Copolymer with core-shell structure, PC / ASA mixture and preparation method

Abstract

The present invention provides a core-shell structure copolymer, a PC / ASA mixture and a preparation method, and relates to the technical field of polymer resin mixtures and preparation thereof, the core-shell structure copolymer uses a styrene butadiene rubber and butyl acrylate copolymer as a core layer, and uses an acrylonitrile and styrene copolymer as a shell layer. The core-shell structure copolymer prepared by the invention has lower glass transition temperature (Tg) and better colorability, and the prepared PC / ASA mixture can be black and brighter visually and has better low temperature resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer resin mixtures and preparation thereof, in particular to a core-shell structure copolymer, a PC / ASA mixture and a preparation method thereof. Background Art

[0002] PC, or polycarbonate, is a widely used transparent engineering plastic with high heat resistance, high strength, and dimensional stability, but it also suffers from poor weather resistance and processing properties. ASA is a terpolymer composed of styrene, acrylonitrile, and acrylates, and has excellent weather resistance and processing properties. PC and ASA blends combine the excellent properties of both and are widely used in the automotive and electrical and electronic fields. However, because traditional ASA core layers use butyl acrylate rubber, which has poor coloring properties and a high glass transition temperature (Tg), the resulting PC / ASA blends have poor coloring and poor low-temperature toughness.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The object of the present invention is to provide a core-shell structure copolymer, a PC / ASA mixture and a preparation method. The core-shell structure copolymer prepared by the present invention has a lower glass transition temperature (Tg) and better colorability, so that the prepared PC / ASA mixture can be visually darker and have better low-temperature resistance.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The invention provides a core-shell structure copolymer, which uses a copolymer of styrene-butadiene rubber and butyl acrylate as a core layer and a copolymer of acrylonitrile and styrene as a shell layer.

[0007] Furthermore, based on the above technical solution, based on the mass of the core-shell structure copolymer being 100%, the content of the shell layer is 40-60%, preferably 50%; the content of the core layer is 40-60%, preferably 50%.

[0008] Furthermore, based on the above technical solution, the particle size of the core-shell structure copolymer is 100-150 nm;

[0009] And / or, the number average molecular weight of the acrylonitrile-styrene copolymer in the shell layer is between 80,000 and 150,000.

[0010] The present invention also provides a method for preparing the core-shell structure copolymer as described above, comprising the following steps:

[0011] S1: copolymerizing styrene-butadiene rubber and butyl acrylate in latex to obtain a copolymer of styrene-butadiene rubber and butyl acrylate;

[0012] S2: adding styrene and acrylonitrile to the copolymer of styrene-butadiene rubber and butyl acrylate rubber, and then adding an emulsifier and an initiator to carry out emulsion polymerization to obtain the core-shell structure copolymer.

[0013] Furthermore, based on the above technical solution, based on the total mass of styrene-butadiene rubber, butyl acrylate, styrene and acrylonitrile as 100%, the content of styrene-butadiene rubber is 10-30%; the content of butyl acrylate is 30-40%; the content of styrene is 26-48%; and the content of acrylonitrile is 8-20%.

[0014] Wherein, the mass ratio of styrene to acrylonitrile is 2-4:1, preferably 3:1;

[0015] And / or, the reaction conditions of the latex copolymerization include: temperature of 50-70° C., reaction time of 2-3 h;

[0016] and / or, the reaction temperature of the emulsion polymerization is 70-75° C., and the reaction time is 1-2 h;

[0017] And / or, the emulsifier is sodium dodecylbenzenesulfonate, and the total content of the emulsifier accounts for 0.3%-0.5% of the total mass of the emulsion polymerization system;

[0018] And / or, the initiator is potassium persulfate, and the total content of the initiator accounts for 0.3%-0.5% of the total mass of the emulsion polymerization system.

