A high impact bulk abs resin and a continuous polymerization process for its preparation

Abstract

This invention discloses a high-impact bulk ABS resin and its continuous polymerization preparation method, belonging to the field of polymer materials technology. The ABS resin raw materials include 50-70 parts styrene, 15-25 parts acrylonitrile, 8-15 parts toughening rubber, 10-20 parts ethylbenzene solvent, 0.02-0.1 parts initiator, 0.05-0.3 parts composite chain transfer agent, and 0.1-0.5 parts antioxidant. The preparation method employs a four-reactor series plug flow reactor, using a segmented feeding and gradient heating process: toughening rubber, some ethylbenzene and styrene, and all acrylonitrile are formulated into a raw rubber solution, which is then sequentially subjected to R1 prepolymerization, R2 phase transformation, R3 addition of remaining monomers and additives, R4 post-curing, and finally devolatilization and granulation. This invention achieves precise control of rubber particle morphology through the synergistic combination of composite chain transfer agents and multi-stage feeding process. The resulting ABS resin has a simple beam impact strength ≥35 kJ / m², and the average particle size of the rubber particles is 0.5~2.0 μm. The process is stable and the product is pure, making it suitable for automotive parts, electronic product casings and other fields.

Description

Technical Field

[0001] This invention belongs to the field of polymer synthesis technology, and specifically discloses a high-impact bulk ABS resin and its continuous polymerization preparation method. Background Technology

[0002] ABS resin, due to its excellent mechanical strength, toughness, and processing properties, is widely used in the automotive, electronics, and consumer goods industries. Bulk polymerization is one of the key processes for producing ABS resin, offering advantages over emulsion polymerization, including a shorter process flow, less waste, and higher product purity. Typical bulk polymerization processes, such as Dow Chemical's continuous plug flow reactor process, have become industry standards.

[0003] With the increasing demands for material performance in downstream applications, especially in automotive interior and exterior trim and high-end tool housings, higher requirements are being placed on the impact toughness of ABS resin, such as a notched impact strength of over 35 kJ / m² for simply supported beams. However, in bulk polymerization processes, the size, distribution, and morphology of the rubber phase are crucial to the impact strength of the final product. Current technologies often employ methods such as increasing rubber content and adjusting initiation and grafting systems to improve impact strength. However, these methods frequently lead to decreased melt flow properties, processing difficulties, or reactor blockage and crystal point formation during polymerization due to concentrated heat of reaction and uncontrollable phase transitions. This makes it difficult to achieve stable and continuous production while maintaining high toughness.

[0004] Therefore, existing bulk ABS resin technologies struggle to achieve ultra-high impact resistance (simple beam impact strength ≥ 35 kJ / m²) under stable and continuous process conditions. 2 To address the technical problem of [the present invention], this invention provides a new formulation system and a matching four-reactor tandem continuous polymerization process. Through the synergistic effect of specific components and precise segmented reaction control, the morphology of rubber particles can be precisely controlled, thereby producing high-performance, high-quality bulk ABS resin. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and solve the problem that bulk ABS resin is difficult to achieve ultra-high impact resistance (simple beam impact strength ≥35 kJ / m) under stable and continuous process conditions. 2 (Technical issues)

[0006] The technical solution adopted in this invention is as follows: In a first aspect, the present invention provides a continuous preparation method for a high-impact bulk ABS resin, wherein the raw materials of the ABS resin, by mass parts, include: 50-70 parts of styrene, 15-25 parts of acrylonitrile, 8-15 parts of toughening rubber, 10-20 parts of ethylbenzene, 0.02-0.1 parts of initiator, 0.05-0.3 parts of chain transfer agent, and 0.1-0.5 parts of antioxidant; The preparation method includes the following steps: (1) Preparation of raw rubber solution: Dissolve toughening rubber, 50%~80% of the total amount of ethylbenzene, 40%~60% of the total amount of styrene and all acrylonitrile monomers at 30~60℃ to obtain a homogeneous raw rubber solution. The toughening rubber is low-cis polybutadiene rubber, or a compound of low-cis polybutadiene rubber and solution-polymerized styrene-butadiene rubber in a mass ratio of 7:3 to 3:7. (2) First reaction stage: The raw rubber solution from step (1), 40-60% of the total amount of initiator and 20-30% of the total amount of composite chain transfer agent are added to the first plug flow reactor R1 for prepolymerization. The temperature of R1 is controlled at 92-108℃ and the outlet monomer conversion rate is 15-25%. The composite chain transfer agent is composed of dodecyl alcohol and C2-C6 aliphatic diol in a mass ratio of (4:1) to (1:1); (3) Second reaction stage: The R1 discharge is fed into the second plug flow reactor R2, and the remaining initiator and 10-20% of the total amount of chain transfer agent are added to the R2 inlet. The temperature of R2 is controlled at 105-120℃, and the monomer conversion rate at the outlet is 35-45%. (4) Third reaction stage: The R2 discharge is fed into the third plug flow reactor R3, and the remaining ethylbenzene and styrene, the remaining chain transfer agent and antioxidant are added to the R3 inlet. The temperature of R3 is controlled at 120~135℃, and the monomer conversion rate at the outlet is 50~60%. (5) Fourth reaction stage: The R3 discharge is fed into the fourth plug flow reactor R4 for post-maturation of the polymerization reaction. The temperature of R4 is controlled at 135~155℃, and the final monomer conversion rate at the outlet is 70~80%. (6) Deviation and granulation: R4 is fed into a devolatilization device to remove unreacted monomers and solvents under vacuum conditions of 230~250℃. Then, it is extruded, water-cooled and pelletized to obtain the high-impact bulk ABS resin.

