A heat-resistant transparent ABS resin and a method for preparing the same

Abstract

This invention relates to a heat-resistant transparent ABS resin and its preparation method, belonging to the field of synthetic resin technology. The invention modifies transparent ABS resin through synthesis by grafting heat-resistant monomers (α-methylstyrene, N-phenylmaleimide) onto the polybutadiene polymer molecular chain via chemical bonds, preparing MBS powder with heat-resistant functional groups, namely N-MBS powder. This N-MBS powder is then melt-blended with a heat-resistant MSAN matrix resin to obtain a heat-resistant transparent ABS resin. This method solves the incompatibility problem caused by directly blending and modifying transparent ABS with heat-resistant agents, thus improving the heat resistance of the transparent ABS resin. The prepared heat-resistant transparent ABS resin has a heat distortion temperature ≥80℃ (6.4mm 1.8MPa, ASTM D648) and a light transmittance ≥85% (3.0mm ASTM D1003).

Description

Technical Field

[0001] This invention belongs to the field of synthetic resin technology, specifically relating to a heat-resistant transparent ABS resin and its preparation method. Background Technology

[0002] Transparent ABS resin (MABS resin) is a quaternary polymer composed of butadiene, styrene, acrylonitrile, and methyl methacrylate. In addition to possessing the excellent mechanical and processing properties of general-purpose ABS resin, it also exhibits superior light transmittance. The main production methods for transparent ABS resin are continuous bulk polymerization and emulsion-grafted bulk SAN blending, with the latter being the current primary production route. The notched impact strength of transparent ABS resin is generally 50~200 J / m (ASTM D256), the melt flow rate is 10~50 g / 10 min (ASTM D1238), and the transmittance is 80~92% (3.0 mm, ASTM D1003). However, general-purpose transparent ABS resin has a shortcoming in heat resistance. Actual tests on the main transparent ABS resin products on the market show that their heat distortion temperature (HDT) is usually between 70~75℃ (6.4 mm, 1.8 MPa, ASTM D648). When the operating temperature exceeds a certain range, the thermal motion at the molecular chain ends intensifies, and the transparent ABS resin begins to soften and deform. Its mechanical properties and light transmittance decrease significantly, seriously affecting the application fields of transparent ABS resin. Therefore, improving the heat resistance of transparent ABS resin is very important.

[0003] The methyl methacrylate (Mmethacrylate) content in transparent ABS resin is typically between 50% and 70%. The Mmethacrylate backbone is an aliphatic carbon chain. Although the polar interaction between the ester and methyl groups restricts the movement of molecular chain segments to some extent, the molecular chain exhibits high flexibility and low rotational resistance of the ester groups. Under high-temperature conditions, the molecular chain segments readily undergo thermal motion. Styrene segments also possess a degree of flexibility. Therefore, the heat resistance of transparent ABS resin is not particularly outstanding. To improve the heat resistance of transparent ABS resin, heat-resistant monomers such as α-methylstyrene and N-phenylmaleimide can be introduced. α-Methylstyrene has significant steric hindrance, while N-phenylmaleimide introduces a five-membered ring and a rigid benzene ring structure, hindering the movement of molecular chain segments, making the molecular structure more stable, reducing the creep and deformation of polymer chains at high temperatures, and improving the heat resistance of transparent ABS resin.

[0004] For example, Chinese invention patent CN117924873A discloses a low-orientation heat-resistant ABS material and its preparation method. This method improves the heat resistance of ABS material by adding a styrene-(N-phenylmaleimide)-maleic anhydride terpolymer, glass fiber, and epoxy resin fiber to ABS resin through melt blending. Chinese invention patent CN114437496B discloses a heat-resistant plastic and its preparation method. This method uses inorganic particle filling modification to improve the heat resistance of ABS resin. Heat-resistant ABS resin is prepared by melt blending inorganic materials with heat-resistant characteristics to ABS resin. By altering the intermolecular forces, the movement of macromolecular chains is hindered, thereby increasing the resin's heat distortion temperature. However, the above two methods do not produce transparent ABS resin. Currently, there are no heat-resistant transparent ABS resin preparations or related products on the market. Moreover, the heat-resistant agents on the market have poor compatibility with transparent ABS resin. When they are directly added to transparent ABS resin by melt blending, it is difficult for the molecular chains of the two to form effective forces. This not only fails to effectively improve the heat resistance of transparent ABS resin, but also reduces its mechanical properties, seriously affects its light transmittance, and causes heat-resistant polymer aggregation, as well as delamination and whitening of the products.

