High-performance chloroprene rubber and preparation method thereof

Abstract

The invention relates to the technical field of high-molecular compounds obtained through a carbon-carbon unsaturated bond reaction and synthetic high-molecular sealing materials, and discloses a high-performance chloroprene rubber and a preparation method thereof, and the high-performance chloroprene rubber is prepared by copolymerizing the following raw materials in parts by mass: 90-95 parts of first monomer chloroprene and 5-10 parts of second monomer dichlorobutadiene. According to the scheme, a dichlorobutadiene molecular branch chain is introduced into a common chloroprene rubber polychloroprene molecular main chain, so that the hardness and stress at definite elongation of the chloroprene rubber at low temperature are reduced, the elasticity is improved, and the low-temperature use temperature of the chloroprene rubber is increased. Specifically, the chloroprene rubber material produced by the scheme still has excellent cold resistance at the limit low temperature of-50 to 55 DEG C, and fully meets the application requirements of the chloroprene rubber material under the low-temperature condition.

Description

Technical Field

[0001] The invention relates to the technical field of polymer compounds obtained by carbon-carbon unsaturated bond reactions and synthetic polymer sealing materials, and in particular to high-performance chloroprene rubber and a preparation method thereof. Background Art

[0002] Neoprene is a synthetic rubber produced with chloroprene as the main raw material. It has excellent properties such as good air tightness, oil resistance, weather resistance, ozone resistance, heat resistance, flame resistance, flexibility resistance and chemical resistance. It is widely used in the manufacture of various seals, oil-resistant hoses, wires, cables, rubber sheets, tarpaulins, capsules, air cushions, conveyor belts, transmission belts, tent fabrics, air guides, lifeboats, oil-resistant rubber boots, shock-absorbing products, etc. Its important application areas include automobiles, construction, electricity and many other fields.

[0003] However, the cold resistance of chloroprene rubber is worse than that of all general rubbers and many special synthetic rubbers, but better than chlorinated polyethylene, polyacrylate rubber, some nitrile rubber and fluororubber. Its low temperature use limit is usually -30 to -40℃. Under lower temperature conditions, it is easy to harden and become brittle and lose its unique elasticity, which limits the use value of chloroprene rubber under low temperature conditions. For example, in severe cold areas such as the Northeast and other low temperature environments, the use of chloroprene rubber is severely restricted.

[0004] Prior art CN110804116A discloses a cold-resistant chloroprene rubber and its preparation method, which improves the cold-resistant performance of the medium-crystalline chloroprene rubber itself in the formula, solves the limitation of ordinary chloroprene rubber in low temperature conditions, overcomes the shortcomings of ordinary chloroprene rubber in low temperature crystallization and poor cold resistance, and can still maintain rubber elasticity without embrittlement under low temperature conditions of -42°C, greatly breaks through the low temperature resistance of chloroprene rubber, and expands the area and scope of use of chloroprene rubber. However, the cold-resistant performance of the chloroprene rubber produced by the prior art is still biased, and it cannot meet the performance requirements at low temperatures, which narrows the application scope of chloroprene rubber materials.

[0005] In view of this, developing a preparation method for high-performance chloroprene rubber with simple process and stable production can not only effectively make up for the shortcomings of the existing technology, but also effectively expand the low-temperature application temperature field of chloroprene rubber, which is of great significance to expanding the application scope of chloroprene rubber materials. Summary of the invention

[0006] The present invention aims to provide a high-performance chloroprene rubber and a preparation method thereof, so as to solve the technical problem that the chloroprene rubber produced by the prior art has poor cold resistance and cannot meet the performance requirements under low temperatures.

[0007] To achieve the above object, the present invention adopts the following technical scheme: a high-performance chloroprene rubber is prepared by copolymerizing the following raw materials in parts by weight: 90 to 95 parts of a first monomer chloroprene and 5 to 10 parts of a second monomer dichloroprene.

[0008] The principles and advantages of this solution are:

[0009] 1. Compared with the existing technology that improves the cold resistance of medium-crystalline chloroprene rubber in the formula, the product still cannot meet the performance requirements of low-temperature applications of chloroprene rubber. This solution reduces the hardness and tensile stress of chloroprene rubber at low temperatures, improves elasticity, and improves the low-temperature use temperature of chloroprene rubber by introducing dichloroprene molecular side chains into the main chain of ordinary chloroprene rubber polychloroprene molecules. Specifically, the chloroprene rubber material produced by this solution still has excellent cold resistance at the extreme low temperature of -50 to -55°C, fully meeting its application requirements under low temperature conditions.

