Thermoplastic resin composition

Abstract

The present invention relates to a thermoplastic resin composition. The resin composition contains an aromatic vinyl-vinyl cyanide-acrylic crosslinked copolymer, and has a glossiness at 60° measured with a gloss meter of 25 or less according to the evaluation method of ASTM D523, an impact strength of 15 kgf·cm / cm or more measured for a sample with a thickness of 1 / 4 inch according to the evaluation method of ASTM D256, and a light reflection variation coefficient calculated by the following formula 1 of 1.5 or less. The present invention is characterized in that a matte finish can be achieved even by injection molding. [Formula 1] C LR =D L / M L In the above formula 1, C LR is the light reflection variation coefficient, D L is the standard deviation of the light intensity, and M L is the average light intensity.

Description

[Technical Field]

[0001] This application claims priority rights under Korean Patent Application No. 10-2022-0139506 dated October 26, 2022, and Korean Patent Application No. 10-2022-0138522 dated October 25, 2022, and all content disclosed in the documents of said Korean Patent Applications is incorporated herein by reference.

[0002] This invention relates to a thermoplastic resin composition that enables the creation of a non-reflective surface. [Background technology]

[0003] Generally, acrylonitrile-butadiene-styrene (hereinafter referred to as ABS) resin is widely used in a variety of applications, including automobiles, electrical and electronic equipment, office equipment, home appliances, toys, and stationery, due to its excellent impact resistance and processability. However, because ABS resin is easily oxidized by oxygen, ultraviolet light, light, and heat due to the double bonds in the butadiene rubber used as an impact reinforcement agent, its use as an exterior material is severely limited due to its fragility, which causes discoloration of the resin's exterior and degrades its appearance quality. Even as an interior material, discoloration can prevent it from meeting consumer requirements.

[0004] Recently, with the trend towards higher-end materials in home appliances and automotive interiors, there has been growing interest in sensory resins that can express a soft, unpainted, low-gloss texture as an alternative to cold, artificially glossy materials. In the automotive industry, too, due to regulations on indoor air quality and environmental concerns, there is a trend to omit coating and painting processes and directly use low-gloss resins.

[0005] One method applied to manufacture low-gloss resins is to achieve a low-gloss effect by greatly adjusting the smoothness of the resin surface and scattering incident light through diffuse reflection. Specifically, one method involves manufacturing and using ultra-large diameter rubber particles with an average particle size of 1 μm or more. However, while resins manufactured in this way can reduce the gloss deviation across the entire surface of molded products, they have problems with insufficient low-gloss effect and reduced heat resistance and impact strength.

[0006] Another method involves applying an embossing treatment to the mold to create irregularities on the surface of the molded product, thereby producing a low-gloss effect on the surface of the injection-molded product. However, while products manufactured in this way excel in the low-gloss effect, they require a different mold for each product shape, and the problem of uneven gloss in the low-gloss resin itself cannot be resolved, resulting in areas with increased gloss. As the size of molded products to which low-gloss resin is applied is increasing, gloss deviations, where the gloss is unevenly high, are occurring during molding. To solve this, mold analysis, which adjusts injection molding conditions and the position of the mold gate, is being attempted, but there are limitations.

[0007] Another method involves graft polymerization of monomers such as ethylene-unsaturated carboxylic acids into the resin. While this method yields good physical properties, it suffers from a problem of a rapid decrease in heat resistance.

[0008] U.S. Patent No. 4,460,742 (Patent Document 1) discloses a low-gloss resin composition using a cross-linked copolymer. This composition exhibits a quenching effect by incorporating large-diameter rubber particles or a quenching agent. However, it requires an excessive amount of quenching agent, which leads to problems such as reduced impact strength and heat resistance.

[0009] Therefore, the development of a new low-gloss thermoplastic material that simultaneously exhibits excellent weather resistance, heat resistance, and low-gloss properties, and can uniformly exhibit low-gloss properties across the entire surface area of ​​the molded product, has been recognized. [Prior art documents] [Patent Documents]

[0010]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0011] In the present invention, by dividing and adding a crosslinking agent or the like, the reactivity between monomers and the reactivity between the chain and the crosslinking agent during polymerization are adjusted to provide a crosslinked copolymer in which the degree of crosslinking and the glass transition temperature are controlled.

[0012] Further, in the present invention, by including the copolymer, the heat resistance and impact strength are maintained at an excellent level, and the fluidity is good, so that it can have engineering merits, and a matte thermoplastic resin composition having a uniform surface is provided.

Means for Solving the Problems

[0013] In order to solve the above problems, the present invention provides a resin composition containing an aromatic vinyl-vinyl cyanide-acrylic crosslinked copolymer, having a glossiness at 60° measured by a gloss meter of 25 or less according to the evaluation method of ASTM D523, an impact strength of 15 kgf·cm / cm or more measured for a sample having a thickness of 1 / 4 inch according to the ASTM D256 evaluation method, and a light reflection variation coefficient calculated by the following formula 1 of 1.5 or less. [Formula 1] C LR =D L / M L In the above formula 1, C LR is the light reflection variation coefficient, D L is the standard deviation of the light intensity, and M L is the average light intensity.

Effects of the Invention

[0014] The resin composition according to the present invention achieves a glossless surface by controlling the gloss level and the coefficient of variation of light reflection to a low level, while ensuring surface uniformity, without any reduction in heat resistance or impact strength, and also offers excellent fluidity and process advantages. [Modes for carrying out the invention]

[0015] The present invention will be described in more detail below to facilitate understanding of it.

[0016] The terms and words used herein and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather in a manner consistent with the technical idea of ​​the present invention, in accordance with the principle that inventors may define the concepts of terms as appropriate to best describe their invention.

[0017] Unless otherwise defined, the terms and measurement methods used in this invention may be defined as follows.

[0018] As used in this invention, the term "composition" includes not only reaction products and decomposition products formed from the materials of the composition, but also mixtures of materials containing the composition.

[0019] In this invention, the terms "monomer unit," "crosslinking unit," or "crosslinking portion" may refer to a repeating unit formed by a compound used as a monomer or a compound used as a crosslinking agent participating in a polymerization reaction or a crosslinking reaction, a structure resulting therefrom, or the substance itself.

[0020] The term "derivative" as used in this invention may refer to a compound having a structure in which one or more of the hydrogen atoms constituting the initial compound are substituted with a halogen group, an alkyl group, or a hydroxyl group.

[0021] In the present invention, the "polymerization conversion rate" indicates the degree to which monomers are polymerized by a polymerization reaction to form a polymer. During the polymerization, a part of the polymer in the reactor is sampled, and after calculating the weight of the polymer other than water according to the following formula 3, the sample is dissolved in a tetrahydrofuran (THF) solvent and then precipitated with methanol (MeOH) to remove unreacted monomers. After that, the weight of the polymer obtained by drying the precipitated suspension is measured and calculated according to the following formula 4.