[0005] Therefore, bonding heat-resistant monomers to the rubber backbone via chemical bonds and modifying them through copolymerization significantly improves the heat resistance of transparent ABS resin. Summary of the Invention

[0006] This invention modifies transparent ABS resin through synthesis by grafting heat-resistant monomers (α-methylstyrene, N-phenylmaleimide) onto the polybutadiene polymer molecular chain via chemical bonding to prepare MBS powder with heat-resistant functional groups, namely N-MBS powder. This powder is then melt-blended with heat-resistant MSAN matrix resin to prepare heat-resistant transparent ABS resin. This invention solves the incompatibility problem caused by directly blending and modifying transparent ABS with heat-resistant agents, and improves the heat resistance of transparent ABS resin.

[0007] The preparation method of the heat-resistant transparent ABS resin of the present invention comprises the following steps:

[0008] (1) Place 60-70 parts by weight of homogenized polybutadiene latex, 5-20 parts by weight of deionized water, 0.01-1 parts by weight of electrolyte, 0.1-5 parts by weight of emulsifier, 0.1-1 parts by weight of chelating agent, 0.01-0.5 parts by weight of reducing agent ferrous sulfate, and 0.1-1 parts by weight of co-reducing agent into a grafting reactor, turn on the stirring paddle of the grafting reactor and heat it, set the stirring speed to 50-400 rpm, and keep the temperature constant at 50-60℃;

[0009] (2) Then, after adding 0.01~0.1 parts by mass of initiator to the grafting reactor in step (1) in batches, the first shell monomer is grafted, that is, 1~5 parts by mass of styrene, 1~5 parts by mass of α-methylstyrene and 0.01~0.3 parts by mass of initiator are continuously and simultaneously added for 10~30 minutes; after the first grafted shell monomer is added, the second shell monomer and initiator are added, that is, 5~25 parts by mass of N-phenylmaleimide dissolved in 0.1~5 parts by mass are continuously and simultaneously added. Methyl methacrylate of amine and 0.01-1 parts by mass of initiator are added dropwise over a time of 40-60 minutes. α-Methylstyrene and N-phenylmaleimide are bonded to the polybutadiene backbone in the first and second graft layers, respectively. After the second shell monomer and initiator are added dropwise, the reaction temperature is set to 70-85°C. Once the temperature reaches the set value, 0.01-0.3 parts by mass of initiator are added, and the mixture is allowed to mature for 40-60 minutes to obtain MBS latex with heat-resistant functional groups, i.e., N-MBS latex.

[0010] (3) Add the N-MBS latex obtained in step (2) to a sulfuric acid solution with a mass concentration of 0.1~1%, and coagulate, demulsify and mature the N-MBS latex at 65~95℃. Then, centrifuge the matured slurry and dry the separated N-MBS wet powder to obtain heat-resistant MBS high-rubber powder, i.e. N-MBS powder.

[0011] (4) Place 10-20 parts by weight of styrene, 5-20 parts by weight of acrylonitrile, 40-70 parts by weight of methacrylate, 5-20 parts by weight of α-methylstyrene, and 5-20 parts by weight of N-phenylmaleimide into a polymerization reactor. Add 5-30 parts by weight of solvent ethylbenzene and 0.001-0.2 parts by weight of 1,1-di-tert-butylcyclohexane peroxide to the reactor. Turn on the stirring paddle and reactor heating of the polymerization reactor. The heating temperature is 110-150°C. The residence time of the monomer in the reactor is set to 1-4 hours. The reaction is carried out by continuous polymerization. After polymerization, the reactants in the reactor are transported to a flash tank by a melt pump to remove unreacted monomers. After the monomers are removed, they are pumped to a twin-screw extruder. The temperature of the extruder is set to 190-240°C, the flash devolatilization pressure is set to -0.1 MPa, and the screw speed is set to 100-300 rpm. After extrusion and granulation, heat-resistant MSAN matrix resin is obtained.

[0012] (5) 20-30 parts by weight of N-MBS adhesive powder obtained in step (3) and 70-80 parts by weight of heat-resistant MSAN matrix resin obtained in step (4) are melt-blended in a twin-screw extruder. The temperature of the extruder is set at 210-230°C. After extrusion granulation, the heat-resistant transparent ABS resin of the present invention is obtained.

[0013] Furthermore, the electrolyte mentioned in step (1) is one or more of sodium chloride, magnesium chloride, calcium chloride, potassium chloride, sodium sulfate, and potassium carbonate;

[0014] Furthermore, the homogenized polybutadiene latex described in step (1) has a particle size between 100 and 300 nm and a particle size dispersion coefficient between 0.1 and 0.3.

[0015] Furthermore, the emulsifier mentioned in step (1) is a mixture of a non-reactive emulsifier and a reactive emulsifier, with a mass ratio of 1 to 2:1. The non-reactive emulsifier is potassium disproportionate or potassium fatty acid, and the reactive emulsifier is C 16 ~C 18 One of the following: dipotassium alkenylsuccinate, sodium allyl sulfonate, sodium allyloxyhydroxypropane sulfonate, sodium 3-allyloxy-2-hydroxy-1-propane sulfonate, or sodium p-styrene sulfonate;

[0016] Furthermore, the chelating agent mentioned in step (1) is one or both of disodium ethylenediaminetetraacetate and tetrasodium pyrophosphate;

[0017] Furthermore, the reducing agent mentioned in step (1) is one or two of fructose, glucose, or sodium formaldehyde sulfoxylate.