[0010] 2. This solution effectively improves the low-temperature performance (including high elasticity and low-temperature flexibility) of the produced chloroprene rubber by limiting the usage ratio of the first monomer chloroprene and the second monomer dichloroprene, while ensuring the high strength, wear resistance, chemical resistance and flame retardancy of the chloroprene rubber material, thereby effectively expanding the application range of the chloroprene rubber material. The applicant has found through long-term experiments that if there is too much dichloroprene, while effectively improving the high elasticity, low-temperature flexibility and easy processing, it may reduce other properties of the material and reduce its performance; if there is too little dichloroprene, the material will be too hard and its low-temperature elasticity and flexibility will be reduced, and thus it will not be able to meet the low-temperature application requirements.

[0011] Preferably, as an improvement, the following raw materials are also included in parts by weight: based on the total amount of monomers, 0.2 to 0.5 parts of a regulator, 0.3 to 0.6 parts of an emulsifier, 0.2 to 0.5 parts of an initiator, 0.03 to 0.04 parts of a dispersant, 1 to 1.5 parts of an antioxidant, and 98 to 100 parts of water.

[0012] Technical effect: This scheme adopts the above-mentioned setting, which is convenient for preparing chloroprene rubber materials that take into account high and low temperature elasticity and good flexibility, high strength, wear resistance, chemical resistance and flame retardancy, and meet the application requirements in various scenarios. The applicant found through long-term experiments that if the amount of regulator is too high, the tensile strength will be too low due to the small molecular weight; if the amount of regulator is too low, the cross-linking degree will be high due to the high molecular weight, and the scorch time will be too low. If the amount of emulsifier is too high, the material overflow will be caused by excessive reaction foam; if the amount of emulsifier is too low, the oligomers will be more due to poor emulsification effect, and the scorch time will be too low. If the amount of initiator is too high, the material will be rushed due to the fast reaction speed; if the amount of initiator is too low, the reaction speed will be too slow to reach the end point of the reaction, and the product performance will be reduced. If the amount of dispersant is too high, the material benefit phenomenon will be caused by the large amount of dispersant foam; if the amount of dispersant is too low, the late gel will stick to the kettle due to poor dispersion effect. If the amount of antioxidant is too high, the product appearance will be dark due to excessive dosage; if the amount of antioxidant is too low, the scorch time of the product will be too low due to poor termination effect. If the amount of water is too high, the emulsification state will change, resulting in an increase in self-aggregates, which will affect the scorch time of the product; if the amount of water is too low, the emulsification state will change, resulting in poor heat transfer, which will affect the scorch time of the product.

[0013] Preferably, as an improvement, the regulator is one or more combinations of regulator butyl, n-dodecyl mercaptan, and tert-dodecyl mercaptan.

[0014] Technical effect: This solution adopts the above configuration to adapt to the different performance uses of chloroprene rubber. The applicant has found through long-term experiments that if different chloroprene rubber models are limited to using a single regulator, the molecular weight, crystallization, plasticity, etc. of the chloroprene rubber will be restricted due to the single regulator, and it cannot be used for different purposes.

[0015] Preferably, as an improvement, the emulsifier is one or more combinations of rosin, sodium petroleum sulfonate, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate.

[0016] Technical effect: This solution adopts the above configuration to form a good emulsion system. The applicant has found through long-term experiments that if different chloroprene rubber types are limited to using a single emulsifier, the emulsification system will be unstable and the polymerization reaction will not be complete due to poor emulsification effect.

[0017] Preferably, as an improvement, the initiator is formed by thermal decomposition of one or more combinations of potassium persulfate, ammonium persulfate, sodium persulfate, methyl ether sulfinic acid, and bleaching agent.

[0018] Technical effect: This solution adopts the above configuration to facilitate the adaptation to different performance uses of chloroprene rubber. The applicant has found through long-term experiments that if different chloroprene rubber models are limited to using a single initiator, the polymerization reaction speed will be affected due to different polymerization reaction temperature control indicators.

[0019] Preferably, as an improvement, the dispersant is a combination of one or more of WPF and LOMAR PW.

[0020] Technical effect: This scheme adopts the above-mentioned setting, which is convenient for adapting to different processes of chloroprene rubber polymerization and post-processing. The applicant has found through long-term experiments that if different chloroprene rubber models are limited to using a single domestic WPF, the impurity content of WPF will cause gel to be produced during polymerization and post-processing acid gel, causing production interruption or loss. According to the different processes of producing chloroprene rubber, WPF, LOMAR PW (sodium salt of naphthalenesulfonic acid formaldehyde condensation product) or a combination of the two can be selected to effectively adapt to the performance requirements of the chloroprene rubber produced by production.

