High-toughness carboxylic butadiene-acrylonitrile latex and preparation method thereof

Abstract

The invention discloses high-toughness carboxylic butadiene-acrylonitrile latex and a preparation method thereof. The high-toughness carboxylic butadiene-acrylonitrile latex is prepared from the following raw materials: a butadiene water solution, acrylonitrile, acrylic acid, a carboxylic acid monomer, an emulsifier, an initiator and a reaction aid. The specific formula comprises the following raw materials: 30-40 parts of a butadiene water solution, 30-40 parts of acrylonitrile, 10-20 parts of acrylic acid, 2-5 parts of a carboxylic acid monomer, 2-3 parts of an emulsifier, 1-3 parts of an initiator and 1-2 parts of a reaction aid. The reaction aid is introduced to promote effective graft copolymerization among butadiene, acrylonitrile, acrylic acid and carboxylic acid monomers, the added reaction aid assists cross-linking to increase the bonding strength among the components and improve the performance of the latex, then the rotating speed is increased for centrifugal treatment to remove a whey solvent, and casein is added for concentration, so that the latex is obtained. And the structure of colloid particles in the emulsion is more compact, the stability of the latex is improved, the toughness and strength of the latex particles are further improved, and the carboxylic butyronitrile latex has good mechanical properties such as high strength and high toughness.

Description

Technical Field

[0001] The invention relates to the technical field of nitrile latex, and in particular to a high-toughness carboxyl nitrile latex and a preparation method thereof. Background Art

[0002] Acrylonitrile latex is obtained by polymerization of butadiene and acrylonitrile monomers, and carboxylated nitrile latex as its modified product is a terpolymer of butadiene, acrylonitrile and acrylic acid or methacrylic acid. The introduction of carboxyl improves the performance of acrylonitrile rubber, and the introduction of carboxyl further enhances the polarity, and can be cross-linked and vulcanized in a variety of ways to obtain various excellent properties, which is significantly better than ordinary nitrile latex. In terms of application, due to the fact that some people are allergic to protein, and carboxylated nitrile latex does not contain protein, the possibility of latex allergy is fundamentally eliminated, and it is widely used in the production of various dipped rubber products. Although existing carboxylated nitrile latex has certain advantages such as solvent resistance and aging resistance, its strength and flexibility need to be improved, which greatly limits its application in certain fields. Summary of the invention

[0003] In view of the defects of the prior art, the object of the present invention is to provide a high-strength and tough carboxyl nitrile latex and a preparation method thereof to solve the problems raised in the above background technology.

[0004] The present invention solves the technical problem by adopting the following technical solution:

[0005] The present invention provides a high-toughness carboxyl nitrile latex, comprising the following raw materials:

[0006] Butadiene aqueous solution, acrylonitrile, acrylic acid, carboxylic acid monomer, emulsifier, initiator, reaction aid;

[0007] The specific formula includes the following raw materials: 30-40 parts of butadiene aqueous solution, 30-40 parts of acrylonitrile, 10-20 parts of acrylic acid, 2-5 parts of carboxylic acid monomer, 2-3 parts of emulsifier, 1-3 parts of initiator and 1-2 parts of reaction aid.

[0008] Preferably, the high-toughness carboxyl nitrile latex comprises the following raw materials:

[0009] 35 parts of butadiene aqueous solution, 35 parts of acrylonitrile, 15 parts of acrylic acid, 3 parts of carboxylic acid monomer, 2 parts of emulsifier, 2 parts of initiator, and 1 part of reaction aid.

[0010] Preferably, the acrylic acid is a mixture of methacrylic acid and alkyl acrylate containing carbon atoms in an amount of 80-95% by mass.

[0011] Preferably, the emulsifier is one of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, alkylphenol polyoxyethylene ether, sorbitan fatty acid ester and fatty alcohol polyoxyethylene ether.

[0012] Preferably, the initiator is one of sodium persulfate, azobisisobutyronitrile, azobisisobutylamidine hydrochloride, ammonium persulfate or potassium persulfate.

[0013] Preferably, the reaction aid is one of ferrous sulfate, sodium bisulfite, sodium sulfite and sodium thiosulfate.

