Preparation method of large-particle-size high-solid-content styrene-butadiene latex

Abstract

The application belongs to the technical field of new chemical materials, and particularly relates to a preparation method of large-particle-size and high-solid-content butyl styrene latex, which comprises the following steps: (1) preparation of an agglomeration agent, raw materials comprising 10-50 parts of an olefin amide, 1-50 parts of a diene acid anhydride, 1-20 parts of styrene, 1.5-3 parts of an emulsifier, 0.5-1.5 parts of an initiator, and 180-220 parts of deionized water; (2) agglomeration and concentration, wherein, at 10-30 DEG C, the agglomeration agent is added into the latex at a weight ratio of 1 / 100,000 to 3 / 100,000 of the dry latex, agglomeration is performed for 5-30 min, and then evaporation concentration is performed, finally, butyl styrene latex with a solid content of 65-68%, a viscosity of 700-800 cp, and a particle size of 300-350 nm is obtained, the method provided by the application has the characteristics of simple process, extremely low cost, safety and environmental protection, and the prepared large-particle-size and high-solid-content butyl styrene latex can be widely used in the fields of latex foaming products and modified road asphalt.

Description

Technical Field

[0001] This invention belongs to the field of new chemical materials technology, specifically relating to a method for preparing styrene-butadiene latex with large particle size and high solid content. Background Technology

[0002] Styrene-butadiene rubber (SBR) latex is a synthetic latex formed by the emulsion polymerization of butadiene and styrene. High-solids SBR latex refers to SBR latex with a solids content greater than 60%. High-solids SBR latex is widely used in modified emulsified asphalt, latex foaming, and other fields, with very high demand. However, there is still no commercial production of high-solids SBR latex in China, and the demand is basically met by imports.

[0003] For conventional processes producing styrene-butadiene latex, the solid content is around 40%, and the viscosity is 1000-1500 cp. If further concentration is applied, the solid content increases, and the viscosity increases dramatically, causing the latex to lose its fluidity and become unusable. Studies have shown that at the same solid content, the larger the latex particle size, the lower the viscosity. Therefore, the key to preparing high-solids-content styrene-butadiene latex is to first obtain latex with a large particle size.

[0004] Agglomeration is currently the most successful and effective method for preparing large-particle-size, high-solids-content styrene-butadiene latex. Agglomeration methods are divided into physical agglomeration and chemical agglomeration. Physical agglomeration refers to the aggregation of latex particles into larger particles due to the instability caused by stimuli such as temperature and pressure. Physical agglomeration mainly includes pressure agglomeration and freeze agglomeration. Overall, however, it has poor agglomeration effects, minimal particle size increase, and a tendency to form flocs, and has been gradually abandoned by the industry. Chemical agglomeration methods are further divided into small-molecule agglomeration methods and polymer agglomeration methods. For example, CN103159893B uses small-molecule agglomerating agents, such as polyacid amines, to increase the particle size of styrene-butadiene latex from 200nm to 350nm. However, this method involves agglomeration at a high temperature of 70°C, resulting in high energy consumption and high cost. Furthermore, polyacid amines easily generate polyacids at high temperatures, leading to latex demulsification. Compared to small-molecule agglomerating agents, polymer agglomerating agents have advantages such as lower agglomeration temperature, lower dosage, and better agglomeration effect, thus their development has been very rapid in recent decades. However, current patent reports on polymer agglomerating agents mainly target butadiene latex and ABS emulsions, while there are almost no reports on polymer agglomerating agents suitable for styrene-butadiene latex. Summary of the Invention

[0005] To address the existing technical problems, this invention provides a method for preparing styrene-butadiene latex with large particle size and high solids content. It uses a self-made polyacrylamide-acrylic anhydride-styrene copolymer as an agglomerating agent, which requires less dosage, has a lower agglomeration temperature, is safe and environmentally friendly, has a simple process, and achieves good agglomeration effect.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A method for preparing styrene-butadiene latex with large particle size and high solids content includes the following steps:

[0008] (1) Preparation of agglomerating agent, the raw materials include the following components in parts by weight:

[0009] Alkenylamides: 10-50 parts

[0010] Diene anhydrides: 1-50 parts

[0011] Styrene: 1-20 parts

[0012] Emulsifier: 1.5-3 parts

[0013] Initiator: 0.5-1.5 parts

[0014] Deionized water: 180-220 parts

[0015] (2) Aggregation Concentration

[0016] At 10-30℃, an agglomerating agent of 1 to 3 parts per 100,000 of the dry rubber weight is added to the latex, agglomerates for 5-30 minutes, and then evaporates and concentrates to finally obtain a styrene-butadiene latex with a solid content of 65-68%, a viscosity of 700-800 cp, and a particle size of 300-350 nm; the weight of the dry rubber is the weight of the latex multiplied by the solid content.

[0017] Preferably, the olefin amide is one or more of methacrylamide, acrylamide, butenamide, and N-hydroxymethylacrylamide.

[0018] Preferably, the diene anhydride is one or more of methacrylic anhydride, maleic anhydride, angelic anhydride, and itaconic anhydride.

[0019] Preferably, the emulsifier is two or more selected from potassium oleate, sodium dodecylbenzenesulfonate, potassium disproportionated rosinate, alkylamine polyoxyethylene ether, and alkylphenol polyoxyethylene ether. The synergistic effect of multiple emulsifiers through compounding results in a better emulsification effect.

[0020] Preferably, the initiator is one or more of water-soluble ammonium persulfate, potassium persulfate, and sodium persulfate.

[0021] Preferably, the specific steps of the preparation method of the agglomerating agent are as follows: add deionized water and emulsifier, start stirring at a speed of 280-350 rpm / min, then add olefin amide, diene anhydride and styrene, replace the air in the reaction vessel with nitrogen to ensure that the reaction is carried out under anaerobic conditions, finally add initiator to polymerization reactor, heat to 45-55℃, react for 3.5-4.5 hours, and after the reaction is completed, the agglomerating agent can be obtained.

[0022] More preferably, the agglomeration temperature is 20°C.

[0023] Further preferred, the amount of agglomerating agent added is three parts per 100,000 of the latex.

[0024] The application of styrene-butadiene latex prepared by a method for producing large-particle-size, high-solids-content latex in modified road asphalt and foaming fields, such as the preparation of latex mattresses and latex pillows.

[0025] The beneficial effects of this invention are:

[0026] (1) The agglomerating agent is prepared by emulsion polymerization, which does not require post-treatment. The process is simple, and the raw materials required for the agglomerating agent synthesis are non-toxic, harmless, safe and environmentally friendly, and can be industrialized.

[0027] (2) The self-made polyacrylamide-acrylic anhydride-styrene copolymer is used as an agglomerating agent. Due to hydrogen bonding, it can form a network structure, thereby capturing more latex particles for aggregation. At the same time, the introduction of styrene improves the affinity between the agglomerating agent and styrene-butadiene rubber molecules, resulting in good agglomeration effect. A small amount of agglomerating agent can be added to obtain large-particle-size styrene-butadiene latex. The existing technology has a large amount of agglomerating agent added, resulting in poor agglomeration effect or causing latex demulsification. The present invention uses a low amount of agglomerating agent added, which will not have an adverse effect on the performance of latex products, and at the same time effectively avoids the problem of excessive agglomerating agent content.

[0028] (3) The agglomeration temperature is low, and agglomeration can be carried out at room temperature. The energy consumption is low, which saves costs. At the same time, agglomeration does not have high requirements for equipment and the process is controllable.

[0029] (4) A styrene-butadiene latex with a large particle size of 300-350 nm, a solid content of 65-68%, and a viscosity of 700-800 cp is obtained. It has good fluidity and good mechanical stability.