[0021] Preferably, as an improvement, the reducing agent is one or more combinations of bleaching powder and methyl ether sulfinic acid.

[0022] Technical effect: This scheme adopts the above-mentioned setting, which is convenient for adapting to the performance uses of different chloroprene rubbers.

[0023] Preferably, as an improvement, the antioxidant is a hindered phenol AX-503 antioxidant, and the preparation method is as follows: the antioxidant is a hindered phenol AX-503 antioxidant, and the preparation method is as follows: 450-500 parts of the main antioxidant are heated to 105-110°C to melt, 45-55 parts of the auxiliary antioxidant are added to melt, and after cooling to 90-100°C, stirred at 500-600rps, all the melted materials are placed in an emulsifying kettle; when the temperature drops to 95-98°C, 28-50 parts of the main emulsifier are added, After mixing at 1500-3000rps for 5-10min, add 19.5-30 parts of auxiliary emulsifier I, 10-20 parts of auxiliary emulsifier II, and 1-5 parts of defoamer when the temperature is below 95°C; then, add 24-30 parts of 20% potassium hydroxide aqueous solution under stirring, and add 1-2 parts of auxiliary emulsifier II after saponification reaction; when it is impossible to stir, add 500-520 parts of 90°C hot water, and add 1-2 parts of defoamer in small amounts and multiple times as needed, adjust the pH value to 10-11, cool down, and set aside;

[0024] The main antioxidant is the antioxidant Wingstay L, and the auxiliary antioxidant is a carbon radical scavenger, which is selected from any one or more of hindered amine stabilizer (HAS), hydroxylamine, bisphenol monoacrylate, LT251, benzofuranone and ortho-allyl substituted phenol in any proportion; the main emulsifier is emulsifier TX-10; the auxiliary emulsifier I and auxiliary emulsifier II are both one or more combinations of oleic acid, rosin, sodium petroleum sulfonate, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate.

[0025] Technical effect: Antioxidants need to be added in time after the polymerization of chloroprene rubber is terminated to prevent aging and quality reduction during post-processing and product storage. There are many types of antioxidants for chloroprene rubber and they are used alone in various types of chloroprene rubber, but the effect is not ideal. Chloroprene rubber CR121 currently uses the antioxidant N-phenyl-2-naphthylamine (chemical name N-phenyl-2-naphthylamine). At present, N-phenyl-2-naphthylamine is included in the list of Class 3 carcinogens published by the World Health Organization's International Agency for Research on Cancer.

[0026] And hindered phenol AX-503 antioxidant aqueous emulsion is a kind of highly active, low volatility, multi-purpose, pollution-free polymerized hindered phenol antioxidant, is the recommended excellent antioxidant of natural and synthetic rubber polymer and butadiene compound, has good antioxidant effect in latex equally, and has excellent dispersibility or compatibility. And this scheme prepares the gained AX-503 antioxidant fully can replace chloroprene rubber CR121 and currently uses antioxidant butyl (chemical name N-phenyl-2-naphthylamine), and the raw materials are mostly environmentally friendly raw materials, no chemical reaction process, simple process, stable production. Through nearly four years, it has been used in two well-known chloroprene rubber manufacturers in China, and the effect is good, and the user's reputation is deeply won. In specific application, antioxidant AX-503 is dispersed in CR-121 chloroprene rubber latex and adds about 2% (relative monomer amount) of the number of parts, can obviously delay the early vulcanization tendency of CR-121 chloroprene rubber, prolong the scorch time, and improve the stability of CR121 chloroprene rubber products.

[0027] Preferably, as an improvement, the method comprises the following steps:

[0028] Step 1, oil phase preparation: melt and mix the raw materials chloroprene, reducing agent, dispersant, regulator butyl, emulsifier rosin and dichloroprene in steps to obtain an oil phase;

[0029] Step 2, water phase preparation: dispersing the emulsifiers sodium petroleum sulfonate and sodium hydroxide into water, and heating to obtain a water phase;

[0030] Step 3, emulsification: mixing the oil phase and the water phase, emulsifying for 10 to 15 minutes to obtain an emulsion;

[0031] Step 4, polymerization: After heating the emulsion to 38-42°C, add initiator in batches, polymerize at 40±2°C for 2-3h, and obtain high-performance chloroprene rubber material.

