A high-flow transparent ABS resin with pomegranate structure and preparation method thereof

Abstract

The invention prepares a hydrophilic small-particle polybutadiene latex by copolymerizing a hydrophilic monomer with butadiene, then constructs a transition layer on the surface of the small-particle latex, and then further expands the diameter and performs alkali treatment to obtain a large-particle polybutadiene latex with a hollow structure. The latex is used as a core latex, and monomers such as styrene, acrylonitrile and methyl methacrylate are swollen into the interior of the hollow microspheres by a swelling technology, and an oil-soluble initiator is added to initiate polymerization to form a pomegranate structure. Finally, a polystyrene layer and a polymethyl methacrylate layer are constructed on the surface to prepare a MABS graft copolymer, and the transparent ABS resin can be obtained by melt blending with an MSAN resin.

Description

Technical Field

[0001] The invention belongs to the field of synthetic resins, and in particular relates to a method for preparing a transparent ABS resin with a pomegranate structure. Background Art

[0002] Transparent ABS resin is a special grade of ABS resin. In addition to the advantages of good mechanical properties, processing properties and solvent resistance of general-grade ABS resin, it also has good light transmittance, with a light transmittance of more than 89%, and is widely used in the fields of household appliances and automobiles. Transparent ABS resin is different from traditional ABS resin in that it introduces low refractive index monomer methyl methacrylate (MMA), and copolymerizes low refractive index MMA with high refractive index styrene (St), and then regulates its refractive index, so that the refractive index of the matrix phase and the dispersed phase in the transparent ABS resin matches each other, and the difference is less than 0.005, so as to achieve transparency.

[0003] At present, the methods for preparing transparent ABS resin in the industry can be divided into two methods: bulk polymerization technology and emulsion blending technology. For example, patents CN106699981A and CN 111944098 A disclose a method for preparing transparent ABS resin using a continuous bulk device, which uses a parallel two-stage series tubular plug flow reactor, uses styrene-butadiene rubber as the rubber phase, and styrene, methyl methacrylate, and acrylonitrile as the continuous phase to construct a bulk transparent ABS resin. The technical key of this method is that the refractive index of the terpolymer of styrene, methyl methacrylate, and acrylonitrile must be consistent with the size of the rubber phase, thereby constructing a transparent ABS resin; patent CN106221114A discloses a large-domain transparent ABS resin composition and a preparation method thereof, which also uses bulk polymerization technology. The technical key is that in addition to matching the refractive index between the rubber phase and the resin phase, the domain size of the dispersed phase in the continuous phase is controlled by adjusting the molecular weight distribution of the continuous phase, so that the domain size of the dispersed phase is between 0.3 and 1.2 um, realizing the preparation of a large-domain transparent ABS resin. The transparent ABS resin prepared by the method exhibits an internal inclusion structure, and the method belongs to the technology of preparing transparent ABS resin by intermittent bulk polymerization technology.

[0004] Patent CN 105008406 A discloses a method for preparing a transparent ABS resin and a transparent ABS resin composition by emulsion blending technology. The method uses a polybutadiene latex with a size of 250 to 400 nm as a core layer latex, and utilizes an emulsion grafting technology to graft copolymerize styrene, acrylonitrile and methyl methacrylate monomers on the surface of the polybutadiene latex to form core-shell structure particles with polybutadiene as the core and styrene, acrylonitrile and methyl methacrylate as the shell. A cross-linking agent is introduced during the grafting process to minimize the swelling effect of styrene on butadiene. Finally, the prepared core-shell structured ABS graft copolymer is melt-blended with an MSAN resin prepared by a bulk method to prepare a transparent ABS resin. The journal Materials Guide (2022, 36: 21070096-6) reported a method of agglomerating small-particle styrene butadiene latex into large-particle styrene butadiene latex by acetic acid agglomeration technology, then copolymerizing styrene and methyl methacrylate on the surface of polystyrene butadiene latex by emulsion grafting technology to prepare core-shell MBS graft copolymer, and then melt blending the MBS graft copolymer with polymethyl methacrylate (PMMA) and styrene and acrylonitrile copolymer (SAN) to prepare a transparent ABS resin. The light transmittance of this method can reach 86%. The journal New Chemical Materials (2008, 36, 33-34) reported a method of preparing styrene butadiene latex by one-step emulsion polymerization technology, then grafting styrene and methyl methacrylate to prepare MBS graft copolymer by emulsion grafting technology, and then preparing MSAN resin by suspension polymerization technology and melt blending with MBS graft copolymer to finally prepare transparent ABS resin.

[0005] To summarize the current existing technologies, the rubber phase used in the bulk polymerization method for preparing transparent ABS resin is butadiene or styrene butadiene rubber prepared by solution polymerization, and then the rubber surface is grafted by intermittent polymerization or continuous polymerization. The grafted rubber particles are relatively large, generally larger than 1um. The emulsion blending technology uses polybutadiene latex or styrene butadiene latex as the core layer latex, and then constructs a shell layer of styrene, methyl methacrylate and acrylonitrile on the surface of the latex, and finally uses melt blending technology to blend with MSAN resin to prepare transparent ABS resin. The transparent ABS resin prepared by the above method has poor fluidity and low impact strength, which can only be maintained at 15KJ / m 2 about. Summary of the invention

