Preparation method of ABS grafting latex and application thereof

Abstract

The application discloses a preparation method of ABS grafted latex and application of the ABS grafted latex. The ABS grafted latex comprises polybutadiene latex, a comonomer, an emulsifier and an initiator. The stability of MMA in the emulsion graft polymerization reaction process is improved by controlling the type of the emulsifier, the process continuity of the ABS grafted latex production process is better, the residue amount in the production process is obviously reduced, and when the ABS grafted latex is further prepared into transparent ABS resin, the finished product has a lower haze level.

Description

Technical Field

[0001] This invention relates to the field of ABS resin, and more particularly to a method for preparing ABS grafted latex and its application. Background Technology

[0002] ABS resin is a terpolymer of three monomers: acrylonitrile (A), butadiene (B), and styrene (S).

[0003] Because of the significant difference in refractive index between its dispersed phase polybutadiene latex particles and the continuous phase SAN, ABS resin is usually opaque and cannot be used to prepare transparent products.

[0004] To prepare transparent ABS resin, the following two methods are commonly used in the prior art:

[0005] 1) Reducing the particle size of the raw material polybutadiene latex can reduce the refraction / scattering of visible light at the interface between the two phases, thereby achieving transparency; however, after the particle size of polybutadiene latex is reduced, the impact performance of the product is significantly reduced, which affects the application of the product. Therefore, this method is rarely used.

[0006] 2) By using copolymerization to increase the refractive index of the dispersed phase or decrease the refractive index of the continuous phase, the refractive indices of the two phases are matched, eliminating refraction / scattering at the interface between the two phases to achieve transparency. For example, patent CN101336255A uses MMA / styrene / acrylonitrile copolymerization to reduce the refractive index of the continuous phase to within 0.002 of the difference between the continuous phase and the dispersed phase, thereby achieving the preparation of transparent ABS.

[0007] Patent CN104136530B uses acrylate monomer copolymerization to control the difference in refractive index of the dispersed phase polybutadiene latex, polybutadiene latex graft, and continuous phase SAN to <0.005, thereby achieving the preparation of transparent ABS.

[0008] Patent CN114736334A uses a method of introducing styrene copolymerization into the dispersed phase and introducing acrylate monomers copolymerization into the continuous phase to control the difference in refractive index between the two phases, thereby achieving resin transparency.

[0009] The methods described above can all achieve the preparation of transparent ABS. However, in actual production, when using emulsion graft polymerization to prepare MMA-containing polybutadiene latex grafts as mentioned in patent CN104136530B, the stability of the ABS during the emulsion polymerization process is significantly reduced due to the introduction of MMA, making large-scale demulsification very likely. This phenomenon makes the continuous and stable production of transparent ABS extremely challenging.

[0010] Therefore, it is necessary to further improve the emulsion instability after the introduction of MMA into the emulsion graft polymerization system, so as to achieve continuous and stable production of transparent ABS resin. Summary of the Invention

[0011] To address the above technical problems, this invention provides a method for preparing ABS grafted latex and its application. This method improves the stability of the emulsion polymerization system by controlling the proportion of C16 components in the emulsifier used during the emulsion graft polymerization process, thereby reducing resin residue during the reaction and significantly lowering the haze index of the finished resin.

[0012] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0013] An ABS grafted latex includes polybutadiene latex, comonomer, emulsifier, and initiator.

[0014] Preferably, the amount of the comonomer is 50-200% of the dry weight of the polybutadiene latex;

[0015] Preferably, the amount of emulsifier used is 0.5-5% of the dry weight of the polybutadiene latex; and / or,

[0016] Preferably, the total amount of the initiator is 0.1-1% of the dry weight of the polybutadiene latex;

[0017] The comonomers include styrene monomers, acrylonitrile monomers, and methacrylate monomers.