[0032] Technical effect: This scheme adopts the above-mentioned setting, which facilitates the polymerization of the first monomer and the second monomer into a high-performance chloroprene rubber material.

[0033] Preferably, as an improvement, in step 4, the temperature is monitored during the reaction and the reaction temperature is controlled to 40±2°C by adding an inhibitor or initiator; the inhibitor is any one of phenothiazine, amine inhibitors, nitroxide free radical compounds and their derivative inhibitors.

[0034] Technical effect: This scheme adopts the above-mentioned setting to facilitate the control of reaction speed. The applicant has found through long-term experiments that in addition to controlling the polymerization temperature at 40±2°C by means of starting and stopping stirring and adjusting the opening size of the brine pneumatic regulating valve, the polymerization temperature can also be controlled by adding inhibitors or initiators during the polymerization process, thereby avoiding the polymerization temperature from suddenly changing and causing the polymerization reaction to be too fast or too slow. Specifically, if the polymerization temperature rises rapidly and the aforementioned method cannot be controlled, the reaction rate can be reduced by adding a small amount of inhibitor, thereby effectively reducing the polymerization temperature. If the reaction rate is too slow and the aforementioned method cannot be controlled, an appropriate amount of initiator solution can be added to ensure balanced control of the polymerization temperature.

[0035] Preferably, as an improvement, in step 4, it also includes measuring the specific gravity of the polymer liquid after 1.5 hours of polymerization reaction, and after the specific gravity of the latex reaches 1.080-1.082, placing the latex into a termination kettle, adding 0.1-0.5 parts of a terminator and 3-5 parts of an antioxidant AX-503 under stirring, stirring for 15 minutes, stopping stirring, and sending for post-processing to obtain cold-resistant chloroprene rubber; the terminator is one or a combination of two of the antioxidants B and phenothiazine.

[0036] Technical effect: In the early stage of the polymerization reaction, the density of the monomer is low. As the reaction proceeds, the monomer is gradually converted into a polymer, and the density of the polymer gradually increases. When the reaction approaches the end point, the monomer is almost completely converted and the density of the polymer tends to be stable. This solution can observe the density change trend by measuring the specific gravity of the reaction system in the later stage of the polymerization reaction. When the density change tends to be flat or no longer increases significantly, it indicates that the reaction is close to the end point, the monomer conversion rate is high, and the cross-linking reaction is basically completed. At this time, adding inhibitors and antioxidants can effectively prevent the polymer from being oxidized and degraded, ensuring the high performance of the polymer. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The process flow chart of preparing chloroprene rubber antioxidant in Example 1 of the present invention is shown.

[0038] Figure 2 The process flow chart of preparing high-performance chloroprene rubber in Example 1 of the present invention is shown.

[0039] Figure 3 The infrared spectra of the chloroprene rubbers prepared in Example 1 and Comparative Example 1 of the present invention are as follows (a: ordinary chloroprene rubber produced in Comparative Example 1; b: 2-DCB homopolymer; c: cold-resistant chloroprene rubber produced in Example 1). DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the technical means used in the following examples and experimental examples are conventional means well known to those skilled in the art, and the materials, reagents, etc. used can be obtained from commercial sources.

[0041] Example 1

[0042] This scheme provides a method for preparing a chloroprene rubber antioxidant, the process flow is as follows Figure 1 As shown, the method comprises the following steps: the antioxidant is a hindered phenol AX-503 antioxidant, and the preparation method is as follows: 450 to 500 parts of the main antioxidant (as a reference, the specific antioxidant Wingstay L) is heated to 105-110°C and melted, 45-55 parts of auxiliary antibiotics (as a reference, the auxiliary antibiotic can be selected from any one or more of hindered amine stabilizer (HAS), hydroxylamine, bisphenol monoacrylate, LT251, benzofuranone and ortho-allyl substituted phenol in any proportion, and the present embodiment specifically uses carbon radical scavenger LT251) are added to melt, and after cooling to 90-100°C, it is stirred at 500-600rps, and all the melted materials are placed in an emulsifier; when the temperature drops to 95-98°C, 28-50 parts of primary emulsifier (as a reference, emulsifier TX-10 can be selected), 1500-3000rps are mixed for 5-10 minutes, and 19.5-30 parts are added when it is below 95°C Auxiliary emulsifier I (as a reference, one or more combinations of oleic acid, rosin, sodium petroleum sulfonate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate can be selected, and oleic acid is specifically selected in this embodiment), 10-20 parts of auxiliary emulsifier II (as a reference, one or more combinations of oleic acid, rosin, sodium petroleum sulfonate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate can be selected, and sodium dodecylbenzene sulfonate is specifically selected in this embodiment) and 1-5 parts of defoamer are added; then, 24-30 parts of 20% potassium hydroxide aqueous solution are added under stirring, and 1-2 parts of auxiliary emulsifier II are added after saponification reaction; when it is impossible to stir, 500-520 parts of 90°C hot water are added, and 1-2 parts of defoamer are added in small amounts and multiple times as appropriate, and the pH value is adjusted to 10-11, and the temperature is lowered and cooled for standby use.