[0022] [Formula 3] (Actual weight of polymer) = (Sampled polymer) - (Sampled polymer × Water content rate)

[0023] [Formula 4] Polymerization conversion rate (%) = [(Weight of polymer obtained by drying) / (Actual weight of polymer)] × 100

[0024] thermoplastic resin composition The resin composition according to the present invention contains an aromatic vinyl-vinyl cyanide-acrylic crosslinked copolymer, and according to the evaluation method of ASTM D523, the glossiness at 60° measured with a gloss meter is 25 or less. According to the ASTM D256 evaluation method, the impact strength measured for a sample with a thickness of 1 / 4 inch is 15 kgf·cm / cm or more, and the light reflection variation coefficient calculated by the following formula 1 is 1.5 or less.

[0025] [Formula 1] C LR =D L / M L

[0026] In the above formula 1, C LR is the light reflection variation coefficient, D<00{\rm 00011}is the standard deviation of light intensity, and M L is the average light intensity.

[0027] According to one embodiment of the present invention, the resin composition may have a gloss level of 25 or less, preferably 20 or less, more preferably 17 or less, and even more preferably 15 or less. Gloss level is a representative numerical value that can express whether a resin is glossy (high gloss, low gloss) or matte. Generally, for commercially available matte molded products, the gloss level is above 30, which is not substantially considered matte. However, when using the resin composition of the present invention, a gloss level of 25 or less can be achieved, making it possible to realize matte products.

[0028] Conventional non-reflective products are typically manufactured by roughening the surface of the injection mold through corrosion treatment or other methods before injecting resin, thereby giving the surface properties that allow for diffuse reflection. However, this method makes it difficult to achieve true non-reflective properties, and the process efficiency is poor due to wear on the injection mold, making it unsuitable for mass production.

[0029] On the other hand, some molded products attempt to achieve a matte finish by applying post-treatment to low-gloss products. For example, one method involves co-extruding a film containing a crosslinking agent to form a pattern on the surface, or applying a crosslinking agent to the product and then applying a pattern to the surface by UV curing. However, in this case, there are limitations to the achievable gloss level, and surface uniformity is poor.

[0030] On the other hand, the resin composition according to one embodiment of the present invention has the glossiness described above, a light reflection variation coefficient of 1.5 or less, and can provide a matte molded product with ensured surface uniformity. The light reflection variation coefficient can be 1.5 or less, preferably 1.4 or less, more preferably 1.3 or less, and even more preferably 1.2 or less.

[0031] The aforementioned coefficient of light reflection variation indicates the uniformity of the surface of the molded product and also reflects its glossiness. It means that the surface is uniform throughout and diffuse reflection occurs to a similar degree everywhere on the surface of the molded product, thus enabling the provision of high-quality, non-reflective molded products. In other words, a coefficient of light reflection variation exceeding 1.5 may mean that the surface is not uniform and that diffuse reflection does not occur in a part of the surface.

[0032] The aforementioned coefficient of variation in light reflection can be derived using phyton by the following method.

[0033] 1) Image creation of the sample: Using a DSLR camera (Canon 750D) and a 200mm x 200mm surface illumination (White LED, Collimated Backlight LTS-3PFT), the prepared sample was photographed and imaged with the camera distance set to 40cm, the distance between the sample and the illumination to 100cm, and the angle set to 90°.

[0034] 2) Grayscale conversion of sample image: The sample image is converted to grayscale (0-255) using the OpenCV library. Here, a grayscale value is assigned to each pixel in the sample image, and this grayscale value is used as the luminosity.

[0035] 3) Image reconstruction: The image is divided into a 200 μm × 200 μm grid, and the luminosity value (grayscale value) of the pixels within each grid is averaged to reconstruct the image. Here, each grid has one averaged luminosity value.

[0036] 4) Luminous intensity correction: The target grid is designated as the first zone, the eight grids adjacent to the first zone as the second zone, and the sixteen grids adjacent to the second zone as the third zone. After assigning correction coefficients of 1 for the first zone, -0.0625 for the second zone, and -0.03125 for the third zone, the corrected luminous intensity value of the target grid is derived using the following formula 2.

[0037]

number

[0038] In the above formula 2, L is the corrected luminosity value of the grating to be measured, and L 1 L is the luminosity of the first area grating. 2 1, L 2 2, L 2 3, ..., L 2 8 is the luminosity of each of the 8 grids in the second area, L 3 1, L 3 2, L 3 3, ..., L 3 16 This represents the luminosity of each of the 16 gratings in the third zone.

[0039] The aforementioned correction coefficient is intended to readjust the luminosity, taking into account the visual suppression effect, and may be intended to minimize errors due to optical illusions, where the luminosity of the target grid may be evaluated differently depending on the luminosity of the surrounding grid when observed visually. Specifically, for "no light," when the product is commercialized, human visual perception is more important, and not only must the value measured by the instrument indicate no light, but it must also be perceived as no light visually. Therefore, the above-mentioned correction coefficient can be applied to the measured value so that the measured value derived by the instrument is at a level equivalent to the actual visual effect considering optical illusions.

[0040] 5) Derivation of mean and standard deviation: The mean and standard deviation are determined from the corrected luminous intensity values ​​of each grating, and the coefficient of variation of light reflection is derived using the mean and standard deviation of the luminous intensity thus obtained, according to Equation 1.

[0041] Furthermore, according to one embodiment of the present invention, the resin composition can have an impact strength of 15 kgf·cm / cm or more when measured against a 1 / 4 inch thick sample in accordance with the evaluation method of ASTM D256, and specifically, it can have an impact strength of 15.5 kgf·cm / cm or more, 16 kgf·cm / cm or more, 16.5 kgf·cm / cm or more, or 17 kgf·cm / cm or more.

[0042] According to one embodiment of the present invention, the resin composition has low gloss and a low coefficient of variation of light reflectance, as described above, making it possible to provide a matte molded product with a uniform surface and improved impact strength. These properties can be achieved by including an aromatic vinyl-vinyl cyanide-acrylic crosslinked copolymer, and this crosslinked copolymer can solve the problems of conventional matte molded products.

[0043] (1) Aromatic vinyl-vinylcyanate-acrylic crosslinked copolymer and method for producing the same According to one embodiment of the present invention, the aromatic vinyl-vinyl cyanide-acrylic crosslinked copolymer comprises a crosslinked portion containing crosslinked functional compound units, aromatic vinyl monomer units, vinyl cyanide monomer units, and primary alkyl (meth)acrylate monomer units, and has a glass transition temperature of less than 90°C and a degree of crosslinking of 40% to 70%.

