure the weight of the solid coagulated content, and calculated according to the following mathematical formula 8.

[0219] [Mathematical Formula 8]

[0220] Coagulated content (weight%) = [Weight of dried coagulated material after separation by mesh structure (g) / Weight of total rubber and monomer used in polymerization (g)] × 100

[0221]

[0222] Experimental Example 3 - Measurement of Physical Properties of Resin Composition

[0223] Using specimens prepared by injecting the pellets prepared in Examples 1 to 5 and Comparative Examples 1 to 6 at an injection molding machine at an injection temperature of 250 ℃, the impact strength, heat distortion temperature, Vicat softening temperature, and low-temperature whitening were measured in the following manner and are listed in Tables 1 and 2 below.

[0224]

[0225] * Impact strength (kgf·cm / cm): According to the ASTM D256 method, a 1 / 4 inch thick specimen was notched, and the notched izod impact strength was measured at room temperature (23 ℃) using an impact strength measuring instrument (TINIUS OLSEN).

[0226]

[0227] * Heat distortion temperature (HDT, °C): Measured under a stress of 18.6 kgf using a 6.4 mm thick specimen according to the ASTM D648 method.

[0228]

[0229] * Vicat softening temperature (°C): Measured according to the ASTM D1525 method using a specimen with a width of 10 mm and a thickness of 3.2 mm under a load of 50 N, a maximum penetration of 1.0 mm, and a temperature of 50°C / hr.

[0230]

[0231] * Haze: Haze was measured on a 3 mm thick specimen using a haze meter HZ-V3 instrument according to the ASTM D1003 method.

[0232]

[0233] * Low-temperature whitening (△Haze): Haze was measured on a 3 mm thick specimen using a HZ-V3 haze meter according to the ASTM D1003 method. Afterward, the specimen was stored in a low-temperature chamber at -40 ℃ for 12 hours, the haze was measured again, and the change in haze was calculated according to the following Equation 7.

[0234] [Mathematical Formula 7]

[0235] △Haze = (Haze of specimen after cold storage) - (Haze of specimen before cold storage)

[0236]

[0237] Example 1 2 3 4 5 Graft copolymer type ABCAA Content (parts by weight) 30 30 30 30 30 Degree of crosslinking of conjugated diene polymer (%) 90 85 95 90 90 Degree of swelling of conjugated diene polymer 9.5 12.8 89.5 9.5 Degree of swelling of graft copolymer 11 15 9.5 11 11 Styrene copolymer type AAA ABC Content (parts by weight) 70 70 70 70 70 Resin composition Impact strength (kgf·cm / cm) 10.5 10.8 10.3 10.8 11.3 Heat distortion temperature (°C) 10 2.8 10 2.6 10 2.2 10 0.7 9 5.7 Vicat softening temperature (°C) 11 2.1 11 2.7 11 2.5 10 9.0 10 6.3 Transparency (Haze) 2.0 2.0 2.0 1.9 1.8 Low temperature Haze (△Haze)0.60.70.90.60.6

[0238] Comparative Example 1 2 3 4 5 6 Graft copolymer type DE AB CF content (parts by weight) 30 30 30 30 30 30 Degree of crosslinking of conjugated diene polymer (%) 8 0 8 0 9 0 8 5 9 5 80 Degree of swelling of conjugated diene polymer 18 1 4 9.5 1 2.8 8 13 Degree of swelling of graft copolymer 17 1 5 1 1 1 5 9.5 16 Styrene copolymer type BB D D DB content (parts by weight) 7 7 0 7 0 7 7 70 70 Resin composition Impact strength (kgf·cm / cm) 8 5 6 7 1 3 3 1 4 2 1 5 5 5 7 Heat distortion temperature (°C) 10 0 4 1 0 0 6 8 3 3 8 3 8 2 9 1 0 0 5 Vicat Softening Temperature (°C) 108.7 109.0 94.8 93.9 95.3 108.8 Transparency (Haze) 2.0 2.0 1.9 1.9 1.9 2.0 Low-Temperature Whitening (△Haze) 3.4 2.7 0.4 0.5 0.4 2.2

[0239] Referring to Tables 1 and 2 above, the resin compositions of Examples 1 to 5 satisfy the range of a degree of crosslinking of the conjugated diene polymer of 85% or more and a degree of swelling of 13 or less, and a degree of swelling of the graft copolymer of 5 or more and 16 or less. This allows for greater alleviation of stress that may occur at low temperatures due to the difference in glass transition temperature (Tg) between the graft copolymer and the matrix resin, which is a styrene copolymer. Accordingly, it can be confirmed that the impact strength and heat resistance are excellent, transparency is ensured, and low-temperature whitening resistance is excellent at 1.0 or less.