[0006] The present invention adopts a large-particle polybutadiene latex with a hollow structure as a core layer latex, and then uses a swelling polymerization technology to completely swell styrene, acrylonitrile and methacrylate monomers into the interior of the polybutadiene particles to form a pomegranate structure. Finally, a styrene, acrylonitrile and methacrylate polymer layer is constructed on the surface of the polybutadiene latex with a pomegranate structure to prepare a MABS graft copolymer with a pomegranate structure, and finally, it is melt-blended with an MSAN resin prepared by bulk or suspension polymerization to prepare a high-flow transparent ABS resin. The characteristic of the present invention is that a polybutadiene latex with a hollow structure is used to absorb styrene, methyl methacrylate and acrylonitrile monomers into the interior of the polybutadiene latex, thereby constructing a pomegranate-shaped structure. The polybutadiene particles with a pomegranate-shaped structure promote the fluidity of the transparent ABS resin on the one hand, and on the other hand, the refractive index of the dispersed phase inside the dispersed phase is more matched with the continuous phase, thereby improving the light transmittance of the transparent ABS resin. In addition, the wall thickness of the polybutadiene particles with a pomegranate structure is only at the level of tens of nanometers, which will not cause scattering when light passes through, thereby helping to reduce the haze of the transparent ABS resin.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] A method for preparing a high-flow transparent ABS resin having a pomegranate structure by hollow polybutadiene latex, comprising the following steps:

[0009] (1) adding an emulsifier, a molecular weight regulator, and distilled water into a polymerization reactor by weight, adding butadiene monomer, comonomer I, comonomer II, and an initiator into the reactor, heating the reactor to 60 to 80° C. to initiate polymerization, and maintaining the temperature for 2 to 5 hours to prepare a hydrophilic small-particle polybutadiene latex;

[0010] (2) Continue to add butadiene monomer and comonomer I to the reactor at the same time, and control the addition time to 2-3 hours.

[0011] 5 hours, constructing a transition layer on the surface of the hydrophilic small-particle polybutadiene latex;

[0012] (3) continuing to add butadiene to the autoclave at a uniform speed, the adding time being controlled within 5 to 15 hours, adding an initiator after the addition is completed, raising the temperature to 85 to 90° C., and keeping the temperature for 1 to 3 hours; continuing to add a strong base to the autoclave and keeping the temperature for 1 to 3 hours to obtain a large-particle polybutadiene latex with a hollow structure; (4) using the large-particle polybutadiene latex with a hollow structure obtained in the above steps as a core layer latex, and preparing a MABS graft latex with a pomegranate structure through an emulsion graft polymerization reaction after the monomer is swollen The specific steps are as follows: ① placing the above-obtained polybutadiene latex with a hollow structure (dry basis) in a reaction kettle, adding an emulsifier, an oil-soluble initiator, a redox initiation system, and a comonomer I, and swelling at room temperature for 0.5 to 1 hour; ② raising the temperature of the system to 60 to 70°C, starting to initiate polymerization, and simultaneously dropping styrene monomer into the system for 0.5 to 1 hour; ③ after the dropping is completed, continue to drop methyl methacrylate monomer for 0.5 to 2 hours, and after the dropping is completed, raise the temperature to 75 to

[0013] Keep the temperature at 85°C for 0.5 hour to obtain the MABS graft copolymer latex;

[0014] (5) adding the MABS graft copolymer latex obtained in step (4) into the aqueous flocculant solution at 65-80°C.

[0015] Flocculation and demulsification are carried out at 85°C, and after demulsification, the solid and water are separated and then dried at 60-80°C to obtain MABS graft copolymer powder;

[0016] (6) The obtained MABS graft copolymer powder is melt-blended with MSAN resin and extruded and granulated to obtain transparent ABS resin.

[0017] In the present invention, in the step (1), the amount of the emulsifier is 2 to 3 parts, the amount of the molecular weight regulator is 0.1 to 1 part, the amount of distilled water is 80 to 150 parts, the amount of butadiene monomer is 5 to 10 parts, the amount of comonomer I is 0 to 3 parts, the amount of comonomer II is 0.5 to 3 parts, and the amount of the initiator is 0.3 to 1 part;

[0018] In the present invention, in the step (2), the amount of butadiene monomer added is 10 to 20 parts, and the amount of comonomer I added is 2 to 5 parts by weight;

[0019] In the present invention, in the step (3), the amount of butadiene monomer added is 70 to 85 parts by weight, the amount of initiator added is 0.03 to 0.06 parts by weight, and the amount of strong base added is 0.2 to 1 parts, wherein the strong base is one of potassium hydroxide or sodium hydroxide;

[0020] In the present invention, in the step (4), the amount of the polybutadiene latex with a hollow structure added is 100 parts, the amount of the emulsifier added is 1 to 3 parts, the amount of the oil-soluble initiator added is 0.01 to 1 part, the amount of the redox initiator system added is 0.4 to 1 part, the amount of the comonomer I added is 0.5 to 5 parts, the amount of the styrene monomer added is 15 to 17 parts, and the amount of the methyl methacrylate monomer added is 45 to 51 parts.

[0021] In the present invention, the emulsifiers in the steps (1) and (4) are independently selected from one or a mixture of disproportionated rosin acid potassium soap, oleate potassium soap, and fatty acid potassium soap; the molecular weight regulator in the step (1) is tert-dodecyl mercaptan; the comonomer I is one or a mixture of styrene, methyl methacrylate, and acrylonitrile; the comonomer II is one of acrylic acid, methacrylic acid, and itaconic acid, and the initiator used is potassium persulfate;

[0022] The oil-soluble initiator in step (4) of the present invention is one of azobisisobutyronitrile and benzoyl peroxide; the redox initiation system comprises a redox initiation system composed of cumene hydroperoxide, ferrous sulfate, glucose or fructose, and sodium pyrophosphate, and the mass ratio of cumene hydroperoxide, ferrous sulfate, glucose or fructose, and sodium pyrophosphate in the redox initiation system is preferably: 1:0.02:0.6:0.8.

