A method for preparing anionic high solid content styrene-butadiene latex

Abstract

The invention discloses a preparation method of anionic high-solid-content styrene-butadiene latex. The raw materials of the anionic high-solid-content styrene-butadiene latex are as follows, including 100-200 parts by mass of butadiene monomer, 40-80 parts by mass of styrene monomer, 4-8 parts by mass of anionic emulsifier, 1-3 parts by mass of molecular weight regulator, 10-17 parts by mass of defoamer, 2-3 parts by mass of anionic agglomerating agent, 5-13 parts by mass of anti-skinning agent, 200-800 parts by mass of deionized water, 2-4 parts by mass of dispersant NNO, 1-2 parts by mass of pH regulator, and 1-5 parts by mass of phosphoric acid. Due to the special electronegativity of anionic emulsifier, anionic emulsifier is used as both emulsifier and initiator, and in the polymerization process of styrene-butadiene rubber emulsion, the polymerization reaction is promoted, and then adsorbed on the surface of latex particles, and the stability of styrene-butadiene latex is increased. While rationally controlling various parameters of the preparation process, defoamer and anti-skinning agent are added to solve the problems between high-temperature and efficient dehydration and latex skinning, glue hanging, and foaming.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, in particular to a method for preparing anionic high-solid-content styrene-butadiene latex. Background Art

[0002] Styrene-butadiene latex is a stable emulsion made of butadiene and styrene through low-temperature polymerization, with a pH value between 3-7. It has high and low temperature resistance, water resistance, chemical corrosion resistance, good electrical insulation, good low-temperature flexibility, excellent tensile properties, and good resistance to oxygen and ozone. In addition, it also has the characteristics of water absorption, plasticity, adhesion and bonding, and is widely used in adhesives, coatings, rubber products, papermaking, inks, adhesives, leather processing and other fields.

[0003] The existing invention patent application disclosure CN202210463775.7 discloses a cationic neutralizer, a high-solid-content styrene-butadiene latex and a preparation method thereof. The cationic neutralizer is mainly prepared by emulsion polymerization with butadiene, styrene, epoxidized monomers, molecular weight regulators and cationic emulsifiers as raw materials; the cationic neutralizer is an emulsion with a solid content of 25-40% and a pH value of 6-7. The preparation method of the high-solid-content styrene-butadiene latex is to stir and mix anionic styrene-butadiene latex and a neutralizer; the neutralizer is the cationic neutralizer described above; the pH value of the mixed latex is adjusted to 8-10, and then dehydrated to obtain a high-solid-content styrene-butadiene latex. By using the cationic neutralizer provided by the present invention, high-content cationic and anionic styrene-butadiene latexes can be obtained respectively, meeting the large particle size requirements of different types of latexes, while avoiding the polymerization of latexes.

[0004] The above-mentioned cationic neutralizer, high-solid-content styrene-butadiene latex and preparation method thereof, the cationic neutralizer provided, can obtain high-content cationic and anionic styrene-butadiene latex respectively, meet the large particle size requirements of different types of latex, and avoid the aggregation and generation of latex. However, there are still contradictions between high-temperature and high-efficiency dehydration and latex skinning and glue hanging, as well as contradictions between high-efficiency dehydration efficiency and latex foaming. In actual operation, it is necessary to find a suitable balance point, which can ensure high-temperature and high-efficiency dehydration, and avoid latex skinning, glue hanging and foaming. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the deficiencies in the prior art, the present invention provides a method for preparing anionic high-solid content styrene-butadiene latex, which solves the contradiction between high-temperature and high-efficiency dehydration and latex skinning and glue hanging, as well as the contradiction between high-efficiency dehydration efficiency and latex foaming.

[0007] (II) Technical solution

[0008] To achieve the above objectives, in a first aspect, the present application provides a method for preparing anionic high solid content styrene-butadiene latex, using the following technical scheme:

[0009] The invention discloses an anionic high-solid-content styrene-butadiene latex, which is prepared by combining cis-9-octadecenoic acid salt as an anionic emulsifier with other materials.

