A kind of nitrile latex and its preparation method and application

Abstract

The present invention relates to the technical field of polymer material synthesis, and more particularly to a kind of nitrile latex and its preparation method and application, the preparation method comprises the following steps: put into a polymerization reactor, start stirring, vacuumize, add oil phase, initiator phase, add monomer phase, react, and obtain a reaction solution; add pH regulator A and antioxidant into the polymerization reactor, stir the reaction, warm up to 60 ℃-80 ℃, and extract; cool to 30 ℃-40 ℃, adjust the pH value of the reaction product to 8-9, and obtain nitrile latex. The present invention adopts soap-free emulsion polymerization, deionized water is the dispersion medium of the polymerization reaction system, butadiene and acrylonitrile are the main monomers, and the prepared nitrile latex has good mechanical and chemical stability, less residual matter, high purity, low odor, and excellent mechanical properties.

Description

Technical Field

[0001] The invention relates to the technical field of polymer material synthesis, and in particular to a butadiene-acrylonitrile latex and a preparation method and application thereof. Background Art

[0002] In order to better protect people's vital interests and promote social progress and economic development, it is necessary to fundamentally provide people with safe, reliable, healthy and environmentally friendly labor protection products to ensure people's safety. Among them, labor protection gloves are the most commonly used and basic protective products. They are also the most widely used and widely used protective products for people's safety protection, which directly affects the user's hand safety.

[0003] At present, there are many types of protective gloves on the market with uneven quality, so how to choose suitable labor protection gloves is a difficult problem facing users; among labor protection gloves, nitrile labor protection gloves are widely used in labor protection in various fields of operation processes because of their excellent oil resistance, wear resistance, corrosion resistance and other characteristics.

[0004] Since protective equipment is the first line of defense to protect the safety and health of users, and nitrile latex is the main component of the film-forming substance on the surface of labor protection gloves, the quality of nitrile latex and the performance of the film-forming substance are the key factors affecting the quality of labor protection gloves. At present, the nitrile latex used in the impregnated labor protection gloves commonly used in the market has the problem of many precipitates. The impregnated labor protection gloves manufactured in this way have a strong odor and many precipitates on the surface or inside of the gloves. As a result, during the use of the labor protection gloves, a large amount of precipitates will penetrate into the user's skin, causing harm to the user's health. Summary of the invention

[0005] In order to solve the problem of many precipitates in nitrile latex in the prior art, the present invention provides a method for preparing nitrile latex. The preparation method adopts a preparation process of soap-free emulsion polymerization, which effectively prevents the risk of small molecule surfactants migrating and precipitating from the latex, thereby solving the problem of many precipitates in nitrile latex in the prior art.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A method for preparing a nitrile latex comprises the following steps:

[0008] S1: preparing a base material using deionized water, a chelating agent, an oxygen scavenger, a stabilizer, an electrolyte, and an initiator A as raw materials;

[0009] S2: preparing an oil phase using acrylonitrile, butadiene, functional monomers and molecular weight regulator A as raw materials;

[0010] S3: preparing an initiator phase using deionized water and initiator B as raw materials;

[0011] S4: preparing a supplementary monomer phase using molecular weight regulator B and crosslinking monomer as raw materials;

[0012] S5: Add the bottom material into the polymerization reactor, start stirring, evacuate to -0.085MPPa~-0.095MPa, add the oil phase, the initiator phase, and the additional monomer phase, react, and obtain a reaction solution;

[0013] S6: Add pH adjuster A and antioxidant to the polymerization reactor, stir the reaction, raise the temperature to 60°C-80°C, start extraction, and when the vacuum degree reaches -0.075MPa~-0.085MPa, start timing the reaction for 3~5 hours, and the extraction is completed;

[0014] S7: Cooling to 30° C.-40° C., adding pH adjuster B to adjust the pH value of the reaction product to 8-9, adding bactericide, stirring, discharging, filtering, and packaging to obtain nitrile latex.

[0015] Optionally, step S5 is performed according to the following process:

[0016] S51: Adding a bottom material into the polymerization reactor, starting stirring, evacuating to -0.085 MPPa~-0.095 MPa, and then adding a portion of the oil phase into the polymerization reactor;

[0017] S52: heating the polymerization reactor to 35° C.-45° C., adding a portion of the initiator phase to the polymerization reactor, and starting a polymerization reaction; when the conversion rate reaches 70%-80%, adding the remaining oil phase, the remaining initiator phase, and a portion of the additional monomer phase to the polymerization reactor;

[0018] S53: When the conversion rate reaches 80%-90%, the remaining monomer phase is added to the polymerization reactor, the temperature is raised to 40°C-50°C, and the pressure is controlled between 0.4MPa-0.5MPa until the conversion rate reaches 95%, thereby obtaining a reaction solution.

[0019] Optionally, the functional monomer is selected from at least one of unsaturated carboxylic acid functional monomers, unsaturated carboxylic acid ester functional monomers, and unsaturated aromatic functional monomers.

[0020] Optionally, the functional monomer is selected from at least one of 4-vinyl biphenyl, methacrylic acid, acrylic acid, phenyl methacrylate, ethylene glycol dimethacrylate, itaconic acid, maleic acid, and trimethylolpropane triacrylate.

[0021] Optionally, the crosslinking monomer is an unsaturated polyolefin.

[0022] Optionally, the molecular weight regulator A and the molecular weight regulator B are both a mixture of a polymer molecular weight regulator and a chain transfer agent in a mass ratio of 1:(5-10).

[0023] Optionally, the polymer molecular weight regulator is a thermoplastic phenolic resin.

[0024] Optionally, the chain transfer agent is selected from at least one of ethanol, propanol, isopropanol, glycerol, n-octanol, phenylselenol, dodecylselenol and pentaerythritol.