[0023] The flocculant aqueous solution in step (5) of the present invention is a sulfuric acid or magnesium sulfate aqueous solution with a concentration of 0.2-1%, preferably a sulfuric acid or magnesium sulfate aqueous solution with a concentration of 0.3%-0.6%.

[0024] In step (6) of the present invention, the amount of MABS graft copolymer powder is 23-27 parts, and the amount of MSAN resin is 73-77 parts; the melt extrusion temperature is 200-240° C., preferably 210-225° C. The MSAN resin is a terpolymer of styrene, acrylonitrile and methyl methacrylate, which can be obtained by bulk polymerization, suspension polymerization and the like.

[0025] On the other hand, the present invention also provides a high-flow transparent ABS resin having a pomegranate structure prepared by the above preparation method.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] A hydrophilic small-particle polybutadiene latex is prepared by copolymerizing a hydrophilic monomer with butadiene, and then a transition layer is constructed on the surface of the small-particle latex, and then a large-particle polybutadiene latex with a hollow structure can be obtained after further expansion and alkali treatment. With this latex as the core latex, monomers such as styrene, acrylonitrile and methyl methacrylate are swollen into the interior of the hollow microspheres by swelling technology, and an oil-soluble initiator is added to initiate polymerization to form a pomegranate structure. Finally, a polystyrene layer and a polymethyl methacrylate layer are constructed on its surface to prepare a MABS graft copolymer, which can be melt-blended with an MSAN resin to obtain a transparent ABS resin. The advantage of the present invention is that the size of the pomegranate structure formed is relatively small, and the fluidity of the resin is enhanced while not affecting the light transmittance. In addition, due to the presence of a transition layer between the interfaces, the diffuse reflection of light is reduced, so that the transparent ABS resin prepared by it has a high transmittance and a low haze value. In addition, due to the presence of the pomegranate-shaped internal inclusion structure, the interfacial interaction between the dispersed phase and the continuous phase is reduced, so that the transparent stability of the transparent ABS resin prepared by the present invention is better than that of the transparent ABS resin prepared by the prior art, which is specifically manifested in that the variance value of the transmittance test is small on the basis of the high average transmittance value. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a TEM electron microscope image of the transparent ABS resin frozen section stained under liquid nitrogen in Example 1 of the present invention;

[0029] Figure 2 This is a TEM electron microscope image of a transparent ABS resin prepared by the method of Comparative Example 1 after being frozen and stained under liquid nitrogen. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0031] Raw materials and sources: Butadiene, styrene, methyl methacrylate and other monomers used in the present invention were purchased from China Petroleum Jilin Petrochemical Company. The disproportionate rosin acid potassium soap used was purchased from Lanzhou Xiangxin Industry and Trade Co., Ltd., and the potassium oleate used was purchased from Shandong Ruinuo New Materials Co., Ltd. Other raw materials were purchased from Shanghai Aladdin Reagent Co., Ltd.

[0032] Example 1

[0033] (1) adding 2 parts by weight of an emulsifier, disproportionated rosin acid potassium soap, 0.5 parts by weight of a fatty acid potassium soap, 0.1 parts by weight of a molecular weight regulator, tert-dodecyl mercaptan, and 150 parts by weight of distilled water into a high-pressure polymerization reactor, pumping 5 parts by weight of a butadiene monomer, 1 part by weight of a comonomer I, 1 part by weight of a comonomer II, acrylic acid, and 0.3 parts by weight of an initiator, into the reactor using a pressure pump, raising the temperature to 65° C. to initiate polymerization, and maintaining the temperature for 3 hours to prepare a hydrophilic small-particle polybutadiene latex;

[0034] (2) continuing to uniformly add 10 parts of butadiene monomer and 2 parts of comonomer I methyl methacrylate into the autoclave at the same time, and controlling the adding time to 4 hours, to construct a transition layer on the surface of the hydrophilic small-particle polybutadiene latex;

[0035] (3) Continue to add 85 parts of butadiene to the autoclave at a uniform rate, and the addition time is controlled within 12 hours. After the addition is completed, add 0.05 parts of initiator potassium persulfate, raise the temperature to 85° C., and keep it warm for 2 hours. Continue to add 0.2 parts of potassium hydroxide to the autoclave, and keep it warm for 2 hours to obtain a large-particle polybutadiene latex with a hollow structure;

[0036] (4) The large-particle polybutadiene latex with a hollow structure obtained in the above step is used as a core layer latex, and a MABS graft latex with a pomegranate structure is prepared by an emulsion graft polymerization reaction after the monomer is swollen. The specific steps are as follows: ① 100 parts (dry basis) of the polybutadiene latex with a hollow structure obtained in the above step are placed in a reactor, and 1 part of an emulsifier, potassium disproportionate rosin acid, 0.01 part of an oil-soluble initiator, and 0.8 part of a redox initiator system (the redox initiator system is prepared according to the formula of cumene hydroperoxide, ferrous sulfate, and glucose); The mass ratio of glucose to sodium pyrophosphate is 1:0.02:0.6:0.8), the copolymer monomer I is 0.5 parts of styrene and 1.5 parts of methyl methacrylate, and the mixture is swollen at room temperature for 1 hour; ② the system is heated to 65°C to initiate polymerization, and 16 parts of styrene monomer is added dropwise to the system for 0.5 hours; ③ after the addition is completed, 50 parts of methyl methacrylate monomer is added dropwise for 1.5 hours, and after the addition is completed, the temperature is raised to 75°C and kept for 1 hour to obtain MABS graft copolymer latex;

[0037] (5) adding the MABS graft copolymer latex obtained in step (4) into a flocculant (0.3% sulfuric acid solution) to carry out flocculation and demulsification at 80° C., separating the solid from the water by a centrifuge after demulsification, and then drying to obtain the MABS graft copolymer powder;

[0038] (6) 25 parts of the obtained MABS graft copolymer powder and 75 parts of MSAN resin are melt-blended and extruded at 220° C. to obtain a transparent ABS resin.