[0010] The anionic emulsifier is prepared from the following materials: 100-150 parts by mass of oleic acid, 100-150 parts by mass of sodium hydroxide, and 200-300 parts by mass of water. It is prepared by the following method:

[0011] A1: Add a certain amount of oleic acid into the reactor, then slowly add sodium hydroxide solution into the oleic acid while stirring;

[0012] A2: Continue to stir the mixture to allow the two to react until no more white precipitate is generated, which means the reaction is over. Cool the mixture to room temperature and let it stand for a while to allow the cis-9-octadecenoic acid salt to fully precipitate;

[0013] A3: Filter out the supernatant, collect the precipitate, and wash it with an appropriate amount of water to remove impurities;

[0014] A4: Dry the collected cis-9-octadecenoic acid salt precipitate to obtain pure cis-9-octadecenoic acid salt.

[0015] Preferably, the sodium hydroxide solution needs to be added while being stirred.

[0016] The invention discloses an anionic high-solid-content styrene-butadiene latex, which is prepared by combining chloromethylstyrene and divinylbenzene copolymer base balls as anionic copolymerizers and other materials.

[0017] The anionic copolymer preparation materials required are as follows: 20-30 parts by mass of chloromethylstyrene, 15-20 parts by mass of divinylbenzene, 5-6 parts by mass of sodium dodecylbenzene sulfonate, 40-50 parts by mass of deionized water, 3-7 parts by mass of sodium persulfate, 200-500 parts by mass of sodium persulfate, and 50-70 parts by mass of sulfuric acid. It is prepared by the following method:

[0018] B1: Add chloromethylstyrene, divinylbenzene, sodium dodecylbenzene sulfonate and deionized water into a blender and set the temperature to 90°C.

[0019] B2: Add sodium persulfate to the mixer, control the dropping speed, keep the temperature at 85°C for 1 hour, then cool to room temperature, centrifuge at 800 rpm, and discard the supernatant.

[0020] B3: Soaking and washing the precipitate with ethanol, and then drying it in an oven at 60°C for 24 hours to obtain chloromethylstyrene and divinylbenzene copolymer-based balls.

[0021] B4: In an ice-water bath, the prepared chloromethylstyrene and divinylbenzene copolymer base balls are dispersed in a sulfuric acid solution, and stirred continuously to obtain a suspension. The suspension is poured into an ice-water bath solution, filtered, and washed with water to obtain an anionic agglomerating agent.

[0022] Preferably, ethanol is used for soaking and washing to remove unreacted monomers and emulsifiers.

[0023] Preferably, the suspension is poured into an ice-water solution in order to terminate the reaction.

[0024] In a second aspect, the present application provides a method for preparing anionic high solid content styrene butadiene latex, using the following technical solution:

[0025] A method for preparing anionic high-solid content styrene-butadiene latex comprises 100-200 parts by weight of butadiene monomer, 40-80 parts by weight of styrene monomer, 4-8 parts by weight of anionic emulsifier, 1-3 parts by weight of molecular weight regulator, 10-17 parts by weight of defoamer, 2-3 parts by weight of anionic agglomerating agent, 5-13 parts by weight of anti-skinning agent, 200-800 parts by weight of deionized water, 2-4 parts by weight of dispersant NNO, 1-2 parts by weight of pH regulator and 1-5 parts by weight of phosphoric acid.

[0026] Preferably, the mass ratio of the butadiene monomer to the styrene monomer is 10-5:2-4.

[0027] Preferably, the defoaming agent is a defoaming agent and the anti-skinning agent is a polyoxyethylene ether nonionic surfactant.

[0028] Among them, it should be specifically noted that by adding defoaming agents and anti-skinning agents, the problems between high-temperature and high-efficiency dehydration and latex skinning, glue hanging, and foaming are fundamentally reduced.

[0029] Preferably, the anionic emulsifier acts as both an emulsifier and an initiator.

[0030] It should be specifically noted that the anionic emulsifier acts as both an emulsifier and an initiator. In the polymerization process of styrene-butadiene rubber emulsion, it promotes the polymerization reaction and then adsorbs on the surface of latex particles to increase the stability of styrene-butadiene rubber latex.

[0031] Specifically, when preparing emulsions such as styrene butadiene latex, cis-9-octadecenoic acid salt is used as an anionic emulsifier, and its anionic part can generate electrostatic interaction with positively charged surfactants or colloid particles, thereby reducing surface tension and improving the stability of the emulsion. In addition, cis-9-octadecenoic acid salt also has good emulsifying properties and calcium soap dispersing properties, which is helpful for preparing styrene butadiene latex with excellent performance.