[0018] Furthermore, the total reaction time for steps (1) and (2) is 4-5 hours;

[0019] Furthermore, the N-MBS adhesive powder mentioned in step (3) is a pentagonal copolymer with a core-double-layer heat-resistant shell structure; the core is polybutadiene rubber, the first heat-resistant shell is a grafted shell layer composed of α-methylstyrene and styrene, and the second heat-resistant shell is a grafted shell layer composed of N-phenylmaleimide and methyl methacrylate.

[0020] Furthermore, in the N-MBS adhesive powder mentioned in step (3), the mass ratio of the core to the double-layer heat-resistant shell is 55:45~75:25;

[0021] Furthermore, in the N-MBS adhesive powder described in step (3), the grafting mass ratio of styrene to α-methylstyrene in the first shell is 1:0.5~1.5, and the grafting mass ratio of methyl methacrylate to N-phenylmaleimide in the second shell is 5~10:1.

[0022] Furthermore, the twin-screw extruder described in steps (4) and (5) has a total of 9 temperature zones. The 1st to 9th temperature zones of the twin-screw extruder described in step (4) are set to 190℃, 200℃, 210℃, 210℃, 220℃, 230℃, 230℃, 240℃, and 230℃, respectively. The 1st to 9th temperature zones of the twin-screw extruder described in step (5) are set to 210℃, 215℃, 220℃, 220℃, 220℃, 225℃, 225℃, 230℃, and 225℃, respectively.

[0023] Furthermore, in step (4), the temperature of the twin-screw extruder is set to 190~240℃, the flash devolatilization pressure is set to -0.1Mpa, and the screw speed is set to 100~300rpm; in step (5), the temperature of the twin-screw extruder is set to 210~230℃.

[0024] According to step (4) of the present invention, the heat distortion temperature of the 6.4 mm standard part prepared by injection molding of heat-resistant transparent ABS resin is ≥80℃ (1.8MPa, ASTM D648), and the light transmittance of the 3.0 mm standard part at room temperature is ≥85% (ASTM D1003).

[0025] The beneficial effects of this invention are as follows: by chemically bonding the heat-resistant monomers α-methylstyrene and N-phenylmaleimide to the toughening rubber molecular chain, the compatibility between transparent ABS resin and heat-resistant monomers or polymers is effectively improved, and the interfacial area between the two is reduced. While ensuring the mechanical properties and light transmittance of transparent ABS resin, the heat resistance of transparent ABS resin is effectively improved. Detailed Implementation

[0026] The technical solution of the present invention will be described below through specific embodiments. However, it should be noted that the following embodiments are only used to describe the content of the invention and do not constitute a limitation on the scope of protection of the present invention.

[0027] Example 1

[0028] (1) Preparation of N-MBS adhesive powder with a core-shell ratio of 65:35: 71 parts by mass of homogenized polybutadiene latex (particle size 269 nm, particle size distribution coefficient 0.169), 12 parts by mass of deionized water, 0.05 parts by mass of potassium carbonate, 0.7 parts by mass of potassium fatty acid, and 0.7 parts by mass of C 18 Dipotassium alkenyl succinate, 0.4 parts by mass of tetrasodium pyrophosphate, 0.1 parts by mass of ferrous sulfate reducing agent, and 0.2 parts by mass of fructose co-reducing agent are placed in a grafting reactor. The stirring of the grafting reactor is turned on and heated. The stirring speed is set at 130 rpm and the temperature is kept constant at 60℃.

[0029] (2) After adding 0.02 parts by mass of cumene hydroperoxide to the grafting reactor in batches, the first shell layer monomer is grafted, that is, 1.8 parts by mass of styrene, 1.2 parts by mass of α-methylstyrene and 0.03 parts by mass of cumene hydroperoxide are continuously and simultaneously added for 20 minutes. After the first grafted shell layer monomer is added, the second shell layer monomer and cumene hydroperoxide are added, that is, 11.1 parts by mass of methyl methacrylate dissolved with 1.7 parts by mass of N-phenylmaleimide and 0.2 parts by mass of cumene hydroperoxide are continuously and simultaneously added for 60 minutes. α-methylstyrene and N-phenylmaleimide are bonded to the polybutadiene backbone in the first graft layer and the second graft layer, respectively. After the second shell monomer and initiator are added, the reaction temperature is set to 70℃. After the temperature reaches the set value, 0.03 parts by mass of cumene hydrogen peroxide is added and the mixture is cured for 60 minutes to obtain MBS latex with heat-resistant functional groups, namely N-MBS latex.

