A carboxyl butadiene-styrene latex, its preparation method and use

Abstract

The application discloses a kind of carboxyl butadiene-styrene latex and its preparation method and application.The carboxyl butadiene-styrene latex is the emulsion of three monomer copolymers of butadiene, styrene and 4-vinyl benzoic acid.The preparation method is to use 100 parts of deionized water as water phase, 35-45 parts of butadiene, 15-20 parts of styrene and 2-8 parts of 4-vinyl benzoic acid as organic phase, and is prepared by 0.05-0.1 parts of water-soluble and 0.1-0.15 parts of oil-soluble compound initiator to initiate emulsion polymerization.The carboxyl butadiene-styrene latex prepared in the application has better stability and adhesion than conventional acrylic-butadiene-styrene latex, and can be used as an additive in oil and gas well engineering to plug cracks and reduce leakage.

Description

Technical Field

[0001] This invention relates to the field of carboxylated latex technology, and particularly to a carboxylated butadiene-styrene latex, its preparation method, and its application. Background Technology

[0002] Styrene-butadiene rubber (SBR) latex refers to a latex produced by emulsion polymerization of monomers such as butadiene and styrene. Due to its excellent rubber properties, it is widely used in impregnated products such as oil-resistant gloves, leather surface treatment, nonwoven fabrics, carpet backings and decorative fabrics, paper processing, and latex adhesives. Carboxylated SBR latex refers to a latex produced by introducing unsaturated acids such as acrylic acid, methacrylic acid, or itaconic acid into the butadiene and styrene monomers, followed by emulsion polymerization. It is called carboxylated SBR latex because the polymer backbone contains carboxyl groups. Compared to ordinary SBR latex, carboxylated SBR latex, due to the presence of strongly polar carboxyl groups on the polymer molecular chain, exhibits better adhesion and film-forming properties, better mechanical properties and freeze-thaw stability, and superior light resistance, heat resistance, and aging resistance.

[0003] Although there are relevant literature and patent reports on the preparation of carboxylated butadiene-styrene latex by introducing unsaturated acids, the preparation of carboxylated styrene-butadiene latex still faces challenges in component distribution. The main difficulty lies in the fact that the introduction of a third unsaturated acid, such as acrylic acid, results in the ternary copolymerization of three monomers, making it difficult to control the monomer sequence distribution during emulsion polymerization. On the one hand, the copolymerization abilities (reactivity ratios) of the three monomers differ; butadiene has a lower reactivity ratio than the other monomers, while acrylic acid exhibits the strongest homopolymerization reactivity. On the other hand, the solubility of the three monomers differs; butadiene and styrene monomers are highly soluble in organic solvents, while the unsaturated acid (easily soluble) has high solubility in the aqueous phase. Therefore, in emulsion polymerization, the solubility of the monomers in the latex particles affects the distribution of the components in the final polymer product. In particular, the unsaturated acid monomer, which is easily soluble in water, has a high reactivity ratio and high water solubility. The simultaneous addition of all three monomers can create long-chain segments of unsaturated acid or their homopolymers, thus affecting the final properties of the latex. Therefore, the development of butadiene-styrene latex with uniform carboxyl group distribution has important practical application value. Summary of the Invention

[0004] To address the problem of uneven component distribution in the preparation of carboxybutadiene-styrene latex using existing technologies, this invention provides a carboxybutadiene-styrene latex, its preparation method, and its applications.

[0005] In the first aspect, this application provides a carboxybutadiene-styrene latex, which is achieved by the following technical solution.

[0006] A carboxybutadiene-styrene latex, wherein the carboxybutadiene-styrene latex is an emulsion of a copolymer of three monomers: butadiene, styrene, and 4-vinylbenzoic acid.

[0007] Furthermore, the mass ratio of the three monomers, butadiene, styrene and 4-vinylbenzoic acid, is (35-45):(15-20):(2-8).

[0008] Furthermore, the carboxybutadiene-styrene latex is mainly made from the following raw materials in parts by weight:

[0009]

[0010] By adopting the above technical solution, this application introduces carboxyl groups by introducing 4-vinylbenzoic acid. Since 4-vinylbenzoic acid is a carboxylic acid-substituted styrene, it is a homologue of styrene monomers and therefore has similar copolymerization reactivity. Simultaneously, by adding water-soluble and oil-soluble initiators, the polymerization rate of the monomers is further synergistically controlled, ultimately yielding a carboxylated butadiene-styrene latex with uniform component distribution.

[0011] Preferably, the butadiene monomer comprises 38-42 parts; the styrene monomer comprises 16-18 parts; and the 4-vinylbenzoic acid comprises 4-6 parts.

[0012] Preferably, the mass ratio of oil-soluble initiator to water-soluble initiator is 2:1.