[0032] A preparation method of a method for preparing an anionic high-solid content styrene-butadiene latex comprises the following steps:

[0033] S1: First, evenly mix deionized water, pH adjuster and phosphoric acid.

[0034] S2: In a spiral reactor, first fill with inert gas, then add the mixed liquid in S1, and then add butadiene monomer, styrene monomer, anionic emulsifier, molecular weight regulator, anti-skinning agent, defoaming agent and dispersant in sequence, set the stirring speed to 340 rpm, and set the temperature to 40°C.

[0035] S3: Then, anionic agglomerating agent is added to start polymerization reaction. After 2 hours, the temperature setting is changed to 50°C. After 4 hours, the temperature is set to 60°C. After keeping the temperature for 3 hours, the material is discharged.

[0036] S4: Heat the prepared styrene-butadiene latex to 60°C and add it to a model evaporator for dehydration. Set the parameters of vacuum degree -0.075Mpa, feed rate 50L / h, and after 2h, the latex viscosity reaches 600-800cp, and then discharge.

[0037] Preferably, the polymerization is carried out by an isogradient temperature rise method.

[0038] It should be specifically noted that the method of increasing the temperature with an arithmetic gradient during polymerization fundamentally solves the agglomeration problem caused by uneven materials during polymerization and the problem of low synthesis efficiency.

[0039] Preferably, a film evaporator is used for dehydration.

[0040] Among them, it should be specifically noted that by using a membrane evaporator, some high-viscosity, particle-containing materials that are difficult to handle with conventional evaporators can be processed, and the materials are not easy to coke or scale in the membrane evaporator, thereby reducing the problems between high-temperature and high-efficiency dehydration and latex skinning and glue hanging.

[0041] (III) Beneficial effects

[0042] The present invention provides a method for preparing anionic high-solid content styrene-butadiene latex, which has the following beneficial effects:

[0043] (1) The preparation method of the anionic high-solid content styrene-butadiene latex is characterized in that the anionic emulsifier is used as both an emulsifier and an initiator. In the styrene-butadiene rubber emulsion polymerization process, the polymerization reaction is promoted, and then adsorbed on the surface of the latex particles to increase the stability of the styrene-butadiene latex. Meanwhile, the cis-9-octadecenoic acid salt is used as an anionic emulsifier, and its anionic part can generate electrostatic interaction with positively charged surfactants or colloid particles, thereby reducing surface tension and improving the stability of the emulsion. In addition, the cis-9-octadecenoic acid salt also has good emulsifying properties and calcium soap dispersibility, which helps to prepare styrene-butadiene latex with excellent performance.

[0044] (2) The method for preparing anionic high-solid content styrene-butadiene latex fundamentally reduces the problems between high-temperature and high-efficiency dehydration and latex skinning, glue hanging, and foaming by adding a defoaming agent and an anti-skinning agent. In addition, the use of a film evaporator as a dehydration device can process some high-viscosity and particle-containing materials that are difficult to process with conventional evaporators. At the same time, the materials are not easy to coke or scale in the film evaporator, thereby reducing the problems between high-temperature and high-efficiency dehydration and latex skinning and glue hanging. DETAILED DESCRIPTION

[0045] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0046] Preparation Example

[0047] Preparation Example 1-3

[0048] An anionic emulsifier, the raw materials and corresponding weights of which are shown in Table 1 below, is prepared by the following preparation method:

[0049] A1: Add a certain amount of oleic acid into the reactor, and then slowly add the sodium hydroxide solution into the oleic acid while stirring.

[0050] A2: Continue to stir the mixture to allow the two to react until no more white precipitate is generated, which means the reaction is complete. Cool the mixture to room temperature and let it stand for a while to allow the cis-9-octadecenoic acid salt to fully precipitate.

[0051] A3: Filter out the supernatant, collect the precipitate, and wash it with an appropriate amount of water to remove impurities.

[0052] A4: Dry the collected cis-9-octadecenoic acid salt precipitate to obtain pure cis-9-octadecenoic acid salt.