[0240] It can be confirmed that the resin compositions of Comparative Examples 1 and 2, in which the degree of crosslinking of the conjugated diene polymer is less than 85% and the degree of swelling exceeds 13, exhibit lower low-temperature whitening properties compared to the Examples. In particular, in the case of Comparative Example 2, it can be confirmed that low-temperature whitening properties deteriorate even when the degree of swelling of the graft copolymer satisfies a desirable range. This confirms that in order to suppress low-temperature whitening caused by the difference in heat resistance between the graft copolymer and the matrix, not only must the degree of crosslinking and the degree of swelling of the conjugated diene polymer satisfy a desirable range, but the degree of swelling of the graft copolymer must also satisfy a desirable range.

[0241] It was confirmed that Comparative Examples 3 to 5, which use a styrene copolymer not containing maleimide monomer units, had extremely poor heat resistance even though they contained the same graft copolymer as Examples 1 to 3.

[0242] Comparative Example 6, in which the swelling degree of the conjugated diene polymer and the swelling degree of the graft copolymer satisfy the desirable range but the degree of crosslinking of the conjugated diene polymer is less than 85, was found to have reduced impact strength and low-temperature whitening compared to the examples.

Claims

1. A graft copolymer comprising a conjugated diene polymer, an alkyl (meth)acrylate monomer unit, an aromatic vinyl monomer unit, and a vinyl cyanide monomer unit; and A styrene copolymer comprising alkyl (meth)acrylate monomer units, aromatic vinyl monomer units, and maleimide monomer units, and The degree of crosslinking of the above conjugated diene polymer is 85% or more, and the degree of swelling is 14 or less, and A resin composition having a swelling degree of the graft copolymer of 5 or more and 16 or less.

2. In Paragraph 1, The above graft copolymer is a resin composition having a refractive index of 1.515 or higher and 1.520 or lower.

3. In Paragraph 1, A resin composition in which the difference in refractive index between the graft copolymer and the styrene-based copolymer is 0.1 or less.

4. In Paragraph 1, The above graft copolymer is a resin composition having a weight-average molecular weight of 85,000 g / mol or more and 125,000 g / mol or less.

5. In Paragraph 1, The above graft copolymer is a resin composition having a graft rate of 40% or more.

6. In Paragraph 1, The above graft copolymer is: It contains 20% by weight or more and 70% by weight or less of a conjugated diene polymer, and It contains alkyl (meth)acrylate monomer units in an amount of 25% by weight or more and 55% by weight or less, It contains aromatic vinyl monomer units in an amount of 1% by weight or more and 15% by weight or less, and A resin composition containing 5 weight percent or less of vinyl cyanide monomer units.

7. In Paragraph 1, The above styrene-based copolymer is: It contains 60% by weight or more and 90% by weight or less of alkyl (meth)acrylate monomer units, and It contains aromatic vinyl monomer units in an amount of 1% by weight or more and 20% by weight or less, A resin composition comprising 1% by weight or more and 20% by weight or less of maleimide-based monomer units.

8. In Paragraph 1, The above graft copolymer is included in an amount of 10% by weight or more and 40% by weight or less, and A resin composition comprising 60% by weight or more and 90% by weight or less of the above-mentioned styrene-based copolymer.

9. In Paragraph 1, A resin composition having a haze change amount of 1.0 or less calculated according to the following Equation 7, after measuring the haze on a 3 mm thick specimen by the ASTM D1003 method, storing the specimen in a low-temperature chamber at -40 ℃ for 24 hours, and then measuring the haze again. [Mathematical Formula 7] △Haze = (Haze of specimen after cold storage) - (Haze of specimen before cold storage) 10. In Paragraph 1, A resin composition having a heat distortion temperature of 90.0 ℃ or higher, measured under a stress of 18.6 kgf using a 6.4 mm thick specimen according to the ASTM D648 method.

11. A graft copolymer comprising a conjugated diene polymer, an alkyl (meth)acrylate monomer unit, an aromatic vinyl monomer unit, and a vinyl cyanide monomer unit, and A graft copolymer having a degree of crosslinking of 85% or more and a degree of swelling of 14 or less, and a degree of swelling of 5 or more and 16 or less of the graft copolymer.

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