[0030] (3) Add the N-MBS latex obtained above to a sulfuric acid solution with a mass concentration of 0.2%, coagulate and demulsify the N-MBS latex at 88°C, and mature it at 93°C. Separate the matured slurry by centrifugation, and then dry the N-MBS wet powder obtained by separation to obtain heat-resistant MBS high-rubber powder, i.e., N-MBS powder.

[0031] (4) Place 7 parts by weight of styrene, 7 parts by weight of acrylonitrile, 65 parts by weight of methacrylate, 15 parts by weight of α-methylstyrene, and 6 parts by weight of N-phenylmaleimide into a reactor. Add 30 parts by weight of solvent ethylbenzene and 0.003 parts by weight of 1,1-di-tert-butylcyclohexane peroxide to the reactor. Turn on the agitator and reactor heating. The heating temperature is 130°C. The residence time of the monomer in the reactor is set to 2.5 hours. The reaction is carried out by continuous polymerization. After polymerization in the reactor, the reactants are pumped to a flash tank for unreacted monomer removal using a melt pump. After monomer removal, the reactants are pumped to a twin-screw extruder (the extruder has 9 temperature zones, with zones 1 to 9 set at 190℃, 200℃, 210℃, 210℃, 220℃, 230℃, 230℃, 240℃, and 230℃ respectively). The flash devolatilization pressure is set to -0.1 MPa, and the screw speed is set to 270 rpm. Heat-resistant MSAN resin can be obtained by extrusion granulation.

[0032] (5) 24 parts by weight of N-MBS heat-resistant high-rubber powder obtained in step (3) and 76 parts by weight of heat-resistant MSAN matrix resin obtained in step (4) are melt-blended in a twin-screw extruder (the extruder has 9 temperature zones, and the temperature zones 1 to 9 are set to 210℃, 215℃, 220℃, 220℃, 225℃, 225℃, 230℃, and 225℃ respectively). The screw speed is set to 270 rpm. Heat-resistant transparent ABS resin is obtained by extrusion granulation.

[0033] Example 2

[0034] (1) Preparation of N-MBS adhesive powder with a core-shell ratio of 60:40: 65 parts by mass of homogenized polybutadiene latex (particle size 293 nm, particle size distribution coefficient 0.157), 16 parts by mass of deionized water, 0.06 parts by mass of potassium carbonate, 0.8 parts by mass of potassium fatty acid, and 0.8 parts by mass of C 18 Dipotassium alkenyl succinate, 0.5 parts by mass of tetrasodium pyrophosphate, 0.12 parts by mass of ferrous sulfate reducing agent, and 0.3 parts by mass of fructose co-reducing agent are placed in a grafting reactor. The stirring of the grafting reactor is turned on and heated. The stirring speed is set at 130 rpm and the temperature is kept constant at 60℃.

[0035] (2) After adding 0.02 parts by mass of cumene hydroperoxide to the grafting reactor in batches, the first shell layer monomer is grafted, that is, 2 parts by mass of styrene, 1.4 parts by mass of α-methylstyrene and 0.03 parts by mass of cumene hydroperoxide are continuously and simultaneously added for 20 minutes. After the first grafted shell layer monomer is added, the second shell layer monomer and initiator are added, that is, 12.7 parts by mass of methyl methacrylate containing 2.5 parts by mass of N-phenylmaleimide and 0.25 parts by mass of cumene hydroperoxide are continuously and simultaneously added for 60 minutes. α-methylstyrene and N-phenylmaleimide are bonded to the polybutadiene backbone in the first graft layer and the second graft layer, respectively. After the second shell monomer and cumene hydroperoxide are added dropwise, the reaction temperature is set to 70℃. After the temperature reaches the set value, 0.04 parts by mass of cumene hydroperoxide are added and the mixture is aged for 60 minutes to obtain MBS latex with heat-resistant functional groups, namely N-MBS latex.

[0036] (3) Add the N-MBS latex obtained above to a sulfuric acid solution with a mass concentration of 0.2%, coagulate and demulsify the N-MBS latex at 88°C, and mature it at 93°C. Separate the matured slurry by centrifugation, and dry the separated N-MBS wet powder to obtain heat-resistant MBS high-rubber powder, i.e., N-MBS powder.