[0053] Table 1: Components and their weights in Preparation Examples 1-3 (parts by mass)

[0054]

[0055] Preparation Example 4-6

[0056] An anionic agglomerating agent, the raw materials and corresponding weights of which are shown in Table 2 below, is prepared by the following preparation method:

[0057] B1: Add chloromethylstyrene, divinylbenzene, sodium dodecylbenzene sulfonate and deionized water into a blender and set the temperature to 90°C.

[0058] B2: Add sodium persulfate to the mixer, control the dropping speed, keep the temperature at 85°C for 1 hour, then cool to room temperature, centrifuge at 800 rpm, and discard the supernatant.

[0059] B3: Soaking and washing the precipitate with ethanol, and then drying it in an oven at 60°C for 24 hours to obtain chloromethylstyrene and divinylbenzene copolymer-based balls.

[0060] B4: In an ice-water bath, the prepared chloromethylstyrene and divinylbenzene copolymer base balls are dispersed in a sulfuric acid solution, and stirred continuously to obtain a suspension. The suspension is poured into an ice-water bath solution, filtered, and washed with water to obtain an anionic agglomerating agent.

[0061] Table 2: Components and their weights in Preparation Examples 4-6 (parts by mass)

[0062]

[0063] Example

[0064] Example 1

[0065] Specifically, it is an anionic high solid content styrene butadiene latex, which is composed of the following raw materials:

[0066] 140 parts by mass of butadiene monomer, 60 parts by mass of styrene monomer, 6 parts by mass of anionic emulsifier, 1.5 parts by mass of molecular weight regulator, 13 parts by mass of defoamer, 2 parts by mass of anionic agglomerating agent, 8 parts by mass of anti-skinning agent, 260 parts by mass of deionized water, 3 parts by mass of dispersant NNO, 2 parts by mass of pH regulator, and 3 parts by mass of phosphoric acid. The preparation method of the above-mentioned anionic high solid content styrene butadiene latex is as follows:

[0067] S1: First, evenly mix deionized water, pH adjuster and phosphoric acid.

[0068] S2: In a spiral reactor, first fill with inert gas, then add the mixed liquid in S1, and then add butadiene monomer, styrene monomer, anionic emulsifier, molecular weight regulator, anti-skinning agent, defoaming agent and dispersant in sequence, set the stirring speed to 340 rpm, and set the temperature to 40°C.

[0069] S3: Then, anionic agglomerating agent is added to start polymerization reaction. After 2 hours, the temperature setting is changed to 50°C. After 4 hours, the temperature is set to 60°C. After keeping the temperature for 3 hours, the material is discharged.

[0070] S4: Heat the prepared styrene-butadiene latex to 60°C and add it to a model evaporator for dehydration. Set the parameters of vacuum degree -0.075Mpa, feed rate 50L / h, and after 2h, the latex viscosity reaches 600-800cp, and then discharge.

[0071] It is noted that the anionic emulsifier used is prepared in Preparation Example 1, and the anionic emulsifier used is prepared in Preparation Example 5.

[0072] Example 2

[0073] The invention discloses an anionic high-solid-content styrene-butadiene latex, which is prepared from the following raw materials: 140 parts by weight of butadiene monomer, 60 parts by weight of styrene monomer, 6 parts by weight of anionic emulsifier, 2.5 parts by weight of molecular weight regulator, 13 parts by weight of defoamer, 2 parts by weight of anionic agglomerating agent, 8 parts by weight of anti-skinning agent, 260 parts by weight of deionized water, 3 parts by weight of dispersant NNO, 2 parts by weight of pH regulator and 3 parts by weight of phosphoric acid.

[0074] The preparation steps are as in Example 1, except that the molecular weight regulator is 2.5 parts by mass.

[0075] Example 3

[0076] The invention discloses an anionic high-solid-content styrene-butadiene latex, which is prepared from the following raw materials: 140 parts by weight of butadiene monomer, 60 parts by weight of styrene monomer, 6 parts by weight of anionic emulsifier, 1.5 parts by weight of molecular weight regulator, 13 parts by weight of defoamer, 2 parts by weight of anionic agglomerating agent, 11 parts by weight of anti-skinning agent, 260 parts by weight of deionized water, 3 parts by weight of dispersant NNO, 2 parts by weight of pH regulator and 3 parts by weight of phosphoric acid.

[0077] The preparation steps are as in Example 1, except that the amount of the anti-skinning agent is 11 parts by weight.