[0030] The present invention provides a method for preparing large-particle-size, high-solids-content styrene-butadiene latex, which is characterized by simple process, extremely low cost, safety and environmental protection. The prepared large-particle-size, high-solids-content styrene-butadiene latex can be widely used in the fields of latex foam products and modified road asphalt. Attached Figure Description

[0031] Figure 1 A schematic diagram of the molecular structure of the agglomerant prepared in Example 1;

[0032] Figure 2 The particle size distribution diagrams are those of the concentrated latex in Example 1 and the concentrated latex in Comparative Example 4. Detailed Implementation

[0033] The following detailed embodiments further illustrate the above-described content of the present invention, but should not be construed as limiting the scope of the subject matter of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Unless otherwise specified, the following embodiments are all implemented using conventional prior art.

[0034] In the following specific embodiments and comparative examples, all raw materials are commercially available products with the following specifications:

[0035]

[0036]

[0037] Example 1

[0038] A method for preparing styrene-butadiene latex with large particle size and high solids content:

[0039] (1) Preparation of agglomerating agents

[0040] 1g sodium dodecylbenzenesulfonate, 0.8g potassium oleate, and 0.9g dodecylamine polyoxyethylene ether were mixed evenly and added to a polymerization reactor. Then, 200g deionized water was added to the polymerization reactor, and stirring was started at 300 rpm / min. Next, 20g acrylamide, 10g methacrylic anhydride, and 3g styrene were added to the polymerization reactor. The air in the polymerization reactor was replaced with nitrogen to ensure that the reaction was carried out under anaerobic conditions. Finally, 0.5g potassium persulfate was added to the polymerization reactor, the temperature was raised to 50℃, and the reaction was carried out for 4 hours. After the reaction was completed, no post-treatment was required to obtain the agglomerating agent. Figure 1 The diagram shows the molecular structure of the obtained agglomerator. The molecule has amide groups, which can form intermolecular hydrogen bonds to form a network structure. The introduction of acid anhydride further increases the polarity of the agglomerator, making the network structure more robust. The introduction of styrene increases the affinity between the agglomerator and styrene-butadiene rubber molecules, further improving the agglomeration effect.

[0041] (2) Aggregation and Concentration

[0042] At 25°C, 0.03% (calculated as 0.03% by weight of dry rubber) of the agglomerating agent prepared above was added to 1502 latex. After 20 minutes, the temperature was raised to 70°C and concentrated to obtain styrene-butadiene latex with large particle size and high solid content. Figure 2 The particle size distribution diagram of the agglomerated latex in Example 1 is shown below. Figure 2 The latex has an average particle size of 330 nm and a wide distribution, which is beneficial for increasing the solid content.

[0043] Example 2

[0044] A method for preparing styrene-butadiene latex with large particle size and high solids content:

[0045] (1) Preparation of agglomerating agents

[0046] 1g sodium dodecylbenzenesulfonate, 0.8g potassium oleate, and 0.9g dodecylamine polyoxyethylene ether were mixed evenly and added to a polymerization reactor. Then, 200g deionized water was added to the polymerization reactor, and stirring was started at 300 rpm / min. Next, 15g acrylamide, 10g methacrylic anhydride, and 3g styrene were added to the polymerization reactor. The air in the polymerization reactor was replaced with nitrogen to ensure that the reaction was carried out under anaerobic conditions. Finally, 0.5g potassium persulfate was added to the polymerization reactor, the temperature was raised to 50℃, and the reaction was carried out for 4 hours. After the reaction was completed, no post-treatment was required to obtain the agglomerating agent.

[0047] (2) Aggregation and Concentration

[0048] At 25°C, 0.03% (calculated as 0.03% by weight of dry rubber) of the agglomerating agent prepared above was added to 1502 latex. After 20 minutes, the temperature was raised to 70°C for concentration to obtain styrene-butadiene latex with large particle size and high solid content.