[0025] Another object of the present invention is to provide a nitrile latex, which is prepared by the preparation method of the nitrile latex as described above.

[0026] Another object of the present invention is to provide a use of the nitrile latex as described above in protective gloves.

[0027] The beneficial effects of the present invention are:

[0028] The preparation method of the nitrile latex provided by the present invention adopts a soap-free emulsion polymerization method, uses deionized water as a dispersion medium of a polymerization reaction system, uses butadiene and acrylonitrile as main monomers, and cooperates with a cross-linking monomer, a functional monomer and other auxiliary agents to prepare the nitrile latex, which has the appearance of a uniform milky white liquid, has the characteristics of good mechanical and chemical stability, less residual substances, high purity, low odor, and excellent mechanical properties. When used as a film-forming emulsion for impregnated labor protection gloves, the characteristics of the product with low odor and high purity can greatly improve the production environment of downstream glove manufacturers, reduce the damage to user health caused by residual substances in the gloves, improve the use safety, wearing comfort and service life of the impregnated labor protection nitrile gloves, and provide better protection for user safety. DETAILED DESCRIPTION

[0029] The present invention is now further described in detail. The embodiments described below are exemplary and intended to be used to explain the present invention, but cannot be understood as limiting the present invention. All other embodiments obtained by ordinary technicians in this field without creative work based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0030] The nitrile latex used in the impregnated labor protection gloves currently on the market has the problems of large amount of additives, large residual odor and large amount of precipitates. The impregnated labor protection gloves manufactured in this way have a strong odor and many precipitates on the surface or inside of the gloves, resulting in a large amount of precipitates penetrating into the user's skin during the use of the labor protection gloves, and at the same time causing the density, protective performance and safety performance of the labor protection gloves to decrease, thereby affecting the normal use of the user.

[0031] In order to solve the problem of many precipitates in nitrile latex in the prior art, the present invention provides a method for preparing nitrile latex, which comprises the following raw materials in parts by weight:

[0032] 50~60 parts of deionized water;

[0033] 1~3 copies of functional monomer;

[0034] Stabilizer 1~6 parts;

[0035] Butadiene 20-30 parts;

[0036] Acrylonitrile 10-15 parts;

[0037] 1~3 parts of cross-linking monomer;

[0038] Electrolyte 0.1~0.5 parts;

[0039] Initiator 0.1~0.6 parts;

[0040] Molecular weight regulator 0.1~5 parts;

[0041] In addition, other chelating agents, pH regulators, deoxidizers, antioxidants, bactericides, etc. required for emulsion polymerization may also be included.

[0042] The preparation method comprises the following steps:

[0043] S1: preparing a base material using deionized water, a chelating agent, an oxygen scavenger, a stabilizer, an electrolyte, and an initiator A as raw materials;

[0044] Specifically, it is preferred that this step is performed according to the following process:

[0045] According to weight parts, 0.05-0.1 parts of chelating agent, 0.05-0.1 parts of deoxygenating agent, 1-6 parts of stabilizer, 0.1-0.5 parts of electrolyte, and 0.1-0.2 parts of initiator A are added to 40-50 parts of deionized water at 30° C.-50° C., and stirred to obtain a base material;

[0046] S2: preparing an oil phase using acrylonitrile, butadiene, functional monomers and molecular weight regulator A as raw materials;

[0047] Preferably, this step is performed as follows:

[0048] According to weight parts, 10-15 parts of acrylonitrile, 20-30 parts of butadiene, 1-3 parts of functional monomers, and 0.1-3 parts of molecular weight regulator A are mixed to obtain an oil phase;

[0049] S3: preparing an initiator phase using deionized water and initiator B as raw materials;

[0050] Preferably, this step is performed as follows:

[0051] In parts by weight, 10-20 parts of deionized water and 0.1-0.4 parts of initiator B are mixed to obtain an initiator phase;

[0052] S4: preparing a supplementary monomer phase using molecular weight regulator B and crosslinking monomer as raw materials;

[0053] Preferably, this step is performed as follows:

[0054] According to weight percentage, 0.1-2 parts of molecular weight regulator B and 1-3 parts of crosslinking monomer are mixed to obtain a supplementary monomer phase;

[0055] S5: Add the bottom material into the polymerization reactor, start stirring, evacuate to -0.085MPPa~-0.095MPa, add the oil phase, initiator phase, and additional monomer phase, react, and obtain a reaction liquid;

[0056] S6: Add pH adjuster A and antioxidant to the polymerization reactor, stir the reaction, raise the temperature to 60°C-80°C, start extraction, and when the vacuum degree reaches -0.075MPa~-0.085MPa, start timing the reaction for 3~5 hours, and the extraction is completed;

[0057] Preferably, according to weight parts, 0.9-2.7 parts of pH adjuster A and 0.1-0.5 parts of antioxidant are added to the polymerization reactor, and the reaction is stirred, preferably for 1-3 hours, and the temperature is raised to 60° C.-80° C. to start extraction. When the vacuum degree reaches -0.075 MPa~-0.085 MPa, the reaction time is started for 3~5 hours, and the extraction is completed;

[0058] S7: cooling to 30°C-40°C, adding pH adjuster B to adjust the pH value of the reaction product to 8-9, adding bactericide, stirring, discharging, filtering, and packaging to obtain nitrile latex;

[0059] Preferably, in this step, the polymerization reaction system is cooled to 30°C to 40°C, 0.1 to 1.5 parts of a pH adjuster are added to adjust the pH value of the reaction product to 8 to 9, 0.01 to 0.1 parts of a fungicide are added, and the mixture is stirred at a uniform speed for 0.5 to 1.5 hours. After discharging, filtering, packaging and other processes, the nitrile latex is obtained.

