High-stability latex for coated paper and preparation method thereof

Abstract

The invention discloses a kind of high stability latex for coated paper and preparation method thereof, the preparation method comprises the following steps: in a batching tank, fumaric acid, tetrasodium EDTA and seed emulsion are fully dissolved and uniformly mixed to obtain a mixed solution; steam is passed into a reactor, and after vacuum is formed in the reactor to remove free oxygen by an external cooling cycle, the mixed solution is added to the reactor and stirred, and steam is passed into the reactor; when the temperature in the reactor reaches 86 ° C, styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator, emulsifier are added sequentially after the stirring speed is changed to 92 revs / min, and the temperature in the reactor is maintained at 85.5-87.5 ° C; initiator and emulsifier are added again, and after being kept warm for 1h, it is cooled to 78-80 ° C to obtain pre-coated latex; acrylamide is added to pre-coated latex to obtain high stability latex. The present invention enhances stability while ensuring latex particle size, viscosity and glass transition temperature, reduces latex demulsification probability, improves paper surface strength, reduces the sticking cylinder of paper machine, reduces paper resource waste and increases production capacity.

Description

Technical Field

[0001] The invention relates to latex stability technology, in particular to a high-stability latex for coated paper and a preparation method thereof. Background Art

[0002] With the rapid development of coating machines and faster and faster speeds, coating machines need a highly stable and high-strength latex to meet the operation of paper machines. Because the speed of paper machines is too fast and the latex is not stable enough, it is easy to break the emulsion, which will cause some paper machines to stick to the cylinder, affecting the performance, increasing the amount of paper returned, causing waste of paper and energy, reducing the amount of paper returned and solving the problem of sticking to the cylinder. Summary of the invention

[0003] Purpose of the invention: The present invention aims to provide a high-stability latex for coated paper that is not easy to demulsify; another purpose of the present invention is to provide a method for preparing the high-stability latex for coated paper.

[0004] Technical solution: The high-stability latex for coated paper of the present invention comprises the following components, measured by mass percentage: 3.1%-3.5% of liquid alkali, 0.8%-1.0% of defoaming agent, 36%-39% of butadiene, 48%-52% of styrene, 1.6%-1.8% of emulsifier, 1.8%-2.0% of acrylic acid, 0.7%-0.9% of seed emulsion, 1.0%-1.2% of fumaric acid, 0.8%-1.0% of ammonium persulfate, 0.7%-0.9% of tert-dodecyl mercaptan, 0.03%-0.05% of chelating agent, and 1.65%-1.85% of acrylamide.

[0005] Furthermore, the chelating agent is tetrasodium EDTA.

[0006] The method for preparing the high-stability latex for coated paper of the present invention comprises the following steps:

[0007] (1) Fully dissolve fumaric acid, tetrasodium EDTA, and seed emulsion in a mixing tank and mix them evenly;

[0008] (2) introducing steam into the reactor, and after forming a vacuum in the reactor to remove free oxygen through an external cooling cycle, adding the solution obtained in step (1) into the reactor and starting stirring, and continuing to introduce steam into the reactor;

[0009] (3) When the temperature in the reactor reaches 86°C, the stirring speed in the reactor is changed from 70 rpm to 92 rpm, and styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator, and emulsifier are pumped into the reactor in sequence. The feeding time is 4 hours, and the temperature in the reactor is controlled at 85.5-87.5°C;

[0010] (4) adding initiator and emulsifier to the reaction kettle again for 1.5-5.5 hours, keeping warm for 1 hour and then cooling to a transfer temperature of 78-80° C., transferring the latex in the kettle to a stripping kettle to obtain a pre-coated latex;

[0011] (5) Add acrylamide to the pre-coated latex to obtain a high-stability latex.

[0012] Furthermore, in step (1), the mass ratio of fumaric acid, tetrasodium EDTA and seed emulsion is 26:1:21.

[0013] Furthermore, the emulsifier in step (3) is a 30% concentration solution prepared by adding water to sodium dodecylbenzene sulfonate.

[0014] Furthermore, the initiator in step (3) is ammonium persulfate

[0015] Furthermore, in step (3), the mass ratio of styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator solution and emulsifier solution is 49:37:1.9:0.8:0.9:1.7.