[0049] Comparative Example 1

[0050] A method for preparing styrene-butadiene latex with large particle size and high solids content:

[0051] (1) Preparation of agglomerating agents

[0052] 1g sodium dodecylbenzenesulfonate, 0.8g potassium oleate, and 0.9g dodecylamine polyoxyethylene ether were mixed evenly and added to a polymerization reactor. Then, 200g of deionized water was added to the polymerization reactor, and stirring was started at 300 rpm / min. Next, 10g methacrylic anhydride and 3g styrene were added to the polymerization reactor. The air in the polymerization reactor was replaced with nitrogen to ensure that the reaction was carried out under anaerobic conditions. Finally, 0.5g potassium persulfate was added to the polymerization reactor, the temperature was raised to 50℃, and the reaction was carried out for 4 hours. After the reaction was completed, no post-treatment was required to obtain the agglomerating agent.

[0053] (2) Aggregation and Concentration

[0054] At 25°C, add 0.03% (calculated as 0.03% by weight of dry rubber) of the agglomerating agent prepared above to 1502 latex, and after 20 minutes raise the temperature to 70°C for concentration.

[0055] Comparative Example 2

[0056] (1) Preparation of agglomerating agents

[0057] 1g sodium dodecylbenzenesulfonate, 0.8g potassium oleate, and 0.9g dodecylamine polyoxyethylene ether were mixed evenly and added to a polymerization reactor. Then, 200g deionized water was added to the polymerization reactor, and stirring was started at 300 rpm / min. Next, 20g acrylamide and 3g styrene were added to the polymerization reactor. The air in the polymerization reactor was replaced with nitrogen to ensure that the reaction was carried out under anaerobic conditions. Finally, 0.5g potassium persulfate was added to the polymerization reactor, the temperature was raised to 50℃, and the reaction was carried out for 4 hours. After the reaction was completed, no post-treatment was required to obtain the agglomerating agent.

[0058] (2) Aggregation and Concentration

[0059] At 25°C, add 0.03% (calculated as 0.03% by weight of dry rubber) of the agglomerating agent prepared above to 1502 latex, and after 20 minutes raise the temperature to 70°C for concentration.

[0060] Comparative Example 3

[0061] A method for preparing styrene-butadiene latex with large particle size and high solids content:

[0062] (1) Preparation of agglomerating agents

[0063] 1g sodium dodecylbenzenesulfonate, 0.8g potassium oleate, and 0.9g dodecylamine polyoxyethylene ether were mixed evenly and added to a polymerization reactor. Then, 200g of deionized water was added to the polymerization reactor, and stirring was started at 300 rpm / min. Next, 3g of styrene was added to the polymerization reactor, and the air in the polymerization reactor was replaced with nitrogen to ensure that the reaction was carried out under anaerobic conditions. Finally, 0.5g of potassium persulfate was added to the polymerization reactor, the temperature was raised to 50℃, and the reaction was carried out for 4 hours. After the reaction was completed, no post-treatment was required to obtain the agglomerating agent.

[0064] (2) Aggregation and Concentration

[0065] At 25°C, add 0.03% (calculated as 0.03% by weight of dry rubber) of the agglomerating agent prepared above to 1502 latex, and after 20 minutes raise the temperature to 70°C for concentration.

[0066] Comparative Example 4

[0067] A method for preparing styrene-butadiene latex with large particle size and high solids content:

[0068] The 1502 latex was heated at 25°C for 10 minutes, and then the temperature was increased to 70°C for concentration. Figure 2 The particle size distribution diagram of the latex in Comparative Example 4 is shown below. Figure 2 The average particle size of the latex is only 90nm, and the dispersion is narrow, which is not conducive to increasing the solid content.

[0069] The concentrated latexes obtained in Examples 1-2 and Comparative Examples 1-4 were tested. The testing methods and standards for the latexes are as follows:

[0070] Total solids content: SH / T1154-92

[0071] Viscosity: SH / T1152-92

[0072] Mechanical stability: SH / T1151-92

[0073] Particle size analyzer: Mastersizer 10000

[0074] The test results are shown in Table 1.