[0037] (4) Place 12 parts by mass of styrene, 6 parts by mass of acrylonitrile, 60 parts by mass of methacrylate, 12 parts by mass of α-methylstyrene, and 10 parts by mass of N-phenylmaleimide into a reactor. Add 15 parts by mass of solvent ethylbenzene and 0.002 parts by mass of 1,1-di-tert-butylcyclohexane peroxide to the reactor. Turn on the agitator and reactor heating. The heating temperature is 110°C. The residence time of the monomer in the reactor is set to 3 hours. Continuous polymerization is carried out. After polymerization in the reactor is completed, the reactants are transported to a flash tank by a melt pump to remove unreacted monomers. After monomer removal, the reactants are pumped to a twin-screw extruder (the extruder has 9 temperature zones, with zones 1 to 9 set at 190℃, 200℃, 210℃, 210℃, 220℃, 230℃, 230℃, 240℃, and 230℃ respectively). The flash devolatilization pressure is set to -0.1 MPa, and the screw speed is set to 300 rpm. After extrusion and granulation, heat-resistant MSAN resin can be obtained.

[0038] (5) 21 parts by weight of N-MBS heat-resistant high-rubber powder obtained in step (3) and 79 parts by weight of heat-resistant MSAN matrix resin obtained in step (4) are melt-blended in a twin-screw extruder (the extruder has 9 temperature zones, and the temperature zones 1 to 9 are set to 210℃, 215℃, 220℃, 220℃, 225℃, 225℃, 230℃, and 225℃ respectively), and heat-resistant transparent ABS resin is obtained after extrusion granulation.

[0039] Example 3

[0040] (1) Preparation of N-MBS adhesive powder with a core-shell ratio of 70:30: 76.2 parts by mass of homogenized polybutadiene latex (particle size 247 nm, particle size distribution coefficient 0.167), 8.4 parts by mass of deionized water, 0.04 parts by mass of potassium carbonate, 0.65 parts by mass of potassium fatty acid, and 0.65 parts by mass of C 18 Dipotassium alkenyl succinate, 0.3 parts by mass tetrasodium pyrophosphate, 0.1 parts by mass ferrous sulfate reducing agent, and 0.2 parts by mass fructose co-reducing agent were placed in a grafting reactor. The stirring of the grafting reactor was turned on and heated. The stirring speed was set to 130 rpm and the temperature was kept constant at 65℃.

[0041] (2) After adding 0.02 parts by mass of initiator to the grafting reactor in batches, the first shell layer monomer is grafted. 1.5 parts by mass of styrene, 1 part by mass of α-methylstyrene and 0.02 parts by mass of cumene hydroperoxide are continuously and simultaneously added for 20 minutes. After the first grafted shell layer monomer is added, the second shell layer monomer and initiator are added. 9.5 parts by mass of methyl methacrylate that dissolves 1.4 parts by mass of N-phenylmaleimide and 0.2 parts by mass of cumene hydroperoxide are continuously and simultaneously added for 60 minutes. α-methylstyrene and N-phenylmaleimide are bonded to the polybutadiene backbone in the first and second grafted layers, respectively. After the second shell monomer and cumene hydroperoxide are added dropwise, the reaction temperature is set to 73℃. After the temperature reaches the set value, 0.03 parts by mass of cumene hydroperoxide are added in batches and cured for 60 minutes to obtain MBS latex with heat-resistant functional groups, namely N-MBS latex.

[0042] (3) Add the N-MBS latex obtained above to a sulfuric acid solution with a concentration of 0.2%, coagulate and demulsify the N-MBS latex at 88°C, and mature it at 93°C. Use centrifugation to separate the matured slurry, and dry the separated N-MBS wet powder to obtain heat-resistant MBS high-rubber powder, i.e., N-MBS powder.

[0043] (4) Place 14 parts by mass of styrene, 16 parts by mass of acrylonitrile, 54 parts by mass of methacrylate, 9 parts by mass of α-methylstyrene, and 7 parts by mass of N-phenylmaleimide into a reactor. Add 25 parts by mass of solvent ethylbenzene and 0.001 parts by mass of 1,1-di-tert-butylperoxycyclohexane to the reactor. Turn on the stirring paddle and reactor heating of the polymerization reactor. The heating temperature is 140°C. The residence time of the monomer in the reactor is set to 1 hour. The reaction is carried out by continuous polymerization. After polymerization in the reactor, the reactants are pumped to a flash tank for unreacted monomer removal using a melt pump. After monomer removal, the reactants are pumped to a twin-screw extruder (the extruder has 9 temperature zones, with zones 1 to 9 set at 190℃, 200℃, 210℃, 210℃, 220℃, 230℃, 230℃, 240℃, and 230℃ respectively) for melt blending. The flash devolatilization pressure is set to -0.1 MPa, and the screw speed is set to 270 rpm. After extrusion and granulation, heat-resistant MSAN resin can be obtained.

[0044] (5) 24 parts by weight of N-MBS heat-resistant high-rubber powder obtained in step (3) and 76 parts by weight of heat-resistant MSAN matrix resin obtained in step (4) are melt-blended in a twin-screw extruder (the extruder has 9 temperature zones, and the temperature zones 1 to 9 are set to 210℃, 215℃, 220℃, 220℃, 225℃, 225℃, 230℃, and 225℃ respectively), and heat-resistant transparent ABS resin is obtained after extrusion granulation.