[0013] Preferably, the emulsifier is sodium dodecylbenzenesulfonate or calcium stearate.

[0014] Preferably, the oil-soluble initiator is selected from one of tert-butyl hydroperoxide, azobisisobutyronitrile, and benzoyl peroxide, and more preferably azobisisobutyronitrile or benzoyl peroxide.

[0015] Preferably, the water-soluble initiator is selected from sodium persulfate, potassium persulfate, and ammonium persulfate, and more preferably sodium persulfate or potassium persulfate.

[0016] Preferably, the chain transfer agent is dodecyl mercaptan.

[0017] Preferably, the electrolyte is sodium carbonate or potassium carbonate.

[0018] Secondly, this application provides a method for preparing carboxybutadiene-styrene latex, which is achieved by the following technical solution.

[0019] A method for preparing the above-mentioned carboxybutadiene-styrene latex includes the following steps:

[0020] S1. Dissolve a specified amount of water-soluble initiator and electrolyte in deionized water to form aqueous phase A;

[0021] S2. Dissolve a specified amount of oil-soluble initiator and chain transfer agent in a mixed organic liquid of butadiene monomer, styrene monomer and 4-vinylbenzoic acid to form organic phase B;

[0022] S3. Mix and stir the aqueous phase A and organic phase B at room temperature and add the specified amount of emulsifier. Stir for 30 to 60 minutes to form a stable emulsion. Then stir the emulsion at 20 to 30°C for 1 to 4 hours.

[0023] S4. The emulsion prepared in step S3 is heated to 50-60°C and stirred for another 1.5-3.5 hours.

[0024] S5. Cool the emulsion prepared in step S4 to room temperature, add alkali solution dropwise to adjust the pH of the emulsion to 6-8, and obtain carboxybutadiene-styrene latex.

[0025] Furthermore, in steps S3 and S4, the stirring speed is 400-500 rpm.

[0026] Preferably, in step S3, the reaction temperature of the emulsion is 25°C and the reaction time is 2 to 3 hours.

[0027] Preferably, in step S4, the reaction temperature of the emulsion is 55°C and the reaction time is 2 to 3 hours.

[0028] Furthermore, in step S5, the alkaline solution is a 30% sodium hydroxide aqueous solution.

[0029] Preferably, in step S5, the pH of the emulsion is adjusted to 7-8.

[0030] Thirdly, this application provides a use of carboxybutadiene-styrene latex, which is achieved by the following technical solution.

[0031] The application of the above-mentioned carboxybutadiene-styrene latex as a cementing additive in oil and gas well engineering.

[0032] Specifically, the latex prepared in this application is added at 5-15% of the cement mass fraction, and the cement slurry is prepared according to the standard process for preparing cement slurry for well cementing. The resulting latex cementing can significantly reduce water loss. Preferably, the amount of latex prepared in this application added is 8-10% of the cement mass fraction.

[0033] This application has the following beneficial effects.

[0034] (1) The present invention uses oil-soluble initiator and water-soluble initiator to jointly initiate monomer copolymerization. By adjusting the ratio of oil-soluble initiator and water-soluble initiator, the polymerization rate of the three monomers is controlled, which solves the problem of uneven monomer distribution during polymerization caused by the large difference in solubility of the three monomers.

[0035] (2) In this invention, 4-vinylbenzoic acid is introduced as a third monomer to introduce carboxyl groups. 4-vinylbenzoic acid is a homologue of styrene monomer and its copolymerization reactivity is not much different from that of styrene. Therefore, the component distribution of the prepared carboxyl styrene-butadiene latex product is more uniform.

[0036] (3) The carboxybutadiene-styrene latex prepared by the present invention can be used as an additive for cementing in the field of oil and gas well engineering, and can significantly reduce the leakage of cementing. Attached Figure Description

[0037] Figure 1 This is a physical image of the carboxybutadiene-styrene latex prepared in Example 7 of this application. Detailed Implementation

[0038] The present patent application will be further described below with reference to the embodiments.

[0039] Experimental methods in the following embodiments of this application that do not specify specific conditions are generally performed under conventional conditions in the art or under conditions recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are all commercially available from conventional markets.

[0040] Example 1

[0041] A method for preparing a carboxybutadiene-styrene latex includes the following steps:

[0042] S1. Dissolve 0.05g of water-soluble initiator sodium persulfate and 0.25g of electrolyte sodium carbonate in 100g of deionized water to form aqueous phase A;

[0043] S2. Dissolve 0.15g of oil-soluble initiator azobisisobutyronitrile and 0.2g of chain transfer agent dodecyl mercaptan in a mixed organic liquid of 40g butadiene monomer, 20g styrene monomer and 6g 4-vinylbenzoic acid to form organic phase B;

[0044] S3. Mix and stir the aqueous phase A and organic phase B at room temperature and add 2g of emulsifier sodium dodecylbenzenesulfonate. Mechanically stir at 400-500 rpm for 30 minutes to form a stable emulsion. Then, heat the emulsion from room temperature to 25°C and maintain a stirring speed of 400-500 rpm for 3 hours.