[0016] Furthermore, in step (5), the mass ratio of the pre-coating latex to acrylamide is between 500:8.5 and 500:9.0.

[0017] Furthermore, the concentration of acrylamide is between 84% and 86%.

[0018] Furthermore, the viscosity of the high-stability latex obtained in step (5) is 100 to 374 cps, and the stability of the latex functional groups is 0.5 to 0.9 mg / g.

[0019] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: the present invention can enhance stability while ensuring the particle size, viscosity and glass transition temperature of latex, reduce the probability of latex demulsification, reduce the sticking of paper machines, reduce the waste of paper resources and increase production capacity. DETAILED DESCRIPTION

[0020] The method for preparing the high-stability latex for coated paper of the present invention comprises the following steps:

[0021] (1) Fully dissolve fumaric acid, tetrasodium EDTA, and seed emulsion in a batching tank and uniformly mix them; the mass ratio of fumaric acid, tetrasodium EDTA, and seed emulsion is 26:1:21;

[0022] (2) introducing steam into the reactor, and after forming a vacuum in the reactor to remove free oxygen through an external cooling cycle, adding the solution obtained in step (1) into the reactor and starting stirring, and continuing to introduce steam into the reactor;

[0023] (3) When the temperature in the reactor reaches 86° C., the stirring speed in the reactor is changed from 70 rpm to 92 rpm, and styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator, and emulsifier are pumped into the reactor in sequence. The feeding time is 4 hours, and the temperature in the reactor is controlled to be 85.5-87.5° C.; the emulsifier is a 30% solution of sodium dodecylbenzene sulfonate and water, and the initiator is ammonium persulfate; the mass ratio of styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator solution, and emulsifier solution is 49:37:1.9:0.8:0.9:1.7;

[0024] (4) adding 0.8%-1.0% initiator and 1.6%-1.8% emulsifier to the reactor again, with a feeding time of 1.5-5.5 hours, keeping warm for 1 hour and then cooling to a transfer temperature of 78-80° C., transferring the latex in the reactor to a stripping reactor to obtain a pre-coated latex;

[0025] (5) Adding acrylamide to the pre-coating latex to obtain a high-stability latex; the mass ratio of the pre-coating latex to acrylamide is between 500:8.5 and 500:9.0; the concentration of acrylamide is between 84% and 86%; the viscosity of the obtained high-stability latex is 100 to 374 cps, and the stability of the latex functional groups is 0.55 to 0.90 mg / g.

[0026] The high-stability latex is prepared by using a seed emulsion of butadiene, styrene, tert-dodecyl mercaptan and carboxylic acid, an initiator of ammonium persulfate and an emulsifier of a 30% concentration solution of sodium dodecylbenzene sulfonate and water.

[0027] The surface strength in the following examples and comparative examples refers to the surface strength of IBH paper coated with high stability latex, with a paper weight of 255.

[0028] Example 1

[0029] (1) Fully dissolve fumaric acid, tetrasodium EDTA, and seed emulsion in a batching tank and uniformly mix them; the mass ratio of fumaric acid, tetrasodium EDTA, and seed emulsion is 26:1:21;

[0030] (2) introducing steam into the reactor, and after forming a vacuum in the reactor to remove free oxygen through an external cooling cycle, adding the solution obtained in step (1) into the reactor and starting stirring, and continuing to introduce steam into the reactor;

[0031] (3) When the temperature in the reactor reaches 86° C. and the stirring speed in the reactor is changed from 70 rpm to 92 rpm, styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator, and emulsifier are pumped into the reactor in sequence. The feeding time is 4 hours, and the temperature in the reactor is controlled to be 85.5-87.5° C.; the emulsifier is a 30% solution of sodium dodecylbenzene sulfonate and water, and the initiator is ammonium persulfate; the mass ratio of styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator solution, and emulsifier solution is 49:37:1.9:0.8:0.9:1.7;

[0032] (4) adding initiator and emulsifier to the reactor again for 1.5 hours, keeping warm for 1 hour and then cooling to a transfer temperature of 78-80° C., transferring the latex in the reactor to a stripping reactor to obtain a pre-coated latex;

[0033] (5) Adding acrylamide to the pre-coated latex to obtain a high-stability latex; the mass ratio of the pre-coated latex to acrylamide is 500:8.5; the concentration of acrylamide is 85%; the obtained high-stability latex has a viscosity of 374 cps, a stability of the latex functional group of 0.80 mg / g, a good degree of encapsulation, and a surface strength of 35 Kn / mm 2 .