[0044] The resin composition contains an aromatic vinyl-vinyl cyanide-acrylic crosslinked copolymer, and the aromatic vinyl-vinyl cyanide-acrylic crosslinked copolymer can be included in an amount of 1 to 30 parts by weight, preferably 3 to 20 parts by weight, per 100 parts by weight of the resin composition.

[0045] The crosslinked copolymer imparts surface properties to the resin composition such that light can be diffusely reflected from the surface. By being crosslinked, it is manufactured in a form with higher strength, and as a result, it can be uniformly distributed within the matrix resin. When the crosslinked copolymer is included in the resin composition, very low gloss and light reflection coefficient can be achieved. When the crosslinked copolymer is included within the range described above, the above effects can be achieved even better.

[0046] According to one embodiment of the present invention, the crosslinked copolymer may have a glass transition temperature of less than 90°C, preferably 88°C or lower, and more preferably 87°C or lower. Furthermore, the crosslinked copolymer may have a degree of crosslinking of 40% to 70%, preferably 45% to 65%.

[0047] Generally, the glass transition temperature can be affected by the ratio of monomers in the copolymer and the degree of crosslinking by the crosslinking agent. A high glass transition temperature leads to a problem of reduced impact strength. On the other hand, in order to maintain a uniform state with extremely low surface gloss in a molded product, a crosslinked copolymer must be applied to induce diffuse reflection on the surface of the molded product. Crosslinked copolymers generally have the disadvantage of having a high glass transition temperature and being brittle in terms of impact strength.

[0048] However, according to one embodiment of the present invention, by controlling the method of adding polymerization additives such as crosslinking agents and molecular weight modifiers, it is possible to provide a crosslinked copolymer that has a low glass transition temperature and can achieve the same level of crosslinking as conventional crosslinked copolymers, thereby providing a molded article that has a uniform, non-reflective surface and excellent impact strength.

[0049] Therefore, if the glass transition temperature is 90°C or higher, the impact strength may be inferior, and if the degree of crosslinking is lower than 40% or higher than 70%, the glossiness will increase, and the uniformity of the surface may also be inferior due to a decrease in dispersibility, etc. For this reason, the crosslinked copolymer can have a glass transition temperature of 90°C or higher and a degree of crosslinking of 40% to 70%.

[0050] According to one embodiment of the present invention, the crosslinked portion may include crosslinked functional compound units, and the crosslinked functional compound may include one or more selected from the group consisting of silicon-based compounds, acrylic-based compounds, and vinyl-based compounds, and the crosslinked portion may be composed of units derived from these compounds.

[0051] In one embodiment of the present invention, the crosslinked copolymer can have a very uniform distribution of crosslinks within it, the degree of distribution of crosslinks is appropriate, and the fluidity between the chains as a whole can be maintained.

[0052] According to one embodiment of the present invention, the crosslinked copolymer may contain, per 100 parts by weight of the entire copolymer, 40 to 65 parts by weight of the aromatic vinyl monomer units, 15 to 35 parts by weight of the vinyl cyanide monomer units, 5 to 35 parts by weight of the first alkyl (meth)acrylate monomer units, and 0.05 to 5.00 parts by weight of the crosslinked portion. When the above range is satisfied, a desired level of glass transition temperature can be achieved, an appropriate level of crosslinking can be realized, and excellent impact strength and photophobic properties can be obtained simultaneously.

[0053] The crosslinked copolymer can be a random copolymer, and the composition of aromatic vinyl monomer units and vinyl cyanide monomer units within the copolymer can be uniform. Uniform composition of monomer units means that the ratio of each monomer unit present in the polymer grown by the polymerization reaction of monomers is maintained uniformly. Specifically, as polymerization progresses, that is, as the polymerization time changes during polymerization, when a portion of the polymer is sampled from the reactor, the ratio of each monomer unit forming the polymer is maintained uniformly.

[0054] According to one embodiment of the present invention, the aromatic vinyl monomer unit and the vinyl cyanide monomer unit may refer to repeating units formed by the polymerization reaction of the aromatic vinyl monomer and the vinyl cyanide monomer, respectively. Specifically, the polymerization reaction may be a radical polymerization reaction, thereby referring to repeating units derived from carbon-carbon double bonds present in the aromatic vinyl monomer and the vinyl cyanide monomer.

[0055] According to one embodiment of the present invention, the crosslinked copolymer may further contain vinyl ester monomer units or dialkyl (meth)acrylate monomer units. The crosslinked copolymer may be a ternary copolymer, and preferably a quaternary copolymer. In the case of a quaternary copolymer, it may be advantageous compared to the case of a ternary copolymer in controlling the glass transition temperature by controlling the monomer content and in controlling the functional group content within the copolymer.

[0056] According to one embodiment of the present invention, a method for producing an aromatic vinyl-vinyl cyanide-acrylic crosslinked copolymer includes the steps of: (S1) adding a first reaction solution containing an aromatic vinyl monomer, a vinyl cyanide monomer, and an acrylic monomer to a reactor to start polymerization; and (S2) polymerizing while adding a second reaction solution containing a crosslinked functional compound to the reactor, wherein the second reaction solution can be added in two or more separate portions.

[0057] Step (S1) is a step to initiate polymerization, in which the reaction solution is introduced into the reactor and the temperature of the reactor is raised to a predetermined temperature. In step (S1), when the internal temperature of the reactor rises above the predetermined temperature, polymerization is carried out in the presence of a polymerization initiator, and in step (S1), the internal temperature of the reactor can be raised to about 60°C to 120°C, preferably to 70°C to 110°C.

[0058] According to one embodiment of the present invention, the first reaction solution of step (S1) may contain an aromatic vinyl monomer, a vinyl cyanide monomer, and a primary alkyl (meth)acrylate monomer. The aromatic vinyl monomer may be one or more selected from the group consisting of styrene, α-methylstyrene, α-ethylstyrene, p-methylstyrene, o-methylstyrene, ot-butylstyrene, bromostyrene, chlorostyrene, trichlorostyrene, and derivatives thereof, and a specific example may be styrene.

[0059] The aromatic vinyl monomer can be added in amounts of 30 to 95 parts by weight, 35 to 85 parts by weight, 40 to 75 parts by weight, or 40 to 70 parts by weight, relative to 100 parts by weight of the total amount of monomer added. Within this range, a copolymer can be obtained with a high polymerization conversion rate, the mechanical properties of the copolymer can be maintained, it can be central to achieving a photophobicity, it can function in controlling the glass transition temperature, and it has the effect of excellent compatibility with thermoplastic resins. Preferably, 10% to 50% by weight of the aromatic vinyl monomer can be added to the first reaction solution in step (S1) relative to the total amount added, and the remaining 50% to 90% by weight can be included in the second reaction solution in step (S2) and can be added in two or more separate additions.

[0060] According to one embodiment of the present invention, the vinyl cyanide monomer can be one or more selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile and derivatives thereof, and a specific example is acrylonitrile.