[0078] Example 4

[0079] The invention discloses an anionic high-solid-content styrene-butadiene latex, which is prepared from the following raw materials: 140 parts by mass of butadiene monomer, 60 parts by mass of styrene monomer, 6 parts by mass of anionic emulsifier, 2.5 parts by mass of molecular weight regulator, 13 parts by mass of defoamer, 2 parts by mass of anionic agglomerating agent, 11 parts by mass of anti-skinning agent, 260 parts by mass of deionized water, 3 parts by mass of dispersant NNO, 2 parts by mass of pH regulator and 3 parts by mass of phosphoric acid.

[0080] The preparation steps refer to Example 1, except that the molecular weight regulator is 2.5 parts by mass and the anti-skinning agent is 11 parts by mass.

[0081] Example 5

[0082] The invention discloses an anionic high-solid-content styrene-butadiene latex, which is prepared from the following raw materials: 140 parts by weight of butadiene monomer, 60 parts by weight of styrene monomer, 6 parts by weight of anionic emulsifier, 1.5 parts by weight of molecular weight regulator, 13 parts by weight of defoaming agent, 2 parts by weight of anionic agglomerating agent, 13 parts by weight of anti-skinning agent, 260 parts by weight of deionized water, 3 parts by weight of dispersant NNO, 2 parts by weight of pH regulator and 3 parts by weight of phosphoric acid.

[0083] The preparation steps are as shown in Example 1, except that the amount of the anti-skinning agent is 13 parts by weight.

[0084] Example 6

[0085] The invention discloses an anionic high-solid-content styrene-butadiene latex, which is prepared from the following raw materials: 140 parts by weight of butadiene monomer, 60 parts by weight of styrene monomer, 6 parts by weight of anionic emulsifier, 2.5 parts by weight of molecular weight regulator, 13 parts by weight of defoaming agent, 2 parts by weight of anionic agglomerating agent, 13 parts by weight of anti-skinning agent, 260 parts by weight of deionized water, 3 parts by weight of dispersant NNO, 2 parts by weight of pH regulator and 3 parts by weight of phosphoric acid.

[0086] The preparation steps refer to Example 1, except that the molecular weight regulator is 2.5 parts by mass and the anti-skinning agent is 13 parts by mass.

[0087] Example 7

[0088] The invention discloses an anionic high-solid-content styrene-butadiene latex, which is prepared from the following raw materials: 200 parts by weight of butadiene monomer, 60 parts by weight of styrene monomer, 6 parts by weight of anionic emulsifier, 1.5 parts by weight of molecular weight regulator, 13 parts by weight of defoamer, 2 parts by weight of anionic agglomerating agent, 8 parts by weight of anti-skinning agent, 340 parts by weight of deionized water, 3 parts by weight of dispersant NNO, 2 parts by weight of pH regulator and 3 parts by weight of phosphoric acid.

[0089] The preparation steps refer to Example 1, except that the mass ratio of butadiene to styrene is 10:4, and the mass ratio of deionized water is 340 parts by mass.

[0090] Example 8

[0091] The invention discloses an anionic high-solid-content styrene-butadiene latex, which is prepared from the following raw materials: 200 parts by mass of butadiene monomer, 60 parts by mass of styrene monomer, 6 parts by mass of anionic emulsifier, 2.5 parts by mass of molecular weight regulator, 13 parts by mass of defoamer, 2 parts by mass of anionic agglomerating agent, 8 parts by mass of anti-skinning agent, 340 parts by mass of deionized water, 3 parts by mass of dispersant NNO, 2 parts by mass of pH regulator and 3 parts by mass of phosphoric acid.

[0092] The preparation steps refer to Example 1, except that the mass ratio of butadiene to styrene is 10:4, and the molecular weight regulator is 2.5 parts by mass.

[0093] Example 9

[0094] The invention discloses an anionic high-solid-content styrene-butadiene latex, which is prepared from the following raw materials: 200 parts by mass of butadiene monomer, 60 parts by mass of styrene monomer, 6 parts by mass of anionic emulsifier, 1.5 parts by mass of molecular weight regulator, 13 parts by mass of defoamer, 2 parts by mass of anionic agglomerating agent, 11 parts by mass of anti-skinning agent, 340 parts by mass of deionized water, 3 parts by mass of dispersant NNO, 2 parts by mass of pH regulator and 3 parts by mass of phosphoric acid.