[0019] The present invention also provides a PC / ASA mixture, which comprises the following components, calculated by mass: 45-75 parts of PC resin, 10-20 parts of the core-shell structure copolymer described above, 10-20 parts of styrene-acrylonitrile copolymer resin, 0.2-0.4 parts of antioxidant, 0.4-1 parts of ultraviolet absorber, and 2-5 parts of black masterbatch.

[0020] Furthermore, based on the above technical solution, the number average molecular weight of the styrene-acrylonitrile copolymer resin is between 80,000 and 150,000;

[0021] and / or, the antioxidant comprises at least one of a hindered phenol antioxidant or a phosphite antioxidant;

[0022] And / or, the UV absorber is a macromolecular phenyl acrylate, and its number average molecular weight is ≥1000;

[0023] And / or, the black masterbatch is a black masterbatch coated with no carrier wax, wherein the carbon black content is 40-60%, preferably 50%.

[0024] Furthermore, based on the above technical solution, the hindered phenol antioxidant includes one or more of: 2,6-di-tert-butyl-4-methylphenol, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (1076);

[0025] And / or, the phosphite antioxidant includes one or more of tris(2,4-di-tert-butylphenyl)phosphite (168), bis(2,4-di-tert-butyl)tetrahydrogen phosphate, and pentaerythritol bisphosphite dioctadecyl ester;

[0026] And / or, the phenyl acrylate UV absorber is pentaerythritol tetrakis(2-cyano-3,3-diphenylacrylate).

[0027] The present invention also provides a method for preparing the PC / ASA mixture as described above, comprising the following steps:

[0028] (1) PC resin, the core-shell structure copolymer described above, styrene-acrylonitrile copolymer resin, antioxidant, ultraviolet absorber and black masterbatch are added to a high-pressure mixer in proportion for premixing;

[0029] (2) The premixed material is melt-extruded through a twin-screw extruder, cooled in a water tank, and granulated by a pelletizer to obtain high-gloss black, low-temperature impact-resistant, and weather-resistant PC / ASA mixture particles.

[0030] Furthermore, based on the above technical solution, the speed of the high-speed mixer is 18-22 rad / s, and the time is 3-7 minutes;

[0031] And / or, the barrel temperature of the twin-screw extruder is 230° C.-270° C., the main extruder speed is 350-450 rad / min, and the feeder speed is 8-12 rad / min.

[0032] The present invention provides a core-shell structure copolymer, PC / ASA mixture and preparation method, which have the following beneficial effects:

[0033] 1. The rubber in the core layer of the core-shell structure copolymer provided by the present invention is copolymerized with styrene-butadiene rubber and butyl acrylate, and the prepared core-shell structure copolymer has a small particle size of 100-150 nm. The small particle size rubber powder has a lower glass transition temperature (Tg) and better colorability, so that the prepared PC / ASA mixture can be visually darker and have better low-temperature resistance.

[0034] 2. The present invention uses macromolecular phenyl acrylates as UV absorbers, which have good migration resistance and can withstand longer continuous photoaging experiments than traditional small-molecule types.

[0035] 3. The black masterbatch selected in the present invention is carbon black coated with no carrier wax. Compared with traditional carbon black and PC-based coated black masterbatch, due to the presence of the coating layer wax, it has a better dispersion effect when melted at high temperature, which can make the visual black brightness of the product better. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. The process parameters for which specific conditions are not specified in the following examples are generally in accordance with conventional conditions.

[0037] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to form one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in the present invention.

[0038] According to the first aspect of the present invention, a core-shell structure copolymer (ASA-1) is provided, wherein a copolymer of styrene-butadiene rubber (SBR) and butyl acrylate (BA) is used as a core layer, and a copolymer of acrylonitrile and styrene is used as a shell layer.

[0039] Specifically, due to their unique chemical structures, styrene-butadiene rubber (SBR) and butyl acrylate (BA) give the core layer a lower glass transition temperature (Tg) and better flexibility; the styrene-acrylonitrile copolymer in the shell layer has good compatibility with PC and AS in the blend system.