[0061] Furthermore, according to one embodiment of the present invention, the vinyl cyanide monomer can be added in amounts of 5 to 70 parts by weight, 10 to 60 parts by weight, 15 to 50 parts by weight, or 15 to 40 parts by weight relative to the total amount of monomer added. Within this range, a copolymer can be obtained with a high polymerization conversion rate, while maintaining the mechanical properties of the copolymer and providing excellent compatibility with thermoplastic resins. Preferably, 10% to 50% by weight of the vinyl cyanide monomer can be added to the first reaction solution in step (S1) relative to the total amount added, and the remaining 50% to 90% by weight can be included in the second reaction solution in step (S2) and can be added in two or more separate portions.

[0062] According to one embodiment of the present invention, the first alkyl (meth)acrylate monomer can be one or more selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, and lauryl (meth)acrylate. Specifically, the alkyl (meth)acrylate monomer can be one or more selected from the group consisting of methyl methacrylate, ethyl methacrylate, butyl methacrylate, methyl acrylate, ethyl acrylate, and butyl acrylate.

[0063] Furthermore, according to one embodiment of the present invention, the first alkyl (meth)acrylate monomer can be added in amounts of 1 to 50 parts by weight, 3 to 45 parts by weight, 5 to 40 parts by weight, or 5 to 35 parts by weight relative to the total amount of monomer added. Within this range, a copolymer can be obtained with a high polymerization conversion rate, the glass transition temperature can be easily adjusted, and it can function to realize impact strength and anti-photorealistic properties. Preferably, 10% to 50% by weight of the first alkyl (meth)acrylate monomer can be added to the first reaction solution in step (S1) relative to the total amount added, and the remaining 50% to 90% by weight can be included in the second reaction solution in step (S2) and can be added in two or more separate additions.

[0064] According to one embodiment of the present invention, as described above, the quaternary copolymer can be further comprising additional monomers, the additional monomers may be secondary alkyl (meth)acrylate monomers or vinyl ester monomers, and these monomers may also be included in the first reaction solution or the second reaction solution, and if they are added in portions, the amount added can be applied in the same manner as the monomers described above.

[0065] The second alkyl (meth)acrylate monomer is a different compound from the first alkyl (meth)acrylate monomer described above, but can similarly be selected from the types of compounds described above. For example, vinyl ester monomers such as vinyl acetate, vinyl propionate, vinyl butanoate, vinyl pentanoate, or vinyl hexanoate can be used.

[0066] Furthermore, according to one embodiment of the present invention, the second alkyl (meth)acrylate monomer or vinyl ester monomer can be added in an amount of 1 to 40 parts by weight, 5 to 35 parts by weight, or 10 to 30 parts by weight relative to the total monomer content. Within this range, if further addition is made to form a quaternary copolymer, the glass transition temperature and degree of crosslinking are more likely to be achieved within the desired numerical range, which is advantageous for achieving excellent impact strength and luminosity.

[0067] According to one embodiment of the present invention, the method for producing the crosslinked copolymer can be carried out by a suspension polymerization method, wherein the first reaction solution in step (S1) may further contain one or more additives selected from the group consisting of polymerization initiators, water-soluble solvents, dispersants, dispersion aids, and molecular weight modifiers as a solvent for carrying out polymerization, and the method may be carried out in the presence of these.

[0068] According to one embodiment of the present invention, the polymerization initiator is used to facilitate the initiation of polymerization and is not particularly limited as long as it does not adversely affect polymerization, but for example, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, di(t-butylperoxy-isopropyl)benzene, t-butylcumylperoxide, di-(t-amyl)-peroxide, dicumylperoxide, butyl4,4-di(t-butylperoxy)valerate, t-butylperoxybenzoate, 2,2-di(t-butylperoxy)butane, t-amylperoxy-benzoate, t-butylperoxy-acetate, t-butylperoxy-(2-ethylhexyl)carbonate, t-butylperoxyisopropyl carbonate, t-butylperoxy-3,5,5- It can be one or more selected from the group consisting of methyl-hexanoate, 1,1-di(t-butylperoxy)cyclohexane, t-amylperoxyacetate, t-amylperoxy-(2-ethylhexyl)carbonate, 1,1-di(t-butylperoxy)-3,5,5-trimethylcyclohexane, 1,1-di(t-amylperoxy)cyclohexane, t-butyl-monoperoxymalate, 1,1'-azoddi(hexahydrobenzonitrile), and 1,1'-azobis(cyclohexane-1-cyclonitrile), and specifically, it can be one or more selected from the group consisting of dicumylperoxide, 1,1-di(t-butylperoxy)cyclohexane, and 1,1'-azobis(cyclohexanecarbonitride).

[0069] Furthermore, the polymerization initiator can be used in amounts of 0.001 to 0.5 parts by weight, specifically 0.003 to 0.45 parts by weight or 0.06 to 0.3 parts by weight, per 100 parts by weight of the total amount of monomers used in polymerization. When used within these ranges, the polymerization reaction can be made easier, and the polymerization conversion rate can be increased.

[0070] According to one embodiment of the present invention, the water-soluble solvent may be ion-exchanged water or deionized water. On the other hand, according to one embodiment of the present invention, the monomer droplets may contain a water-soluble solvent, where the water-soluble solvent may be ion-exchanged water or deionized water, and may be the same as the water-soluble solvent introduced before the start of polymerization.

[0071] According to one embodiment of the present invention, the dispersant can be one or more selected from the group consisting of water-soluble polyvinyl alcohol, partially saponified polyvinyl alcohol, polyacrylic acid, a copolymer of vinyl acetate and maleic anhydride, hydroxypropyl methylcellulose, gelatin, calcium phosphate, tricalcium phosphate, hydroxyapatite, sorbitan monolaurate, sorbitan triolate, polyoxyethylene, sodium lauryl sulfate, sodium dodecylbenzenesulfonate, and sodium dioctyl sulfosuccinate, and a specific example is tricalcium phosphate.

[0072] According to one embodiment of the present invention, the dispersant can be used in amounts of 0.5 to 2.0 parts by weight, 0.5 to 1.5 parts by weight, or 1.0 to 1.5 parts by weight per 100 parts by weight of the total amount of monomers added. Within this range, the dispersion stability of the monomers in the polymerization system can be increased, and a copolymer having more uniform particles can be produced.

[0073] Furthermore, according to one embodiment of the present invention, the method for producing the crosslinked copolymer can be carried out by further including a dispersion aid during polymerization. Specifically, the dispersion aid can be a polyoxyethylene-based dispersion aid, and more specifically, it can be a polyoxyethylene alkyl ether phosphate, in which case there is an effect of excellent polymerization stability.