[0060] It should be noted that initiator A, initiator B, molecular weight regulator A, molecular weight regulator B, pH regulator A, pH regulator B, etc. in the present invention are only used to distinguish the amount of each component in different steps, and do not represent different selections.

[0061] The present invention adopts a polymerization process of heating and pressurizing hydrogenation in the later stage of the polymerization reaction, so as to improve the conversion rate of the polymerization reaction product, improve the aging resistance and flexibility of the nitrile latex, and improve the product structure.

[0062] The preparation method of the nitrile latex provided by the present invention adopts a soap-free emulsion polymerization method, uses deionized water as a dispersion medium of a polymerization reaction system, uses butadiene and acrylonitrile as main monomers, and cooperates with a cross-linking monomer, a functional monomer and other auxiliary agents to prepare the nitrile latex, which has the appearance of a uniform milky white liquid, has the characteristics of good mechanical and chemical stability, less residual substances, high purity, low odor, and excellent mechanical properties. When used as a film-forming emulsion for impregnated labor protection gloves, the characteristics of the product with low odor and high purity can greatly improve the production environment of downstream glove manufacturers, reduce the damage to user health caused by residual substances in the gloves, improve the use safety, wearing comfort and service life of the impregnated labor protection nitrile gloves, and provide better protection for user safety.

[0063] In order to shorten the production cycle and improve the conversion rate, the preferred step S5 of the present invention is carried out according to the following process:

[0064] S51: Adding bottom material into the polymerization reactor, starting stirring, evacuating to -0.085MPPa~-0.095MPa, and then adding a portion of the oil phase into the polymerization reactor, preferably 50%-70% of the total oil phase mass;

[0065] S52: heating the polymerization kettle to 35°C-45°C, adding a portion of the initiator phase to the polymerization kettle, preferably adding 40%-60% of the mass of the total initiator phase, to start the polymerization reaction; when the conversion rate reaches 70%-80%, adding the remaining oil phase, the remaining initiator phase, and a portion of the additional monomer phase to the polymerization kettle, preferably adding 40%-60% of the mass of the total additional monomer phase;

[0066] S53: When the conversion rate reaches 80%-90%, the remaining additional monomer phase is added to the polymerization reactor, the temperature is raised to 40°C-50°C, and the pressure is controlled between 0.4MPa-0.5MPa until the conversion rate reaches 95% to obtain a reaction solution.

[0067] The present invention prepares a nitrile latex with low production cost, short production cycle, high conversion rate, large molecular weight, good flexibility, high film-forming strength, good wear resistance and aging resistance, and good wettability to glove lining materials through segmented addition of polymerization monomers, segmented temperature control, and pressurized hydrogenation polymerization process.

[0068] In the present invention, the preferred chelating agent is selected from at least one of EDTA-4Na, EDTA-2Na, ethylenediamine, ethylenediaminetetramethylenephosphonic acid, and hydroxyethylenediphosphonic acid; the preferred oxygen scavenger is selected from at least one of ascorbic acid, hydrosulfite, glucose, hydroquinone, and thiobisphenol; the preferred initiator is selected from at least one of ammonium persulfate, potassium persulfate, and tert-butyl hydroperoxide; and the preferred bactericide is selected from at least one of kasson, sodium pentachlorophenol, 2-hydroxybiphenyl sodium salt, and 1,2-benzisothiazolin-3-one.

[0069] The preferred functional monomer of the present invention is selected from at least one of unsaturated carboxylic acid functional monomers, unsaturated carboxylic acid ester functional monomers, and unsaturated aromatic functional monomers; specifically, the preferred functional monomer is selected from at least one of 4-vinyl biphenyl, methacrylic acid, acrylic acid, phenyl methacrylate, ethylene glycol dimethacrylate, itaconic acid, maleic acid, and trimethylolpropane triacrylate.

[0070] The preferred stabilizer of the present invention is selected from at least one of unsaturated sulfonates, unsaturated carboxylates, and unsaturated oxyethylene ethers. Specifically, the preferred stabilizer is selected from at least one of allyloxy-2-hydroxy-1-propanesulfonic acid sodium salt, sodium acrylamido-2-methylpropanesulfonate, sodium 3-chloro-2-hydroxypropane sulfonate, disodium butenedioate, and polyoxyethylene propylene alcohol ether.

[0071] The crosslinking monomer of the present invention is preferably an unsaturated polyolefin, and specifically preferably the crosslinking monomer is at least one selected from isoprene, trans-butadiene, piperylene, cyclopentadiene, 1,4-hexadiene, dicyclopentadiene, 1,7-octadiene, and ethylidene norbornene.

[0072] The electrolyte preferably used in the present invention is an inorganic salt, and further preferably the electrolyte is selected from at least one of sodium chloride, potassium chloride, sodium sulfate, potassium sulfate, sodium carbonate, sodium bicarbonate, and sodium pyrophosphate.

[0073] The preferred molecular weight regulator of the present invention, that is, the molecular weight regulator A and the molecular weight regulator B are both a mixture of a polymer molecular weight regulator and a chain transfer agent in a mass ratio of 1: (5-10).

[0074] Specifically, it is preferred that the polymer molecular weight regulator is a thermoplastic phenolic resin, and it is further preferred that the polymer molecular weight regulator is a terminal phenolic phenolic resin with a molecular weight of less than 1000, and it is further preferred that the thermoplastic phenolic resin is selected from at least one of phenol-formaldehyde resin, bisphenol A type phenolic resin, terpene phenolic resin, amide-modified phenolic resin, and epoxy-modified phenolic resin.

[0075] The preferred chain transfer agent of the present invention is a non-thiol environmentally friendly chain transfer agent, and further preferably the chain transfer agent is selected from at least one of ethanol, propanol, isopropanol, glycerol, n-octanol, phenylselenol, dodecylselenol, and pentaerythritol.