[0040] Furthermore, the SBR in the core layer has good colorability and a low glass transition temperature (Tg), while the BA provides excellent aging resistance. By rationally optimizing the SBR and BA in the core layer, the prepared PC / ASA alloy has better colorability, low temperature resistance and light aging resistance.

[0041] As an optional embodiment of the present invention, based on the mass of the core-shell structure copolymer as 100%, the content of the shell layer is 40-60% (for example, 43%, 45%, 50%, 53%, 55%, 57%, etc.), preferably 50%; the content of the core layer is 40-60% (for example, 43%, 45%, 50%, 53%, 55%, 57%, etc.), preferably 50%.

[0042] As an optional embodiment of the present invention, the particle size of the core-shell structure copolymer is 100-150 nm (such as 110 nm, 120 nm, 130 nm, 140 nm, etc.).

[0043] As an optional embodiment of the present invention, the number average molecular weight (Mn) of the acrylonitrile-styrene copolymer in the shell layer is between 80,000 and 150,000 (eg, 90,000, 100,000, 130,000, etc.).

[0044] According to a second aspect of the present invention, there is provided a method for preparing the core-shell copolymer (ASA-1) as described above, comprising the following steps:

[0045] S1: copolymerizing styrene-butadiene rubber and butyl acrylate in latex to obtain a copolymer of styrene-butadiene rubber and butyl acrylate;

[0046] S2: adding styrene and acrylonitrile to the copolymer of styrene-butadiene rubber and butyl acrylate rubber, and then adding an emulsifier and an initiator to carry out emulsion polymerization to obtain the core-shell structure copolymer.

[0047] As an optional embodiment of the present invention, based on the total mass of styrene-butadiene rubber, butyl acrylate, styrene and acrylonitrile as 100%, the content of the styrene-butadiene rubber is 10-30% (for example, 12%, 15%, 17%, 20%, 23%, 25%, 27%, etc.), preferably 20%; the content of butyl acrylate is 30-40% (for example, 33%, 35%, 37%, etc.), preferably 30%; the content of styrene is 26-48% (for example, 30%, 33%, 35%, 37%, 40%, 45%, etc.); the content of acrylonitrile is 8-20% (for example, 10%, 14%, 16%, 18%, etc.);

[0048] Specifically, although traditional ASA materials meet weather resistance requirements, their rubber core is butyl acrylate, which has a high glass transition temperature (Tg) and poor colorability. The present invention significantly improves the material's low-temperature resistance and colorability while ensuring weather resistance by rationally regulating the ratio of butyl acrylate to styrene-butadiene rubber.

[0049] The mass ratio of styrene to acrylonitrile is 2-4:1 (such as 2.5:1, 3:1, 3.5:1), preferably 3:1.

[0050] Specifically, the present invention limits the styrene to acrylonitrile mass ratio to 2-4:1 because at this ratio, the prepared core-shell copolymer (ASA-1) not only exhibits moderate fluidity and toughness, but also exhibits excellent compatibility with PC and AS resins. Both excessively high and low styrene contents result in poor compatibility of the styrene acrylonitrile copolymer shell with PC and AS resins, resulting in poor toughness and poor coloration of the blended product.

[0051] As an optional embodiment of the present invention, the reaction conditions of the latex copolymerization include:

[0052] The temperature is 50-70°C (e.g., 55°C, 60°C, 65°C, etc.), and the reaction time is 2-3h (e.g., 2.3h, 2.5h, 2.7h, etc.);

[0053] As an optional embodiment of the present invention, the reaction temperature of the emulsion polymerization is 70-75°C (such as 72°C, 73°C, 74°C, etc.), and the reaction time is 1-2h (such as 1.2h, 1.5h, 1.7h, etc.).

[0054] As an optional embodiment of the present invention, the emulsifier is sodium dodecylbenzenesulfonate, and the total content of the emulsifier accounts for 0.3%-0.5% (such as 0.35%, 0.4%, 0.45%, etc.) of the total mass of the emulsion polymerization system;

[0055] The initiator is potassium persulfate, and the total content of the initiator accounts for 0.3%-0.5% (such as 0.35%, 0.4%, 0.45%, etc.) of the total mass of the emulsion polymerization system.