[0074] According to one embodiment of the present invention, the molecular weight modifier can be one or more selected from the group consisting of, for example, α-methylstyrene dimer, t-dodecyl mercaptan, n-dodecyl mercaptan, octyl mercaptan, carbon tetrachloride, methylene chloride, methylene bromide, tetraethyl thiuram disulfide, dipentamethylenethiuram disulfide, and diisopropyl xanthogen disulfide, and a specific example is t-dodecyl mercaptan.

[0075] According to one embodiment of the present invention, the molecular weight modifier can be used in amounts of 0.01 to 0.40 parts by weight, 0.05 to 0.30 parts by weight, or 0.10 to 0.25 parts by weight per 100 parts by weight of the total monomer input, and within this range, a copolymer having an appropriate weight-average molecular weight can be produced.

[0076] According to one embodiment of the present invention, in step (S2), the second reaction solution containing the crosslinking functional compound can be added in two or more portions, preferably three or more portions. The crosslinking functional compound may contain functional groups such as siloxane groups, vinyl groups, or acrylic groups, and a single crosslinking functional compound may contain two or more, preferably three or more, of these functional groups.

[0077] When the aforementioned crosslinking functional compound (hereinafter also referred to as "crosslinking agent") is added only in the initial stages of polymerization, the crosslinking effect may be relatively inferior. However, if the concentration of the crosslinking agent is high in the initial stages of polymerization, the possibility of side reactions where the crosslinking agents bond to each other may increase. As polymerization progresses and the concentration of the crosslinking agent decreases, it becomes more difficult for the crosslinked regions within the copolymer chain to be uniformly distributed, resulting in less smooth formation of the crosslinked copolymer and potentially a significantly lower yield of the crosslinked copolymer. Such problems ultimately lead to an increase in gloss and the coefficient of variation of light reflectance, and the non-uniformity can even cause a decrease in impact strength.

[0078] According to one embodiment of the present invention, the crosslinked functional compound is added in step (S2), can be added immediately after step (S1), can be added in two or more portions during polymerization, and preferably can be added in three or more portions.

[0079] According to one embodiment of the present invention, the time difference between the divided additions when the crosslinking functional compound is added in step (S2) can be 1% to 30% of the total polymerization time. When a time difference is given between the divided additions, the degree of crosslinking within the entire copolymer chain in the crosslinked copolymer can be made uniform and at an appropriate level, and the crosslinking density is also excellent, which can play an important role in providing diffuse reflection to the surface of the resin molded product. Furthermore, the divided addition of the crosslinking agent can be carried out over a period of 20% to 70% of the total polymerization time, and it is preferable to start and end the divided additions within this time range in order to provide a sufficient crosslinking effect.

[0080] According to one embodiment of the present invention, the crosslinked functional compound can be added immediately after step (S1) and can be added in stages so as to be completed before the polymerization conversion rate reaches 50% to 75%.

[0081] According to one embodiment of the present invention, the crosslinking functional compound added in installments during polymerization in step (S2) can be added in an amount of 0.05 to 0.30 parts by weight, preferably 0.05 to 0.20 parts by weight, and more preferably 0.05 to 0.15 parts by weight, relative to 100 parts by weight of the total amount of monomer added. If the amount of the polyene-based crosslinking agent added is less than 0.05 parts by weight, there will be insufficient crosslinking functional compound to form a crosslinked body overall, and the desired level of crosslinking cannot be achieved. If the amount is more than 0.3 parts by weight, the degree of crosslinking will be excessively high, which may lead to a loss of uniformity, and the formation of oligomers due to reactions between crosslinking agents and reactions between crosslinking agents and monomers may adversely affect the photophobic properties. Furthermore, the amount of the crosslinking functional compound added between each installment may be the same or different, and it is preferable to adjust the deviation between the amounts so that it is not large, and the above-mentioned amounts may refer to the total amount added in installments.

[0082] As described above, the crosslinked functional compound is a compound having two or more vinyl groups, acrylic groups, or siloxane groups, and can be, for example, a silicon-based compound or a polyene-based compound. The polyene-based compound can be a vinyl-based compound or an acrylic-based compound. Specifically, the polyene-based compound can be one or more selected from the group consisting of divinylbenzene, trivinylbenzene, ethylene glycol di(meth)acrylate, allyl(meth)acrylate, diallyl phthalate, diallyl malate, triallyl isocyanurate, and trialkyl isocyanurate, with divinylbenzene or allyl methacrylate being preferred.

[0083] Furthermore, the silicon-based compounds include, for example, 1,3,5-triisopropyl-1,3,5-trivinyl-cyclotrisiloxane, 1,3,5,7-tetraisopropyl-1,3,5,7-tetravinyl-cyclotetrasiloxane, 1,3,5,7,9-pentaisopropyl-1,3,5,7,9-pentavinyl-cyclopentasiloxane, and 1,3,5-trisec-butyl-1,3,5-trivinyl-cyclo Trisiloxane, 1,3,5,7-tetrasec-butyl-1,3,5,7-tetravinyl-cyclotetrasiloxane, 1,3,5,7,9-pentasec-butyl-1,3,5,7,9-pentavinyl-cyclopentasiloxane, 1,3,5-trimethyl-1,3,5-trivinyl-cyclotrisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinyl-cyclotetrasiloxane, 1, These may include 3,5,7,9-pentamethyl-1,3,5,7,9-pentavinyl-cyclopentasiloxane, 1,3,5-triethyl-1,3,5-trivinyl-cyclotrisiloxane, 1,3,5,7-tetraethyl-1,3,5,7-tetravinyl-cyclotetrasiloxane, 1,3,5,7,9-pentaethyl-1,3,5,7,9-pentavinyl-cyclopentasiloxane, or mixtures thereof, and may be used in combination with, but is not limited to, divinylsilane, trivinylsilane, dimethyldivinylsilane, divinylmethylsilane, methyltrivinylsilane, diphenyldivinylsilane, divinylphenylsilane, trivinylphenylsilane, divinylmethylphenylsilane, tetravinylsilane, dimethylvinyldisiloxane, divinyldiphenylchlorosilane, etc.

[0084] The silicon-based compound can preferably be 1,3,5-trimethyl-1,3,5-trivinylcyclotrisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7,9-pentamethyl-1,3,5,7,9-pentavinylcyclopentasiloxane, 1,3,5-triethyl-1,3,5-trivinylcyclotrisiloxane, 1,3,5,7-tetraethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7,9-pentaethyl-1,3,5,7,9-pentavinylcyclopentasiloxane, or a mixture thereof, and more preferably 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane.

[0085] According to one embodiment of the present invention, a method for producing an aromatic vinyl-vinyl cyanide-acrylic crosslinked copolymer comprises the steps of: (S1) adding a first reaction solution containing an aromatic vinyl monomer, a vinyl cyanide monomer, and a primary alkyl (meth)acrylate monomer to a reactor to start polymerization; and (S2) polymerizing while adding a second reaction solution containing a crosslinking functional compound to the reactor, wherein the second reaction solution can be added in two or more separate portions, and the second reaction solution may further contain one or more of a molecular weight modifier and a polymerization initiator.

