Thermoplastic resin composition

Abstract

The present invention relates to a thermoplastic resin composition. The resin composition contains an aromatic vinyl-vinyl cyanide crosslinked copolymer, and according to the evaluation method of ASTM D523, the glossiness at 60° measured with a gloss meter is 25 or less, and the light reflection variation coefficient calculated by the following formula 1 is 2.0 or less. The resin composition is characterized in that a matte finish can be achieved 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 discloses a low-gloss resin composition using a crosslinked copolymer. This composition exhibits a quenching effect when large-diameter rubber particles or a quenching agent are added. 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] U.S. Patent No. 4,460,742 [Summary of the Invention] [Problems to be Solved by the Invention]

[0011] An object of the present invention is to provide a matte thermoplastic resin composition capable of having a uniform matte surface by injection molding without applying another corrosion treatment to the surface of a mold. [Means for Solving the Problems]

[0012] In order to solve the above problems, the present invention provides a resin composition containing an aromatic vinyl-vinyl cyanide-based crosslinked copolymer, having a glossiness at 60° measured with a gloss meter of 25 or less according to the evaluation method of ASTM D523, and a light reflection variation coefficient calculated by the following formula 1 of 2.0 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.

[0013] The present invention also provides an injection molded product containing the thermoplastic resin composition. [Effects of the Invention]

[0014] The resin composition according to the present invention has a low glossiness and can achieve a matte appearance and ensure surface uniformity by controlling the light reflection variation coefficient to be low. There is an advantage that such a matte and uniform surface can be realized by injection molding without applying another corrosion treatment to the injection mold. [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] The terms "monomer unit," "crosslinking unit," or "crosslinking portion" used in this invention may mean 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 this invention, the "polymerization conversion rate" indicates the extent to which monomers are polymerized by a polymerization reaction to form a polymer. During polymerization, a portion of the polymer in the reactor is taken, and the weight of the polymer other than water is calculated using the following formula 3. Then, the sample is dissolved in tetrahydrofuran (THF) solvent, precipitated with methanol (MeOH), unreacted monomers are removed, and the weight of the polymer obtained by drying the precipitated suspended matter is measured and calculated using the following formula 4.

[0022] [Formula 3] (Actual weight of polymer) = (Collected polymer) - (Collected polymer × Moisture content)

[0023] [Equation 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 - based crosslinked copolymer, and according to the evaluation method of ASTM D523, the glossiness at 60° measured with a gloss meter is 25 or less, and the light reflection variation coefficient calculated by the following formula 1 is 2.0 or less.

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

[0026] In the above formula 1, C LR is the light reflection variation coefficient, D L is the standard deviation of light intensity, and M L is the average light intensity.

[0027] According to an embodiment of the present invention, the resin composition has a glossiness of 25 or less, preferably 20 or less, more preferably 17 or less, and even more preferably 15 or less. Glossiness is a typical numerical value that can represent the shiny (high gloss, low gloss) or matte appearance of the resin. Generally, in the case of commercial matte molded products, it exceeds 30, but this cannot be regarded as substantially matte. However, when using the resin composition of the present invention, the glossiness can be realized at a very low level of 25 or less, and it is 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 is unsuitable for mass production because the process efficiency decreases due to wear on the injection mold.

[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, this method has the problem of being economically disadvantageous due to its very high defect rate, low reproducibility of the physical properties of the produced products, and the need for additional processes such as coating and curing.

[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 2.0 or less, and can provide a matte molded product with surface uniformity. The light reflection variation coefficient can be 2.0 or less, preferably 1.9 or less, more preferably 1.8 or less, even more preferably 1.7 or less, and most preferably 1.5 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 2.0 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 target grating, 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 316 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] As described above, the resin composition according to one embodiment of the present invention has low gloss and a low coefficient of variation of light reflectance, making it possible to provide a matte molded product with a uniform surface. Such properties can be achieved by including an aromatic vinyl-vinyl cyanide crosslinked copolymer, and this crosslinked copolymer can solve the problems of conventional matte molded products.

[0042] (1) Aromatic vinyl-vinyl cyanide crosslinked copolymer and method for producing the same According to one embodiment of the present invention, the resin composition comprises an aromatic vinyl-vinyl cyanide crosslinked copolymer, and the aromatic vinyl-vinyl cyanide crosslinked copolymer may 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.