[0056] According to a third aspect of the present invention, a PC / ASA mixture is provided, comprising the following components, in parts by mass: 45-75 parts (e.g., 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, etc.) of a PC resin, 10-20 parts (e.g., 12 parts, 14 parts, 16 parts, 18 parts, etc.) of the core-shell structure copolymer described above, 10-20 parts (e.g., 12 parts, 14 parts, 16 parts, 18 parts, etc.) of a styrene-acrylonitrile copolymer (AS) resin, 0.2-0.4 parts (e.g., 0.25 parts, 0.3 parts, 0.35 parts, etc.) of an antioxidant, 0.4-1 parts (e.g., 0.5 parts, 0.7 parts, 0.9 parts, etc.) of a UV absorber, and 2-5 parts (e.g., 3 parts, 4 parts, etc.) of a black masterbatch.

[0057] Specifically, the present invention replaces butyl acrylate that affects the coloring core layer of ASA rubber powder with a copolymer of styrene-butadiene rubber and butyl acrylate to obtain a core-shell structure copolymer ASA-1. The introduction of styrene-butadiene rubber with good coloring properties and low glass transition temperature can significantly improve the coloring and low-temperature resistance of the PC / ASA blend. Combined with a large molecular weight phenyl acrylate UV absorber and carrier-free wax-coated carbon black, the overall weather resistance and coloring properties of the system can be improved, making the performance of the PC / ASA mixture even better and expanding its application in the automotive and consumer electronics fields.

[0058] As an optional embodiment of the present invention, the PC resin is a phosgene-processed PC resin, which is a polycarbonate formed by interfacial polycondensation of bisphenol A and phosgene.

[0059] As an optional embodiment of the present invention, the number average molecular weight (Mn) of the styrene-acrylonitrile copolymer (AS) resin is between 80,000 and 150,000 (eg, 90,000, 100,000, 130,000, etc.).

[0060] Specifically, the present invention limits the molecular weight of the styrene-acrylonitrile copolymer (AS) resin to be close to that of the copolymer of acrylonitrile and styrene in the shell layer of the core-shell copolymer because the AS resin within this range has intermediate fluidity and good compatibility with both the core-shell copolymer and the PC resin, thereby improving the compatibility, toughness, fluidity and other properties of the PC / ASA mixture.

[0061] As an optional embodiment of the present invention, the antioxidant includes at least one of a hindered phenol antioxidant or a phosphite antioxidant.

[0062] As an optional embodiment of the present invention, the hindered phenol antioxidant includes: one or more of 2,6-di-tert-butyl-4-methylphenol and β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (1076);

[0063] And / or, the phosphite antioxidant includes one or more of tris(2,4-di-tert-butylphenyl)phosphite (168), bis(2,4-di-tert-butyl)tetrahydrogen phosphate, and pentaerythritol bisphosphite dioctadecyl ester.

[0064] As an optional embodiment of the present invention, the ultraviolet absorber is a macromolecular phenyl acrylate, and its number average molecular weight is ≥1000.

[0065] Specifically, the present invention selects high molecular weight phenyl acrylate UV absorbers, which have good migration resistance and can withstand longer continuous photoaging experiments than traditional small molecule UV absorbers (number average molecular weight <1000).

[0066] As an optional embodiment of the present invention, the phenyl acrylate ultraviolet absorber is pentaerythritol tetrakis (2-cyano-3,3-diphenylacrylate).

[0067] As an optional embodiment of the present invention, the black masterbatch is a black masterbatch coated with no carrier wax, wherein the carbon black content is 40-60% (such as 45%, 50%, 55%, etc.), preferably 50%.