[0086] Thus, when the second reaction solution contains a molecular weight regulator and / or polymerization initiator and is added in stages along with the crosslinking functional compound, it becomes easier to control the reactivity between monomers and the reactivity between the polymerization chain and the crosslinking agent. This allows for easy control of the glass transition temperature and degree of crosslinking, resulting in molded articles that maintain excellent levels of impact strength and heat resistance, and have low gloss and light reflectance coefficient of variation, as well as being uniform and reflective.

[0087] On the other hand, according to one embodiment of the present invention, although the crosslinking functional compound is added in part in step (S2), polymerization can be initiated while it is contained in the first reaction solution. If it is contained in the first reaction solution, it cannot be replaced by being added in step (S2), but if a further crosslinking effect is to be obtained, this can be applied by adding a crosslinking agent before polymerization starts.

[0088] On the other hand, in the method for producing the copolymer according to one embodiment of the present invention, the polymerization in step (S1) can be carried out in a temperature range of 50°C to 150°C, preferably 60°C to 130°C, and more preferably 65°C to 120°C. When polymerization is carried out in this temperature range, it is preferable to obtain the final polymerization conversion rate, desired particle size characteristics, and other polymer properties.

[0089] (2) Aromatic vinyl-vinyl cyanide non-crosslinked copolymer According to one embodiment of the present invention, the resin composition may contain an aromatic vinyl-vinyl cyanide non-crosslinked copolymer. The aromatic vinyl-vinyl cyanide non-crosslinked copolymer comprises aromatic vinyl monomer units and vinyl cyanide monomer units, the types of these monomers may be similarly selected from the types listed for the crosslinked copolymer.

[0090] The non-crosslinked copolymer can play the role of a matrix in a resin composition, and since this non-crosslinked copolymer has excellent heat resistance, impact resistance, and fluidity, it can play a fundamental role in realizing excellent physical properties of resin molded articles. The non-crosslinked copolymer can generally be made from commercially available resins and can be obtained by commercialized methods or by methods that do not use crosslinking agents as described above for producing crosslinked copolymers, and is not particularly limited thereto.

[0091] (3) Graft copolymer According to one embodiment of the present invention, the graft copolymer may include a conjugated diene polymer, aromatic vinyl monomer units, and vinyl cyanide monomer units, or it may include an acrylic polymer, aromatic vinyl monomer units, and vinyl cyanide monomer units. In other words, the graft copolymer may be an acrylonitrile-butadiene-styrene copolymer or an acrylic polymer-based graft copolymer (Acrylic-Styrene-Acrylonitrile, ASA). The following description will focus on the case where the graft copolymer is an acrylonitrile-butadiene-styrene copolymer.

[0092] The acrylonitrile-butadiene-styrene copolymer provides excellent moldability and impact resistance to the thermoplastic resin composition and can be a graft copolymer with a core-shell structure comprising a core containing conjugated diene monomer units and a shell enclosing the core and containing aromatic vinyl monomer units and vinyl cyanide monomer units.

[0093] According to one embodiment of the present invention, the conjugated diene monomer of the graft copolymer can be one or more selected from the group consisting of 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene, and isoprene, and a specific example is 1,3-butadiene.

[0094] Furthermore, the types of aromatic vinyl monomers and vinyl cyanide monomers can be similarly selected from the types listed for the crosslinked copolymer.

[0095] According to one embodiment of the present invention, the acrylonitrile-butadiene-styrene copolymer can be produced by emulsion polymerization and emulsion graft polymerization. For example, a conjugated diene monomer can be emulsion polymerized to produce a rubbery polymer core (or seed), and a vinyl cyanide monomer and an aromatic vinyl monomer can be added to the core and then emulsion graft polymerization can be performed to produce the copolymer.

[0096] Furthermore, the acrylonitrile-butadiene-styrene copolymer may include 30% to 70% by weight of a core containing units derived from conjugated diene monomers, and 30% to 70% by weight of a shell surrounding the core, containing units derived from aromatic vinyl monomers and vinyl cyanide monomers, wherein the shell may contain aromatic vinyl monomer units and vinyl cyanide monomer units in a weight ratio of 7:3 to 8:2. In this case, the impact resistance, mechanical properties, and moldability of the copolymer can be further improved.

[0097] The graft copolymer can generally be obtained using commercially available resins and by commercially available methods, but is not particularly limited thereto.

[0098] others A resin composition according to one embodiment of the present invention may further contain, if necessary, one or more additives selected from the group consisting of impact reinforcers, lubricants, heat stabilizers, anti-dripping agents, antioxidants, light stabilizers, ultraviolet blocking agents, pigments, and inorganic fillers. In this case, the additive may be used in an amount of 5.0 parts by weight or less, or 0.1 to 1.0 parts by weight, per 100 parts by weight of the copolymer and thermoplastic resin.

[0099] Furthermore, the specific substances of the additive are not particularly limited as long as they are used in thermoplastic resin compositions. For example, the cargo protection agent can be one or more selected from the group consisting of Teflon®, polyamide, polysilicon, PTFE (polytetrafluoroethylene), and TFE-HFP (tetrafluoroethylene-hexafluoropropylene) copolymers, in terms of further improving flame retardancy. The inorganic filler can be one or more selected from the group consisting of barium sulfate, barium glass filler, and barium oxide.

[0100] Molded product The present invention provides a molded article containing the aforementioned resin composition. For example, the molded article can be applied to various industrial fields such as various electrical and electronic products and automotive parts. As for the molding method, general molding methods such as extrusion, injection, and casting can be applied. For example, in injection molding, compared to products that attempt to provide a matte molded article by corroding the surface of the mold, the molded article according to the present invention does not require corroding the surface of the mold, and it is possible to provide a molded article that has a matte and uniform surface in the state in which it was injected, without any post-processing of the molded article.

[0101] Examples Hereinafter, embodiments of the present invention will be described in detail so that they can be easily implemented by a person with ordinary skill in the art to which the present invention pertains. However, the present invention can be realized in various different forms and is not limited to the embodiments described herein.

[0102] Manufacturing Example 1 200 parts by weight of deionized water, 55 parts by weight of styrene, 30 parts by weight of acrylonitrile, and 15 parts by weight of 2-ethylhexyl acrylate were added to the reactor. After raising the reactor temperature to 70°C, 0.2 parts by weight of 1,1'-azobis(cyclohexane-1-carbonitride), 0.25 parts by weight of t-dodecyl mercaptan, and 0.1 parts by weight of allyl methacrylate were added to the reactor in three separate additions at 1-hour intervals, and polymerization was carried out for a total of 5 hours. Next, the mixture was washed with water, dehydrated, and dried to produce a crosslinked copolymer in powder form.