[0034] Example 2

[0035] (1) Fully dissolve fumaric acid, tetrasodium EDTA, and seed emulsion in a batching tank and uniformly mix them; the mass ratio of fumaric acid, tetrasodium EDTA, and seed emulsion is 26:1:21;

[0036] (2) introducing steam into the reactor, and after forming a vacuum in the reactor to remove free oxygen through an external cooling cycle, adding the solution obtained in step (1) into the reactor and starting stirring, and continuing to introduce steam into the reactor;

[0037] (3) When the temperature in the reactor reaches 86° C. and the stirring speed in the reactor is changed from 70 rpm to 92 rpm, styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator, and emulsifier are pumped into the reactor in sequence. The feeding time is 4 hours, and the temperature in the reactor is controlled to be 85.5-87.5° C.; the emulsifier is a 30% solution of sodium dodecylbenzene sulfonate and water, and the initiator is ammonium persulfate; the mass ratio of styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator solution, and emulsifier solution is 49:37:1.9:0.8:0.9:1.7;

[0038] (4) adding initiator and emulsifier to the reactor again, the feeding time is 1.5 hours, keeping warm for 1 hour and then cooling to the transfer temperature of 78-80° C., transferring the latex in the reactor to the stripping reactor to obtain pre-coated latex;

[0039] (5) Adding acrylamide to the pre-coated latex to obtain a high-stability latex; the mass ratio of the pre-coated latex to acrylamide is 500:4; the concentration of acrylamide is 85%; the obtained high-stability latex has a viscosity of 280 cps, a stability of the latex functional group of 0.55 mg / g, a good degree of encapsulation, and a surface strength of 45 Kn / mm 2 .

[0040] After testing, indicators such as solid content, viscosity, particle size, pH value, glass transition temperature, and ion stability still meet the production process standards, as shown in the following table.

[0041]

[0042] Example 3

[0043] (1) Fully dissolve fumaric acid, tetrasodium EDTA, and seed emulsion in a batching tank and uniformly mix them; the mass ratio of fumaric acid, tetrasodium EDTA, and seed emulsion is 26:1:21;

[0044] (2) introducing steam into the reactor, and after forming a vacuum in the reactor to remove free oxygen through an external cooling cycle, adding the solution obtained in step (1) into the reactor and starting stirring, and continuing to introduce steam into the reactor;

[0045] (3) When the temperature in the reactor reaches 86° C. and the stirring speed in the reactor is changed from 70 rpm to 92 rpm, styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator, and emulsifier are pumped into the reactor in sequence. The feeding time is 4 hours, and the temperature in the reactor is controlled to be 85.5-87.5° C.; the emulsifier is a 30% solution of sodium dodecylbenzene sulfonate and water, and the initiator is ammonium persulfate; the mass ratio of styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator solution, and emulsifier solution is 49:37:1.9:0.8:0.9:1.7;

[0046] (4) adding initiator and emulsifier to the reactor again for 1.5 hours, keeping warm for 1 hour and then cooling to a transfer temperature of 78-80° C., transferring the latex in the reactor to a stripping reactor to obtain a pre-coated latex;

[0047] (5) Adding acrylamide to the pre-coated latex to obtain a high-stability latex; the mass ratio of the pre-coated latex to acrylamide is 500:9.0; the concentration of acrylamide is 60%; the obtained high-stability latex has a viscosity of 270 cps, a stability of the latex functional group of 0.9 mg / g, a good degree of encapsulation, and a surface strength of 35 Kn / mm 2 .