[0014] The present invention also provides a method for preparing a high-toughness carboxyl nitrile latex, comprising the following steps:

[0015] Step 1: Add butadiene aqueous solution, acrylonitrile, acrylic acid, carboxylic acid monomer, emulsifier, initiator and reaction aid into different titration tanks for standby use, and then introduce nitrogen into the reactor to replace the air;

[0016] Step 2: Add a butadiene aqueous solution and an emulsifier into a reaction kettle, then start stirring and keep stirring until the reaction is completed, then add acrylonitrile, acrylic acid, carboxylic acid monomers and an initiator, and during the stirring process, copolymerize them in the presence of the initiator to generate a copolymer glue;

[0017] Step 3, stirring the obtained copolymer glue solution at a speed of 500-700 r / min and heating it to above 90° C., then adding a reaction aid and keeping the temperature for 300 minutes for cross-linking to obtain a cross-linked emulsion;

[0018] Step 4: centrifuge the cross-linked emulsion at a speed of 1200-1500 r / min for 20-30 min to remove the whey solvent to obtain a homogeneous emulsion;

[0019] Step 5: adding 0.2-1% by weight of casein to the obtained homogeneous emulsion, concentrating to obtain high-strength and tough carboxyl nitrile latex, and finally degassing the latex after polymerization.

[0020] Preferably, in step 2, acrylonitrile, acrylic acid, carboxylic acid monomers and initiator are added three times, with each addition amount being 1 / 3 of the total mass, and the copolymerization reaction is carried out by staged temperature control.

[0021] Preferably, in step 2, stirring is started until the reaction is completed, and the temperature in the reactor is raised to 50-80°C.

[0022] Preferably, during the degassing treatment, the latex is heated to 55-60°C and the pressure is maintained at -0.06 to -0.08 MPa for degassing. After the degassing is completed, the temperature is lowered to 28-32°C.

[0023] The high-strength and tough carboxylated nitrile latex prepared by the present invention and the preparation method thereof promote effective graft copolymerization between butadiene, acrylonitrile, acrylic acid and carboxylic acid monomers by introducing a reaction aid, and the added reaction aid assists in cross-linking, thereby increasing the bonding strength between the components, improving the performance of the latex, and enhancing the adhesion of the latex. Then, the rotation speed is increased to perform centrifugal treatment to remove the whey solvent, and casein is added for concentration, so that the colloidal particle structure in the emulsion is more compact, the stability of the latex is improved, and the toughness and strength of the latex particles are further improved, so that the carboxylated nitrile latex has good mechanical properties of high strength and high toughness. DETAILED DESCRIPTION

[0024] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The present invention of this embodiment provides a high-toughness carboxyl nitrile latex, including the following raw materials: butadiene aqueous solution, acrylonitrile, acrylic acid, carboxylic acid monomer, emulsifier, initiator, reaction aid;

[0026] The specific formula includes the following raw materials: 30-40 parts of butadiene aqueous solution, 30-40 parts of acrylonitrile, 10-20 parts of acrylic acid, 2-5 parts of carboxylic acid monomer, 2-3 parts of emulsifier, 1-3 parts of initiator and 1-2 parts of reaction aid.

[0027] The high-toughness carboxyl nitrile latex of this embodiment includes the following raw materials:

[0028] 35 parts of butadiene aqueous solution, 35 parts of acrylonitrile, 15 parts of acrylic acid, 3 parts of carboxylic acid monomer, 2 parts of emulsifier, 2 parts of initiator, and 1 part of reaction aid.

[0029] The acrylic acid in this embodiment is a mixture of methacrylic acid and alkyl acrylate containing carbon atoms with a mass fraction of 80-95%.

[0030] The emulsifier of this embodiment is one of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, alkylphenol polyoxyethylene ether, sorbitan fatty acid ester and fatty alcohol polyoxyethylene ether.

[0031] The initiator of this embodiment is one of sodium persulfate, azobisisobutyronitrile, azobisisobutylamidine hydrochloride, ammonium persulfate or potassium persulfate.

[0032] The reaction aid in this embodiment is one of ferrous sulfate, sodium bisulfite, sodium sulfite, and sodium thiosulfate. The use of the reaction aid can improve the performance of the latex.