[0018] The styrene monomer is selected from one or more of styrene, α-methylstyrene, p-methylstyrene, and vinyltoluene;

[0019] The acrylonitrile monomer is selected from one or more of acrylonitrile, methacrylonitrile and ethyl acrylonitrile;

[0020] The methacrylate monomer is selected from one or more of methyl methacrylate, ethyl methacrylate, propyl methacrylate, and 2-ethylhexyl methacrylate;

[0021] The emulsifier is selected from carboxylate salts with 10-20 carbon atoms, preferably one or more of potassium oleate and fatty soaps, and the mass percentage of carboxylate salts with fewer than 17 carbon atoms in the emulsifier is >20%.

[0022] The initiator is a peroxide, preferably one or more of dicumyl peroxide, cumyl hydroperoxide, and tert-butyl hydroperoxide.

[0023] In a preferred embodiment of the present invention, the comonomer comprises, by weight 100%, the following raw materials:

[0024] Styrene monomer 10-30wt%, acrylonitrile monomer 5-20wt%, methacrylate monomer 60-80wt%.

[0025] As a preferred embodiment of the present invention, the polybutadiene latex has a particle size of 260-350 nm and a solid content of 40-60 wt%.

[0026] The preparation process of the polybutadiene latex is known, for example, it can be prepared by referring to the scheme in patent CN107001515A, and will not be described in detail here.

[0027] In a preferred embodiment of the present invention, a chain transfer agent, a complexing agent, a reducing agent, a co-reducing agent, or water are also added to the polymerization reaction.

[0028] In a preferred embodiment of the present invention, the chain transfer agent is one of n-octyl mercaptan, tert-dodecyl mercaptan, and n-dodecyl mercaptan, preferably tert-dodecyl mercaptan; and / or,

[0029] The complexing agent is one or more selected from the following: trisodium aminetriacetate, disodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, sodium pyrophosphate, and sodium hexametaphosphate, preferably sodium pyrophosphate; and / or,

[0030] The reducing agent is one or more selected from sodium dithionite, sodium formaldehyde sulfoxylate, isoascorbic acid, glucose, and lactose, preferably glucose; and / or,

[0031] The reducing agent is one or more of ferrous sulfate, ferrous chloride, and sodium bisulfite, with ferrous sulfate being preferred.

[0032] The amount of the chain transfer agent is 0.1-1% of the dry weight of the polybutadiene latex; and / or,

[0033] The amount of the complexing agent is 0.1-1% of the dry weight of the polybutadiene latex; and / or,

[0034] The amount of reducing agent used is 0.001-0.01% of the dry weight of polybutadiene latex; and / or,

[0035] The amount of the reducing agent is 0.1-1% of the dry weight of the polybutadiene latex; and / or,

[0036] The amount of water used is 50-100% of the dry weight of the polybutadiene latex.

[0037] A method for preparing ABS grafted latex includes the following steps: mixing and reacting polybutadiene latex, comonomer, emulsifier and initiator to polymerize and obtain ABS grafted latex;

[0038] The comonomer can be added in batches or continuously by dripping.

[0039] In a preferred embodiment of the present invention, the total amount of the comonomer is 50-200% of the dry weight of polybutadiene latex;

[0040] As a preferred embodiment of the present invention, the preparation method includes:

[0041] 1) Foundation stage: Add polybutadiene latex, some comonomers, some initiator, emulsifier and water to the reactor, stir to swell first and then heat up to polymerize;

[0042] 2) Continuous dripping stage: The remaining comonomer and initiator are dripped into the reactor to continue the reaction until it is complete, thus obtaining ABS grafted latex.

[0043] Preferably, in step 1), the polymerization reaction temperature is 40-80℃, more preferably 50-70℃;

[0044] Preferably, the amount of comonomer added in step 1) is 10-50% of the total mass of the comonomer.

[0045] Preferably, the amount of initiator added in step 1) is 10-50% of the total mass of the initiator. Preferably, in step 2), the polymerization reaction temperature is 40-90℃, preferably 50-80℃.

[0046] Preferably, in step 2), the addition time of the copolymer monomer and initiator is 1-5 hours.