[0045] To further demonstrate the beneficial effects of the present invention and to better understand it, the technical features disclosed in the present invention are further illustrated by the following comparative examples, but these should not be construed as limiting the present invention. Other improvements made by those skilled in the art based on the above description of the invention, without inventive effort, are also considered to fall within the protection scope of the present invention.

[0046] Comparative Example 1:

[0047] (1) Preparation of MBS powder with a core-shell ratio of 65:35 and no heat-resistant functional groups: 71 parts by mass of homogenized polybutadiene latex (particle size 269 nm, particle size distribution coefficient 0.169), 12 parts by mass of deionized water, 0.05 parts by mass of potassium carbonate, 0.7 parts by mass of potassium fatty acid, and 0.7 parts by mass of C 18 Dipotassium alkenyl succinate, 0.4 parts by mass of tetrasodium pyrophosphate, 0.1 parts by mass of ferrous sulfate reducing agent, and 0.2 parts by mass of fructose co-reducing agent are placed in a grafting reactor. The stirring of the grafting reactor is turned on and heated. The stirring speed is set at 130 rpm and the temperature is kept constant at 60℃.

[0048] (2) After adding 0.02 parts by mass of cumene hydroperoxide to the grafting reactor in batches, the first shell layer monomer is grafted, that is, 3 parts by mass of styrene and 0.03 parts by mass of cumene hydroperoxide are continuously and simultaneously added for 20 minutes. After the first grafted shell layer monomer is added, the second shell layer monomer and initiator are added, that is, 11.1 parts by mass of methyl methacrylate and 0.2 parts by mass of cumene hydroperoxide are continuously and simultaneously added for 60 minutes. Styrene and methyl methacrylate are in the first graft layer and the second graft layer, respectively. After the second shell layer monomer and cumene hydroperoxide are added, the reaction temperature is set to 70°C. After the temperature reaches the set value, 0.03 parts by mass of cumene hydroperoxide is added and the mixture is matured for 60 minutes to obtain MBS latex.

[0049] (3) Add the MBS latex obtained above to a sulfuric acid solution with a mass concentration of 0.2%, coagulate and demulsify the MBS latex at 88°C, and mature it at 93°C. Separate the matured slurry by centrifugation, and dry the separated MBS wet powder to obtain MBS high-polymer powder.

[0050] (4) Place 20 parts by mass of styrene, 15 parts by mass of acrylonitrile, and 65 parts by mass of methacrylate in a reactor. Add 20 parts by mass of solvent ethylbenzene and 0.003 parts by mass of 1,1-di-tert-butylcyclohexane peroxide to the reactor. Turn on the stirring paddle and reactor heating of the polymerization reactor. The heating temperature is 130°C. The residence time of the monomer in the reactor is set to 2.5 hours. The reaction is carried out by continuous polymerization. After the polymerization is completed in the reactor, the reactants are transported to a flash tank by a melt pump to remove unreacted monomers. After the monomers are removed, they are pumped to an extruder (the extruder has 9 temperature zones, and the temperature zones 1 to 9 are set to 190°C, 200°C, 210°C, 210°C, 220°C, 230°C, 230°C, 240°C, and 230°C, respectively). The flash devolatilization pressure is set to -0.1 MPa, and the screw speed is set to 270 rpm. After extrusion and granulation, MSAN resin can be obtained.

[0051] (5) 24 parts by weight of MBS high-rubber powder obtained in step (3) and 76 parts by weight of MSAN matrix resin obtained in step (4) are melt-blended in a twin-screw extruder (the extruder has 9 temperature zones, and the temperature zones 1 to 9 are set to 210℃, 215℃, 220℃, 220℃, 225℃, 225℃, 230℃ and 225℃ respectively), and then extruded and granulated to obtain transparent ABS resin.

[0052] Comparative Example 2:

[0053] The transparent ABS resin was physically modified by the blending extrusion method. The heat-resistant agent was melt-blended with the transparent ABS resin to prepare heat-resistant transparent ABS resin: 24 parts by mass of MBS high-rubber powder prepared in step (3) of Comparative Example 1, 76 parts by mass of MSAN matrix resin and 5 parts by mass of N-phenylmaleimide were melt-blended in a twin-screw extruder (the extruder has 9 temperature zones, and the temperature zones 1 to 9 are set to 210℃, 215℃, 220℃, 220℃, 225℃, 225℃, 230℃ and 225℃ respectively), and the transparent ABS resin was obtained after extrusion granulation.