[0076] In the present invention, after the conversion rate of the preferred polymerization reaction system reaches more than 95%, a pH agent is added to adjust the pH value, and then the antioxidant added is selected from at least one of hydrazine hydrate, hydrogen, carbohydrazide, and p-toluenesulfonyl hydrazide; the pH agent is preferably selected from at least one of sodium hydroxide, potassium hydroxide, ammonia water, lithium hydroxide, and ethanolamine.

[0077] The preparation method of the nitrile latex provided by the invention adopts a soap-free emulsion polymerization method, uses deionized water as a dispersion medium of a polymerization reaction system, uses butadiene and acrylonitrile as main monomers, uses unsaturated carboxylic acids and their esters, and unsaturated aromatics as functional monomers, uses unsaturated polyolefins as cross-linking monomers, uses unsaturated sulfonates, unsaturated carboxylates, unsaturated oxyethylene ethers and other reactive surfactants as stabilizers and dispersants of the polymerization reaction system, uses thermal decomposition type peroxide as an initiator of the reaction system, uses inorganic salts as electrolytes of the polymerization reaction system, and in the polymerization reaction process, adds a reducing organic polymer molecular weight regulator with a high chain transfer constant and a non-thiol environmentally friendly chain transfer agent in batches, and prepares the nitrile latex by adding polymerization monomers in stages, controlling the temperature in stages, and performing a pressurized hydrogenation polymerization process. The nitrile latex has low production cost, short production cycle, high conversion rate, large molecular weight, good flexibility, high film-forming strength, good wear resistance, good aging resistance, and good wettability to glove lining materials. After the post-processing process of extraction reaction, the prepared nitrile latex has the appearance of a uniform milky white liquid, good mechanical and chemical stability, less residual matter, high purity, low odor, and excellent mechanical properties. When used as a film-forming emulsion for impregnated labor protection gloves, the product's low odor and high purity characteristics can greatly improve the production environment of downstream glove manufacturers, reduce the harm of residual substances in the gloves to users' health, and improve the safety of use, wearing comfort and service life of impregnated labor protection nitrile gloves, providing better protection for user safety.

[0078] In order to improve the safety protection performance of the impregnated labor protection gloves and better protect the health and safety of users, the present invention adopts a preparation process of soap-free emulsion polymerization to fundamentally and effectively prevent the risk of small molecule surfactants migrating and precipitating from latex, uses unsaturated carboxylic acids and esters thereof as functional monomers, and adjusts the molecular structure of the functional monomers and the main chain of the molecule by adding a molecular weight regulator, thereby reducing the production cost, improving the strength, wear resistance, heat resistance and other properties of the nitrile latex film-forming material, and enhancing the bonding strength and wettability with the lining material, using unsaturated polyolefins as cross-linking monomers of the polymerization reaction system to improve the strength of the polymerization product, thereby reducing the amount of additives used in the manufacturing process of the protective gloves, and adopting the reaction condition control of gradually increasing the temperature, pressurizing and hydrogenating polymerization in the later stage to improve the regularity of the latex structure and the strength, density, flexibility and aging resistance of the film-forming material, while improving the conversion rate of the polymerization product, improving the utilization rate of raw materials, reducing the production cost, improving the performance of the product, and reducing the pollution to the environment, and adopting an extraction process at the end of the polymerization reaction to reduce the residual substances in the latex, thereby improving the product quality of the impregnated labor protection gloves and promoting the development of the labor protection gloves industry.

[0079] The preparation method of the nitrile latex provided by the invention is mainly used as a film-forming substance on the surface of gloves in the production process of labor protection gloves, and can be widely used in the production and manufacturing of disposable nitrile gloves, or semi-immersed or fully-immersed labor protection gloves prepared with cotton, linen, cloth, nylon, and fiber as lining materials, such as oil-resistant, wear-resistant, non-slip, acid- and alkali-resistant, cold-resistant, and low-temperature-resistant coated gloves and other special properties, to improve the strength, comfort, and service life of the labor protection gloves, and play an important role in ensuring the safety of users.

[0080] Another object of the present invention is to provide a nitrile latex, which is prepared by the preparation method of the nitrile latex as described above.

[0081] The nitrile latex provided by the invention is prepared by a soap-free emulsion polymerization method. In the preparation process, deionized water is used as a dispersion medium of a polymerization reaction system, butadiene and acrylonitrile are used as main monomers, and the nitrile latex prepared by synergistic action with a cross-linking monomer, a functional monomer and other auxiliary agents has the appearance of a uniform milky white liquid, has the characteristics of good mechanical and chemical stability, less residual substances, high purity, low odor, and excellent mechanical properties. When used as a film-forming emulsion for impregnated labor protection gloves, the characteristics of the product with low odor and high purity can greatly improve the production environment of downstream glove manufacturers, reduce the damage to user health caused by residual substances in the gloves, improve the use safety, wearing comfort and service life of the impregnated labor protection nitrile gloves, and provide better protection for user safety.

[0082] The nitrile latex provided by the present invention has a particle size of 100-150nm, presents a uniform normal distribution, and has the characteristics of a narrow dispersion index. The latex has good mechanical stability and chemical stability, high purity, low residual substances, and the film-forming substance has the characteristics of high strength, oil resistance, acid and alkali resistance, cold resistance and low temperature resistance, and good corrosion resistance. The latex can be used as a main film-forming substance for a protective coating of labor protection gloves, improves the dispersion and stability between the latex and a vulcanizing auxiliaries and pigments and fillers, reduces the amount of auxiliaries used in the production process of impregnated labor protection gloves, reduces the pinhole rate of the glove protective layer, reduces the precipitation of small molecular substances, improves the safety and protective performance of the impregnated labor protection gloves, and is widely used in the production and manufacture of disposable nitrile latex gloves and semi-impregnated or fully-impregnated coated protective gloves.