[0039] Example 2

[0040] (1) adding, by weight, 1 part of an emulsifier, fatty acid potassium soap, 1 part of an oleate potassium soap, 0.2 parts of a molecular weight regulator, tert-dodecyl mercaptan, and 100 parts of distilled water into a high-pressure polymerization reactor, pumping 10 parts of a butadiene monomer, 1 part of a comonomer I, methyl methacrylate, 1 part of a comonomer II, and 0.3 parts of an initiator, potassium persulfate, into the reactor using a pressure pump, raising the temperature to 65° C. to initiate polymerization, and maintaining the temperature for 3 hours to prepare a hydrophilic small-particle polybutadiene latex;

[0041] (2) continuing to uniformly add 10 parts of butadiene monomer, 1 part of comonomer I methyl methacrylate and 1 part of acrylonitrile to the autoclave at the same time, and controlling the adding time to 4 hours, to construct a transition layer on the surface of the hydrophilic small-particle polybutadiene latex;

[0042] (3) Continue to uniformly add 80 parts of butadiene to the autoclave over a period of 14 hours. After the addition is complete, add 0.05 parts of initiator potassium persulfate, raise the temperature to 85° C., and keep the temperature for 2 hours. Continue to add 0.6 parts of potassium hydroxide to the autoclave, and keep the temperature for 2 hours to obtain a large-particle polybutadiene latex with a hollow structure;

[0043] (4) The large-particle polybutadiene latex with a hollow structure obtained in the above step is used as a core layer latex, and a MABS graft latex with a pomegranate structure is prepared by an emulsion graft polymerization reaction after the monomer is swollen. The specific steps are as follows: ① 100 parts (dry basis) of the polybutadiene latex with a hollow structure obtained in the above step are placed in a reactor, and 1 part of an emulsifier potassium oleate, 0.01 part of an oil-soluble initiator benzoyl peroxide, and 0.7 part of a redox initiator system (the redox initiator system is prepared according to the formula of cumene hydroperoxide, ferrous sulfate, The mass ratio of fructose to sodium pyrophosphate is 1:0.02:0.6:0.8), the copolymer monomer I is 0.5 parts of styrene and 1.5 parts of methyl methacrylate, and the mixture is swelled at room temperature for 1 hour; ② the system is heated to 65°C to initiate polymerization, and 16 parts of styrene monomer is added dropwise to the system for 1 hour; ③ after the addition is completed, 50 parts of methyl methacrylate monomer is added dropwise for 2 hours, and after the addition is completed, the temperature is raised to 80°C and kept for 1 hour to obtain the MABS graft copolymer latex;

[0044] (5) adding the MABS graft copolymer latex obtained in step (4) to a flocculant (0.5% magnesium sulfate solution) to perform flocculation and demulsification at 80° C., separating the solid from the water after demulsification, and drying the solid to obtain MABS graft copolymer powder;

[0045] (6) 25 parts of the obtained MABS graft copolymer powder and 75 parts of MSAN resin are melt-blended and extruded and granulated at 220° C. to obtain a transparent ABS resin.

[0046] Example 3

[0047] (1) adding 2 parts by weight of an emulsifier, potassium disproportionate rosin acid soap, 0.1 parts by weight of a molecular weight regulator, tert-dodecyl mercaptan, and 80 parts by weight of distilled water into a high-pressure polymerization reactor, pumping 5 parts of butadiene monomer, 1 part of comonomer I styrene, 0.5 parts of comonomer II acrylic acid, and 0.25 parts of an initiator, potassium persulfate, into the reactor using a pressure pump, raising the temperature to 60° C. to initiate polymerization, and maintaining the temperature for 5 hours to prepare a hydrophilic small-particle polybutadiene latex;

[0048] (2) continuing to uniformly add 10 parts of butadiene monomer and 1 part of comonomer I styrene to the autoclave at the same time, and controlling the adding time to 5 hours, to construct a transition layer on the surface of the hydrophilic small-particle polybutadiene latex;

[0049] (3) Continue to add 80 parts of butadiene to the autoclave at a uniform rate, and the addition time is controlled within 15 hours. After the addition is completed, add 0.05 parts of initiator potassium persulfate, raise the temperature to 85° C., and keep it warm for 3 hours. Continue to add 0.4 parts of sodium hydroxide to the autoclave, and keep it warm for 3 hours to obtain a large-particle polybutadiene latex with a hollow structure;

[0050] (4) The large-particle polybutadiene latex with a hollow structure obtained in the above step is used as a core layer latex, and a MABS graft latex with a pomegranate structure is prepared by an emulsion graft polymerization reaction after the monomer is swollen. The specific steps are as follows: ① 100 parts (dry basis) of the polybutadiene latex with a hollow structure obtained in the above step are placed in a reactor, and 1 part of an emulsifier fatty acid soap, 0.01 part of an oil-soluble initiator azobisisobutyronitrile, and 0.4 parts of a redox initiation system (the redox initiation system is prepared according to the formula of cumene hydroperoxide, sulfuric acid, etc.) are added. The mass ratio of ferrous iron, glucose and sodium pyrophosphate is 1:0.02:0.6:0.8), the copolymer monomer I is 0.5 parts of styrene, and it swells at room temperature for 0.5 hours; ② the system is heated to 60°C, the polymerization is initiated, and 16 parts of styrene monomer is added dropwise to the system for 0.5 hours; ③ after the addition is completed, 50 parts of methyl methacrylate monomer is added dropwise for 1.5 hours, and after the addition is completed, the temperature is raised to 75°C and kept warm for 1 hour to obtain MABS graft copolymer latex;