[0103] Here, each of the aforementioned parts by weight is based on the total amount of monomer input, which is 100 parts by weight.

[0104] Manufacturing Example 2 A crosslinked copolymer was produced in the same manner as in Production Example 1, except that 60 parts by weight of styrene and 20 parts by weight of acrylonitrile were added, 20 parts by weight of ethyl acrylate were added instead of 15 parts by weight of 2-ethylhexyl acrylate, and 0.2 parts by weight of divinylbenzene were added instead of 0.1 parts by weight of allyl methacrylate.

[0105] Manufacturing Example 3 A crosslinked copolymer was produced in the same manner as in Production Example 1, except that 45 parts by weight of styrene and 25 parts by weight of acrylonitrile were added, 30 parts by weight of methyl acrylate were added instead of 15 parts by weight of 2-ethylhexyl acrylate, and 0.15 parts by weight of diallyl maleate were added instead of 0.1 parts by weight of allyl methacrylate.

[0106] Manufacturing Example 4 A crosslinked copolymer was produced in the same manner as in Production Example 1, except that 55 parts by weight of styrene and 20 parts by weight of acrylonitrile were added, 25 parts by weight of butyl acrylate were added instead of 15 parts by weight of 2-ethylhexyl acrylate, and 0.15 parts by weight of diallyl terephthalate were added instead of 0.1 parts by weight of allyl methacrylate.

[0107] Manufacturing Example 5 A crosslinked copolymer was produced in the same manner as in Production Example 1, except that 45 parts by weight of styrene and 25 parts by weight of acrylonitrile were added, 10 parts by weight of butyl acrylate and 20 parts by weight of butyl methacrylate were added instead of 15 parts by weight of 2-ethylhexyl acrylate, and 0.2 parts by weight of ethylene glycol dimethacrylate was added instead of 0.1 parts by weight of allyl methacrylate.

[0108] Manufacturing Example 6 A crosslinked copolymer was produced in the same manner as in Production Example 1, except that 50 parts by weight of styrene and 20 parts by weight of acrylonitrile were added, 10 parts by weight of ethyl acrylate and 20 parts by weight of vinyl acetate were added instead of 15 parts by weight of 2-ethylhexyl acrylate, and 0.2 parts by weight of tetraethylene glycol diacrylate was added instead of 0.1 parts by weight of allyl methacrylate.

[0109] Comparative Manufacturing Example 1 A crosslinked copolymer was produced in the same manner as in Production Example 1, except that 75 parts by weight of styrene and 25 parts by weight of acrylonitrile were added instead of 55 parts by weight of styrene, 30 parts by weight of acrylonitrile and 15 parts by weight of 2-ethylhexyl acrylate, and allyl methacrylate was not added.

[0110] Comparative Manufacturing Example 2 A crosslinked copolymer was produced in the same manner as in Production Example 1, except that 60 parts by weight of styrene and 35 parts by weight of acrylonitrile were added instead of 55 parts by weight of styrene, 30 parts by weight of acrylonitrile, and 15 parts by weight of 2-ethylhexyl acrylate, and 2-ethylhexyl acrylate was omitted.

[0111] Comparative Manufacturing Example 3 A crosslinked copolymer was produced in the same manner as in Production Example 1, except that instead of 55 parts by weight of styrene, 30 parts by weight of acrylonitrile, and 15 parts by weight of 2-ethylhexyl acrylate, 60 parts by weight of styrene, 20 parts by weight of acrylonitrile, and 20 parts by weight of ethyl acrylate were added, and 0.02 parts by weight of allyl methacrylate was added.

[0112] Experimental Example 1 The glass transition temperature and degree of crosslinking were measured for the copolymers produced in Production Examples 1-6 and Comparative Production Examples 1-3 using the method described below, and the results are shown in Table 1 below.

[0113] (1) Glass transition temperature (Tg, °C): After taking 0.01 g samples from the polymer and copolymer, the glass transition temperature was measured using a differential scanning calorimeter (DSC, manufactured by METTLER TOLEDO) by first heating from room temperature (20°C to 25°C) to 180°C to remove foreign matter, then cooling to room temperature (20°C to 25°C), and then heating again to 180°C.

[0114] (2) Degree of crosslinking (%): Dissolve 0.25 g of copolymer in 25 g of acetone, stir at room temperature for 24 hours, filter the solution through a 100 mesh SUS filter, dry the copolymer remaining on the filter at 80°C for 24 hours, measure its weight, and calculate the ratio (%) of the measured weight to the initial copolymer weight of 0.25 g.

[0115] [Table 1]

[0116] As can be seen from Table 1 above, in the case of the crosslinked copolymers of Production Examples 1 to 6 according to the present invention, the glass transition temperature was measured to be below 90°C in all cases, and the degree of crosslinking was at the 40% to 70% level. On the other hand, in the case of comparative production example 1, which was not crosslinked, the glass transition temperature was shown to be very high, and in comparative production example 2, in which the crosslinking agent was not added in divided portions, the degree of crosslinking was shown to be at the level of the examples, but in comparative production example 3, which had a high glass transition temperature and a small amount of crosslinking agent added, it can be seen that the degree of crosslinking was measured to be low even though the glass transition temperature was low.

[0117] This confirms that it is possible to achieve appropriate levels of glass transition temperature and degree of crosslinking by adjusting the amount of crosslinking agent added and using acrylate monomers.

[0118] Examples 1-9 and Comparative Examples 1-3 15 parts by weight of the crosslinked copolymer produced in Production Examples 1-6 and Comparative Production Examples 1-3, 58 parts by weight of aromatic vinyl-vinyl cyanide non-crosslinked copolymer (SAN, LG Chem, 83SF), 27 parts by weight of graft copolymer (G-ABS, LG Chem, DP270E), 0.1 parts by weight of heat stabilizer (BASF, IRGANOX 1010), and titanium dioxide (Chemours, Ti-Pure TM Resin compositions were prepared by incorporating R-350, and these were designated as Examples 1-6 and Comparative Examples 1-3, respectively.

[0119] 18 parts by weight of the crosslinked copolymer produced in Production Example 1, 55 parts by weight of aromatic vinyl-vinyl cyanide non-crosslinked copolymer (SAN, LG Chem, 83SF), 27 parts by weight of graft copolymer (G-ABS, LG Chem, DP270E), 0.1 parts by weight of heat stabilizer (BASF, IRGANOX 1010), and titanium dioxide (Chemours, Ti-Pure TM A resin composition was prepared by incorporating R-350, and this was designated as Example 7.