[0095] The preparation steps refer to Example 1, except that the mass ratio of butadiene to styrene is 10:4, the mass ratio of deionized water is 340 parts by mass, and the mass ratio of the anti-skinning agent is 11 parts by mass.

[0096] Example 10

[0097] The invention discloses an anionic high-solid-content styrene-butadiene latex, which is prepared from the following raw materials: 200 parts by mass of butadiene monomer, 60 parts by mass of styrene monomer, 6 parts by mass of anionic emulsifier, 2.5 parts by mass of molecular weight regulator, 13 parts by mass of defoamer, 2 parts by mass of anionic agglomerating agent, 11 parts by mass of anti-skinning agent, 340 parts by mass of deionized water, 3 parts by mass of dispersant NNO, 2 parts by mass of pH regulator and 3 parts by mass of phosphoric acid.

[0098] The preparation steps refer to Example 1, except that the mass ratio of butadiene to styrene is 10:4, the molecular weight regulator is 2.5 parts by mass, and the anti-skinning agent is 11 parts by mass.

[0099] Embodiment 11

[0100] The invention discloses an anionic high-solid-content styrene-butadiene latex, which is prepared from the following raw materials: 200 parts by mass of butadiene monomer, 60 parts by mass of styrene monomer, 6 parts by mass of anionic emulsifier, 1.5 parts by mass of molecular weight regulator, 13 parts by mass of defoaming agent, 2 parts by mass of anionic agglomerating agent, 13 parts by mass of anti-skinning agent, 340 parts by mass of deionized water, 3 parts by mass of dispersant NNO, 2 parts by mass of pH regulator and 3 parts by mass of phosphoric acid.

[0101] The preparation steps refer to Example 1, except that the mass ratio of butadiene to styrene is 10:4, the mass ratio of deionized water is 340 parts by mass, and the mass ratio of the anti-skinning agent is 13 parts by mass.

[0102] Example 12

[0103] The invention discloses an anionic high-solid-content styrene-butadiene latex, which is prepared from the following raw materials: 200 parts by mass of butadiene monomer, 60 parts by mass of styrene monomer, 6 parts by mass of anionic emulsifier, 2.5 parts by mass of molecular weight regulator, 13 parts by mass of defoamer, 2 parts by mass of anionic agglomerating agent, 13 parts by mass of anti-skinning agent, 340 parts by mass of deionized water, 3 parts by mass of dispersant NNO, 2 parts by mass of pH regulator and 3 parts by mass of phosphoric acid.

[0104] The preparation steps refer to Example 1, except that the mass ratio of butadiene to styrene is 10:4, the molecular weight regulator is 2.5 parts by mass, and the anti-skinning agent is 13 parts by mass.

[0105] Embodiment 13

[0106] An anionic high-solid content styrene-butadiene latex is prepared from the following raw materials: 200 parts by mass of butadiene monomer, 80 parts by mass of styrene monomer, 6 parts by mass of anionic emulsifier, 1.5 parts by mass of molecular weight regulator, 13 parts by mass of defoamer, 2 parts by mass of anionic agglomerating agent, 8 parts by mass of anti-skinning agent, 400 parts by mass of deionized water, 3 parts by mass of dispersant NNO, 2 parts by mass of pH regulator and 3 parts by mass of phosphoric acid.

[0107] The preparation steps refer to Example 1, except that the mass ratio of butadiene to styrene is 10:4, and 400 parts by mass of deionized water are used.

[0108] Embodiment 14

[0109] An anionic high-solid content styrene-butadiene latex is prepared from the following raw materials: 200 parts by mass of butadiene monomer, 800 parts by mass of styrene monomer, 6 parts by mass of anionic emulsifier, 2.5 parts by mass of molecular weight regulator, 13 parts by mass of defoamer, 2 parts by mass of anionic agglomerating agent, 8 parts by mass of anti-skinning agent, 400 parts by mass of deionized water, 3 parts by mass of dispersant NNO, 2 parts by mass of pH regulator, and 3 parts by mass of phosphoric acid.

[0110] The preparation steps refer to Example 1, except that the mass ratio of butadiene to styrene is 10:4, the molecular weight regulator is 2.5 parts by mass, and the deionized water is 400 parts by mass.