[0007] Preferably, the first to fourth plug flow reactors R1 to R4 are connected in series, and the interior of each reactor is divided into three independent temperature control zones along the axial direction: upper, middle, and lower. The temperatures of the upper, middle, and lower zones of R1 are 92~98℃, 100~105℃, and 105~108℃, respectively; the temperatures of the three zones of R2 are 105~110℃, 112~118℃, and 118~120℃, respectively; the temperatures of the three zones of R3 are 120~125℃, 128~132℃, and 132~135℃, respectively; and the temperatures of the three zones of R4 are 135~145℃, 145~152℃, and 150~155℃, respectively.

[0008] Preferably, the initiator is 1,1-di(tert-butylperoxy)cyclohexane.

[0009] Preferably, the C2-C6 aliphatic diol is ethylene glycol, 1,2-propanediol, or 1,4-butanediol.

[0010] Secondly, the present invention provides a high-impact bulk ABS resin obtained by the preparation method described in the first aspect, wherein the simply supported beam impact strength of the ABS resin is ≥35 kJ / m. 2 The average particle size of the rubber particles dispersed in its matrix is ​​0.5~2.0 μm.

[0011] Preferably, the ABS resin has a tensile strength ≥40 MPa and a melt flow rate (220℃ / 10kg) of 10~15g / 10min; the number of crystal points with a diameter greater than 400 nm in the ABS resin is no more than 5 per m².

[0012] Thirdly, the present invention provides the application of the high-impact ABS resin in automotive parts, electronic product housings, or high-end tool housings.

[0013] The beneficial effects achieved by this invention are as follows: 1. Excellent impact performance: By using LCBR (or LCBR / SSBR blend) as the toughening core and introducing a dodecyl alcohol / diol composite chain transfer agent system, the internal structure of the rubber phase is finely controlled while effectively adjusting the molecular weight of the SAN matrix. This allows the product to more effectively induce crazing and shear banding during impact, absorbing a large amount of energy, thereby stably increasing the impact strength of the simply supported beam to 35 kJ / m. 2 above.

[0014] 2. High process stability: This invention combines a four-reactor series plug flow reactor with a zoned temperature control and multi-stage feeding process. In particular, the strategy of adding chain transfer agent at the R2 inlet and adding the remaining monomer at the R3 inlet effectively disperses the heat of reaction, preventing temperature runaway and glue buildup caused by the violent exothermic reaction during the critical phase transition period, thus ensuring the stability of continuous production and product consistency.

[0015] 3. Excellent product quality: Precise temperature and feed control ensure a smooth and thorough phase transformation process, resulting in uniform rubber particle size distribution, a pure product appearance, and extremely few internal crystal points (no more than 5 crystal points over 400nm / m). 2 This meets the stringent requirements of high-end applications for material appearance and processing performance.

[0016] 4. Environmentally friendly: Compared with traditional thiol chain transfer agents, the alcohol chain transfer agent used in this invention has a less odor (the diol can effectively inhibit the decomposition of thiols to produce hydrogen sulfide, which not only reduces the tendency of the product to yellow, but also reduces the odor), making it more environmentally friendly. Attached Figure Description

[0017] Figure 1 This is a flow chart of the pilot-scale process of the high-impact ABS body described in this invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the following embodiments.

[0019] It should be noted that the present invention is not limited to the following embodiments. Unless otherwise specified, all methods described are conventional methods. Unless otherwise specified, all raw materials are available from publicly available commercial sources.