[0047] In step 2), the reaction is considered complete when the total conversion rate of the comonomer is >96%.

[0048] Application of an ABS grafted latex prepared according to the method described above in the preparation of transparent ABS resin.

[0049] A method for preparing transparent ABS resin includes the following steps: coagulating and demulsifying the ABS graft latex obtained by the method to obtain ABS powder, and then mixing and extruding it with methacrylate-styrene-acrylonitrile copolymer (MSAN resin) through an extruder to obtain transparent ABS resin.

[0050] MSAN resin refers to a methyl methacrylate-styrene-acrylonitrile copolymer with a refractive index of 1.515±0.005, preferably with a weight-average molecular weight of 100,000-140,000.

[0051] The MSAN resin can be prepared by any known method (such as bulk polymerization) or can be purchased directly from commercially available finished products (such as LG Chem XT500), without any restrictions.

[0052] The method for coagulating and demulsifying ABS grafted latex is known to those skilled in the art. It mainly involves mixing ABS grafted latex with inorganic acid or its salt, aging it at high temperature, and then filtering and drying it to obtain ABS powder.

[0053] The mass ratio of ABS powder to MSAN resin can be (20-30):(70-80). After being mixed and extruded at 200-220℃, the mixture is cooled and granulated to obtain transparent ABS resin.

[0054] The researchers of this invention discovered that when MMA is introduced into emulsion graft polymerization, the shell resin MSAN of the latex has a significant difference in hydrophilicity compared to the shell SAN of general ABS latex (the contact angle difference between the two is >10°). This difference causes a change in the arrangement of the original emulsifier on the shell. The MSAN shell emulsifier, which has better hydrophilicity, tends to be arranged in a more collapsed manner, and the electrostatic repulsion that maintains the stability of the emulsion is significantly weakened. Therefore, it is more prone to large-scale demulsification.

[0055] This invention improves the stability of MMA in the emulsion graft polymerization process by using an emulsifier with a specific composition, which has a shorter chain length and a smaller adhesion area on the shell. When the hydrophilicity of the shell changes, the decrease in electrostatic repulsion caused by collapse is not significant. This results in better process continuity in the production of ABS graft latex, a significant reduction in slag output during production, and further preparation of transparent ABS resin, with finished parts having a lower haze level. Detailed Implementation

[0056] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0057] Unless otherwise specified, all raw materials used in the following specific embodiments of the present invention can be obtained commercially. Specifically, the polybutadiene latex was prepared according to the method in Example 1 of patent CN107001515A. By adjusting the amounts of 1,3-butadiene and ion-exchanged water, polybutadiene latex A (particle size 303 nm, solid content 56.3%), polybutadiene latex B (particle size 272 nm, solid content 55.7%), and polybutadiene latex C (particle size 336 nm, solid content 57.1%) were obtained.

[0058] MSAN resin: grade XT500, purchased from LG Chem.

[0059] Potassium oleate and fatty soaps containing more than 20% carboxylate components with fewer than 17 carbon atoms can be produced by manufacturers by controlling the types of raw oils used, or by adding commercially available pure potassium hydroxide neutralizers such as hexadecanoic acid and tetradecanoic acid to the raw oils.

[0060] The main methods used in the following specific embodiments of the present invention are as follows:

[0061] (1) Latex particle size: Mix 1g of latex with 100g of deionized water, and measure the average particle size using a Malvern Mastersizer laser particle size analyzer according to the dynamic laser scattering method.

[0062] (2) Latex solid content / conversion rate: Take 2g of grafted latex and dry it at 180℃ using a Mettler HC103 moisture analyzer to obtain the solid content; the conversion rate of the grafting process can be calculated according to the feed formula, or the conversion rate can be calculated by testing the residual comonomers using gas chromatography.

[0063] (3) Latex stability: According to GB / T 20623, weigh 400g of emulsion and disperse it at 2500r / min for 0.5h using a high-speed disperser. Then filter it with a 100-mesh filter and observe whether the emulsion breaks down and whether there are obvious flocculations. Weigh the weight of the residue on the filter screen.