[0068] Specifically, the black masterbatch selected in the present invention is carbon black coated with no carrier wax (such as PE wax, etc.). Compared with traditional carbon black and PC-based coated black masterbatch, due to the presence of wax, it has a better dispersion effect under high-temperature melting, which can make the product's visual black brightness better.

[0069] According to a fourth aspect of the present invention, there is provided a method for preparing the PC / ASA mixture as described above, comprising the steps of:

[0070] (1) Premixing PC resin, the core-shell copolymer, styrene-acrylonitrile copolymer (AS) resin, antioxidant, UV absorber and black masterbatch according to the proportions;

[0071] (2) The premixed material is melt-extruded, cooled in a water tank, and pelletized by a pelletizer to obtain high-gloss black, low-temperature impact-resistant, and weather-resistant PC / ASA mixture particles.

[0072] Furthermore, on the basis of the above technical solution, the premixing treatment adopts a high-speed mixer, the speed of the high-speed mixer is 18-22 rad / s (such as 19 rad / s, 20 rad / s, etc.), and the time is 3-7 minutes (such as 4 minutes, 5 minutes, 6 minutes, etc.);

[0073] And / or, the melt extrusion process adopts a twin-screw extruder, the barrel temperature of the twin-screw extruder is 230°C-270°C (for example, 240°C, 250°C, 260°C, etc.), the extruder main engine speed is 350-450rad / min (for example, 370rad / min, 400rad / min, 420rad / min, etc.), and the feeder speed is 8-12rad / min (for example, 9rad / min, 10rad / min, 11rad / min, etc.).

[0074] The present invention will be further described in detail below with reference to specific examples and comparative examples.

[0075] Example 1

[0076] The core-shell structure copolymer (ASA-1) prepared in this example has a copolymer of styrene-butadiene rubber and butyl acrylate as the core layer and a copolymer of acrylonitrile and styrene as the shell layer.

[0077] Based on the mass of the core-shell structure copolymer being 100%, the content of the shell layer is 50%; and the content of the core layer is 50%.

[0078] The preparation method of the core-shell copolymer (ASA-1) comprises the following steps:

[0079] S1: Based on the total mass of styrene-butadiene rubber, butyl acrylate, styrene and acrylonitrile as 100%, 20% styrene-butadiene rubber and 30% butyl acrylate were latex copolymerized at 60°C for 2 hours to obtain a copolymer of styrene-butadiene rubber and butyl acrylate;

[0080] S2: 37.5% styrene and 12.5% ​​acrylonitrile were added to a copolymer of styrene-butadiene rubber and butyl acrylate rubber, and then sodium dodecylbenzenesulfonate and potassium peroxydisulfate were added. Emulsion polymerization was carried out at 75° C. for 1.5 h, and the core-shell structure copolymer was obtained after washing and drying.

[0081] Among them, the mass ratio of styrene to acrylonitrile is 3:1;

[0082] The particle size of the core-shell structure copolymer obtained was 120 nm, and the number average molecular weight (Mn) of the copolymer of acrylonitrile and styrene in the shell layer was 80,000.

[0083] This embodiment also provides a high-gloss black, low-temperature impact-resistant, and weather-resistant PC / ASA mixture, which includes the following components, by mass: 70 parts of PC resin, 15 parts of the core-shell structure copolymer (ASA-1) described above, 15 parts of AS resin, 0.3 parts of antioxidant, 0.5 parts of UV absorber, and 3 parts of black masterbatch.

[0084] The PC resin is Teijin's phosgene-processed PC, brand PC1225Y. The AS resin is Ningbo Formosa Chemical's NF2200, with a number-average molecular weight (Mn) of 80,000-100,000. The antioxidant is a blend of BASF's hindered phenol antioxidant 1076 and phosphite 168 (tris(2,4-di-tert-butylphenyl)phosphite) in a 1:2 ratio. The UV absorber is BASF's pentaerythritol tetrakis(2-cyano-3,3-diphenylacrylate), abbreviated as UV3030, with a molecular weight of 1061. The black masterbatch is carbon black coated with uncarrier wax, with a PE wax coating and a carbon black active content of 50%.