[0045] S4. Continue heating the prepared emulsion to 55°C and react for 2 hours while maintaining a rotation speed of 400-500 rpm;

[0046] S5. Then, after the reaction is complete, the emulsion is cooled to room temperature, and 30% sodium hydroxide aqueous solution is added dropwise while stirring to adjust the pH of the emulsion to 7.5, thus obtaining carboxybutadiene-styrene latex.

[0047] Example 2

[0048] A method for preparing carboxybutadiene-styrene latex differs from Example 1 in that the type and amount of initiator are different. Specifically, this example uses 0.05g of water-soluble potassium persulfate initiator and 0.15g of oil-soluble azobisisobutyronitrile initiator.

[0049] Example 3

[0050] A method for preparing carboxybutadiene-styrene latex differs from Example 1 in that the type and amount of initiator are different. Specifically, this example uses 0.1g of water-soluble sodium persulfate initiator and 0.1g of oil-soluble benzoyl peroxide initiator.

[0051] Example 4

[0052] A method for preparing carboxybutadiene-styrene latex differs from Example 1 in that the type and amount of initiator are different. Specifically, this example uses 0.05g of water-soluble potassium persulfate initiator and 0.1g of oil-soluble benzoyl peroxide initiator.

[0053] Example 5

[0054] A method for preparing carboxybutadiene-styrene latex differs from Example 4 in that the amounts of the three monomers added are different. Specifically, this example uses 35g butadiene, 20g styrene, and 6g 4-vinylbenzoic acid.

[0055] Example 6

[0056] A method for preparing carboxybutadiene-styrene latex differs from Example 4 in that the amounts of the three monomers added are different. Specifically, this example uses 45g butadiene, 20g styrene, and 6g 4-vinylbenzoic acid.

[0057] Example 7

[0058] A method for preparing carboxybutadiene-styrene latex differs from Example 4 in that the amounts of the three monomers added are different. Specifically, this example uses 40g butadiene, 15g styrene, and 6g 4-vinylbenzoic acid.

[0059] Example 8

[0060] A method for preparing carboxybutadiene-styrene latex differs from Example 4 in that the amounts of the three monomers added are different. Specifically, this example uses 40g butadiene, 15g styrene, and 4g 4-vinylbenzoic acid.

[0061] Example 9

[0062] A method for preparing carboxybutadiene-styrene latex differs from Example 4 in that the amounts of the three monomers added are different. Specifically, this example uses 40g butadiene, 18g styrene, and 2g 4-vinylbenzoic acid.

[0063] Example 10

[0064] A method for preparing carboxybutadiene-styrene latex differs from Example 4 in that the amounts of the three monomers added are different. Specifically, this example uses 40g butadiene, 18g styrene, and 8g 4-vinylbenzoic acid.

[0065] Comparative Example 1

[0066] In this comparative example, butadiene and styrene were copolymerized without the addition of the carboxyl-containing monomer 4-vinylbenzoic acid to prepare a conventional styrene-butadiene latex. The initiator used was 0.15 g of the oil-soluble initiator benzoyl peroxide. The rest of the process was the same as in Example 7.

[0067] Comparative Example 2

[0068] In this comparative example, butadiene, styrene, and acrylic acid were copolymerized, and 4-vinylbenzoic acid was replaced with acrylic acid monomer to prepare carboxylated styrene-butadiene latex. The rest of the process was the same as in Example 7.

[0069] Comparative Example 3

[0070] This comparative example copolymerizes butadiene, styrene, and 4-vinylbenzoic acid using a single oil-soluble initiator. The initiator used is 0.15 g of oil-soluble benzoyl peroxide. The remainder is the same as in Example 7.

[0071] Comparative Example 4

[0072] This comparative example copolymerizes butadiene, styrene, and 4-vinylbenzoic acid using a single water-soluble initiator. The initiator used is 0.10 g of water-soluble potassium persulfate. The remainder is the same as in Example 7.

[0073] Performance testing

[0074] The performance of the carboxylated styrene-butadiene latex samples prepared in Examples 1-10 and Comparative Examples 1-4 was tested according to the national standard GB / T25260.1-2010. The test results are shown in Table 1.