[0064] (4) Impact performance test: ABS resin chips were used to prepare samples and test their impact performance according to GB / T1043 rigid plastic simply supported beam impact test method.

[0065] (5) Transmittance / Haze: The resin was sampled according to ASTM D1003. A Haze gard 1 transmittance and haze meter was used to test different areas of the optical plate three times and take the average value to obtain the transmittance and haze.

[0066] In the specific embodiments of the present invention, each ingredient part is a mass part.

[0067]

Example 1

[0068] 177.8 parts of polybutadiene latex A (dry weight 100 parts), 20 parts of comonomers (styrene 22 wt%, acrylonitrile 8 wt%, methyl methacrylate 70 wt%), 1.5 parts of fatty soap (adjusted to 27.72% by adding potassium decanoate, the content of carboxylate with less than 17 carbon atoms), 0.3 parts of tert-dodecyl mercaptan, 0.1 parts of sodium pyrophosphate, 0.1 parts of glucose, 0.005 parts of ferrous sulfate, 0.04 parts of cumene hydroperoxide, and 100 parts of water were added to a reactor. The mixture was stirred and swollen for 0.5 h, then heated to 70 °C. The remaining 40 parts of comonomers (styrene 22 wt%, acrylonitrile 8 wt%, methyl methacrylate 70 wt%) and 0.16 parts of cumene hydroperoxide were added dropwise to the reactor at a constant rate over 3 h. The temperature was raised to 80 °C and the reaction continued. When the total conversion rate of the comonomers reached 97.53%, the temperature was lowered to obtain ABS grafted latex.

[0069]

Example 2

[0070] 175.7 parts of polybutadiene latex B (100 parts dry weight), 50 parts of comonomers (30 wt% α-methylstyrene, 10 wt% acrylonitrile, 60 wt% MMA), 2 parts of potassium oleate (adjusted to 34.04% by adding potassium laurate), 0.2 parts of tert-dodecyl mercaptan, 0.2 parts of sodium pyrophosphate, 0.2 parts of lactose, 0.003 parts of ferrous sulfate, 0.2 parts of tert-butyl hydroperoxide, and 60 parts of water were added to a reactor. The mixture was stirred and swollen for 0.5 h. Then, the mixture was heated to 65 °C. The remaining 50 parts of comonomers (30 wt% α-methylstyrene, 10 wt% acrylonitrile, 60 wt% MMA) and 0.6 parts of tert-butyl hydroperoxide were added dropwise to the reactor at a constant rate over 4 h. The temperature was raised to 75 °C and the reaction continued. When the total conversion rate of the comonomers reached 96.68%, the mixture was cooled to obtain ABS grafted latex.

[0071]

Example 3

[0072] 175.7 parts of polybutadiene latex B (100 parts dry weight), 50 parts of comonomers (15 wt% styrene, 20 wt% methacrylonitrile, 65 wt% MMA), 3 parts of potassium oleate (adjusted to 48.6% by adding potassium tetradecanoate), 0.5 parts of n-octyl mercaptan, 0.5 parts of tetrasodium ethylenediaminetetraacetate, 0.7 parts of sodium formaldehyde sulfoxylate, 0.009 parts of ferrous chloride, 0.1 parts of dicumyl peroxide, and 80 parts of water were added to a reactor. The mixture was stirred and swollen for 0.5 h. Then, the mixture was heated to 60 °C. The remaining 100 parts of comonomers (15 wt% styrene, 20 wt% methacrylonitrile, 65 wt% MMA) and 0.3 parts of dicumyl peroxide were added dropwise to the reactor at a constant rate over 5 h. The temperature was raised to 70 °C and the reaction continued. When the total conversion rate of the comonomers reached 96.11%, the mixture was cooled to obtain ABS grafted latex.