[0083] Another object of the present invention is to provide a use of the nitrile latex as described above in protective gloves.

[0084] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below.

[0085] Unless otherwise specified, the base materials in the embodiments and comparative examples of the present invention are configured according to the following formula:

[0086] Deionized water 50kg;

[0087] Chelating agent 0.05kg;

[0088] Deoxidizer 0.05kg;

[0089] Stabilizer 5.0kg;

[0090] Electrolyte 0.4 kg;

[0091] Initiator 0.2kg;

[0092] The chelating agent is ethylenediaminetetramethylenephosphonic acid, the deoxidizer is ascorbic acid, the stabilizer is sodium acrylamido-2-methylpropanesulfonate, the electrolyte is sodium chloride, and the initiator is potassium persulfate;

[0093] The base material is prepared as follows:

[0094] According to the formula, deionized water is added to the base material preparation tank, and after stirring and heating to 40°C, a chelating agent, a deoxidizer, a stabilizer, an electrolyte, and an initiator are added to the base material preparation tank, and stirred for 2 hours to obtain the base material for use.

[0095] The oil phase was prepared according to the following formula:

[0096] Acrylonitrile 15kg;

[0097] Butadiene 25kg;

[0098] Methacrylic acid 1kg;

[0099] Phenyl methacrylate 1.1 kg;

[0100] Molecular weight regulator 0.1kg;

[0101] The molecular weight regulator is a mixture of bisphenol A phenolic resin and isopropyl alcohol in a mass ratio of 1:8;

[0102] The oil phase was prepared as follows:

[0103] According to the formula, acrylonitrile, methacrylic acid, phenyl methacrylate, molecular weight regulator and butadiene were added into the oil phase preparation tank and stirred for 1.5 hours to obtain the oil phase for standby use.

[0104] The initiator phase was prepared according to the following formula:

[0105] Deionized water 15 kg;

[0106] Initiator 0.36 kg;

[0107] The initiator is potassium persulfate;

[0108] The initiator phase was prepared as follows:

[0109] Add deionized water and initiator into the initiator batching tank, stir and dissolve evenly to obtain the initiator phase for standby use;

[0110] The additional monomer phase is prepared according to the following formula:

[0111] Molecular weight regulator 0.1 kg;

[0112] Isoprene 0.7 kg;

[0113] Dicyclopentadiene 0.6 kg;

[0114] The molecular weight regulator is a mixture of bisphenol A phenolic resin and isopropyl alcohol in a mass ratio of 1:8;

[0115] The additional monomer phase is prepared as follows:

[0116] According to the formula, molecular weight regulator, isoprene and dicyclopentadiene were added into the cross-linking monomer batching tank and stirred for 1.5 hours to obtain a supplementary monomer phase for standby use.

[0117] Example 1

[0118] This embodiment provides a method for preparing a nitrile latex, which is carried out according to the following steps:

[0119] Put all the bottom materials into a clean 300L polymerization reactor, start stirring, evacuate the polymerization reactor to -0.091MPa, and then put 25.32kg of oil phase into the polymerization reactor. After heating the polymerization reactor to 36°C, add 7.68kg of initiator phase into the polymerization reactor and start timing the polymerization reaction. During the polymerization process, control the reaction temperature between 33°C and 37°C. Take samples every 2 hours to test the conversion rate. When the conversion rate reaches 75%, add the remaining 16.88kg of oil phase, 7.68kg of initiator, and 0.6kg of additional monomer into the polymerization reactor at once;

[0120] Supplementary reaction: When the conversion rate of the polymerization reaction system reaches 85%, the remaining supplementary monomer phase is added to the polymerization reactor at one time, and then the polymerization reaction system is gradually heated up, the reaction temperature is controlled at 45°C ~ 50°C, and the pressure of the polymerization reaction system is continuously controlled between 0.4MPa ~ 0.5MPa with high-purity nitrogen until the conversion rate of the polymerization reaction system reaches more than 95%.

[0121] Post-treatment: Add 0.9kg of pH regulator sodium hydroxide and 0.2kg of antioxidant hydrazine hydrate to the polymerization reactor, stir and react for 1.5 hours, then raise the temperature of the polymerization reactor to 70°C and start extraction. When the vacuum reaches -0.080MPa, start timing the reaction for 4 hours, and the extraction is complete. Cool the polymerization system to 35°C, add pH regulator sodium hydroxide to adjust the pH value of the reaction product to 8.5, add 0.1kg of fungicide Kathon, stir at a constant speed for 1 hour, and after discharging, filtering, and packaging, obtain a nitrile latex with a solid content of 44.1%, a viscosity of 45.2cps, and a particle size of 121nm. The test results of its physical properties are shown in Table 1.

[0122] Example 2

[0123] Put all the bottom materials into a clean 300L polymerization reactor, start stirring, evacuate the polymerization reactor to -0.090MPa, and then put 29.54kg of oil phase into the polymerization reactor; heat the polymerization reactor to 36°C, add 7.68kg of initiator phase into the polymerization reactor, and start timing the polymerization reaction. During the polymerization process, control the reaction temperature between 33°C and 35°C, take samples every 2 hours to test the conversion rate, and when the conversion rate reaches 75%, add the remaining oil phase, the remaining initiator phase, and 0.7kg of additional monomer phase into the polymerization reactor at one time.