[0111] Embodiment 15

[0112] The invention discloses an anionic high-solid-content styrene-butadiene latex, which is prepared from the following raw materials: 200 parts by mass of butadiene monomer, 80 parts by mass of styrene monomer, 6 parts by mass of anionic emulsifier, 1.5 parts by mass of molecular weight regulator, 13 parts by mass of defoaming agent, 2 parts by mass of anionic agglomerating agent, 11 parts by mass of anti-skinning agent, 400 parts by mass of deionized water, 3 parts by mass of dispersant NNO, 2 parts by mass of pH regulator and 3 parts by mass of phosphoric acid.

[0113] The preparation steps refer to Example 1, except that the mass ratio of butadiene to styrene is 10:4, 400 mass parts of deionized water and 11 mass parts of anti-skinning agent are used.

[0114] Example 16

[0115] An anionic high-solid content styrene-butadiene latex is prepared from the following raw materials: 200 parts by mass of butadiene monomer, 800 parts by mass of styrene monomer, 6 parts by mass of anionic emulsifier, 2.5 parts by mass of molecular weight regulator, 13 parts by mass of defoamer, 2 parts by mass of anionic agglomerating agent, 11 parts by mass of anti-skinning agent, 400 parts by mass of deionized water, 3 parts by mass of dispersant NNO, 2 parts by mass of pH regulator, and 3 parts by mass of phosphoric acid.

[0116] The preparation steps refer to Example 1, except that the mass ratio of butadiene to styrene is 10:4, the molecular weight regulator is 2.5 parts by mass, the deionized water is 400 parts by mass, and the anti-skinning agent is 11 parts by mass.

[0117] Embodiment 17

[0118] The invention discloses an anionic high-solid-content styrene-butadiene latex, which is prepared from the following raw materials: 200 parts by mass of butadiene monomer, 80 parts by mass of styrene monomer, 6 parts by mass of anionic emulsifier, 1.5 parts by mass of molecular weight regulator, 13 parts by mass of defoaming agent, 2 parts by mass of anionic agglomerating agent, 13 parts by mass of anti-skinning agent, 400 parts by mass of deionized water, 3 parts by mass of dispersant NNO, 2 parts by mass of pH regulator and 3 parts by mass of phosphoric acid.

[0119] The preparation steps refer to Example 1, except that the mass ratio of butadiene to styrene is 10:4, 400 mass parts of deionized water and 13 mass parts of anti-skinning agent are used.

[0120] Embodiment 18

[0121] The invention discloses an anionic high-solid-content styrene-butadiene latex, which is prepared from the following raw materials: 200 parts by mass of butadiene monomer, 800 parts by mass of styrene monomer, 6 parts by mass of anionic emulsifier, 2.5 parts by mass of molecular weight regulator, 13 parts by mass of defoaming agent, 2 parts by mass of anionic agglomerating agent, 13 parts by mass of anti-skinning agent, 400 parts by mass of deionized water, 3 parts by mass of dispersant NNO, 2 parts by mass of pH regulator and 3 parts by mass of phosphoric acid.

[0122] The preparation steps refer to Example 1, except that the mass ratio of butadiene to styrene is 10:4, the molecular weight regulator is 2.5 parts by mass, the deionized water is 400 parts by mass, and the anti-skinning agent is 13 parts by mass.

[0123] Comparative Example 1

[0124] Comparative Example 1 is the same as Example 1, except that no anti-skinning agent is added.

[0125] Comparative Example 2

[0126] Comparative Example 1 is the same as Example 1, except that no defoaming agent is added.

[0127] Comparative Example 3

[0128] Comparative Example 1 is the same as Example 1, except that: no agglomerating agent is added, the temperature is directly raised to 60° C. instead of using the isogradient temperature increase method; and the film evaporator is replaced by other evaporators.