[0043] 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.

[0044] According to one embodiment of the present invention, the crosslinked copolymer may contain a crosslinked portion containing a crosslinked functional compound, an aromatic vinyl monomer unit, and a vinyl cyanide monomer unit.

[0045] 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.

[0046] A crosslinked copolymer according to one embodiment of the present invention may have a very uniform distribution of crosslinks within it, an appropriate degree of crosslink distribution, and active fluidity between all chains.

[0047] 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.

[0048] 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.

[0049] According to one embodiment of the present invention, a method for producing an aromatic vinyl-vinyl cyanide crosslinked copolymer includes the steps of: (S1) adding a first reaction solution containing an aromatic vinyl monomer and a vinyl cyanide 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 steps.

[0050] 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.

[0051] According to one embodiment of the present invention, the aromatic vinyl monomer can 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 is styrene.

[0052] The aromatic vinyl monomer can be added in amounts of 30 to 95 parts by weight, 40 to 90 parts by weight, 50 to 85 parts by weight, or 60 to 80 parts by weight per 100 parts by weight of the total amount of monomers including the aromatic vinyl monomer and vinyl cyanide monomer. 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 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 added in two or more separate portions.

[0053] 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.

[0054] 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 20 to 40 parts by weight relative to the total amount of monomers added, including the aromatic vinyl monomer and the vinyl cyanide monomer. 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 added in two or more separate portions.

[0055] 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.

[0056] 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).

[0057] Furthermore, the polymerization initiator can be used in an amount of 0.001 to 0.5 parts by weight, specifically 0.003 to 0.45 parts by weight or 0.06 to 0.25 parts by weight, per 100 parts by weight of the total amount of monomers used in polymerization, i.e., aromatic vinyl monomers and vinyl cyanide monomers. When used within this range, the polymerization reaction can be made easier and the polymerization conversion rate can be increased.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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, and the formation of the crosslinked copolymer is not smooth, which may result in a significantly lower yield of the crosslinked copolymer. Such problems can ultimately lead to an increase in gloss and the coefficient of variation of light reflectance.

[0066] 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.

[0067] 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.

[0068] 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%.

[0069] According to one embodiment of the present invention, the crosslinking functional compound added in fractional amounts during polymerization in step (S2) can be 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, per 100 parts by weight of the total amount of monomer added. If the amount of the crosslinking functional compound added is less than 0.05 parts by weight, there will be insufficient crosslinking functional compound to form a crosslinked body overall, making it difficult to achieve the desired level of crosslinking and resulting in low gloss. If the amount is more than 0.3 parts by weight, the degree of crosslinking will be too high, which may lead to a loss of uniformity, adverse effects on the anti-photorealistic properties due to the formation of oligomers by reactions between crosslinking agents and reactions between crosslinking agents and monomers, and a significant deterioration in polymerization stability, which may lead to polymerization failure or a low yield. Furthermore, the amount of the crosslinking functional compound added between each divided addition may be the same or different, and it is preferable to adjust the amount so that the deviation between additions is not large. The above-mentioned amount of addition may refer to the total amount added in divided stages.

[0070] As described above, the crosslinking 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 crosslinking agent can be, for example, a vinyl-based crosslinking agent or an acrylic-based crosslinking agent, and specifically, 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 can be used, with divinylbenzene being preferred.

[0071] The aforementioned silicon-based crosslinking agents 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-cyclotrisiloxane. Roxane, 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, 1,3, These may include 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 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.

[0072] The silicon-based crosslinking agent 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.

[0073] According to one embodiment of the present invention, a method for producing an aromatic vinyl-vinyl cyanide crosslinked copolymer includes the steps of: (S1) adding a first reaction solution containing an aromatic vinyl monomer and a vinyl cyanide 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.

[0074] Thus, when the second reaction solution contains a molecular weight modifier and / or polymerization initiator and is added in divided portions along with the crosslinking functional compound, a synergy can be created in the effect to be obtained by adding the crosslinking functional compound in divided portions. This makes it easier to control the reactivity between monomers and the reactivity between the polymerization chain and the crosslinking agent, and as a result, a uniform and reflective molded product with low gloss and low coefficient of variation of light reflectance can be obtained.