[0033] A method for preparing a high-toughness carboxyl nitrile latex of the present embodiment comprises the following steps:

[0034] Step 1: Add butadiene aqueous solution, acrylonitrile, acrylic acid, carboxylic acid monomer, emulsifier, initiator and reaction aid into different titration tanks for standby use, and then introduce nitrogen into the reactor to replace the air;

[0035] Step 2: Add a butadiene aqueous solution and an emulsifier into a reaction kettle, then start stirring and keep stirring until the reaction is completed, then add acrylonitrile, acrylic acid, carboxylic acid monomers and an initiator, and during the stirring process, copolymerize them in the presence of the initiator to generate a copolymer glue;

[0036] Step 3, stirring the obtained copolymer glue solution at a speed of 500-700 r / min and heating it to above 90° C., then adding a reaction aid and keeping the temperature for 300 minutes for cross-linking to obtain a cross-linked emulsion;

[0037] Step 4: centrifuge the cross-linked emulsion at a speed of 1200-1500 r / min for 20-30 min to remove the whey solvent to obtain a homogeneous emulsion;

[0038] Step 5: adding 0.2-1% by weight of casein to the obtained homogeneous emulsion, concentrating to obtain high-strength and tough carboxyl nitrile latex, and finally degassing the latex after polymerization.

[0039] In step 2 of this embodiment, acrylonitrile, acrylic acid, carboxylic acid monomers and initiator are added three times, with each addition amount being 1 / 3 of the total mass, and the copolymerization reaction is carried out by staged temperature control.

[0040] In step 2 of this embodiment, stirring is started until the reaction is completed, and the temperature in the reactor is raised to 50-80°C.

[0041] During the degassing treatment in this embodiment, the latex is heated to 55-60°C and the pressure is maintained at -0.06 to -0.08 MPa for degassing. After the degassing is completed, the temperature is lowered to 28-32°C.

[0042] Example 1.

[0043] The present invention of this embodiment provides a high-toughness carboxyl nitrile latex, including the following raw materials: butadiene aqueous solution, acrylonitrile, acrylic acid, carboxylic acid monomer, emulsifier, initiator, reaction aid;

[0044] The specific formula includes the following raw materials: 30 parts of butadiene aqueous solution, 30 parts of acrylonitrile, 10 parts of acrylic acid, 2 parts of carboxylic acid monomer, 2 parts of emulsifier, 1 part of initiator and 1 part of reaction aid.

[0045] The acrylic acid in this embodiment is a mixture of methacrylic acid and alkyl acrylate containing carbon atoms with a mass fraction of 80%.

[0046] The emulsifier of this embodiment is one of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, alkylphenol polyoxyethylene ether, sorbitan fatty acid ester and fatty alcohol polyoxyethylene ether.

[0047] The initiator of this embodiment is one of sodium persulfate, azobisisobutyronitrile, azobisisobutylamidine hydrochloride, ammonium persulfate or potassium persulfate.

[0048] The reaction aid in this embodiment is one of ferrous sulfate, sodium bisulfite, sodium sulfite, and sodium thiosulfate. The use of the reaction aid can improve the performance of the latex.

[0049] A method for preparing a high-toughness carboxyl nitrile latex of the present embodiment comprises the following steps:

[0050] Step 1: Add butadiene aqueous solution, acrylonitrile, acrylic acid, carboxylic acid monomer, emulsifier, initiator and reaction aid into different titration tanks for standby use, and then introduce nitrogen into the reactor to replace the air;

[0051] Step 2: Add a butadiene aqueous solution and an emulsifier into a reaction kettle, then start stirring and keep stirring until the reaction is completed, then add acrylonitrile, acrylic acid, carboxylic acid monomers and an initiator, and during the stirring process, copolymerize them in the presence of the initiator to generate a copolymer glue;

[0052] Step 3, stirring the obtained copolymer glue solution at a speed of 500 r / min and heating it to above 90° C., then adding a reaction aid and keeping the temperature for 300 minutes for cross-linking to obtain a cross-linked emulsion. At this time, due to the existence of emulsification, the cross-linked emulsion has a loose structure, and its internal structure can be observed by a transmission electron microscope;

[0053] Step 4: centrifuge the cross-linked emulsion at a speed of 1200 r / min for 20 min, at which time the rubber and whey of the latex are separated, and the whey solvent is removed to obtain a homogenous emulsion. After removing part of the water and solvent of the latex, the particles shrink and the structure becomes more compact;

[0054] Step 5: adding 0.2% by weight of casein to the obtained homogeneous emulsion, concentrating to obtain high-strength and tough carboxyl nitrile latex, and finally degassing the latex after polymerization.