[0073]

Example 4

[0074] 178.1 parts of polybutadiene latex C (100 parts dry weight), 10 parts of comonomers (20 wt% styrene, 5 wt% acrylonitrile, 75 wt% ethyl methacrylate), 4 parts of fatty soap (adjusted to 53.9% content of carboxylate with less than 17 carbon atoms by adding potassium hexadecanoate), 0.5 parts of n-dodecyl mercaptan, 0.7 parts of sodium hexametaphosphate, 0.2 parts of lactose, 0.005 parts of sodium bisulfite, 0.1 parts of cumene hydroperoxide, and 90 parts of water were added to a reactor. The mixture was stirred and swollen for 0.5 h, then heated to 60 °C. The remaining 40 parts of comonomers (20 wt% styrene, 5 wt% acrylonitrile, 75 wt% ethyl methacrylate) and 0.3 parts of cumene hydroperoxide were added dropwise to the reactor at a constant rate over 3 h. The temperature was raised to 80 °C and the reaction continued. When the total conversion rate of comonomers reached 97.24%, the temperature was lowered to obtain ABS grafted latex.

[0075]

Example 5

[0076] 178.1 parts of polybutadiene latex C (100 parts dry weight), 10 parts of comonomers (20 wt% styrene, 5 wt% acrylonitrile, 75 wt% methyl methacrylate), 4 parts of fatty soap (adjusted to 68.6% by adding potassium hexadecanoate to achieve a content of carboxylate with fewer than 17 carbon atoms), 0.7 parts of tert-dodecyl mercaptan, 0.2 parts of sodium pyrophosphate, 0.3 parts of lactose, 0.002 parts of ferrous sulfate, 0.05 parts of cumene hydroperoxide, and 80 parts of water were added to a reactor. The mixture was stirred and swollen for 0.5 h. Then, the mixture was heated to 60 °C. The remaining 40 parts of comonomers (20 wt% styrene, 5 wt% acrylonitrile, 75 wt% methyl methacrylate) and 0.25 parts of cumene hydroperoxide were added dropwise to the reactor at a constant rate over 4 h. The temperature was raised to 80 °C and the reaction continued. When the total conversion rate of the comonomers reached 97.65%, the mixture was cooled to obtain ABS grafted latex.

[0077] Comparative Example 1

[0078] 177.8 parts of polybutadiene latex A (dry weight 100 parts), 20 parts of comonomers (styrene 22 wt%, acrylonitrile 8 wt%, methyl methacrylate 70 wt%), 1.5 parts of fatty soap (tested to contain 4.88% carboxylate with less than 17 carbon atoms), 0.3 parts of tert-dodecyl mercaptan, 0.1 parts of sodium pyrophosphate, 0.1 parts of glucose, 0.005 parts of ferrous sulfate, 0.04 parts of cumene hydroperoxide, and 100 parts of water were added to a reactor. The mixture was stirred and swollen for 0.5 h, then heated to 70 °C. The remaining 40 parts of comonomers (styrene 22 wt%, acrylonitrile 8 wt%, methyl methacrylate 70 wt%) and 0.16 parts of cumene hydroperoxide were added dropwise to the reactor at a constant rate over 3 h. The temperature was raised to 80 °C and the reaction continued. When the total conversion rate of the comonomers reached 97.14%, the temperature was lowered to obtain ABS grafted latex.

[0079] Comparative Example 2

[0080] 175.7 parts of polybutadiene latex B (dry weight 100 parts), 50 parts of comonomers (22 wt% styrene, 8 wt% acrylonitrile, 70 wt% methyl methacrylate), 2 parts of potassium oleate (tested to contain 7.7% carboxylate with less than 17 carbon atoms), 0.5 parts of tert-dodecyl mercaptan, 0.5 parts of sodium pyrophosphate, 0.5 parts of lactose, 0.002 parts of ferrous sulfate, 0.1 parts of tert-butyl hydroperoxide, and 80 parts of water were added to a reactor. The mixture was stirred and swollen for 0.5 h. Then, the mixture was heated to 60 °C. The remaining 50 parts of comonomers (22 wt% styrene, 8 wt% acrylonitrile, 70 wt% methyl methacrylate) and 0.3 parts of tert-butyl hydroperoxide were added dropwise to the reactor at a constant rate over 4 h. The temperature was raised to 80 °C and the reaction continued. When the total conversion rate of the comonomers reached 96.55%, the mixture was cooled to obtain ABS grafted latex.