[0124] Supplementary reaction: When the conversion rate of the polymerization reaction system reaches 85%, the remaining supplementary monomer phase is added to the polymerization reactor at one time, and then the polymerization reaction system is gradually heated up, the reaction temperature is controlled at 45°C ~ 50°C, and the pressure of the polymerization reaction system is continuously controlled between 0.4MPa ~ 0.5MPa with high-purity nitrogen until the conversion rate of the polymerization reaction system reaches more than 95%.

[0125] Post-treatment: Add 0.9kg of pH regulator sodium hydroxide and 0.2kg of antioxidant hydrazine hydrate to the polymerization reactor. After stirring for 2 hours, raise the temperature of the polymerization reactor to 70°C and start extraction. When the vacuum reaches -0.080MPa, start timing reaction for 4 hours and the extraction is completed. Cool the polymerization system to 35°C, add pH regulator sodium hydroxide to adjust the pH value of the reaction product to 8.5, add 0.1kg of fungicide Kasson, stir at a constant speed for 1 hour, and after discharging, filtering and packaging, obtain a nitrile latex with a solid content of 44.0%, a viscosity of 67.9cps and a particle size of 110nm. The test results of its physical properties are shown in Table 1.

[0126] Example 3

[0127] Put all the bottom materials into a clean 300L polymerization reactor, start stirring, evacuate the polymerization reactor to -0.092MPa, and then put 25.32kg of oil phase into the polymerization reactor. Heat the polymerization reactor to 36°C, add 6.5kg of initiator phase into the polymerization reactor, and start timing the polymerization reaction. During the polymerization process, control the reaction temperature between 35°C and 37°C, take samples every 2 hours to test the conversion rate, and when the conversion rate reaches 75%, add the remaining oil phase, the remaining initiator phase, and 0.8kg of additional monomer phase into the polymerization reactor at once.

[0128] Supplementary reaction: When the conversion rate of the polymerization reaction system reaches 85%, the remaining supplementary monomer phase is added to the polymerization reactor at one time, and then the polymerization reaction system is gradually heated up, the reaction temperature is controlled at 45°C ~ 50°C, and the pressure of the polymerization reaction system is continuously controlled between 0.4MPa ~ 0.5MPa with high-purity nitrogen until the conversion rate of the polymerization reaction system reaches more than 95%.

[0129] Post-treatment: Add 0.9kg of pH regulator sodium hydroxide and 0.2kg of antioxidant hydrazine hydrate to the polymerization reactor. After stirring for 2 hours, raise the temperature of the polymerization reactor to 70°C and start extraction. When the vacuum reaches -0.080MPa, start timing the reaction for 4 hours and the extraction is completed. Cool the polymerization system to 35°C, add pH regulator sodium hydroxide to adjust the pH value of the reaction product to 8.5, add 0.1kg of fungicide Kasson, stir at a constant speed for 1 hour, and after discharging, filtering and packaging, a nitrile latex with a solid content of 44.0%, a viscosity of 33.1cps and a particle size of 127nm is obtained. The physical property test results are shown in Table 1.

[0130] Example 4

[0131] The oil phase was prepared according to the following formula:

[0132] Acrylonitrile 15kg;

[0133] Butadiene 25kg;

[0134] Methacrylic acid 2.1 kg;

[0135] Molecular weight regulator 0.1kg;

[0136] The molecular weight regulator is a mixture of bisphenol A phenolic resin and isopropyl alcohol in a mass ratio of 1:8;

[0137] The oil phase was prepared as follows:

[0138] According to the formula, acrylonitrile, methacrylic acid, phenyl methacrylate, molecular weight regulator and butadiene were added into the oil phase preparation tank and stirred for 1.5 hours to obtain the oil phase for standby use.

[0139] The additional monomer phase is prepared according to the following formula:

[0140] Molecular weight regulator 0.1 kg;

[0141] Isoprene 1.3 kg;

[0142] The molecular weight regulator is a mixture of bisphenol A phenolic resin and isopropyl alcohol in a mass ratio of 1:8;

[0143] The additional monomer phase is prepared as follows:

[0144] According to the formula, molecular weight regulator and isoprene were added into the cross-linking monomer batching tank and stirred for 1.5 hours to obtain a supplementary monomer phase for standby use.

[0145] The preparation method of nitrile latex is as follows:

[0146] Put all the bottom materials into a clean 300L polymerization reactor, start stirring, evacuate the polymerization reactor to -0.090MPa, and then put 25.32kg of oil phase into the polymerization reactor. Heat the polymerization reactor to 35°C, add 7.68kg of initiator phase into the polymerization reactor, and start timing the polymerization reaction. During the polymerization process, control the reaction temperature between 33°C and 37°C, take samples every 2 hours to test the conversion rate, and when the conversion rate reaches 70%, add the remaining oil phase, the remaining initiator phase, and 0.6kg of additional monomer phase into the polymerization reactor at once.

[0147] Supplementary reaction: When the conversion rate of the polymerization reaction system reaches 80%, the remaining supplementary monomer phase is added to the polymerization reactor at once, and then the polymerization reaction system is gradually heated up, the reaction temperature is controlled at 45°C ~ 50°C, and the pressure of the polymerization reaction system is continuously controlled between 0.4MPa ~ 0.5MPa with high-purity nitrogen until the conversion rate of the polymerization reaction system reaches more than 95%.

[0148] Post-treatment: Add 0.9kg of pH regulator sodium hydroxide and 0.2kg of antioxidant hydrazine hydrate to the polymerization reactor. After stirring for 3 hours, raise the temperature of the polymerization reactor to 60°C and start extraction. When the vacuum reaches -0.075MPa, start timing reaction for 5 hours and the extraction is completed. Cool the polymerization system to 40°C, add pH regulator sodium hydroxide to adjust the pH value of the reaction product to 9, add 0.1kg of fungicide Kasson, stir at a constant speed for 1.5 hours, and after discharging, filtering and packaging, obtain a nitrile latex with a solid content of 43.9%, a viscosity of 49.7cps and a particle size of 119nm. The test results of its physical properties are shown in Table 1.