[0055] In step 2 of this embodiment, acrylonitrile, acrylic acid, carboxylic acid monomers and initiator are added three times, with each addition amount being 1 / 3 of the total mass, and the copolymerization reaction is carried out by staged temperature control.

[0056] In step 2 of this embodiment, stirring is started until the reaction is completed, and the temperature in the reactor is raised to 50°C.

[0057] During the degassing treatment in this embodiment, the latex is heated to 55°C and the pressure is maintained at -0.06 MPa for degassing. After the degassing is completed, the temperature is lowered to 28°C.

[0058] Example 2.

[0059] The present invention of this embodiment provides a high-toughness carboxyl nitrile latex, including the following raw materials: butadiene aqueous solution, acrylonitrile, acrylic acid, carboxylic acid monomer, emulsifier, initiator, reaction aid;

[0060] The specific formula includes the following raw materials: 35 parts of butadiene aqueous solution, 35 parts of acrylonitrile, 18 parts of acrylic acid, 3 parts of carboxylic acid monomer, 2.5 parts of emulsifier, 2 parts of initiator, and 1.5 parts of reaction aid.

[0061] The acrylic acid in this embodiment is a mixture of methacrylic acid and alkyl acrylate containing carbon atoms with a mass fraction of 85%.

[0062] The emulsifier of this embodiment is one of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, alkylphenol polyoxyethylene ether, sorbitan fatty acid ester and fatty alcohol polyoxyethylene ether.

[0063] The initiator of this embodiment is one of sodium persulfate, azobisisobutyronitrile, azobisisobutylamidine hydrochloride, ammonium persulfate or potassium persulfate.

[0064] The reaction aid in this embodiment is one of ferrous sulfate, sodium bisulfite, sodium sulfite, and sodium thiosulfate.

[0065] A method for preparing a high-toughness carboxyl nitrile latex of the present embodiment comprises the following steps:

[0066] Step 1: Add butadiene aqueous solution, acrylonitrile, acrylic acid, carboxylic acid monomer, emulsifier, initiator and reaction aid into different titration tanks for standby use, and then introduce nitrogen into the reactor to replace the air;

[0067] Step 2: Add a butadiene aqueous solution and an emulsifier into a reaction kettle, then start stirring and keep stirring until the reaction is completed, then add acrylonitrile, acrylic acid, carboxylic acid monomers and an initiator, and during the stirring process, copolymerize them in the presence of the initiator to generate a copolymer glue;

[0068] Step 3, stirring the obtained copolymer glue solution at a speed of 500-700 r / min and heating it to above 90°C, then adding a reaction aid and keeping it warm for 300 minutes for cross-linking to obtain a cross-linked emulsion. At this time, due to the existence of emulsification, the cross-linked emulsion has a loose structure, and its internal structure can be observed by transmission electron microscopy;

[0069] Step 4: centrifuge the cross-linked emulsion at a speed of 1200 r / min for 20 min, at which time the rubber and whey of the latex are separated, and the whey solvent is removed to obtain a homogenous emulsion. After removing part of the water and solvent of the latex, the particles shrink and the structure becomes more compact;

[0070] Step 5: adding 0.7% by weight of casein to the obtained homogeneous emulsion, concentrating to obtain high-strength and tough carboxyl nitrile latex, and finally degassing the latex after polymerization.

[0071] In step 2 of this embodiment, acrylonitrile, acrylic acid, carboxylic acid monomers and initiator are added three times, with each addition amount being 1 / 3 of the total mass, and the copolymerization reaction is carried out by staged temperature control.

[0072] In step 2 of this embodiment, stirring is started until the reaction is completed, and the temperature in the reactor is raised to 70°C.

[0073] During the degassing treatment in this embodiment, the latex was heated to 58°C and the pressure was maintained at -0.07 MPa for degassing. After the degassing was completed, the temperature was lowered to 29°C.

[0074] Example 3.

[0075] The present invention of this embodiment provides a high-toughness carboxyl nitrile latex, including the following raw materials: butadiene aqueous solution, acrylonitrile, acrylic acid, carboxylic acid monomer, emulsifier, initiator, reaction aid;

[0076] The specific formula includes the following raw materials: 40 parts of butadiene aqueous solution, 40 parts of acrylonitrile, 20 parts of acrylic acid, 5 parts of carboxylic acid monomer, 3 parts of emulsifier, 3 parts of initiator, and 2 parts of reaction aid.