[0120] 12 parts by weight of the crosslinked copolymer produced in Production Example 2, 61 parts by weight of aromatic vinyl-vinyl cyanide non-crosslinked copolymer (SAN, LG Chem, 83SF), 27 parts by weight of graft copolymer (G-ABS, LG Chem, DP270E), 0.1 parts by weight of heat stabilizer (BASF, IRGANOX 1010), and titanium dioxide (Chemours, Ti-Pure TM A resin composition was prepared by incorporating R-350, and this was designated as Example 8.

[0121] 15 parts by weight of the crosslinked copolymer produced in Production Example 1, 58 parts by weight of aromatic vinyl-vinyl cyanide non-crosslinked copolymer (SAN, LG Chem, 83SF), 27 parts by weight of graft copolymer produced on an acrylic polymer base (LG Chem, SA927), 0.1 parts by weight of heat stabilizer (BASF, IRGANOX 1010), and titanium dioxide (Chemours, Ti-Pure TM A resin composition was prepared by incorporating R-350, and this was designated as Example 9.

[0122] Experimental Example 2 The resin compositions produced in Examples 1-9 and Comparative Examples 1-3 were extruded at 220°C and then injected to produce samples. The gloss, light reflectance coefficient, and impact strength of the produced samples were measured using the following method and are shown in Table 2 below.

[0123] (1) Gloss: The gloss was measured at 60° using a gloss meter (Nippon Denshoku Co., Ltd., VG7000) in accordance with the ASTM D523 evaluation method.

[0124] (2) Coefficient of Variation to Light Reflection: Measured using Phyton by the following method. 1) Image creation of the sample: Using a DSLR camera (Canon 750D) and a 200mm x 200mm surface illumination (White LED, Collimated Backlight LTS-3PFT), the prepared sample was photographed and imaged with the camera distance set to 40cm, the distance between the sample and the illumination to 100cm, and the angle set to 90°.

[0125] 2) Grayscale conversion of sample image: The sample image is converted to grayscale (0-255) using the OpenCV library. Here, a grayscale value is assigned to each pixel in the sample image, and this grayscale value is used as the luminance.

[0126] 3) Image reconstruction: The image is divided into a 200 μm × 200 μm grid, and the luminosity value (grayscale value) of the pixels within each grid is averaged to reconstruct the image. Here, each grid has one averaged luminosity value.

[0127] 4) Luminous intensity correction: The target grid is designated as the first zone, the eight grids adjacent to the first zone as the second zone, and the sixteen grids adjacent to the second zone as the third zone. After assigning correction coefficients of 1 for the first zone, -0.0625 for the second zone, and -0.03125 for the third zone, the corrected luminous intensity value of the target grid is derived using the following formula 2.

[0128]

number

[0129] In the above formula 2, L is the corrected luminosity value of the target grating, L 1 L is the luminosity of the first area grating. 2 1, L2 2, L 2 3, ..., L 2 8 is the luminosity of each of the 8 grids in the second area, L 3 1, L 3 2, L 3 3, ..., L 3 16 This represents the luminosity of each of the 16 gratings in the third zone.

[0130] 5) Derivation of mean and standard deviation: The mean and standard deviation are determined from the corrected luminous intensity values ​​of each grid, and the coefficient of variation of light reflection is derived using the mean and standard deviation of the luminous intensity obtained in this way, according to Equation 1 below.

[0131] [Formula 1] C LR =D L / M L

[0132] Said C LR This is the coefficient of variation of light reflection, and D L This is the standard deviation of luminosity, and M L This represents the average luminosity.

[0133] (3) Impact strength (kgf·cm / cm): In accordance with the evaluation method of ASTM D256, a 1 / 4 inch thick sample was used, and the notched izod impact strength was measured by notching the sample at room temperature (23°C).

[0134] [Table 2]

[0135] Referring to Table 2, it can be confirmed that the copolymers of Examples 1 to 6, to which the crosslinked copolymer produced by the manufacturing method of the crosslinked copolymer according to one embodiment of the present invention was applied, exhibited no gloss, excellent surface uniformity, and simultaneously demonstrated excellent impact strength. However, in the case of Comparative Example 1, an uncrosslinked copolymer was applied, and although it was relatively superior to the other comparative examples in terms of surface uniformity, it was not glossy, and a high level of gloss was observed. Furthermore, in the case of Comparative Example 2, since it did not contain an acrylate monomer, the glass transition temperature was high, and it could be confirmed that applying such a crosslinked copolymer resulted in poor impact angle in all parts. In Comparative Example 3, it was found that the degree of crosslinking was low and the gloss was high, and it could be confirmed that the surface uniformity was not good.

Claims

1. It contains an aromatic vinyl-vinyl cyanide-acrylic crosslinked copolymer, In accordance with the ASTM D523 evaluation method, the gloss level at 60° measured with a gloss meter is 25 or less. According to the ASTM D256 evaluation method, the impact strength measured on a 1 / 4 inch thick sample was 15 kgf·cm / cm or higher. A resin composition having a coefficient of variation of light reflectance of 1.5 or less, calculated using the following formula 1. [Formula 1] C ＬＲ =D Ｌ / M Ｌ In the above formula 1, the C ＬＲ This is the coefficient of variation of light reflection, and D Ｌ This is the standard deviation of luminosity, and M Ｌ This represents the average luminosity.

2. The resin composition according to claim 1, wherein the aromatic vinyl-vinyl cyanide-acrylic crosslinked copolymer is contained in 1 to 30 parts by weight per 100 parts by weight of the resin composition.

3. The resin composition according to claim 1, wherein the aromatic vinyl-vinyl cyanide-acrylic crosslinked copolymer is contained in 3 to 20 parts by weight per 100 parts by weight of the resin composition.

4. The resin composition according to claim 1, wherein the gloss level is 24 or less.

5. The resin composition according to claim 1, wherein the coefficient of variation of light reflection is 1.4 or less.

6. The resin composition according to claim 1, wherein the crosslinked copolymer comprises a crosslinked portion containing crosslinked functional compound units, aromatic vinyl monomer units, vinyl cyanide monomer units, and primary alkyl (meth)acrylate monomer units.

7. The resin composition according to claim 6, wherein the crosslinked copolymer further comprises vinyl ester monomer units or dialkyl (meth)acrylate monomer units.

8. The resin composition according to claim 6, wherein the crosslinking functional compound is one or more selected from the group consisting of silicon-based compounds and polyene-based compounds.

9. The resin composition according to claim 1, further comprising one or more copolymers selected from aromatic vinyl-vinyl cyanide non-crosslinked copolymers and graft copolymers.

10. The aforementioned aromatic vinyl-vinyl cyanide non-crosslinked copolymer comprises aromatic vinyl monomer units and vinyl cyanide monomer units. The resin composition according to claim 9, wherein the graft copolymer comprises a conjugated diene polymer, aromatic vinyl monomer units, and vinyl cyanide monomer units.

11. A molded article comprising the resin composition described in claim 1.

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