[0051] (5) adding the MABS graft copolymer latex obtained in step (4) into a flocculant (0.2% magnesium sulfate solution) to carry out flocculation and demulsification at 85° C., separating the solid from the water after demulsification and drying the latex to obtain MABS graft copolymer powder;

[0052] (6) 23 parts of the obtained MABS graft copolymer powder and 77 parts of MSAN resin are melt-blended and extruded and granulated at 200° C. to obtain a transparent ABS resin.

[0053] Example 4

[0054] (1) adding 3 parts by weight of an emulsifier potassium oleate soap, 1 part of a molecular weight regulator tert-dodecyl mercaptan, and 150 parts of distilled water into a high-pressure polymerization reactor, pumping 15 parts of butadiene monomer, 5 parts of comonomer I methyl methacrylate, 3 parts of comonomer II methacrylic acid, and 0.95 parts of an initiator potassium persulfate into the reactor using a pressure pump, raising the temperature to 80° C. to initiate polymerization, and maintaining the temperature for 2 hours to prepare a hydrophilic small-particle polybutadiene latex;

[0055] (2) continuing to uniformly add 20 parts of butadiene monomer and 3 parts of comonomer I methyl methacrylate into the autoclave at the same time, and controlling the adding time to 2 hours, to construct a transition layer on the surface of the hydrophilic small-particle polybutadiene latex;

[0056] (3) Continue to add 80 parts of butadiene to the autoclave at a uniform rate, and the addition time is controlled within 10 hours. After the addition is completed, add 0.05 parts of initiator potassium persulfate, raise the temperature to 80° C., and keep it warm for 1 hour. Continue to add 1 part of potassium hydroxide to the autoclave, and keep it warm for 1 hour to obtain a large-particle polybutadiene latex with a hollow structure;

[0057] (4) The large-particle polybutadiene latex with a hollow structure obtained in the above step is used as a core layer latex, and a MABS graft latex with a pomegranate structure is prepared by an emulsion graft polymerization reaction after the monomer is swollen. The specific steps are as follows: ① 100 parts (dry basis) of the polybutadiene latex with a hollow structure obtained in the above step are placed in a reaction kettle, and 2 parts of emulsifier fatty acid soap and 1 part of potassium oleate soap, 0.1 parts of an oil-soluble initiator azobisisobutyronitrile, and 1 part of a redox initiator system (the redox initiator system is prepared according to the formula of cumene hydroperoxide, sulfuric acid, etc.); ② The mass ratio of ferrous acid, glucose and sodium pyrophosphate is 1:0.02:0.6:0.8), 5 parts of methyl methacrylate as comonomer I are swollen at room temperature for 1 hour; ② The system is heated to 70°C to start polymerization, and 16 parts of styrene monomer are added dropwise to the system for 0.5 hour; ③ After the addition is completed, 50 parts of methyl methacrylate monomer are added dropwise for 1.5 hours, and after the addition is completed, the temperature is raised to 85°C and kept warm for 0.5 hour to obtain MABS graft copolymer latex;

[0058] (5) adding the MABS graft copolymer latex obtained in step (4) into a flocculant (1% magnesium sulfate solution) to perform flocculation and demulsification at 65° C., separating the solid from the water after demulsification, and drying the solid to obtain the MABS graft copolymer powder;

[0059] (6) 27 parts of the obtained MABS graft copolymer powder and 73 parts of MSAN resin are melt-blended and extruded and granulated at 240° C. to obtain a transparent ABS resin.

[0060] Example 5

[0061] (1) adding 2.5 parts by weight of an emulsifier, fatty acid potassium soap, 0.55 parts by weight of a molecular weight regulator, tert-dodecyl mercaptan, and 115 parts by weight of distilled water into a high-pressure polymerization reactor, pumping 15 parts of butadiene monomer, 4 parts of comonomer I acrylonitrile, 1.75 parts of comonomer II itaconic acid, and 0.6 parts of an initiator, potassium persulfate into the reactor using a pressure pump, raising the temperature to 70° C. to initiate polymerization, and maintaining the temperature for 3.5 hours to prepare a hydrophilic small-particle polybutadiene latex;

[0062] (2) continuously adding 5 parts of butadiene monomer and 1 part of comonomer I acrylonitrile into the autoclave at a uniform speed, and controlling the adding time to 3.5 hours to construct a transition layer on the surface of the hydrophilic small-particle polybutadiene latex;

[0063] (3) Continue to add 80 parts of butadiene to the autoclave at a uniform rate, and the addition time is controlled to be 12.5 hours. After the addition is completed, add 0.05 parts of initiator potassium persulfate, raise the temperature to 80° C., and keep it warm for 2 hours. Continue to add 0.7 parts of potassium hydroxide to the autoclave, and keep it warm for 2 hours to obtain a large-particle polybutadiene latex with a hollow structure;