[0149] Example 5

[0150] The oil phase was prepared according to the following formula:

[0151] Acrylonitrile 15kg;

[0152] Butadiene 25kg;

[0153] Acrylic acid 1kg;

[0154] Phenyl methacrylate 1.1 kg;

[0155] Molecular weight regulator 0.1kg;

[0156] The molecular weight regulator is a mixture of bisphenol A phenolic resin and isopropyl alcohol in a mass ratio of 1:8;

[0157] The oil phase was prepared as follows:

[0158] According to the formula, acrylonitrile, acrylic acid, phenyl methacrylate, molecular weight regulator and butadiene were added into the oil phase preparation tank and stirred for 1.5 hours to obtain the oil phase for standby use.

[0159] The additional monomer phase is prepared according to the following formula:

[0160] Molecular weight regulator 0.1 kg;

[0161] Isoprene 1.0 kg;

[0162] Dicyclopentadiene 0.3 kg;

[0163] The molecular weight regulator is a mixture of bisphenol A phenolic resin and isopropyl alcohol in a mass ratio of 1:8;

[0164] The additional monomer phase is prepared as follows:

[0165] According to the formula, molecular weight regulator, isoprene and dicyclopentadiene were added into the cross-linking monomer batching tank and stirred for 1.5 hours to obtain a supplementary monomer phase for standby use.

[0166] The preparation method of nitrile latex is as follows:

[0167] Put all the bottom materials into a clean 300L polymerization reactor, start stirring, evacuate the polymerization reactor to -0.091MPa, and then put 25.32kg of oil phase into the polymerization reactor. Heat the polymerization reactor to 37°C, add 7.68kg of initiator phase into the polymerization reactor, and start timing the polymerization reaction. During the polymerization process, control the reaction temperature between 33°C and 37°C, take samples every 2 hours to test the conversion rate, and when the conversion rate reaches 80%, add the remaining oil phase, the remaining initiator phase, and 0.6kg of additional monomer phase into the polymerization reactor at once.

[0168] Supplementary reaction: When the conversion rate of the polymerization reaction system reaches 90%, the remaining supplementary monomer phase is added to the polymerization reactor at once, and then the polymerization reaction system is gradually heated up, the reaction temperature is controlled at 45°C ~ 50°C, and the pressure of the polymerization reaction system is continuously controlled between 0.4MPa ~ 0.5MPa with high-purity nitrogen until the conversion rate of the polymerization reaction system reaches more than 95%.

[0169] Post-treatment: Add 0.9kg of pH regulator sodium hydroxide and 0.2kg of antioxidant hydrazine hydrate to the polymerization reactor. After stirring for 1 hour, raise the temperature of the polymerization reactor to 80°C and start extraction. When the vacuum reaches -0.085MPa, start timing the reaction for 3 hours and the extraction is completed. Cool the polymerization system to 30°C, add pH regulator sodium hydroxide to adjust the pH value of the reaction product to 8, add 0.1kg of fungicide Kasson, stir at a constant speed for 0.5-1.5 hours, and after discharging, filtering, and packaging, a nitrile latex with a solid content of 44.0%, a viscosity of 25.7cps, and a particle size of 129nm is obtained. The physical property test results are shown in Table 1.

[0170] Comparative Example 1

[0171] The difference between this comparative example and Example 1 is that the nitrile latex is prepared according to the following method:

[0172] Put all the bottom materials into a clean 300L polymerization reactor, start stirring, evacuate the polymerization reactor to -0.091MPa, heat it to 36°C, put all the oil phase, initiator phase, and additional monomer phase into the polymerization reactor, and start timing polymerization. During the polymerization process, control the reaction temperature between 33°C and 37°C, take samples every 2 hours to test the conversion rate, and when the conversion rate reaches 85%, start to gradually heat up the polymerization system, control the reaction temperature between 45°C and 50°C, and use high-purity nitrogen to continuously control the pressure of the polymerization system between 0.4MPa and 0.5MPa until the conversion rate of the polymerization system reaches more than 95%.

[0173] Post-treatment: Add 0.9kg of pH regulator sodium hydroxide and 0.2kg of antioxidant hydrazine hydrate to the polymerization reactor. After stirring for 1.5 hours, raise the temperature of the polymerization reactor to 70°C and start extraction. When the vacuum reaches -0.080MPa, start timing the reaction for 4 hours and the extraction is completed. Cool the polymerization system to 35°C, add pH regulator sodium hydroxide to adjust the pH value of the reaction product to 8.5, add 0.1kg of fungicide Kasson, stir at a constant speed for 1 hour, and after discharging, filtering and packaging, obtain a nitrile latex with a solid content of 44%, a viscosity of 200cps and a particle size of 85nm. The test results of its physical properties are shown in Table 1.

[0174] Comparative Example 2

[0175] The difference between this comparative example and Example 1 is that the oil phase is configured according to the following formula:

[0176] Acrylonitrile 15kg;

[0177] Butadiene 25kg;

[0178] Molecular weight regulator 0.1kg;

[0179] The molecular weight regulator is a mixture of bisphenol A phenolic resin and isopropyl alcohol in a mass ratio of 1:8;

[0180] The oil phase was prepared as follows:

[0181] According to the formula, acrylonitrile, molecular weight regulator and butadiene were added into the oil phase preparation tank and stirred for 1.5 hours to obtain the oil phase for standby use.

[0182] The obtained nitrile latex has a solid content of 43%, a viscosity of 135 cps and a particle size of 109 nm. The test results of its physical properties are shown in Table 1.