[0085] The preparation method of the above-mentioned high gloss black, low temperature impact resistant, and weather resistant PC / ASA mixture comprises the following steps:

[0086] (1) 70 parts of PC resin, 15 parts of the core-shell copolymer described above, 15 parts of AS resin, 0.3 parts of antioxidant, 0.5 parts of UV absorber and 3 parts of black masterbatch were added to a high-speed mixer and premixed at a speed of 20 rad / s for 5 minutes;

[0087] (2) adding the premixed material to the feed port of a twin-screw extruder, extruding it through the twin-screw extruder, cooling it in a water tank, and pelletizing it with a pelletizer to obtain high-gloss black, low-temperature impact-resistant, and weather-resistant PC / ASA mixture particles;

[0088] Among them, the barrel temperature of the twin-screw extruder is 250°C, the main extruder speed is 400rad / min, and the feeder speed is 10rad / min.

[0089] Example 2

[0090] The main difference between this embodiment and embodiment 1 is:

[0091] This embodiment provides a high-gloss black, low-temperature impact-resistant, and weather-resistant PC / ASA mixture, which includes the following components, by mass: 70 parts of PC resin, 10 parts of the core-shell structure copolymer (ASA-1) described above, 15 parts of AS resin, 0.3 parts of antioxidant, 0.5 parts of UV absorber, and 3 parts of black masterbatch.

[0092] Example 3

[0093] The main difference between this embodiment and embodiment 1 is:

[0094] This embodiment provides a high-gloss black, low-temperature impact-resistant, and weather-resistant PC / ASA mixture, which includes the following components, by mass: 70 parts of PC resin, 15 parts of the core-shell structure copolymer (ASA-1) described above, 20 parts of AS resin, 0.3 parts of antioxidant, 0.5 parts of UV absorber, and 2 parts of black masterbatch.

[0095] Comparative Example 1

[0096] The main difference between this comparative example and Example 1 is that the core-shell structure copolymer used is ASA rubber powder of model Guangzhou Energy LP2068 (the core layer is butyl acrylate, the shell layer is a copolymer of acrylonitrile and styrene, and based on the mass of the core-shell structure copolymer being 100%, the mass percentage of butyl acrylate is 50%, and the mass percentage of the acrylonitrile and styrene copolymer is 50%), and its preparation method comprises the following steps:

[0097] 37.5% styrene and 12.5% ​​acrylonitrile were added to 50% butyl acrylate, and then sodium dodecylbenzenesulfonate and potassium peroxodisulfate were added. Emulsion polymerization was carried out at 75° C. for 1.5 hours. After washing and drying, the core-shell structure copolymer was obtained. The remaining steps and technical parameters were the same as those in Example 1.

[0098] Comparative Example 2

[0099] The main difference between this comparative example and Example 1 is that the black masterbatch is replaced with black toner Cabot Black, brand M800, and in order to maintain the same coloring properties as in Example 1, the amount of black toner Cabot Black added is 1.5 parts. The remaining steps and technical parameters are the same as those in Example 1.

[0100] Comparative Example 3

[0101] The main difference between this comparative example and Example 1 is that the ultraviolet absorber UV3030 in Example 1 is replaced with UV234 (BASF's 2-2(2H-benzotriazole-2-yl)-4,6-di{1-methyl-1-phenyl-2-yl}phenol, referred to as UV234, with a molecular weight of 447). The remaining steps and technical parameters are the same as those in Example 1.

[0102] Comparative Example 4

[0103] The main difference between this comparative example and Example 1 is that step S1 of the preparation method of the core-shell structure copolymer is:

[0104] S1: copolymerizing 30% of styrene-butadiene rubber and 20% of butyl acrylate by mass to obtain a copolymer of styrene-butadiene rubber and butyl acrylate;

[0105] The remaining steps and technical parameters are the same as those in Example 1.