[0048] Example 4

[0049] (1) Fully dissolve fumaric acid, tetrasodium EDTA, and seed emulsion in a batching tank and uniformly mix them; the mass ratio of fumaric acid, tetrasodium EDTA, and seed emulsion is 26:1:21;

[0050] (2) introducing steam into the reactor, and after forming a vacuum in the reactor to remove free oxygen through an external cooling cycle, adding the solution obtained in step (1) into the reactor and starting stirring, and continuing to introduce steam into the reactor;

[0051] (3) When the temperature in the reactor reaches 86° C. and the stirring speed in the reactor is changed from 70 rpm to 92 rpm, styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator, and emulsifier are pumped into the reactor in sequence. The feeding time is 4 hours, and the temperature in the reactor is controlled to be 85.5-87.5° C.; the emulsifier is a 30% solution of sodium dodecylbenzene sulfonate and water, and the initiator is ammonium persulfate; the mass ratio of styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator solution, and emulsifier solution is 49:37:1.9:0.8:0.9:1.7;

[0052] (4) adding initiator and emulsifier to the reactor again for 1.5 hours, keeping warm for 1 hour and then cooling to a transfer temperature of 78-80° C., transferring the latex in the reactor to a stripping reactor to obtain a pre-coated latex;

[0053] (5) Adding acrylamide to the pre-coated latex to obtain a high-stability latex; the mass ratio of the pre-coated latex to acrylamide is 500:9.0; the concentration of acrylamide is 85%; the obtained high-stability latex has a viscosity of 280 cps, a stability of the latex functional group of 0.60 mg / g, an excellent degree of encapsulation, and a surface strength of 43 Kn / mm 2 .

[0054] Comparative Example 1

[0055] (1) Fully dissolve fumaric acid, tetrasodium EDTA, and seed emulsion in a batching tank and uniformly mix them; the mass ratio of fumaric acid, tetrasodium EDTA, and seed emulsion is 26:1:21;

[0056] (2) introducing steam into the reactor, and after forming a vacuum in the reactor to remove free oxygen through an external cooling cycle, adding the solution obtained in step (1) into the reactor and starting stirring, and continuing to introduce steam into the reactor;

[0057] (3) When the temperature in the reactor reaches 86° C. and the stirring speed in the reactor is changed from 70 rpm to 92 rpm, styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator, and emulsifier are pumped into the reactor in sequence. The feeding time is 4 hours, and the temperature in the reactor is controlled to be 85.5-87.5° C.; the emulsifier is a 30% solution of sodium dodecylbenzene sulfonate and water, and the initiator is ammonium persulfate; the mass ratio of styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator solution, and emulsifier solution is 49:37:1.9:0.8:0.9:1.7;

[0058] (4) adding initiator and emulsifier to the reactor again for 1.5 hours, keeping warm for 1 hour and then cooling to a transfer temperature of 78-80° C., transferring the latex in the reactor to a stripping reactor to obtain a pre-coated latex;

[0059] (5) Adding acrylamide to the pre-coated latex to obtain a high-stability latex; the mass ratio of the pre-coated latex to acrylamide is 500:1; the concentration of acrylamide is 85%; the viscosity of the obtained high-stability latex is 560 cps, the stability of the latex functional group is 1.20 mg / g, the degree of encapsulation is poor, and the surface strength is 23 Kn / mm 2 .

[0060] Comparative Example 2

[0061] (1) Fully dissolve fumaric acid, tetrasodium EDTA, and seed emulsion in a batching tank and uniformly mix them; the mass ratio of fumaric acid, tetrasodium EDTA, and seed emulsion is 26:1:21;

[0062] (2) introducing steam into the reactor, and after forming a vacuum in the reactor to remove free oxygen through an external cooling cycle, adding the solution obtained in step (1) into the reactor and starting stirring, and continuing to introduce steam into the reactor;

[0063] (3) When the temperature in the reactor reaches 86° C. and the stirring speed in the reactor is changed from 70 rpm to 92 rpm, styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator, and emulsifier are pumped into the reactor in sequence. The feeding time is 4 hours, and the temperature in the reactor is controlled to be 85.5-87.5° C.; the emulsifier is a 30% solution of sodium dodecylbenzene sulfonate and water, and the initiator is ammonium persulfate; the mass ratio of styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator solution, and emulsifier solution is 49:37:1.9:0.8:0.9:1.7;

[0064] (4) adding initiator and emulsifier to the reactor again for 1.5 hours, keeping warm for 1 hour and then cooling to a transfer temperature of 78-80° C., transferring the latex in the reactor to a stripping reactor to obtain a pre-coated latex;

[0065] (5) Adding acrylamide to the pre-coated latex to obtain a high-stability latex; the mass ratio of the pre-coated latex to acrylamide is 500:2; the concentration of acrylamide is 85%; the viscosity of the obtained high-stability latex is 500 cps, the stability of the latex functional group is 1.10 mg / g, the degree of encapsulation is poor, and the surface strength is 28 Kn / mm 2 .