[0075] Table 1 Performance Indicators of Styrene-Butadiene Latex

[0076]

[0077] The base adhesive (1502) used in this invention has a lower solid content, smaller particle size, and finer particle size distribution. Compared with conventional agglomerating agents, the agglomerating agent of this invention can increase the particle size by about 240%, and the agglomerating agent of this invention can increase the particle size by up to 330%. As can be seen from Table 1 above, the solid content and particle size of the styrene-butadiene latex prepared in Examples 1-2 of this invention are significantly greater than those in Comparative Examples 1-4.

[0078] In this invention, the agglomerating agent is prepared using emulsion polymerization, which requires no post-processing, resulting in a simple process. The raw materials required for agglomerating agent synthesis are non-toxic, harmless, safe, and environmentally friendly, enabling industrial production. The agglomerating agent molecules form a network structure due to hydrogen bonding, thereby capturing and agglomerating more latex particles. Simultaneously, the introduction of styrene enhances the affinity between the agglomerating agent and styrene-butadiene rubber (SBR) molecules, leading to excellent agglomeration performance. Only a very small amount of agglomerating agent is needed to obtain large-particle-size SBR latex. In contrast, existing technologies require larger amounts of agglomerating agent, resulting in poor agglomeration effects or even latex demulsification. This invention uses a lower amount of agglomerating agent, which does not adversely affect the performance of the latex product and effectively avoids the problem of excessive agglomerating agent content. The agglomeration temperature is low, allowing for agglomeration at room temperature, resulting in low energy consumption and cost savings. Furthermore, the agglomeration process is not demanding on equipment and is controllable. The resulting SBR latex has a large particle size of 300-350 nm, a solid content of 65-68%, a viscosity of 700-800 cp, good flowability, and good mechanical stability. The present invention provides a method for preparing large-particle-size, high-solids-content styrene-butadiene latex, which is characterized by simple process, extremely low cost, safety and environmental protection. The prepared large-particle-size, high-solids-content styrene-butadiene latex can be widely used in the fields of latex foam products and modified road asphalt.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing styrene-butadiene latex with large particle size and high solids content, characterized in that, Includes the following steps: (1) Preparation of agglomerating agent, the raw materials include the following components in parts by weight: Acrylamide: 10-50 parts Methacrylic anhydride: 1-50 parts Styrene: 1-20 parts Emulsifier: 1.5-3 parts Initiator: 0.5-1.5 parts Deionized water: 180-220 parts The specific steps of the preparation method of the agglomerating agent are as follows: add deionized water and emulsifier, start stirring, then add acrylamide, methacrylic anhydride and styrene, replace the air in the reaction vessel with nitrogen to ensure that the reaction is carried out under anaerobic conditions, finally add initiator to polymerization reactor, heat up and react for a period of time, and after the reaction is completed, the agglomerating agent can be obtained. (2) Agglomeration Concentration At 10-30℃, an agglomerating agent of 1 to 3 parts per 100,000 of the dry rubber weight is added to the latex, agglomerates for 5-30 minutes, and then evaporates and concentrates to finally obtain styrene-butadiene latex with a solid content of 65-68%, a viscosity of 700-800 cp, and a particle size of 300-350 nm.

2. The method for preparing a large-particle-size, high-solids-content styrene-butadiene latex according to claim 1, characterized in that, The emulsifier is two or more of the following: potassium oleate, sodium dodecylbenzene sulfonate, potassium disproportionate, alkylamine polyoxyethylene ether, and alkylphenol polyoxyethylene ether.

3. The method for preparing a large-particle-size, high-solids-content styrene-butadiene latex according to claim 1, characterized in that, The initiator is one or more of the water-soluble ammonium persulfate, potassium persulfate, and sodium persulfate.

4. The method for preparing a large-particle-size, high-solids-content styrene-butadiene latex according to claim 1, characterized in that, The temperature is raised to 45-55℃.

5. The method for preparing a large-particle-size, high-solids-content styrene-butadiene latex according to claim 1, characterized in that, The reaction takes 3.5-4.5 hours.

6. The method for preparing a large-particle-size, high-solids-content styrene-butadiene latex according to claim 1, characterized in that, The stirring speed is 280-350 rpm / min.

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