[0077] The acrylic acid in this embodiment is a mixture of methacrylic acid and alkyl acrylate containing carbon atoms with a mass fraction of 95%.

[0078] The emulsifier of this embodiment is one of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, alkylphenol polyoxyethylene ether, sorbitan fatty acid ester and fatty alcohol polyoxyethylene ether.

[0079] The initiator of this embodiment is one of sodium persulfate, azobisisobutyronitrile, azobisisobutylamidine hydrochloride, ammonium persulfate or potassium persulfate.

[0080] The reaction aid in this embodiment is one of ferrous sulfate, sodium bisulfite, sodium sulfite, and sodium thiosulfate.

[0081] A method for preparing a high-toughness carboxyl nitrile latex of the present embodiment comprises the following steps:

[0082] Step 1: Add butadiene aqueous solution, acrylonitrile, acrylic acid, carboxylic acid monomer, emulsifier, initiator and reaction aid into different titration tanks for standby use, and then introduce nitrogen into the reactor to replace the air;

[0083] Step 2: Add a butadiene aqueous solution and an emulsifier into a reaction kettle, then start stirring and keep stirring until the reaction is completed, then add acrylonitrile, acrylic acid, carboxylic acid monomers and an initiator, and during the stirring process, copolymerize them in the presence of the initiator to generate a copolymer glue;

[0084] Step 3, stirring the obtained copolymer glue solution at a speed of 700 r / min and heating it to above 90° C., then adding a reaction aid and keeping the temperature for 300 min for cross-linking to obtain a cross-linked emulsion. At this time, due to the existence of emulsification, the cross-linked emulsion has a loose structure, and its internal structure can be observed by transmission electron microscopy;

[0085] Step 4: centrifuge the cross-linked emulsion at a speed of 1200 r / min for 20 min, at which time the rubber and whey of the latex are separated, and the whey solvent is removed to obtain a homogenous emulsion. After removing part of the water and solvent of the latex, the particles shrink and the structure becomes more compact;

[0086] Step 5: Add 1% by weight of casein to the obtained homogeneous emulsion, concentrate to obtain high-strength and tough carboxyl nitrile latex, and finally degas the latex after polymerization.

[0087] In step 2 of this embodiment, acrylonitrile, acrylic acid, carboxylic acid monomers and initiator are added three times, with each addition amount being 1 / 3 of the total mass, and the copolymerization reaction is carried out by staged temperature control.

[0088] In step 2 of this embodiment, stirring is started until the reaction is completed, and the temperature in the reactor is raised to 80°C.

[0089] During the degassing treatment in this embodiment, the latex is heated to 60°C and the pressure is maintained at -0.08Mpa for degassing. After the degassing is completed, the temperature is lowered to 32°C.

[0090] Comparative Example 1.

[0091] The difference from Example 3 is that the carboxylated nitrile latex is prepared using a common method.

[0092] The products of Examples 1-3 and Comparative Example 1 were subjected to performance tests;

[0093] Eight carboxyl nitrile latex samples were prepared and divided into four groups with one sample in each group. Each group corresponded to Examples 1-3 and Comparative Example 1 and were numbered A / B / C / D. Finally, the carboxyl nitrile latex samples in groups A / B / C / D were tested respectively, and their particle size distribution was tested using a laser particle size analyzer.

[0094] Tensile strength / Mpa Elongation at break / % Particle size distribution A 32.2 682 Dense B 32.6 683 Dense C 33.2 685 Dense D 25.7 560 loose

[0095] As can be seen from Examples 1-3, the high-strength and tough carboxylated nitrile latex prepared by the present invention can increase the bonding strength between the components, improve the performance of the latex, make the colloidal particle structure in the emulsion more compact, enhance the stability of the latex, and further improve the toughness and strength of the latex particles, so that the carboxylated nitrile latex has good mechanical properties of high strength and high toughness.

[0096] In addition, it is found from Examples 1-3 and Comparative Example 1 that the comprehensive performance of the carboxyl nitrile latex prepared by the existing method is inferior to that of the examples of the present application, and the strength and flexibility need to be improved.

