A matt low odor bulk method abs resin and a method for preparing the same

Abstract

This invention proposes a matte, low-odor bulk ABS resin and its preparation method. Low-cis polybutadiene rubber, ethylbenzene, styrene, and acrylonitrile are mixed and dissolved to form a raw rubber solution. After filtration and preheating, the raw rubber solution and additives are fed into four plug flow reactors connected in series for continuous bulk polymerization. The polymerized material is then extruded for devolatilization and granulation to obtain the matte, low-odor bulk ABS resin. This invention reduces organic gases in the finished product by modifying the process conditions of conventional matte ABS products and adding a reflux device with an adsorption tank to the fourth reactor of the ABS polymerization unit. Simultaneously, it increases the high-temperature reaction time of some materials to reduce unreacted monomers.

Description

Technical Field

[0001] This invention belongs to the field of ABS polymer material preparation technology, specifically relating to a matte, low-odor bulk ABS resin and its preparation method. Background Technology

[0002] ABS resin is a thermoplastic polymer material with excellent comprehensive performance. It is currently the engineering material with the largest output and widest application. It is suitable for household appliance products, such as TV casings, refrigerator liners, vacuum cleaners, etc., as well as plastic products for instruments, telephones, and the automotive industry.

[0003] In recent years, with the continuous development of the automotive industry, ABS resin has been increasingly used in automotive interiors due to its superior mechanical and processing properties. However, the production and processing of ABS resin generates volatile organic compounds (VOCs) from incompletely converted monomers and various additives produced during the polymerization reaction. As the interior temperature of a car rises after being exposed to direct sunlight, these gases are easily released during use, posing a health hazard to the occupants.

[0004] In the bulk ABS resin production process, due to the smaller types and proportions of additives, there are fewer unreacted monomers and volatile organic gases compared to emulsion ABS. However, with the increasing health awareness of people, it is still necessary to further reduce the VOC content of bulk ABS resin. Summary of the Invention

[0005] (a) Technical problems to be solved This invention proposes a matte, low-odor bulk ABS resin and its preparation method to solve the technical problems of how to reduce organic gases in the finished product and reduce unreacted monomers.

[0006] (II) Technical Solution To address the aforementioned technical problems, this invention proposes a method for preparing matte, low-odor bulk ABS resin. This method includes the following steps: mixing and dissolving low-cis polybutadiene rubber, ethylbenzene, styrene, and acrylonitrile to form a raw rubber solution; after filtration and preheating, conveying the raw rubber solution and additives to four plug flow reactors connected in series for continuous bulk polymerization; and then extruding the polymerized material into an extruder for devolatilization and granulation to obtain matte, low-odor bulk ABS resin.

[0007] Further, 10-13 parts by weight of low-cis polybutadiene rubber, 11-14 parts by weight of ethylbenzene, 55-65 parts by weight of styrene and 17-22 parts by weight of acrylonitrile are mixed and dissolved in a glue tank at 40°C to form the original glue solution.

[0008] Furthermore, the adjuvants include initiators, chain transfer agents, and antioxidants.

[0009] Furthermore, the amount of additives added is 0.3-0.8% of the original rubber solution, including an initiator, 1-2% of a chain transfer agent, and 1-2.5% of an antioxidant.

[0010] Furthermore, in the four plug flow reactors connected in series, each reactor is divided into three zones for separate temperature control. The four reactors are divided into 1 to 12 zones in total. The temperature of zones 1 to 9 in the first, second, and third reactors is controlled at 100 to 135°C, with the temperature gradually increasing from zone 1 to zone 9. The temperature of zones 10 to 12 in the fourth reactor is controlled at 140 to 165°C, with the temperature gradually increasing from zone 10 to zone 12.

[0011] Furthermore, some of the material output from the fourth reactor is returned to the second section of the fourth reactor after passing through the adsorption tank, where it undergoes polymerization again, increasing the time for high-temperature polymerization.

[0012] Furthermore, the adsorption tank is filled with a gas adsorbent for absorbing organic gases in the material; the adsorbent is a composite molecular sieve, with ZSM-5 molecular sieve used in the front section and USY molecular sieve used in the back section.

[0013] Furthermore, the stirring speeds of the four reactors were 8, 10, 12, and 12 rpm, respectively.