[0064] (4) The large-particle polybutadiene latex with a hollow structure obtained in the above step is used as a core layer latex, and a MABS graft latex with a pomegranate structure is prepared by an emulsion graft polymerization reaction after the monomer is swollen. The specific steps are as follows: ① 100 parts (dry basis) of the polybutadiene latex with a hollow structure obtained in the above step are placed in a reactor, and 2 parts of an emulsifier, potassium disproportionate rosin soap, 0.05 parts of an oil-soluble initiator, and 0.7 parts of a redox initiator system (the redox initiator system is prepared according to the formula of cumene hydroperoxide, ferrous sulfate, glucose, etc.) are added. , sodium pyrophosphate (mass ratio of 1:0.02:0.6:0.8), comonomer I styrene 2 parts, methyl methacrylate 0.75 parts, swelling at room temperature for 0.75 hours; ② the system is heated to 65 ° C, polymerization is initiated, and styrene monomer 16 parts is added dropwise to the system for 0.5 hours; ③ after the addition is completed, methyl methacrylate monomer 50 parts is added dropwise for 1.5 hours, and after the addition is completed, the temperature is raised to 80 ° C and kept warm for 0.75 hours to obtain MABS graft copolymer latex;

[0065] (5) adding the MABS graft copolymer latex obtained in step (4) into a flocculant (0.6% magnesium sulfate solution) to perform flocculation and demulsification at 75° C., separating the solid from the water after demulsification, and drying the solid to obtain MABS graft copolymer powder;

[0066] (6) 25 parts of the obtained MABS graft copolymer powder and 75 parts of MSAN resin are melt-blended and extruded and granulated at 220° C. to obtain a transparent ABS resin.

[0067] Comparative Example 1

[0068] Based on the technical method reported in the journal "Chemical New Materials" (2008, 36, 33-34), a one-step method is used to prepare large-particle styrene butadiene latex, and the specific steps are to add 2.3 parts of emulsifier potassium disproportionate rosin acid soap and 60 parts of water, 70 parts of butadiene monomer, 30 parts of styrene monomer, and 0.6 parts of initiator sodium persulfate in a 1L high-pressure reactor. Stirring is turned on, the stirring rate is set to 100rpm, the temperature is set to 65℃ for reaction for 18 hours, and then the temperature is raised to 70℃ for continued reaction for 12 hours. After the reaction is completed, styrene butadiene latex (SBR) can be obtained. Take the obtained SBR latex as 55 parts of the core layer latex dry basis and add it into the reactor, add deionized water to adjust the solid content of the SBR latex in the reactor system to 30%), and then add 0.8 parts of sodium pyrophosphate, 0.6 parts of glucose, 0.01 parts of ferrous sulfate, and 0.8 parts of cumene hydroperoxide. Add 15 parts of styrene to the reactor over a period of 1 hour, and then add 30 parts of methyl methacrylate over a period of 2 hours. Finally, heat to 75°C and keep warm for 1 hour to obtain a graft copolymer emulsion. Add the obtained graft copolymer emulsion to a 0.5wt% sulfuric acid aqueous solution at a volume ratio of 1 / 2 for flocculation and demulsification, and then dry the grafted powder after solid-liquid separation to obtain MBS high-glue powder. Melt-extrude and blend 25 parts of the obtained MBS high-glue powder with 75 parts of MSAN resin at 220°C to obtain a transparent ABS resin. It is worth emphasizing that the refractive index of the transparent ABS resin prepared in the paper is 1.534.

[0069] Comparative Example 2

[0070] Based on the preparation method of transparent ABS resin disclosed in patent CN 105008406 A, MABS graft copolymer latex is prepared. The process is to add 50 parts of water, 0.8 parts of fatty acid potassium, 1.0 parts of potassium rosin acid and 1.0 parts of potassium carbonate and start stirring at a stirring rate of 100 rpm. Then add 30 parts of butadiene monomer, 0.3 parts of tert-dodecyl mercaptan, 0.8 parts of polyethylene glycol diacrylate, and 0.3 parts of diisopropylbenzene hydroperoxide to the reactor. Heat to 40°C and react for 6 hours. Then continue to add 15 parts of butadiene to the reactor, raise the temperature of the reactor to 55°C, and continuously drop 55 parts of butadiene into the reactor within 8 hours. Starting from the continuous dropwise addition of butadiene, an emulsion containing 4 parts by weight of deionized water, 0.5 parts by weight of potassium rosin acid and 0.3 parts by weight of tert-butyl hydroperoxide is added to the reactor over 6 hours. Next, 0.0003 parts by weight of ferrous sulfate, 0.05 parts by weight of glucose, 0.04 parts by weight of sodium pyrophosphate and 0.3 parts by weight of tert-butyl hydroperoxide are further added to the reactor. The polybutadiene latex is obtained by keeping the temperature for 2 hours. After the butadiene monomer is added dropwise, the temperature is raised to 75° C. and kept for 2 hours to obtain the polybutadiene latex.

[0071] 100 parts of deionized water, 0.5 parts of reactive emulsifier C 16 -C 18 Dipotassium alkenyl succinate, 27 parts of methyl methacrylate, 10 parts of styrene, 3 parts of acrylonitrile, 0.5 parts of tert-dodecyl mercaptan, 0.048 parts of sodium formaldehyde sulfoxylate, 0.012 parts of sodium ethylenediaminetetraacetate, 0.001 parts by weight of ferrous sulfate and 0.04 parts by weight of tert-butyl hydroperoxide are continuously added to the prepared polybutadiene rubber latex at 75°C for 5 hours for reaction. After the reaction, the reaction mixture is heated to 80°C, then maintained at this temperature for 1 hour, and then the reaction is terminated to obtain a graft copolymer latex. The obtained graft copolymer latex is flocculated and demulsified with 0.5% sulfuric acid with a system ratio of 1 / 2, and high-rubber powder is obtained after drying. 25 parts of high-rubber powder and 75 parts of MSAN resin are melt-extruded and blended at 220°C to obtain transparent ABS resin.