[0066] Comparative Example 3

[0067] (1) Fully dissolve fumaric acid, tetrasodium EDTA, and seed emulsion in a batching tank and uniformly mix them; the mass ratio of fumaric acid, tetrasodium EDTA, and seed emulsion is 26:1:21;

[0068] (2) introducing steam into the reactor, and after forming a vacuum in the reactor to remove free oxygen through an external cooling cycle, adding the solution obtained in step (1) into the reactor and starting stirring, and continuing to introduce steam into the reactor;

[0069] (3) When the temperature in the reactor reaches 86°C and the stirring speed in the reactor is changed from 70 rpm to 92 rpm, styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator, and emulsifier are pumped into the reactor in sequence, the feeding time is 4 hours, and the temperature in the reactor is controlled to be 85.5-87.5°C; the emulsifier is a 30% solution of sodium dodecylbenzene sulfonate and water, and the initiator is ammonium persulfate; the mass ratio of styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator solution, and emulsifier solution is 49:37:1.9:0.8:0.9:1.7;

[0070] (4) adding initiator and emulsifier to the reactor again, the feeding time is 1.5 hours, keeping warm for 1 hour and then cooling to the transfer temperature of 78-80° C., transferring the latex in the reactor to the stripping reactor to obtain pre-coated latex;

[0071] (5) Adding acrylamide to the pre-coated latex to obtain a high-stability latex; the mass ratio of the pre-coated latex to acrylamide is 500:9.0; the concentration of acrylamide is 20%; the viscosity of the obtained high-stability latex is 500 cps, the stability of the latex functional group is 1.1 mg / g, the degree of encapsulation is poor, and the surface strength is 23 Kn / mm 2 .

[0072] Comparative Example 4

[0073] (1) Fully dissolve fumaric acid, tetrasodium EDTA, and seed emulsion in a batching tank and uniformly mix them; the mass ratio of fumaric acid, tetrasodium EDTA, and seed emulsion is 26:1:21;

[0074] (2) introducing steam into the reactor, and after forming a vacuum in the reactor to remove free oxygen through an external cooling cycle, adding the solution obtained in step (1) into the reactor and starting stirring, and continuing to introduce steam into the reactor;

[0075] (3) When the temperature in the reactor reaches 86°C and the stirring speed in the reactor is changed from 70 rpm to 92 rpm, styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator, and emulsifier are pumped into the reactor in sequence, the feeding time is 4 hours, and the temperature in the reactor is controlled to be 85.5-87.5°C; the emulsifier is a 30% solution of sodium dodecylbenzene sulfonate and water, and the initiator is ammonium persulfate; the mass ratio of styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator solution, and emulsifier solution is 49:37:1.9:0.8:0.9:1.7;

[0076] (4) adding initiator and emulsifier to the reactor again, the feeding time is 1.5 hours, keeping warm for 1 hour and then cooling to the transfer temperature of 78-80° C., transferring the latex in the reactor to the stripping reactor to obtain pre-coated latex;

[0077] (5) Adding acrylamide to the pre-coated latex to obtain a high-stability latex; the mass ratio of the pre-coated latex to acrylamide is 500:9.0; the concentration of acrylamide is 45%; the viscosity of the obtained high-stability latex is 400 cps, the stability of the latex functional group is 1.0 mg / g, the degree of encapsulation is poor, and the surface strength is 28 Kn / mm 2 .

[0078] Comparative Example 5

[0079] (1) Fully dissolve fumaric acid, tetrasodium EDTA, and seed emulsion in a batching tank and uniformly mix them; the mass ratio of fumaric acid, tetrasodium EDTA, and seed emulsion is 26:1:21;

[0080] (2) introducing steam into the reactor, and after forming a vacuum in the reactor to remove free oxygen through an external cooling cycle, adding the solution obtained in step (1) into the reactor and starting stirring, and continuing to introduce steam into the reactor;