[0054] Comparative Example 3:

[0055] The transparent ABS resin was physically modified by the blending extrusion method. The heat-resistant agent was melt-blended with the transparent ABS resin to prepare heat-resistant transparent ABS resin: 24 parts by weight of MBS high-rubber powder prepared in step (3) of Comparative Example 1, 76 parts by weight of MSAN matrix resin and 10 parts by weight of N-phenylmaleimide were melt-blended in a twin-screw extruder (the extruder has 9 temperature zones, and the temperature zones 1 to 9 are set to 210℃, 215℃, 220℃, 220℃, 225℃, 225℃, 230℃ and 225℃ respectively). After extrusion granulation, transparent ABS resin was obtained.

[0056] Comparative Example 4:

[0057] The transparent ABS resin was physically modified by the blending extrusion method. The heat-resistant agent was melt-blended with the transparent ABS resin to prepare heat-resistant transparent ABS resin: 24 parts by weight of MBS high-rubber powder prepared in step (3) of Comparative Example 1, 76 parts by weight of MSAN matrix resin and 15 parts by weight of N-phenylmaleimide heat-resistant agent were melt-blended in a twin-screw extruder (the extruder has 9 temperature zones, and the temperature zones 1 to 9 are set to 210℃, 215℃, 220℃, 220℃, 225℃, 225℃, 230℃ and 225℃ respectively), and the transparent ABS resin was obtained after extrusion granulation.

[0058] Comparative Example 5:

[0059] Transparent ABS resin (brand name: 920) manufactured by Toray Industries, Inc. of Japan was used as Comparative Example 5.

[0060] The above-obtained example samples and comparative samples were injection molded according to ASTM standards. The injection molding machine temperature was 230°C. After injection molding, the samples were placed in a constant temperature and humidity environment for 24 hours. After complete annealing, various performance tests were performed.

[0061] Table 1: Performance data of the example samples and comparative sample samples

[0062] Sample Name Impact strength (J / m) Tensile strength (MPa) Light transmittance (%) Heat distortion temperature (°C) Example 1 122 47.2 87.7 82.3 Example 2 108 48.5 87.4 83.4 Example 3 134 45.3 87.1 81.7 Comparative Example 1 127 46.3 90.3 73.1 Comparative Example 2 118 47.4 85.7 74.5 Comparative Example 3 110 48.3 78..5 77.3 Comparative Example 4 97 48.8 74.6 80.2 Comparative Example 5 104 48.7 89.2 73.8

[0063] Based on the above examples and comparative sample test data, the following conclusions can be drawn:

[0064] Compared with Comparative Example 1 (which does not contain heat-resistant monomers) and commercially available general-purpose transparent ABS resin (Toray Industries, Japan 920), the heat-resistant transparent ABS resin prepared by this invention has a significantly higher heat distortion temperature. Compared with the heat-resistant transparent ABS resin prepared by the blending method in Comparative Examples 2-4, the heat-resistant transparent ABS resin prepared by the polymerization process has a higher heat distortion temperature and a significantly higher light transmittance, thus possessing superior heat resistance and light transmittance.

Claims

1. A method for preparing heat-resistant transparent ABS resin, comprising the following steps: (1) Place 60-70 parts by weight of homogenized polybutadiene latex, 5-20 parts by weight of deionized water, 0.01-1 parts by weight of electrolyte, 0.1-5 parts by weight of emulsifier, 0.1-1 parts by weight of chelating agent, 0.01-0.5 parts by weight of reducing agent ferrous sulfate, and 0.1-1 parts by weight of co-reducing agent into a grafting reactor, turn on the stirring paddle of the grafting reactor and heat it, set the stirring speed to 50-400 rpm, and keep the temperature constant at 50-60℃; (2) Then, after adding 0.01~0.1 parts by mass of initiator to the grafting reactor in step (1) in batches, the first shell monomer is grafted, that is, 1~5 parts by mass of styrene, 1~5 parts by mass of α-methylstyrene and 0.01~0.3 parts by mass of initiator are continuously and simultaneously added for 10~30 minutes; after the first grafted shell monomer is added, the second shell monomer and initiator are added, that is, 5~25 parts by mass of N-phenylmaleimide dissolved in 0.1~5 parts by mass are continuously and simultaneously added. Methyl methacrylate of amine and 0.01-1 parts by mass of initiator are added dropwise over a time of 40-60 minutes. α-Methylstyrene and N-phenylmaleimide are bonded to the polybutadiene backbone in the first and second graft layers, respectively. After the second shell monomer and initiator are added dropwise, the reaction temperature is set to 70-85°C. Once the temperature reaches the set value, 0.01-0.3 parts by mass of initiator are added, and the mixture is allowed to mature for 40-60 minutes to obtain MBS latex with heat-resistant functional groups, i.e., N-MBS latex. (3) Add the N-MBS latex obtained in step (2) to a sulfuric acid solution with a mass concentration of 0.1~1%, and coagulate, demulsify and mature the N-MBS latex at 65~95℃. Then, centrifuge the matured slurry and dry the separated N-MBS wet powder to obtain heat-resistant MBS high-rubber powder, i.e. N-MBS powder. (4) Place 10-20 parts by weight of styrene, 5-20 parts by weight of acrylonitrile, 40-70 parts by weight of methacrylate, 5-20 parts by weight of α-methylstyrene, and 5-20 parts by weight of N-phenylmaleimide in a reactor. Add 5-30 parts by weight of solvent ethylbenzene and 0.001-0.2 parts by weight of 1,1-di-tert-butylperoxycyclohexane to the reactor. Turn on the stirring paddle and reactor heating of the polymerization reactor. The heating temperature is 110-150℃. The residence time of the monomer in the reactor is set to 1-4 hours. The reaction is carried out by continuous polymerization. After the polymerization is completed in the reactor, the reactants are transported to a flash tank by a melt pump to remove unreacted monomers. After the monomers are removed, they are pumped to an extruder. The temperature of the extruder is set to 190-240℃, the flash devolatilization pressure is set to -0.1 MPa, and the screw speed is set to 100-300 rpm. After extrusion and granulation, heat-resistant MSAN resin is obtained. (5) 20-30 parts by weight of N-MBS adhesive powder obtained in step (3) and 70-80 parts by weight of heat-resistant MSAN matrix resin obtained in step (4) are melt-blended in a twin-screw extruder. The temperature of the extruder is set at 210-230°C. After extrusion granulation, the heat-resistant transparent ABS resin is obtained.