[0072] Comparative Example 3

[0073] In Example 1, no hydrophilic monomer is added and no polybutadiene latex with a hollow structure is constructed. The specific steps are as follows:

[0074] (1) adding 2 parts by weight of an emulsifier, disproportionated rosin acid potassium soap, 0.5 parts by weight of a fatty acid potassium soap, 0.1 parts by weight of a molecular weight regulator, tert-dodecyl mercaptan, and 150 parts by weight of distilled water into a high-pressure polymerization reactor, pumping 5 parts by weight of a butadiene monomer, 1 part by weight of a comonomer Ⅰ styrene, and 0.3 parts by weight of an initiator, into the reactor using a pressure pump, raising the temperature to 65° C. to initiate polymerization, and maintaining the temperature for 3 hours to prepare a small-particle polybutadiene latex;

[0075] (2) continuing to uniformly add 10 parts of butadiene monomer and 2 parts of comonomer I methyl methacrylate into the autoclave at the same time, and controlling the adding time to 4 hours, to construct a transition layer on the surface of the hydrophilic small-particle polybutadiene latex;

[0076] (3) Continue to uniformly add 85 parts of butadiene to the autoclave over a period of 12 hours, add 0.05 parts of initiator potassium persulfate after the addition is complete, and raise the temperature to 85° C. After keeping the temperature for 2 hours, a large-particle polybutadiene latex with a hollow structure can be obtained;

[0077] (4) The large-particle polybutadiene latex with a hollow structure obtained in the above step is used as a core layer latex, and a MABS graft latex with a pomegranate structure is prepared by an emulsion graft polymerization reaction after the monomer is swollen. The specific steps are as follows: ① 100 parts (dry basis) of the polybutadiene latex obtained in the above step are placed in a reactor, and 1 part of an emulsifier, potassium disproportionate rosin acid, 0.01 part of an oil-soluble initiator, azobisisobutyronitrile, and 0.8 part of a redox initiation system (the redox initiation system is prepared according to cumene hydroperoxide, ferrous sulfate, glucose, The mass ratio of sodium pyrophosphate is 1:0.02:0.6:0.8), the copolymer monomer I is 0.5 parts of styrene and 1.5 parts of methyl methacrylate, and the swelling is carried out at room temperature for 1 hour; ② the system is heated to 65°C, the polymerization is initiated, and 16 parts of styrene monomer are added dropwise to the system at the same time, and the addition time is 0.5 hours; ③ after the addition is completed, 50 parts of methyl methacrylate monomer are continued to be added dropwise, and the addition time is 1.5 hours. After the addition is completed, the temperature is raised to 75°C and kept warm for 1 hour to obtain the MABS graft copolymer latex;

[0078] (5) adding the MABS graft copolymer latex obtained in step (4) into a flocculant (0.3% sulfuric acid solution) to carry out flocculation and demulsification at 80° C., separating the solid from the water by a centrifuge after demulsification, and then drying to obtain the MABS graft copolymer powder;

[0079] (6) 25 parts of the obtained MABS graft copolymer powder and 75 parts of MSAN resin are melt-blended and extruded at 220° C. to obtain a transparent ABS resin.

[0080] The transparent ABS resin prepared in Examples 1-5 and Comparative Examples 1-3 was injected into standard specimens under the same process conditions. The test methods for the impact strength, tensile strength and bending strength of the materials were respectively based on ASTM D256-2006, ASTM D638-2000 and ASTM D790-2000 standards. The melt index test method was based on ASTM D1238-2010 standard (210°C, 10KG). The transmittance and haze test samples were 3mm thick specimens, tested based on GB T 2410-2008 standard. The transmittance test result was the average of 5 test results, and the transmittance variance calculation method was calculated according to the following formula:

[0081]

[0082] In the formula, S 2 is the variance, n represents the specific number of measurements, x i is the actual measured transmittance value, x is the average value of n measured transmittances, and the performance test is shown in the following table:

[0083]

[0084] By comparing the data results in the examples and comparative examples, it can be found that the impact strength and melt index of the transparent ABS resin prepared by the invention are relatively high, which are significantly higher than the data results in the comparative examples. In addition, the transparent ABS resin prepared by the present invention has high light transmittance, low haze value, and small variance value of the test results, which can indicate that the sample prepared by the invention has good transparency and uniformity, and the product quality is stable. Comparative Example 3 is the result of Example 1 without adding hydrophilic monomers in the preparation of polybutadiene latex. The polybutadiene latex prepared without adding hydrophilic monomers does not form a hollow structure, which results in the obstruction of monomer swelling in the subsequent grafting process, making it impossible to form a pomegranate structure, resulting in performance degradation.

[0085] The transparent ABS resin prepared from the samples of Example 1 and Comparative Example 1 was ultra-thinly sliced ​​under liquid nitrogen freezing conditions, and then stained with osmium tetroxide. The morphology and structure were photographed using a transmission electron microscope. The results are as follows: Figure 1 and Figure 2 The black part in the figure is the polybutadiene phase, i.e. the dispersed phase, and the bright part is the resin phase. Figure 1 It can be clearly observed that the black rubber particles contain a bright resin structure, which is similar to a pomegranate structure. The resin phase structure inside the rubber particles is caused by the adsorption of styrene and methyl methacrylate by the hollow polybutadiene during the grafting process. On the one hand, it increases the size of the rubber particles, and on the other hand, it is easier to induce the hollowing process of the rubber particles and enhance their mechanical properties. In addition, since the resin structure inside the rubber particles changes the chain aggregation structure of the rubber particles themselves, it reduces the interaction between the molecular chains inside the butadiene rubber particles, which is beneficial to improve the fluidity of the transparent ABS resin and increase the melt index. Figure 2 A butadiene latex with a normal (solid) structure is used as the core layer structure, so the pomegranate structure does not appear.