[0075] According to one embodiment of the present invention, the crosslinking functional compound is included in the first reaction solution, although it is added in a divided manner in step (S2), and polymerization can be initiated. When included in the first reaction solution, it cannot be replaced by the compound added in step (S2), but if a further crosslinking effect is to be obtained, it can be applied by adding a method of adding the crosslinking agent before the start of polymerization. However, when adding the crosslinking functional compound to the first reaction solution in step (S1), it is necessary to be careful of oligomer formation due to reaction with monomers and destruction of polymerization stability due to the high reactivity of the crosslinking agent, so it is preferable to add a compound with relatively low reactivity and a slow reaction rate. Here, the amount of crosslinking functional compound to be added can be 0.1 parts by weight to 5.0 parts by weight, preferably 0.5 parts by weight to 3.0 parts by weight, and preferably 0.7 parts by weight to 1.0 part by weight, based on 100 parts by weight of the total amount of monomer added, and it is preferable to use a different crosslinking functional compound from the one added in step (S2).

[0076] According to one embodiment of the present invention, in the method for producing the crosslinked copolymer, a molecular weight modifier can be further added during polymerization in step (S1), and the molecular weight modifier can be added in two or more installments. In this case, the same effects and functions as those obtained by adding a polyene-based crosslinking agent in installments can be expected, and a synergy can be created with the effects of adding a polyene-based crosslinking agent in installments.

[0077] 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.

[0078] (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.

[0079] 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.

[0080] (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).

[0081] 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.

[0082] 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.

[0083] Furthermore, the types of aromatic vinyl monomers and vinyl cyanide monomers can be similarly selected from the types listed for the crosslinked copolymer.

[0084] 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.

[0085] 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.

[0086] The graft copolymer can generally be obtained using commercially available resins and by commercially available methods, but is not particularly limited thereto.

[0087] (4) 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] * Copolymer yield: This indicates the extent to which monomers are polymerized to form a polymer by the polymerization reaction. After polymerization, a portion of the polymer in the reactor was collected, and the weight of polymers other than water was calculated using formula 3 below. Then, the sample was dissolved in tetrahydrofuran (THF) solvent, precipitated with methanol (MeOH), and unreacted monomers were removed. The weight of the polymer obtained by drying the precipitated suspended matter was measured and calculated using formula 4 below.

[0092] [Formula 3] (Actual weight of polymer) = (Collected polymer) - (Collected polymer × Water content)

[0093] [Equation 4] Polymerization conversion rate (%) = [(Weight of polymer obtained after drying) / (Weight of actual polymer)] × 100

[0094] Manufacturing Example 1 In a reactor, 120 parts by weight of deionized water, 77 parts by weight of styrene, 23 parts by weight of acrylonitrile, 0.2 parts by weight of 1,1'-azobis(cyclohexane-1-carbonitrile), 0.2 parts by weight of t-dodecyl mercaptan, and 0.7 parts by weight of 1,3,5-trimethyl-1,3,5-trivinylcyclotrisiloxane were added. After raising the reactor temperature to 70°C, 0.14 parts by weight of allyl methacrylate were added to the reactor in three batches at 1-hour intervals. Polymerization was carried out for a total of 5 hours, after which the product was washed with water, dehydrated, and dried to produce a crosslinked copolymer (bead form). The yield was 96%.

[0095] Here, each of the aforementioned parts by weight is based on the total amount of monomer input, which is 100 parts by weight.

[0096] Manufacturing Example 2 The crosslinked copolymer was produced using the same method as in Production Example 1, except that 0.2 parts by weight of allyl methacrylate was added, and the yield was 95%.

[0097] Manufacturing Example 3 The crosslinked copolymer was produced in the same manner as in Production Example 2, except that t-dodecyl mercaptan was not added to the reactor, and after heating, 0.2 parts by weight of allyl methacrylate and 0.2 parts by weight of t-dodecyl mercaptan were added to the reactor three times at 1-hour intervals. The yield was 95%.

[0098] Manufacturing Example 4 The crosslinked copolymer was produced using the same method as in Production Example 1, except that 0.3 parts by weight of allyl methacrylate was added, and the yield was 92%.