[0106] Performance Testing

[0107] The weighed PC / ASA mixture particles prepared in Examples 1-3 and Comparative Examples 1-4 were baked clean in a forced air drying oven at 100°C for 6 hours, and then injection molded into ISO standard specimens and color plates at 260°C for testing physical properties and weather resistance.

[0108] Charpy notched impact strength was tested according to ISO 179.

[0109] Melt flow rate is tested according to ISO 1133 standard.

[0110] The tensile strength was tested according to ISO 527.

[0111] The color test uses Konica Minolta's CM-5 to test the L value under D65 light source. The smaller the L value, the darker the color, the better the visual black brightness of the product, and the better the coloring performance.

[0112] Weathering test: Expose the color plate to a UV lamp with a power of 0.89W @ 340nm, 8 hours of light and 4 hours of darkness, 60°C under light and 50°C in darkness as one cycle, for a total of 500 hours of irradiation. Calculate the color difference before and after the test. The smaller the color difference, the better the weathering resistance.

[0113] Glass transition temperature (Tg) test method: The glass transition temperature (Tg) of the rubber core in the ASA rubber powder in the comparative example and the embodiment was tested by DSC method. The lower the glass transition temperature (Tg), the better its low temperature resistance.

[0114] Performance data

[0115] Table 1

[0116]

[0117]

[0118] As can be seen from Examples 1-3 in Table 1, Example 2 adds less core-shell copolymer ASA-1 than Example 1, and its fluidity and colorability are better, but its notched impact strength and weather resistance are significantly reduced. Compared with Example 1, the physical properties of Example 3 are basically unchanged, and the reduction in the amount of carbon black added without carrier wax coating leads to a significant decrease in colorability and weather resistance.

[0119] As shown in Table 1, compared with Example 1, since Comparative Example 1 uses traditional ASA rubber powder, it can be seen from Example 1 and Comparative Example 1 that traditional PC / ASA has good weather resistance, but its colorability and low temperature resistance are poor.

[0120] As shown in Table 1, compared with Example 1, Comparative Example 2 has poor visual black brightness due to the addition of black toner, which has a greater impact on the melt flow rate and colorability of the prepared PC / ASA mixture.

[0121] As shown in Table 1, compared with Example 1, the weather resistance of Comparative Example 3 is significantly reduced due to the addition of a low molecular weight ultraviolet absorber in Comparative Example 3.

[0122] As shown in Table 1, compared with Example 1, Comparative Example 4 has a lower glass transition temperature due to the content of styrene-butadiene rubber in the core-shell copolymer prepared in Comparative Example 4 being greater than that of butyl acrylate, but its weather resistance is significantly reduced.

[0123] In summary, the present invention adopts a PC / ASA mixture prepared by using a copolymer AS of acrylonitrile and styrene as the shell layer of the ASA rubber powder, a copolymer of styrene-butadiene rubber and butyl acrylate as the core layer, and a small-particle rubber powder with a particle size of 100-150 nm, and a black masterbatch coated with a carrier-free wax having high molecular weight ultraviolet absorption and better coloring performance. The prepared PC / ASA mixture can achieve visually brighter blackness and better low-temperature resistance.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A core-shell structure copolymer, characterized in that The core layer is a copolymer of styrene-butadiene rubber and butyl acrylate, and the shell layer is a copolymer of acrylonitrile and styrene.

2. The core-shell structure copolymer according to claim 1, characterized in that Based on the mass of the core-shell structure copolymer being 100%, the content of the shell layer is 40-60%, preferably 50%; the content of the core layer is 40-60%, preferably 50%.

3. The core-shell structure copolymer according to claim 1, characterized in that The particle size of the core-shell structure copolymer is 100-150 nm; And / or, the number average molecular weight of the acrylonitrile-styrene copolymer in the shell layer is between 80,000 and 150,000.