[0081] (3) When the temperature in the reactor reaches 86°C and the stirring speed in the reactor is changed from 70 rpm to 92 rpm, styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator, and emulsifier are pumped into the reactor in sequence, the feeding time is 4 hours, and the temperature in the reactor is controlled to be 85.5-87.5°C; the emulsifier is a 30% solution of sodium dodecylbenzene sulfonate and water, and the initiator is ammonium persulfate; the mass ratio of styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator solution, and emulsifier solution is 49:37:1.9:0.8:0.9:1.7;

[0082] (4) Adding initiator and emulsifier to the reactor again, the feeding time is 1.5 hours, keeping warm for 1 hour and then cooling to the transfer temperature of 78-80°C, transferring the latex in the reactor to the stripping reactor to obtain pre-coated latex; the viscosity of the pre-coated latex is 385 cps, the stability of the latex functional group is 0.85 mg / g, the degree of encapsulation is poor, and the surface strength is 23 Kn / mm 2 .

[0083] The high-stability latex obtained in the embodiment was tested, and the solid content, viscosity, particle size, pH value, glass transition temperature, ion stability and other indicators still met the production process standards. After the test, when the indicators were normal, the paper machine was tested, and then the finished paper was tested for data. The smoothness was stable and slightly changed, but it did not affect the important indicators. The glossiness was greatly improved by 50% compared with the original. With the improvement of latex stability, the maximum speed can reach about 1100m / h, and stable production can be achieved, and the phenomenon of sticking to the cylinder rarely occurs, which reduces the amount of paper re-copying and thus reduces waste.

Claims

1. A method for preparing a high-stability latex for coated paper, characterized in that: The high-stability latex for coated paper comprises the following components by mass percentage: 3.1%-3.5% of liquid caustic soda, 0.8%-1.0% of defoamer, 36%-39% of butadiene, 48%-52% of styrene, 1.6%-1.8% of emulsifier, 1.8%-2.0% of acrylic acid, 0.7%-0.9% of seed emulsion, 1.0%-1.2% of fumaric acid, 0.8%-1.0% of ammonium persulfate, 0.7%-0.9% of tert-dodecyl mercaptan, 0.03%-0.05% of chelating agent, and 1.65%-1.85% of acrylamide, wherein the chelating agent is tetrasodium EDTA; The preparation method comprises the following steps: (1) Fully dissolve fumaric acid, tetrasodium EDTA and seed emulsion in a mixing tank and mix them evenly; (2) introducing steam into the reactor, and after forming a vacuum in the reactor to remove free oxygen through an external cooling cycle, adding the solution obtained in step (1) into the reactor and starting stirring, and continuing to introduce steam into the reactor; (3) When the temperature in the reactor reaches 86°C, the stirring speed in the reactor is changed from 70 rpm to 92 rpm, and styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator, and emulsifier are pumped into the reactor in sequence. The feeding time is 4 hours, and the temperature in the reactor is controlled at 85.5-87.5°C; (4) Adding initiator and emulsifier into the reactor again for 1.5-5.5 hours, keeping warm for 1 hour and then cooling to the transfer temperature of 78-80°C, transferring the latex in the reactor to the stripping reactor to obtain pre-coated latex; (5) adding acrylamide to the pre-coated latex to obtain a high-stability latex; Wherein, in step (5), the mass ratio of the pre-coated latex to acrylamide is between 500:8.5 and 500:9.0; The acrylamide concentration is between 84% and 86%.

2. The method for preparing the high-stability latex for coated paper according to claim 1, characterized in that: The mass ratio of fumaric acid, tetrasodium EDTA and seed emulsion in step (1) is 26:1:

21.

3. The method for preparing the high-stability latex for coated paper according to claim 1, characterized in that: The emulsifier in step (3) is a 30% concentration solution prepared by adding water to sodium dodecylbenzene sulfonate.

4. The method for preparing the high-stability latex for coated paper according to claim 2, characterized in that: The initiator in step (3) is ammonium persulfate.

5. The method for preparing the high-stability latex for coated paper according to claim 1, characterized in that: In step (3), the mass ratio of styrene, butadiene, acrylic acid, tert-dodecyl mercaptan, initiator solution and emulsifier solution is 49:37:1.9:0.8:0.9:1.

7.

6. The method for preparing the high-stability latex for coated paper according to claim 1, characterized in that: The viscosity of the high-stability latex obtained in step (5) is 100 to 374 cps, and the stability of the latex functional groups is 0.55 to 0.90 mg / g.

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