[0099] Manufacturing Example 5 The crosslinked copolymer was produced in the same manner as in Production Example 1, except that 0.2 parts by weight of allyl methacrylate was added to the reactor in two separate additions at 1-hour intervals. The yield was 91%.

[0100] Comparative Manufacturing Example 1 The crosslinked copolymer was produced using the same method as in Production Example 1, except that 0.2 parts by weight of allyl methacrylate was added, but instead of adding it all at once to the reactor at the beginning rather than after raising the reactor temperature. The yield was 86%.

[0101] Comparative Manufacturing Example 2 The crosslinked copolymer was produced using the same method as in Comparative Production Example 1, except that 0.5 parts by weight of allyl methacrylate was added, and the yield was 80%.

[0102] Example 1 A resin composition was prepared by mixing 20 parts by weight of an aromatic vinyl-vinyl cyanide crosslinked copolymer produced in Production Example 1, 55 parts by weight of an aromatic vinyl-vinyl cyanide non-crosslinked copolymer (LG Chem, 83SF), 25 parts by weight of a graft copolymer (LG Chem, DP270M), and 0.1 parts by weight of a heat stabilizer (BASF, IRGANOX 1010).

[0103] Example 2 The resin composition was formulated in the same manner as in Example 1, except that 20 parts by weight of the aromatic vinyl-vinyl cyanide crosslinked copolymer produced in Production Example 2 were used instead of 20 parts by weight of the aromatic vinyl-vinyl cyanide crosslinked copolymer produced in Production Example 1.

[0104] Example 3 The resin composition was formulated in the same manner as in Example 1, except that 20 parts by weight of the aromatic vinyl-vinyl cyanide crosslinked copolymer produced in Production Example 3 were used instead of 20 parts by weight of the aromatic vinyl-vinyl cyanide crosslinked copolymer produced in Production Example 1.

[0105] Example 4 The resin composition was formulated in the same manner as in Example 1, except that 20 parts by weight of the aromatic vinyl-vinyl cyanide crosslinked copolymer produced in Production Example 4 were used instead of 20 parts by weight of the aromatic vinyl-vinyl cyanide crosslinked copolymer produced in Production Example 1.

[0106] Example 5 The resin composition was formulated in the same manner as in Example 1, except that 20 parts by weight of the aromatic vinyl-vinyl cyanide crosslinked copolymer produced in Production Example 5 were used instead of 20 parts by weight of the aromatic vinyl-vinyl cyanide crosslinked copolymer produced in Production Example 1.

[0107] Example 6 A resin composition was prepared by mixing 30 parts by weight of an aromatic vinyl-vinyl cyanide crosslinked copolymer produced in Production Example 1, 45 parts by weight of an aromatic vinyl-vinyl cyanide non-crosslinked copolymer (LG Chem, 83SF), 25 parts by weight of a graft copolymer (LG Chem, DP270M), and 0.1 parts by weight of a heat stabilizer (BASF, IRGANOX 1010).

[0108] Example 7 A resin composition was prepared by mixing 10 parts by weight of an aromatic vinyl-vinyl cyanide crosslinked copolymer produced in Production Example 1, 65 parts by weight of an aromatic vinyl-vinyl cyanide non-crosslinked copolymer (LG Chem, 83SF), 25 parts by weight of a graft copolymer (LG Chem, DP270M), and 0.1 parts by weight of a heat stabilizer (BASF, IRGANOX 1010).

[0109] Example 8 A resin composition was prepared by mixing 20 parts by weight of an aromatic vinyl-vinyl cyanide crosslinked copolymer produced in Production Example 1, 55 parts by weight of an aromatic vinyl-vinyl cyanide non-crosslinked copolymer (LG Chem, 83SF), 25 parts by weight of a graft copolymer produced on an acrylic polymer base (LG Chem, SA927), and 0.1 parts by weight of a heat stabilizer (BASF, IRGANOX 1010).

[0110] Comparative Example 1 The resin composition was formulated in the same manner as in Example 1, except that 20 parts by weight of the aromatic vinyl-vinyl cyanide crosslinked copolymer produced in Comparative Production Example 1 were used instead of 20 parts by weight of the aromatic vinyl-vinyl cyanide crosslinked copolymer produced in Production Example 1.