[0020] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] Example 1 Prepare the following materials in parts by weight: 60 parts styrene, 20 parts acrylonitrile, 12 parts low cis polybutadiene rubber A55AE, 15 parts ethylbenzene, 0.04 parts DP275B initiator, 0.12 parts composite chain transfer agent (dodecyl alcohol: ethylene glycol = 3:1, by weight), and 0.3 parts antioxidant 1076.

[0022] Preparation process as per Figure 1 : (1) In a sol-gel kettle, A55AE rubber is dissolved in 2 / 3 of the total amount of ethylbenzene, 30 parts of styrene and all of acrylonitrile, and stirred at 50°C for 4 hours to obtain the original rubber solution.

[0023] (2) The raw rubber solution, 60% of DP275B initiator (0.024 parts), and 25% of composite chain transfer agent (0.03 parts) were simultaneously pumped into the first plug flow reactor (R1) from their respective injection points according to the proportions. The temperatures of the upper, middle, and lower zones of R1 were controlled at 95℃, 100℃, and 105℃, respectively, with an average residence time of approximately 1.2 hours and an outlet conversion rate of approximately 20%.

[0024] (3) The R1 discharge enters the second plug flow reactor (R2), while the remaining 40% of the initiator (0.016 parts) and 15% of the composite chain transfer agent (0.018 parts) are added at the inlet. The temperatures of the three zones of R2 are controlled at 108℃, 115℃, and 120℃, with an average residence time of about 1.5 hours and an outlet conversion rate of about 40%.

[0025] (4) The R2 discharge enters the third plug flow reactor (R3). At the inlet, 1 / 3 of the remaining total ethylbenzene, 30 parts of styrene, the remaining 60% of the composite chain transfer agent (0.072 parts), and all antioxidants are added. The temperatures of the three zones of R3 are controlled at 122℃, 128℃, and 133℃, with an average residence time of about 1.8 hours and an outlet conversion rate of about 55%.

[0026] (5) The R3 discharge enters the fourth plug flow reactor (R4). The temperatures of the three zones of R4 are controlled at 140℃, 148℃ and 152℃, with an average residence time of about 1.8 hours and a final conversion rate of about 75% at the outlet.

[0027] (6) R4 is fed to a twin-screw devolatilizer to remove unreacted monomers and solvents under conditions of 240°C and vacuum degree ≤ -0.095 MPa. The product is then extruded, water-cooled, and pelletized to obtain ABS resin particles.

[0028] Example 2 The difference from Example 1 is that the toughening rubber is a compound of A55AE and solution-polymerized styrene-butadiene rubber (S1322) (mass ratio 6:4, total 12 parts). The composite chain transfer agent is a mixture of n-dodecyl alcohol and 1,2-propanediol (mass ratio 4:1, total 0.1 parts).

[0029] Comparative Example 1 The difference from Example 1 is that the composite chain transfer agent is replaced with an equal mass fraction of n-dodecyl mercaptan.

[0030] Comparative Example 2 The difference from Example 1 is that the segmented feeding is cancelled, and all raw materials (except antioxidants added before devolatilization) are added to the inlet of R1 in full proportion at one time. Reactors R1, R2, and R3 use the same temperature control as in Example 1.

[0031] The performance of the ABS resin particles obtained in the above examples and comparative examples was tested, and the results are shown in the table below. The impact strength was tested according to ISO 179-1:2010 standard for notched impact strength of simply supported beams; the tensile strength was tested according to ISO 527-2:2012 standard; and the melt flow rate (MFR) was tested according to ISO 1133:2011 standard under the conditions of 220°C and 10 kg load.

[0032] Table 1 Performance Test Results project Impact strength of a simply supported beam (kJ / m²) Tensile strength (MPa) Melt flow rate (g / 10min, 220℃ / 10kg) Product appearance (crystal spots / black spots) Reactor operating status Example 1 38.5 42 13.2 Very few Stable, no glue residue Example 2 36.8 44 10.6 Very few Stable, no glue residue Comparative Example 1 28.2 46 6.4. small amount R3 has slight glue residue. Comparative Example 2 12.0 40 4.2 More R2 exports are rising sharply. As shown in the table, the ABS resin prepared using the method of the present invention (Examples 1 and 2) has significantly higher impact strength than the comparative examples, better processing flowability (MFR), a cleaner product appearance, and a stable production process. Comparative Example 1 uses a single thiol chain transfer agent, resulting in insufficient impact performance and poorer processability. Comparative Example 2 uses a one-time feeding method, making process control difficult and leading to a significant decrease in product performance.