[0129] The various parameters of the preparation process of the original enzyme beverage based on the extraction system structure of Examples 1-18 and Comparative Examples 1-3 were recorded respectively, and the following results were obtained, as shown in Table 3:

[0130] Table 3: Comparison of test parameters between Examples 1-18 and Comparative Examples 1-3

[0131]

[0132]

[0133]

[0134] According to the comparison of the test data of the embodiment and the comparative example in Table 3, it can be seen that the anionic high-solid content styrene-butadiene latex prepared by the technical solution of the present application is compared with the products on the market. The present application adds cis-9-octadecenoic acid salt as an anionic emulsifier. Due to the special electronegativity of the anionic emulsifier, the anionic emulsifier acts as both an emulsifier and an initiator. During the polymerization process of styrene-butadiene rubber emulsion, the polymerization reaction is promoted, and then adsorbed on the surface of the latex particles to increase the stability of the styrene-butadiene latex.

[0135] According to the comparison of the test data of Examples 1-18 and Comparative Examples 1-3 in Table 3, it can be seen that by adding a defoaming agent and an anti-skinning agent, the problems between high-temperature and high-efficiency dehydration and latex skinning, glue hanging, and foaming are avoided in the preparation process. At the same time, a film evaporator is used as the preparation equipment, so that the material is not easy to coke and scale during the evaporation and dehydration process, thereby effectively reducing the problems between high-temperature and high-efficiency dehydration and latex skinning and glue hanging.

[0136] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing anionic high solid content styrene-butadiene latex, characterized in that: The following steps are involved: S1: first, uniformly mix deionized water, pH regulator and phosphoric acid; S2: In a spiral reactor, first fill with inert gas, then add the mixed liquid in S1, and then add butadiene monomer, styrene monomer, anionic emulsifier, molecular weight regulator, anti-skinning agent, defoaming agent and dispersant in sequence, set the stirring speed to 340 rpm, and the temperature to 40°C; The anionic emulsifier is cis-9-octadecenoic acid salt; S3: Then, anionic agglomerating agent is added to start polymerization reaction. After 2 hours, the temperature setting is changed to 50°C. After 4 hours, the temperature is set to 60°C. After keeping the temperature for 3 hours, the material is discharged. The preparation method of the anionic agglomerating agent is as follows: B1: Add chloromethylstyrene, divinylbenzene, sodium dodecylbenzene sulfonate and deionized water into a blender and set the temperature to 90°C; B2: Add sodium persulfate to the mixer, control the dropwise addition speed, keep the temperature at 85°C for 1 hour, then cool to room temperature, centrifuge at 800 rpm, and discard the supernatant; B3: Soaking and washing the precipitate with ethanol, and then drying it in an oven at 60°C for 24 hours to obtain chloromethylstyrene and divinylbenzene copolymer-based balls; B4: Dispersing the prepared chloromethylstyrene and divinylbenzene copolymer base balls in a sulfuric acid solution under ice-water bath conditions, stirring continuously to obtain a suspension, pouring the suspension into an ice-water bath solution, filtering with suction, and washing with water to obtain an anionic agglomerating agent; S4: The prepared styrene-butadiene latex is heated to 60°C, added into a film evaporator for dehydration treatment, and the parameters of vacuum degree are set to -0.075MPa, feed rate to 50L / h, and after 2h, the latex viscosity reaches 600-800cp, and the material is discharged.

2. The method for preparing an anionic high solid content styrene-butadiene latex according to claim 1, characterized in that: The anti-skinning agent is a polyoxyethylene ether nonionic surfactant.

3. The method for preparing an anionic high solid content styrene-butadiene latex according to claim 1, characterized in that: The mass ratio of the butadiene monomer to the styrene monomer is 10-5:2-4.

4. The method for preparing an anionic high solid content styrene-butadiene latex according to claim 1, characterized in that: In the S4 process, a constant gradient temperature rise method is adopted and a film evaporator is used for dehydration treatment.

5. The method for preparing an anionic high solid content styrene-butadiene latex according to claim 1, characterized in that: The preparation method of the cis-9-octadecenoic acid salt is as follows: A1: Add a certain amount of oleic acid into the reactor, then slowly add the sodium hydroxide solution into the oleic acid while stirring; A2: Continue to stir the mixture to allow the two to react until no more white precipitate is generated. The reaction is complete. The mixture is cooled to room temperature and allowed to stand for a period of time to allow the cis-9-octadecenoic acid salt to fully precipitate. A3: Filter out the supernatant, collect the precipitate, and wash it with an appropriate amount of water to remove impurities; A4: Dry the collected cis-9-octadecenoic acid salt precipitate to obtain pure cis-9-octadecenoic acid salt.

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