[0111] Comparative Example 2 The resin composition was formulated in the same manner as in Example 1, except that 20 parts by weight of the aromatic vinyl-vinyl cyanide crosslinked copolymer produced in Comparative Production Example 2 were used instead of 20 parts by weight of the aromatic vinyl-vinyl cyanide crosslinked copolymer produced in Production Example 1.

[0112] Comparative Example 3 The resin composition was formulated in the same manner as in Example 1, except that 20 parts by weight of aromatic vinyl-vinyl cyanide crosslinked copolymer (manufactured by GE, B-MAT) were used instead of 20 parts by weight of aromatic vinyl-vinyl cyanide crosslinked copolymer produced in Production Example 1.

[0113] Comparative Example 4 A resin composition was prepared by mixing 75 parts by weight of aromatic vinyl-vinyl cyanide non-crosslinked copolymer (LG Chem, 83SF), 25 parts by weight of graft copolymer (LG Chem, DP270M), and 0.1 parts by weight of heat stabilizer (BASF, IRGANOX 1010).

[0114] Experimental Example 1 The resin compositions produced in Examples 1-8 and Comparative Examples 1-4 were fed into a twin-screw extruder, kneaded and extruded at 200°C to produce pellets, and after injection of the pellets at 220°C, the melt index, gloss, and coefficient of variation of light reflectance were measured using the method described below and are shown in Table 1.

[0115] (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.

[0116] (2) Coefficient of variation of light reflection: This was derived 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°.

[0117] 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.

[0118] 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.

[0119] 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.

[0120]

number

[0121] 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, 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.

[0122] 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.

[0123] [Formula 1] C LR =D L / M L

[0124] 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.

[0125] (3) Melt index (g / 10min): Measured according to the ASTM D1238 method under conditions of 220°C and 10 kg.

[0126] [Table 1]

[0127] Referring to Table 1, it can be confirmed that in Examples 1 to 8, applying the crosslinked copolymers of Production Examples 1 to 5 resulted in low gloss and a low coefficient of variation of light reflectance.

[0128] On the other hand, the copolymers of Comparative Production Examples 1 and 2, in which the crosslinking agent was added only at the initial stage of polymerization, had a low yield regardless of the amount added. Comparative Examples 1 and 2, to which this copolymer was applied, showed results with a higher coefficient of variation of light reflectance or higher gloss compared to the examples. Comparative Example 3, which used a commercially available crosslinked copolymer produced by reaction extrusion, also showed relatively higher gloss and a higher coefficient of variation of light reflectance compared to the examples. Comparative Example 4 showed considerably higher gloss depending on the crosslinked copolymer component.

[0129] As a result, when a crosslinked copolymer manufactured using the present invention is applied to a resin composition, it is possible to successfully produce a product with a uniform surface and no glare by injection molding. Furthermore, since this process does not require any specific treatment of the injection mold, it is highly reproducible and suitable for mass production.

Claims

1. It contains an aromatic vinyl-vinyl cyanide crosslinked copolymer, A resin composition having a gloss level of 25 or less at 60° measured with a gloss meter in accordance with the ASTM D523 evaluation method, and a light reflectance variation coefficient of 2.0 or less calculated by 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 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 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 20 or less.

5. The resin composition according to claim 1, wherein the coefficient of variation of light reflection is 1.5 or less.

6. The resin composition according to claim 1, wherein the aromatic vinyl-vinyl cyanide crosslinked copolymer comprises a crosslinked portion containing silicon compound units and polyene compound units, aromatic vinyl monomer units and vinyl cyanide monomer units.

7. 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.

8. Amount to 100 parts by weight of the resin composition: 5 to 35 parts by weight of the aromatic vinyl-vinyl cyanide crosslinked copolymer, 45 to 65 parts by weight of the aromatic vinyl-vinyl cyanide non-crosslinked copolymer, and The resin composition according to claim 7, comprising 20 to 30 parts by weight of the graft copolymer.

9. 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 7, wherein the graft copolymer comprises a conjugated diene polymer, aromatic vinyl monomer units, and vinyl cyanide monomer units.

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

11. The molded article according to claim 10, wherein the molded article is injection molded.

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