4. A method for preparing a core-shell structure copolymer according to any one of claims 1 to 3, characterized in that: The steps include: S1: copolymerizing styrene-butadiene rubber and butyl acrylate in latex to obtain a copolymer of styrene-butadiene rubber and butyl acrylate; S2: adding styrene and acrylonitrile to the copolymer of styrene-butadiene rubber and butyl acrylate rubber, and then adding an emulsifier and an initiator to carry out emulsion polymerization to obtain the core-shell structure copolymer.

5. The method for preparing the core-shell structure copolymer according to claim 4, wherein Based on the total mass of styrene-butadiene rubber, butyl acrylate, styrene and acrylonitrile as 100%, the content of the styrene-butadiene rubber is 10-30%; the content of the butyl acrylate is 30-40%; the content of the styrene is 26-48%; and the content of the acrylonitrile is 8-20%. Wherein, the mass ratio of styrene to acrylonitrile is 2-4:1, preferably 3:1; And / or, the reaction conditions of the latex copolymerization include: temperature of 50-70° C., reaction time of 2-3 h; and / or, the reaction temperature of the emulsion polymerization is 70-75° C., and the reaction time is 1-2 h; And / or, the emulsifier is sodium dodecylbenzenesulfonate, and the total content of the emulsifier accounts for 0.3%-0.5% of the total mass of the emulsion polymerization system; And / or, the initiator is potassium persulfate, and the total content of the initiator accounts for 0.3%-0.5% of the total mass of the emulsion polymerization system.

6. A PC / ASA mixture, characterized in that The invention comprises the following components in parts by mass: 45-75 parts of PC resin, 10-20 parts of the core-shell structure copolymer according to any one of claims 1 to 3 or the core-shell structure copolymer prepared by the preparation method of the core-shell structure copolymer according to any one of claims 4 to 5, 10-20 parts of styrene-acrylonitrile copolymer resin, 0.2-0.4 parts of antioxidant, 0.4-1 parts of ultraviolet absorber, and 2-5 parts of black masterbatch.

7. The PC / ASA mixture according to claim 6, characterized in that The number average molecular weight of the styrene-acrylonitrile copolymer resin is between 80,000 and 150,000; and / or, the antioxidant comprises at least one of a hindered phenol antioxidant or a phosphite antioxidant; And / or, the UV absorber is a macromolecular phenyl acrylate, and its number average molecular weight is ≥1000; And / or, the black masterbatch is a black masterbatch coated with no carrier wax, wherein the carbon black content is 40-60%, preferably 50%.

8. The PC / ASA mixture according to claim 7, characterized in that The hindered phenol antioxidant includes one or more of 2,6-di-tert-butyl-4-methylphenol and β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (1076); And / or, the phosphite antioxidant includes one or more of tris(2,4-di-tert-butylphenyl)phosphite (168), bis(2,4-di-tert-butyl)tetrahydrogen phosphate, and pentaerythritol bisphosphite dioctadecyl ester; And / or, the phenyl acrylate UV absorber is pentaerythritol tetrakis(2-cyano-3,3-diphenylacrylate).

9. A method for preparing a PC / ASA mixture according to any one of claims 6 to 8, characterized in that: The steps include: (1) PC resin, the core-shell structure copolymer according to any one of claims 1 to 3 or the core-shell structure copolymer prepared by the preparation method of the core-shell structure copolymer according to any one of claims 4 to 5, styrene-acrylonitrile copolymer resin, antioxidant, ultraviolet absorber and black masterbatch are added to a high-pressure mixer in proportion for premixing; (2) The premixed material is melt-extruded through a twin-screw extruder, cooled in a water tank, and granulated by a pelletizer to obtain high-gloss black, low-temperature impact-resistant, and weather-resistant PC / ASA mixture particles.

10. The method for preparing the PC / ASA mixture according to claim 9, wherein: The speed of the high-speed mixer is 18-22 rad / s, and the time is 3-7 minutes; And / or, the barrel temperature of the twin-screw extruder is 230° C.-270° C., the main extruder speed is 350-450 rad / min, and the feeder speed is 8-12 rad / min.

Images