2. The method for preparing a heat-resistant transparent ABS resin as described in claim 1, characterized in that: The electrolyte mentioned in step (1) is one or more of sodium chloride, magnesium chloride, calcium chloride, potassium chloride, sodium sulfate, and potassium carbonate.

3. The method for preparing a heat-resistant transparent ABS resin as described in claim 1, characterized in that: The homogenized polybutadiene latex described in step (1) has a particle size between 100 and 300 nm and a particle size dispersion coefficient between 0.1 and 0.

3.

4. The method for preparing a heat-resistant transparent ABS resin as described in claim 1, characterized in that: The emulsifier mentioned in step (1) is a mixture of non-reactive emulsifier and reactive emulsifier, with a mass ratio of 1~2:

1. The non-reactive emulsifier is potassium disproportionate or potassium fatty acid, and the reactive emulsifier is C 16 ~C 18 One of the following: dipotassium alkenylsuccinate, sodium allyl sulfonate, sodium allyloxyhydroxypropane sulfonate, sodium 3-allyloxy-2-hydroxy-1-propane sulfonate, or sodium p-styrene sulfonate.

5. The method for preparing a heat-resistant transparent ABS resin as described in claim 1, characterized in that: The chelating agent mentioned in step (1) is one or two of disodium ethylenediaminetetraacetate and tetrasodium pyrophosphate; the reducing agent is one or two of fructose, glucose or sodium formaldehyde sulfoxylate.

6. The method for preparing a heat-resistant transparent ABS resin as described in claim 1, characterized in that: The total reaction time for steps (1) and (2) is 4 to 5 hours.

7. The method for preparing a heat-resistant transparent ABS resin as described in claim 1, characterized in that: The N-MBS adhesive powder mentioned in step (3) is a pentagonal copolymer with a core-double-layer heat-resistant shell structure; the core is polybutadiene rubber, the first heat-resistant shell is a grafted shell layer composed of α-methylstyrene and styrene, and the second heat-resistant shell is a grafted shell layer composed of N-phenylmaleimide and methyl methacrylate; the mass ratio of the core to the double-layer heat-resistant shell is 55:45~75:

25.

8. The method for preparing a heat-resistant transparent ABS resin as described in claim 7, characterized in that: In N-MBS adhesive powder, the grafting mass ratio of styrene to α-methylstyrene in the first shell is 1:0.5~1.5, and the grafting mass ratio of methyl methacrylate to N-phenylmaleimide in the second shell is 5~10:

1.

9. The method for preparing a heat-resistant transparent ABS resin as described in claim 1, characterized in that: Step (4) The twin-screw extruder has a total of 9 temperature zones, and the temperature zones 1 to 9 are set to 190℃, 200℃, 210℃, 210℃, 220℃, 230℃, 230℃, 240℃, and 230℃ respectively; Step (5) The twin-screw extruder has a total of 9 temperature zones, and the temperature zones 1 to 9 are set to 210℃, 215℃, 220℃, 220℃, 220℃, 225℃, 225℃, 230℃, and 225℃ respectively.

10. A heat-resistant transparent ABS resin, characterized in that: It is prepared by the preparation method described in any one of claims 1 to 9, and the heat distortion temperature of the injection-molded 6.4mm standard part is ≥80℃ (1.8MPa, ASTM D648), and the light transmittance of the 3.0mm standard part at room temperature is ≥85% (ASTM D1003).