[0097] The innovation of the present invention is:

[0098] The invention introduces a reaction aid to promote effective graft copolymerization between butadiene, acrylonitrile, acrylic acid and carboxylic acid monomers, and the added reaction aid assists in cross-linking, thereby increasing the bonding strength between the components, improving the performance of the latex, and enhancing the adhesiveness of the latex. Then, the rotation speed is increased to perform centrifugal treatment to remove the whey solvent, and casein is added for concentration, so that the colloidal particle structure in the emulsion is more compact, the stability of the latex is improved, and the toughness and strength of the latex particles are further improved, so that the carboxylated nitrile latex has good mechanical properties of high strength and high toughness.

[0099] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0100] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A high-toughness carboxyl nitrile latex, characterized in that: Including the following raw materials: butadiene aqueous solution, acrylonitrile, acrylic acid, carboxylic acid monomer, emulsifier, initiator, reaction aid; The specific formula includes the following raw materials (by mass): 30-40 parts of butadiene aqueous solution, 30-40 parts of acrylonitrile, 10-20 parts of acrylic acid, 2-5 parts of carboxylic acid monomer, 2-3 parts of emulsifier, 1-3 parts of initiator and 1-2 parts of reaction aid.

2. A high-toughness carboxyl nitrile latex according to claim 1, characterized in that: Including the following ingredients: 35 parts of butadiene aqueous solution, 35 parts of acrylonitrile, 15 parts of acrylic acid, 3 parts of carboxylic acid monomer, 2 parts of emulsifier, 2 parts of initiator, and 1 part of reaction aid.

3. A high-toughness carboxyl nitrile latex according to claim 1, characterized in that: The acrylic acid is a mixture of methacrylic acid and alkyl acrylate containing carbon atoms with a mass fraction of 80-95%.

4. A high-toughness carboxyl nitrile latex according to claim 1, characterized in that: The emulsifier is one of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, alkylphenol polyoxyethylene ether, sorbitan fatty acid ester and fatty alcohol polyoxyethylene ether.

5. A high-toughness carboxyl nitrile latex according to claim 1, characterized in that: The initiator is one of sodium persulfate, azobisisobutyronitrile, azobisisobutylamidine hydrochloride, ammonium persulfate or potassium persulfate.

6. A high-toughness carboxyl nitrile latex according to claim 1, characterized in that: The reaction aid is one of ferrous sulfate, sodium bisulfite, sodium sulfite and sodium thiosulfate.

7. A method for preparing a high-toughness carboxylated nitrile latex as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Add butadiene aqueous solution, acrylonitrile, acrylic acid, carboxylic acid monomer, emulsifier, initiator and reaction aid into different titration tanks for standby use, and then introduce nitrogen into the reactor to replace the air; Step 2: Add a butadiene aqueous solution and an emulsifier into a reaction kettle, then start stirring and keep stirring until the reaction is completed, then add acrylonitrile, acrylic acid, carboxylic acid monomers and an initiator, and during the stirring process, copolymerize them in the presence of the initiator to generate a copolymer glue; Step 3, stirring the obtained copolymer glue solution at a speed of 500-700 r / min and heating it to above 90° C., then adding a reaction aid and keeping the temperature for 300 minutes for cross-linking to obtain a cross-linked emulsion; Step 4: centrifuge the cross-linked emulsion at a speed of 1200-1500 r / min for 20-30 min to remove the whey solvent to obtain a homogeneous emulsion; Step 5: adding 0.2-1% by weight of casein to the obtained homogeneous emulsion, concentrating to obtain high-strength and tough carboxyl nitrile latex, and finally degassing the latex after polymerization.

8. The method for preparing the high-toughness carboxyl nitrile latex according to claim 7, characterized in that: In the step 2, acrylonitrile, acrylic acid, carboxylic acid monomers and initiator are added three times, with each addition amount being 1 / 3 of the total mass, and copolymerization is carried out by staged temperature control.

9. The method for preparing a high-toughness carboxyl nitrile latex according to claim 8, characterized in that: In the step 2, stirring is started until the reaction is completed, and the temperature in the reactor is raised to 50-80°C.

10. The method for preparing a high-toughness carboxyl nitrile latex according to claim 7, characterized in that: During the degassing treatment, the latex is heated to 55-60°C and the pressure is maintained at -0.06 to -0.08 MPa for degassing. After the degassing is completed, the temperature is lowered to 28-32°C.