[0014] Furthermore, the material after polymerization reaction sequentially enters the first-stage devolatilizer and the second-stage devolatilizer. The temperature of the first-stage devolatilizer is 185~200℃ and the pressure is 0.1KPa. The temperature of the second-stage devolatilizer is 250~265℃ and the pressure is 0.02KPa. The devolatilized material enters the extruder. The extruded material is cooled in a water bath and then pelletized to form the final product.

[0015] Furthermore, the present invention also proposes a matte, low-odor bulk ABS resin, which is prepared by the above method.

[0016] (III) Beneficial Effects This invention proposes a matte, low-odor bulk ABS resin and its preparation method. Low-cis polybutadiene rubber, ethylbenzene, styrene, and acrylonitrile are mixed and dissolved to form a raw rubber solution. After filtration and preheating, the raw rubber solution and additives are fed into four plug flow reactors connected in series for continuous bulk polymerization. The polymerized material is then extruded for devolatilization and granulation to obtain the matte, low-odor bulk ABS resin. This invention reduces organic gases in the finished product by modifying the process conditions of conventional matte ABS products and adding a reflux device with an adsorption tank to the fourth reactor of the ABS polymerization unit. Simultaneously, it increases the high-temperature reaction time of some materials to reduce unreacted monomers. Attached Figure Description

[0017] Figure 1 This is a flowchart of the method for preparing matte, low-odor bulk ABS resin according to the present invention. Detailed Implementation

[0018] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0019] Example This embodiment proposes a method for preparing matte, low-odor bulk ABS resin, the principle of which is as follows: Figure 1 As shown, the specific steps include the following: 12% (mass fraction, the same below) of low-cis polybutadiene rubber, 11% of ethylbenzene, 60% of styrene, and 17% of acrylonitrile are mixed and dissolved in a rubber solution tank at 30°C until a homogeneous raw rubber solution without lumps is obtained. The dissolved solution is then filtered through a 100-mesh filter and preheated to 80°C. It is then conveyed, along with various additives, to four plug flow reactors for bulk polymerization. The additives include an initiator added at 0.3-0.8% of the raw rubber solution volume, a chain transfer agent at 1-2% of the volume, and an antioxidant at 1-2.5% of the volume. The temperature of the first three reactors is controlled at 100-135°C, increasing progressively. The three temperatures of the fourth reactor are controlled at 143°C, 152°C, and 164°C. A portion of the material exiting the fourth reactor is diverted into an adsorption tank. The adsorption tank has a lower layer of material solution and an upper layer of molecular sieve structure; the material level needs to be controlled during production. The molecular sieve employs a composite sieve method, using ZSM-5 molecular sieve in the front stage and USY molecular sieve in the rear stage to achieve full absorption of organic molecules. The material flows out from the side wall of the adsorption tank and is returned to the second section of the fourth-stage reactor. The stirring speeds of the four reactors are 8, 10, 12, and 12 rpm, respectively. The reacted material first enters the first-stage devolatilizer, with the temperature controlled at 185℃ and the pressure controlled at 0.1 kPa, and then enters the second-stage devolatilizer, with the temperature controlled at 265℃ and the pressure controlled at 0.02 MPa. After devolatilization, the material is extruded, cooled in a water bath, and then pelletized to obtain the final ABS resin product. The obtained product is analyzed and statistically analyzed for impact strength, melt index, reaction conversion rate, residual monomer content, and VOC content.

[0020] Comparative Example 12% (mass fraction, the same below) of low-cis polybutadiene rubber, 11% of ethylbenzene, 60% of styrene, and 17% of acrylonitrile were mixed and dissolved in a rubber solution tank at 30°C until a homogeneous raw rubber solution without lumps was obtained. The dissolved solution was then filtered through a 100-mesh filter and preheated to 70°C. This solution, along with various additives, was then conveyed by a conveying device to four plug flow reactors for bulk polymerization. The additives added were 0.3-0.8% of the raw rubber solution volume for initiator, 1-2% for chain transfer agent, and 1-2.5% for antioxidant. The temperature of the first three reactors was controlled at 100-130°C, increasing progressively. The three temperatures of the fourth reactor were controlled at 138°C, 145°C, and 155°C. The stirring speeds of the four reactors were 8, 10, 12, and 12 rpm, respectively. The reacted material first enters the first-stage devolatilizer, where the temperature is controlled at 185℃ and the pressure at 0.1 kPa, and then enters the second-stage devolatilizer, where the temperature is controlled at 265℃ and the pressure at 0.02 MPa. After devolatilization, the material passes through an extruder, is cooled in a water bath, and then pelletized to obtain the final ABS resin product. The obtained product is then tested and statistically analyzed for impact strength, melt index, reaction conversion rate, residual monomer content, and VOC content.