[0081] The particle size, solid content, and emulsion stability of the ABS grafted latex prepared in each embodiment and comparative example were tested. The performance test structure is shown in Table 1.

[0082] Using the ABS grafted latex prepared in the embodiments of the present invention as raw materials, ABS resin was prepared by means of:

[0083] (1) Coagulation / Drying: 100 parts of ABS grafted latex emulsion were added to the reactor and heated to 95°C. 1.2 parts of H2SO4 and 40 parts of deionized water were gradually added to the emulsion and stirred evenly for 1 hour. The resulting coagulated emulsion was filtered through a 200-mesh stainless steel filter cloth to obtain moist grafted powder. The powder was dried in a vacuum drum dryer at 60°C and 2KPaA for 4 hours to obtain grafted powder with a water content of <1wt%.

[0084] (2) Blending: Using a twin-screw extruder at 210°C, XT500 was used as the MSAN resin for blending. The resin was blended at a mass ratio of XT500: the above-mentioned grafted powder = 75:25. After cooling and granulation, transparent ABS resin was obtained.

[0085] Impact strength, light transmittance, and haze were tested on each ABS material, and the test results are shown in Table 1.

[0086] Table 1. Performance Test Results

[0087]

[0088] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. An ABS grafted latex, characterized in that, Including polybutadiene latex, comonomers, emulsifiers, and initiators; The comonomers include styrene monomers, acrylonitrile monomers, and methacrylate monomers; The emulsifier is selected from carboxylates with 10-20 carbon atoms, and the mass percentage of carboxylates with fewer than 17 carbon atoms in the emulsifier is >20% and ≤53.9%. The comonomer comprises the following raw materials in the following weight ratios, based on a total mass of 100%: Styrene monomer 10-30wt%, acrylonitrile monomer 5-20wt%, methacrylate monomer 60-80wt%.

2. The ABS grafted latex according to claim 1, characterized in that, The amount of the comonomer used is 50-200% of the dry weight of polybutadiene latex.

3. The ABS grafted latex according to claim 1, characterized in that, The amount of emulsifier used is 0.5-5% of the dry weight of polybutadiene latex.

4. The ABS grafted latex according to claim 1, characterized in that, The total amount of the initiator is 0.1-1% of the dry weight of the polybutadiene latex.

5. The ABS grafted latex according to claim 1, characterized in that, The styrene monomer is selected from one or more of styrene, α-methylstyrene, p-methylstyrene, and vinyltoluene; The acrylonitrile monomer is selected from one or more of acrylonitrile, methacrylonitrile and ethyl acrylonitrile; The methacrylate monomer is selected from one or more of methyl methacrylate, ethyl methacrylate, propyl methacrylate, and 2-ethylhexyl methacrylate.

6. The ABS grafted latex according to claim 1, characterized in that, The emulsifier is selected from one or more of potassium oleate and fatty soap.

7. The ABS grafted latex according to claim 1, characterized in that, The initiator is a peroxide.

8. The ABS grafted latex according to claim 7, characterized in that, The initiator is selected from one or more of dicumyl peroxide, cumyl hydroperoxide, and tert-butyl hydroperoxide.

9. The ABS grafted latex according to claim 1, characterized in that, The polybutadiene latex has a particle size of 260-350 nm and a solid content of 40-60 wt%.

10. The ABS grafted latex according to claim 1, characterized in that, Chain transfer agents, complexing agents, reducing agents, co-reducing agents, or water are also added during the polymerization reaction.

11. The ABS grafted latex according to claim 10, characterized in that, The chain transfer agent is one or more of n-octyl mercaptan, tert-dodecyl mercaptan, and n-dodecyl mercaptan.