[0033] The above-described embodiments are merely illustrative of the implementation methods of the present invention, but should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. A continuous preparation method for high-impact bulk ABS resin, characterized in that, The raw materials of the ABS resin, by weight, include: 50-70 parts styrene, 15-25 parts acrylonitrile, 8-15 parts toughening rubber, 10-20 parts ethylbenzene, 0.02-0.1 parts initiator, 0.05-0.3 parts chain transfer agent, and 0.1-0.5 parts antioxidant. The preparation method includes the following steps: (1) Preparation of raw rubber solution: Dissolve toughening rubber, 50%~80% of the total amount of ethylbenzene, 40%~60% of the total amount of styrene and all acrylonitrile monomers at 30~60℃ to obtain a homogeneous raw rubber solution. The toughening rubber is low-cis polybutadiene rubber, or a compound of low-cis polybutadiene rubber and solution-polymerized styrene-butadiene rubber in a mass ratio of 7:3 to 3:

7. (2) First reaction stage: The raw rubber solution from step (1), 40-60% of the total amount of initiator and 20-30% of the total amount of composite chain transfer agent are added to the first plug flow reactor R1 for prepolymerization. The temperature of R1 is controlled at 92-108℃ and the outlet monomer conversion rate is 15-25%. The composite chain transfer agent is composed of n-dodecyl alcohol and C2-C6 aliphatic diol in a mass ratio of (4:1) to (1:1); (3) Second reaction stage: The R1 discharge is fed into the second plug flow reactor R2, and the remaining initiator and 10-20% of the total amount of chain transfer agent are added to the R2 inlet. The temperature of R2 is controlled at 105-120℃, and the monomer conversion rate at the outlet is 35-45%. (4) Third reaction stage: The R2 discharge is fed into the third plug flow reactor R3, and the remaining ethylbenzene, styrene, chain transfer agent and antioxidant are added to the R3 inlet. The R3 temperature is controlled at 120~135℃, and the monomer conversion rate at the outlet is 50~60%. (5) Fourth reaction stage: The R3 discharge is fed into the fourth plug flow reactor R4 for post-maturation of the polymerization reaction. The temperature of R4 is controlled at 135~155℃, and the final monomer conversion rate at the outlet is 70~80%. (6) Deviation and granulation: R4 is fed into a devolatilization device to remove unreacted monomers and solvents under vacuum conditions of 230~250℃. Then, it is extruded, water-cooled and pelletized to obtain the high-impact bulk ABS resin.

2. The continuous preparation method of high-impact bulk ABS resin according to claim 1, characterized in that, The first to fourth plug flow reactors R1 to R4 are connected in series, and the interior of each reactor is divided into three independent temperature control zones along the axial direction: upper, middle, and lower. The temperatures of the upper, middle, and lower zones of R1 are 92~98℃, 100~105℃, and 105~108℃, respectively; the temperatures of the three zones of R2 are 105~110℃, 112~118℃, and 118~120℃, respectively; the temperatures of the three zones of R3 are 120~125℃, 128~132℃, and 132~135℃, respectively; and the temperatures of the three zones of R4 are 135~145℃, 145~152℃, and 150~155℃, respectively.

3. The continuous preparation method of high-impact bulk ABS resin according to claim 1, characterized in that, The initiator is 1,1-bis(tert-butylperoxy)cyclohexane.

4. The continuous preparation method of high-impact bulk ABS resin according to claim 1, characterized in that, The C2-C6 aliphatic diol is ethylene glycol, 1,2-propanediol, or 1,4-butanediol.

5. The continuous preparation method of high-impact bulk ABS resin according to claim 1, characterized in that, The antioxidant is antioxidant 1076.

6. A high-impact bulk ABS resin obtained by the preparation method according to any one of claims 1 to 5.

7. The high-impact bulk ABS resin according to claim 6, characterized in that, The average particle size of the rubber particles dispersed in the matrix is ​​0.5~2.0 μm.

8. The high-impact bulk ABS resin according to claim 6, characterized in that, The simply supported beam impact strength of the ABS resin is ≥35 kJ / m. 2 Tensile strength ≥40 MPa, melt flow rate (220℃ / 10kg) is 10~15 g / 10min.

9. The high-impact bulk ABS resin according to claim 6, characterized in that, In the ABS resin, the number of crystal points with a diameter greater than 400 nm is no more than 5 per m².

10. The application of the high-impact bulk ABS resin according to any one of claims 6 to 9 in automotive parts, electronic product housings, or high-end tool housings.

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