Claims

1. A method for preparing a high-flow transparent ABS resin having a pomegranate structure by hollow polybutadiene latex, comprising the following steps: (1) adding an emulsifier, a molecular weight regulator, and distilled water into a polymerization reactor by weight, adding butadiene monomer, comonomer I, comonomer II, and an initiator into the reactor, heating the reactor to 60 to 80° C. to initiate polymerization, and maintaining the temperature for 2 to 5 hours to prepare a hydrophilic small-particle polybutadiene latex; (2) continuing to add butadiene monomer and comonomer I into the reactor simultaneously, and controlling the adding time to be within 2 to 5 hours, so as to construct a transition layer on the surface of the hydrophilic small-particle polybutadiene latex; (3) continuing to add butadiene to the autoclave at a uniform rate, the adding time being controlled within 5 to 15 hours, adding an initiator after the addition is complete, raising the temperature to 85 to 90° C., and keeping the temperature for 1 to 3 hours; continuing to add a strong base to the autoclave and keeping the temperature for 1 to 3 hours to obtain a large-particle polybutadiene latex having a hollow structure; (4) The large-particle polybutadiene latex with a hollow structure obtained in the above step is used as a core layer latex, and a MABS graft latex with a pomegranate structure is prepared by an emulsion graft polymerization reaction after the monomer is swollen. The specific steps are: ① The dry basis of the polybutadiene latex with a hollow structure obtained in the above step is placed in a reaction kettle, and an emulsifier, an oil-soluble initiator, a redox initiation system, and a comonomer I are added, and the swelling is carried out at room temperature for 0.5 to 1 hour; ② The system is heated to 60 to 70° C., and the polymerization is initiated. At the same time, styrene monomer is added dropwise to the system for 0.5 to 1 hour; ③ After the addition is completed, methyl methacrylate monomer is continued to be added dropwise for 0.5 to 2 hours. After the addition is completed, the temperature is raised to 75 to 85° C. and kept warm for 0.5 hours to obtain a MABS graft copolymer latex; (5) adding the MABS graft copolymer latex obtained in step (4) into a flocculant aqueous solution to carry out flocculation and demulsification at 65-85° C., separating the solid from the water after demulsification, and drying at 60-80° C. to obtain the MABS graft copolymer powder; (6) melt-blending the obtained MABS graft copolymer powder with MSAN resin and extruding and granulating them to obtain transparent ABS resin; The comonomer I is one of styrene, methyl methacrylate, and acrylonitrile, or a mixture of several of them; and / or, the comonomer II is one of acrylic acid, methacrylic acid, and itaconic acid.

2. The method according to claim 1, characterized in that In the step (1) and step (4), the emulsifier is independently selected from one or a mixture of disproportionated rosin acid potassium soap, oleate potassium soap, and fatty acid potassium soap; and / or, the molecular weight regulator in the step (1) is tert-dodecyl mercaptan; and / or, and / or, the initiator is potassium persulfate.

3. The method according to claim 1, characterized in that In terms of parts by mass, the amount of emulsifier used in the step (1) is 2 to 3 parts, the amount of molecular weight regulator used is 0.1 to 1 part, the amount of distilled water used is 80 to 150 parts, the amount of butadiene monomer used is 5 to 10 parts, the amount of comonomer I used is 0 to 3 parts, the amount of comonomer II used is 0.5 to 3 parts, and the amount of initiator used is 0.3 to 1 part.

4. The method according to any one of claims 1 to 3, characterized in that In terms of parts by mass, in the step (2), the amount of butadiene monomer added is 10 to 20 parts, and the amount of comonomer I added is 2 to 5 parts.

5. The method according to any one of claims 1 to 3, characterized in that In the step (3), the amount of butadiene monomer added is 70 to 85 parts by weight, the amount of initiator added is 0.03 to 0.06 parts by weight, and the amount of strong base added is 0.2 to 1 parts by weight, wherein the strong base is one of potassium hydroxide or sodium hydroxide.

6. The method according to any one of claims 1 to 3, characterized in that The oil-soluble initiator is one of azobisisobutyronitrile and benzoyl peroxide; the redox initiation system comprises a redox initiation system consisting of cumene hydroperoxide, ferrous sulfate, glucose or fructose, and sodium pyrophosphate.

7. The method according to any one of claims 1 to 3, characterized in that In terms of parts by mass, in the step (4), the amount of the polybutadiene latex having a hollow structure added is 100 parts, the amount of the emulsifier added is 1 to 3 parts, the amount of the oil-soluble initiator added is 0.01 to 1 part, the amount of the redox initiator system added is 0.4 to 1 part, the amount of the comonomer I added is 0.5 to 5 parts, the amount of the styrene monomer added is 15 to 17 parts, and the amount of the methyl methacrylate monomer added is 45 to 51 parts.

8. The method according to any one of claims 1 to 3, characterized in that The flocculant aqueous solution in step (5) is a sulfuric acid or magnesium sulfate aqueous solution with a concentration of 0.2-1%.

9. The method according to any one of claims 1 to 3, characterized in that: In the step (6), the amount of MABS graft copolymer powder is 23-27 parts, and the amount of MSAN resin is 73-77 parts; the melt extrusion temperature is 200-240°C.

10. A high-flow transparent ABS resin having a pomegranate structure prepared by the method according to any one of claims 1 to 8.

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