12. The ABS grafted latex according to claim 11, characterized in that, The chain transfer agent is tert-dodecyl mercaptan.

13. The ABS grafted latex according to claim 10, characterized in that, The complexing agent is one or more of the following: trisodium triamcinolone, disodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, sodium pyrophosphate, and sodium hexametaphosphate.

14. The ABS grafted latex according to claim 13, characterized in that, The complexing agent is sodium pyrophosphate.

15. The ABS grafted latex according to claim 10, characterized in that, The reducing agent is one or more of sodium dithionite, sodium formaldehyde sulfoxylate, isoascorbic acid, glucose, and lactose.

16. The ABS grafted latex according to claim 15, characterized in that, The reducing agent is glucose.

17. The ABS grafted latex according to claim 10, characterized in that, The reducing agent is one or more of ferrous sulfate, ferrous chloride, and sodium bisulfite.

18. The ABS grafted latex according to claim 17, characterized in that, The reducing agent is ferrous sulfate.

19. The ABS grafted latex according to claim 10, characterized in that, The amount of chain transfer agent used is 0.1-1% of the dry weight of polybutadiene latex.

20. The ABS grafted latex according to claim 10, characterized in that, The amount of the complexing agent used is 0.1-1% of the dry weight of the polybutadiene latex.

21. The ABS grafted latex according to claim 10, characterized in that, The amount of reducing agent used is 0.001-0.01% of the dry weight of polybutadiene latex.

22. The ABS grafted latex according to claim 10, characterized in that, The amount of the reducing agent is 0.1-1% of the dry weight of the polybutadiene latex.

23. The ABS grafted latex according to claim 10, characterized in that, The amount of water used is 50-100% of the dry weight of the polybutadiene latex.

24. A method for preparing ABS grafted latex according to any one of claims 1-23, characterized in that, The process includes the following steps: mixing and reacting polybutadiene latex, comonomer, emulsifier and initiator to polymerize and obtain ABS grafted latex.

25. The preparation method according to claim 24, characterized in that, The comonomers are added in batches or continuously.

26. The preparation method according to claim 24, comprising the following steps: 1) Foundation stage: Add polybutadiene latex, some comonomers, some initiator, emulsifier and water to the reactor, stir to swell first and then heat up to polymerize; 2) Continuous dripping stage: The remaining comonomer and initiator are dripped into the reactor to continue the reaction until it is complete, and ABS grafted latex is obtained.

27. The preparation method according to claim 26, characterized in that, In step 1), the polymerization reaction temperature is 40-80℃.

28. The preparation method according to claim 26, characterized in that, The amount of comonomer added in step 1) is 10-50% of the total mass of the comonomer.

29. The preparation method according to claim 26, characterized in that, The amount of initiator added in step 1) is 10-50% of the total mass of the initiator.

30. The preparation method according to claim 26, characterized in that, In step 2), the polymerization reaction temperature is 40-90℃.

31. The preparation method according to claim 26, characterized in that, Step 2) The addition time of the copolymer monomer and initiator is 1-5 hours.

32. The use of an ABS grafted latex according to any one of claims 1-23 or an ABS grafted latex prepared by any one of claims 24-31 in the preparation of transparent ABS resin.

33. A method for preparing transparent ABS resin, characterized in that, Includes the following steps: The ABS grafted latex obtained by the method is coagulated and demulsified to obtain ABS powder, which is then mixed with MSAN resin and extruded through an extruder to obtain transparent ABS resin.

34. The preparation method according to claim 33, characterized in that, MSAN resin refers to a methyl methacrylate-styrene-acrylonitrile copolymer with a refractive index of 1.515±0.

005.

35. The preparation method according to claim 34, characterized in that, The weight-average molecular weight of the MSAN resin is 100,000 to 140,000.

36. The preparation method according to claim 33, characterized in that, The mass ratio of the ABS powder to the MSAN resin is (20-30):(70-80).

Images