[0075] Table 1 Properties of Latex

[0076]

[0077]

[0078] The experimental results above show that:

[0079] (1) Compared with the carboxyl styrene-butadiene latex prepared in Examples 1-10 of the present invention, the styrene-butadiene latex of Comparative Example 1 has poor mechanical stability due to the absence of carboxyl groups, especially the lack of hydrophilic carboxyl groups, which leads to a significant increase in its surface tension. This indicates that the introduction of carboxyl groups can greatly improve the surface properties of the latex as well as its subsequent film-forming and adhesive properties.

[0080] (2) Compared with the carboxylated styrene-butadiene latex prepared in Examples 1-10 of the present invention, the styrene-butadiene latex prepared in Comparative Example 2 is acrylic acid carboxylated, which has poor mechanical stability and high surface tension. Under the same monomer addition, this is mainly because the carboxyl distribution of the carboxylated styrene-butadiene latex prepared in Examples 1-10 of the present invention is more uniform.

[0081] (3) Compared with the carboxylated styrene-butadiene latex prepared in Examples 1-10 of the present invention, the mechanical stability and surface tension of the latex prepared by Comparative Examples 3 and 4 using a single initiator were worse than those of Examples 1-10 under the same raw material composition. This indicates that the use of a compound initiator can more effectively prepare carboxylated styrene-butadiene latex with uniform composition distribution.

[0082] Application examples

[0083] The latexes prepared in Example 7 and Comparative Examples 1-2 were added as additives to oil and gas well cementing cement, and their performance was then tested according to API standards. The specific steps included:

[0084] The cementing cement was prepared with a water-cement ratio of 0.44, and latex was added at 10% of the cement mass fraction. The cement slurry was prepared according to the standard procedure for cementing cement slurry preparation. Application tests were conducted according to the determined formula and three consecutive batches of samples with the same formula. The performance was tested according to API standards, and the average value was taken. The test results of the relevant performance are shown in Table 2.

[0085] Table 2. Effects of Latex on Cement Paste Properties

[0086]

[0087]

[0088] As shown in Table 2, adding 10% of the carboxylated styrene-butadiene latex prepared in Example 7 to the cementing cement can significantly reduce the cement's water loss. This is mainly because the carboxylated styrene-butadiene latex can act as a polymer latex, effectively filling the voids in the cement and reducing water leakage. However, adding the same amount of latex from Comparative Examples 1 and 2 increases the cement's water loss. This is mainly because the carboxylated styrene-butadiene latex prepared in Example 7 has higher carboxyl activity and a more uniform distribution.

[0089] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A carboxylated butadiene-styrene latex characterized in that: The carboxybutadiene-styrene latex is made from the following raw materials in parts by weight: 35-45 parts butadiene; 15-20 parts styrene; 2-8 parts of 4-vinylbenzoic acid; 2 parts emulsifier; 0.1 to 0.15 parts of oil-soluble initiator; 0.05~0.1 parts of water-soluble initiator; 0.2 parts chain transfer agent; Electrolyte 0.25 parts; 100 portions of deionized water.

2. The carboxylated butadiene-styrene latex according to claim 1, characterized in that: The emulsifier is selected from sodium dodecylbenzenesulfonate or calcium stearate.

3. The carboxylated butadiene-styrene latex according to claim 1, characterized in that: The oil-soluble initiator is selected from one of tert-butyl hydroperoxide, azobisisobutyronitrile, and benzoyl peroxide.

4. The carboxybutadiene-styrene latex according to claim 1, characterized in that: The water-soluble initiator is selected from one of sodium persulfate, potassium persulfate, and ammonium persulfate.

5. The carboxybutadiene-styrene latex according to claim 1, characterized in that: The chain transfer agent is selected as dodecyl mercaptan.

6. The carboxybutadiene-styrene latex according to claim 1, characterized in that: The electrolyte is selected from sodium carbonate or potassium carbonate.

7. A method for preparing a carboxybutadiene-styrene latex according to any one of claims 1-6, characterized in that: Includes the following steps: S1. Dissolve a specified amount of water-soluble initiator and electrolyte in deionized water to form aqueous phase A; S2. Dissolve a specified amount of oil-soluble initiator and chain transfer agent in a mixed organic liquid of butadiene monomer, styrene monomer and 4-vinylbenzoic acid to form organic phase B; S3. Mix and stir the aqueous phase A and organic phase B at room temperature and add the specified amount of emulsifier. Stir for 30 to 60 minutes to form a stable emulsion. Then stir the emulsion at 20 to 30°C for 1 to 4 hours. S4. The emulsion prepared in step S3 is heated to 50~60℃ and stirred for another 1.5~3.5 hours. S5. Cool the emulsion prepared in step S4 to room temperature, add alkali solution dropwise to adjust the pH of the emulsion to 6-8, and obtain carboxybutadiene-styrene latex.

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