[0183] Comparative Example 3

[0184] The difference between this comparative example and Example 1 is that the molecular weight regulator is bisphenol A phenolic resin.

[0185] The obtained nitrile latex has a solid content of 43.8%, a viscosity of 76 cps and a particle size of 125 nm. The test results of its physical properties are shown in Table 1.

[0186] Comparative Example 4

[0187] The difference between this comparative example and Example 1 is that the molecular weight regulator is isopropanol.

[0188] The obtained nitrile latex has a solid content of 43.5%, a viscosity of 36 cps and a particle size of 110 nm. The test results of its physical properties are shown in Table 1.

[0189] The standards used in the testing methods of latex in the embodiments of the present invention and the comparative examples are as follows:

[0190] Sampling: SH / T1149;

[0191] Total solid content: GB / T8298-2017;

[0192] Viscosity: SH / T1152-2014;

[0193] pH value: GB / T18012-2021;

[0194] Surface tension: SH / T1156-2014;

[0195] Mechanical stability: SH / T1151.1-2019;

[0196] Chemical stability: SH / T1608-2014;

[0197] Particle size: NKT-N9 nanometer laser particle size analyzer.

[0198] The test results are shown in Table 1.

[0199] Table 1

[0200]

[0201] As can be seen from the data in Table 1, the nitrile latex prepared by the technology of the present invention has a narrow particle size dispersion index, a particle size distribution range of 100-150nm, good fluidity, chemical stability, mechanical stability, and storage stability. At the same time, the prepared latex has a small residual volatile component content and high purity. When the nitrile latex is used to manufacture disposable nitrile latex gloves or dip-coated gloves, the matching rubber material of the latex can form a good infiltration structure on the surface of the glove mold or the lining material, and form a dense and high-strength film-forming material on the surface of the gloves, thereby giving the protective gloves good comprehensive properties such as wear resistance, oil resistance, penetration resistance, corrosion resistance, and service life, so that the protective gloves have better safety performance and protection effect, and the protective gloves have a wider range of application fields and greater application value.

[0202] The difference between Comparative Example 1 and Example 1 is that the preparation process of adding polymerization monomers in stages is not adopted, the preparation process has a violent reaction, the reaction controllability is poor, and the prepared nitrile latex has high viscosity, low particle size, and many agglomerates.

[0203] The difference between Comparative Example 2 and Example 1 is that no functional monomer is added to the oil phase, the reaction is slow, the reaction time is long, and the prepared nitrile latex has a high viscosity.

[0204] The difference between Comparative Example 3 and Example 1 is that no isopropanol is added to the molecular weight regulator, and the prepared nitrile latex has high viscosity and poor film strength.

[0205] The difference between Comparative Example 4 and Example 1 is that no bisphenol A phenolic resin is added to the molecular weight regulator, and the prepared nitrile latex has a smaller particle size, a slow reaction, and a low conversion rate.

[0206] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for preparing a nitrile latex, characterized in that: The steps include: S1: preparing a base material using deionized water, a chelating agent, an oxygen scavenger, a stabilizer, an electrolyte, and an initiator A as raw materials; S2: preparing an oil phase using acrylonitrile, butadiene, functional monomers and molecular weight regulator A as raw materials; S3: preparing an initiator phase using deionized water and initiator B as raw materials; S4: preparing a supplementary monomer phase using molecular weight regulator B and crosslinking monomer as raw materials; S5: Adding the bottom material into the polymerization reactor, starting stirring, evacuating to -0.085MPa~-0.095MPa, adding the oil phase, the initiator phase, and the additional monomer phase, reacting to obtain a reaction solution; S6: Add pH adjuster A and antioxidant to the polymerization reactor, stir the reaction, raise the temperature to 60°C-80°C, start extraction, and when the vacuum degree reaches -0.075MPa~-0.085MPa, start timing the reaction for 3~5 hours, and the extraction is completed; S7: cooling to 30°C-40°C, adding pH adjuster B to adjust the pH value of the reaction product to 8-9, adding bactericide, stirring, discharging, filtering, and packaging to obtain nitrile latex; Step S5 is performed as follows: S51: Adding a bottom material into the polymerization reactor, starting stirring, evacuating to -0.085MPa~-0.095MPa, and then adding a portion of the oil phase into the polymerization reactor; S52: raising the temperature of the polymerization reactor to 35° C.-45° C., adding a portion of the initiator phase to the polymerization reactor, and starting a polymerization reaction; when the conversion rate reaches 70%-80%, adding the remaining oil phase, the remaining initiator phase, and a portion of the additional monomer phase to the polymerization reactor; S53: When the conversion rate reaches 80%-90%, the remaining monomer phase is added to the polymerization reactor, the temperature is raised to 40° C.-50° C., and the pressure is controlled between 0.4 MPa-0.5 MPa until the conversion rate reaches 95%, thereby obtaining a reaction solution; The functional monomer is selected from at least one of 4-vinyl biphenyl, methacrylic acid, acrylic acid, phenyl methacrylate, ethylene glycol dimethacrylate, itaconic acid, maleic acid, and trimethylolpropane triacrylate; The molecular weight regulator A and the molecular weight regulator B are both a mixture of a polymer molecular weight regulator and a chain transfer agent in a mass ratio of 1: (5-10); The polymer molecular weight regulator is a thermoplastic phenolic resin; The chain transfer agent is selected from at least one of ethanol, propanol, isopropanol, glycerol, n-octanol, phenylselenol, dodecylselenol and pentaerythritol.

2. The method for preparing a nitrile latex according to claim 1, wherein The crosslinking monomer is an unsaturated polyolefin.

3. A nitrile latex, characterized in that The method is carried out by the method for preparing the nitrile latex as claimed in claim 1 or 2.

4. Application of nitrile latex as claimed in claim 3 in protective gloves.

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