[0021] Impact strength, melt flow index, reaction conversion rate, residual monomer content, and VOC content were measured and statistically analyzed for the examples and comparative examples, and the results are as follows: Analysis shows that by changing the process conditions of ABS products and adding a reflux device with an adsorption tank to the fourth reactor of the ABS polymerization unit, the high-temperature reaction time of polymerization can be increased, thereby improving the conversion rate. Simultaneously, the adsorption tank adsorbs organic gases generated during polymerization, reducing residual monomers and organic gases in the product and achieving the low-odor requirement. Furthermore, the added process steps have minimal impact on the product's impact resistance and melt flow index.

[0022] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing matte, low-odor bulk ABS resin, characterized in that, The preparation method includes the following steps: mixing and dissolving low-cis polybutadiene rubber, ethylbenzene, styrene and acrylonitrile to form a raw rubber solution; after filtration and preheating, the raw rubber solution and additives are transported to four plug flow reactors connected in series for continuous bulk polymerization; the polymerized material is fed into an extruder for devolatilization and granulation to obtain matte low-odor bulk ABS resin.

2. The method for preparing matte, low-odor bulk ABS resin as described in claim 1, characterized in that, 10-13 parts by weight of low-cis polybutadiene rubber, 11-14 parts by weight of ethylbenzene, 55-65 parts by weight of styrene and 17-22 parts by weight of acrylonitrile are mixed and dissolved in a glue tank at 40°C to form the original glue solution.

3. The method for preparing matte, low-odor bulk ABS resin as described in claim 1, characterized in that, Additives include initiators, chain transfer agents, and antioxidants.

4. The method for preparing matte, low-odor bulk ABS resin as described in claim 3, characterized in that, The amount of additives added is 0.3-0.8% of the original rubber solution, including initiator, 1-2% of chain transfer agent, and 1-2.5% of antioxidant.

5. The method for preparing matte, low-odor bulk ABS resin as described in claim 1, characterized in that, In the four plug flow reactors connected in series, each reactor is divided into three zones for separate temperature control. The four reactors are divided into 1 to 12 zones in total. The temperature of zones 1 to 9 in the first, second and third reactors is controlled at 100 to 135℃, with the temperature gradually increasing from zone 1 to zone 9. The temperature of zones 10 to 12 in the fourth reactor is controlled at 140 to 165℃, with the temperature gradually increasing from zone 10 to zone 12.

6. The method for preparing matte, low-odor bulk ABS resin as described in claim 5, characterized in that, Part of the material output from the fourth reactor is returned to the second section of the fourth reactor after passing through the adsorption tank, where it undergoes polymerization again, increasing the time for high-temperature polymerization.

7. The method for preparing matte, low-odor bulk ABS resin as described in claim 5, characterized in that, The adsorption tank contains a gas adsorbent for absorbing organic gases from the material; the adsorbent is a composite molecular sieve, with ZSM-5 molecular sieve used in the front section and USY molecular sieve used in the back section.

8. The method for preparing matte, low-odor bulk ABS resin as described in claim 5, characterized in that, The stirring speeds of the four reactors were 8, 10, 12 and 12 rpm, respectively.

9. The method for preparing matte, low-odor bulk ABS resin as described in claim 5, characterized in that, After polymerization, the material enters the first-stage devolatilizer and the second-stage devolatilizer in sequence. The temperature of the first-stage devolatilizer is 185~200℃ and the pressure is 0.1KPa. The temperature of the second-stage devolatilizer is 250~265℃ and the pressure is 0.02KPa. The devolatilized material enters the extruder. The extruded material is cooled in a water bath and then pelletized to form the final product.

10. A matte, low-odor bulk ABS resin, characterized in that, The matte, low-odor bulk ABS resin is prepared using the method described in any one of claims 1 to 9.

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