[0043] The present invention also provides a high-performance chloroprene rubber, which is copolymerized by the following raw materials in mass fractions: 90-95 parts of the first monomer chloroprene, 5-10 parts of the second monomer dichloroprene. The following raw materials are also included in mass fractions: based on the total amount of monomers, 0.2-0.5 parts of a regulator, 0.3-0.6 parts of an emulsifier, 0.3-0.5 parts of a dispersant, 0.2-0.5 parts of an initiator, 1-1.5 parts of an antioxidant, and 98-100 parts of water.

[0044] Among them, the regulator is one or more combinations of regulator butyl (also known as diisopropyl xanthate disulfide), n-dodecyl mercaptan, and tert-dodecyl mercaptan. The emulsifier is one or more combinations of rosin, sodium petroleum sulfonate, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate. The initiator is one or more combinations of potassium persulfate, ammonium persulfate, and sodium persulfate decomposed by heat. The reducing agent is one or more combinations of bleaching powder and methyl ether sulfinic acid. The dispersant is one or more combinations of WPF and lomarpw. The antioxidant is the hindered phenol AX-503 antioxidant prepared as described above.

[0045] This solution also provides a method for preparing high-performance chloroprene rubber, the process flow is as follows: Figure 2 As shown, the following steps are included:

[0046] The steps include:

[0047] Step 1, oil phase preparation: melt and mix the raw materials chloroprene, reducing agent (specifically, bleaching agent in this embodiment), dispersant (specifically, lomarpw in this embodiment), regulator butyl, emulsifier rosin and dichloroprene in steps to obtain an oil phase;

[0048] Step 2, water phase preparation: dispersing the emulsifiers sodium petroleum sulfonate and sodium hydroxide into water, and heating to obtain a water phase;

[0049] Step 3, emulsification: mixing the oil phase and the water phase, emulsifying for 10 to 15 minutes to obtain an emulsion;

[0050] Step 4, polymerization: After heating the emulsion to 38-42°C, initiators are added in batches, and after polymerization at 40±2°C for 2-3h, a high-performance chloroprene rubber material is obtained. Specifically, the temperature is monitored during the reaction, and the reaction temperature is controlled to be 40±2°C by adding an inhibitor or an initiator; the inhibitor is any one of phenothiazine, amine inhibitors, nitroxide free radical compounds and their derivative inhibitors, and this embodiment specifically uses an amine inhibitor. After 1.5 hours of polymerization, the specific gravity of the polymer solution was measured. When the specific gravity of the latex reached 1.080-1.082, the emulsion was placed in a termination kettle, and 0.1-0.5 parts of a terminator (as a reference, one or two of antioxidant D and phenothiazine can be selected in any proportion, and antioxidant D is specifically selected in this embodiment) and 3-5 parts of an antioxidant AX-503 were added under stirring, and the mixture was stirred for 15 minutes. The stirring was stopped and the mixture was sent for post-processing (including freezing gel, washing, drying, extrusion molding, cutting, etc., which were completed using conventional operations in the industry and will not be described here) to obtain cold-resistant chloroprene rubber.

[0051] The preparation process of the chloroprene rubber antioxidant in Examples 2 to 3 and Comparative Examples 1 to 3 is basically the same as that in Example 1, except for the different processes and some parameter selections in the antioxidant preparation stage, as shown in Table 1 for details.

[0052] The preparation process of the chloroprene rubber in Comparative Examples 4 to 8 is basically the same as that in Example 1, except for the different processes and some parameter selections in the preparation stage of the chloroprene rubber, as shown in Table 2 for details.

[0053] Table 1 Differences in the production process of antioxidants in Examples 1 to 3 and Comparative Examples 1 to 3

[0054]

[0055] Table 2 Differences in the production process of chloroprene rubber in comparative examples 4 to 8

[0056] Example Mass ratio of the first monomer to the second monomer Antioxidant dosage / portion Example 1 90:10:00 1.2 Example 2 90:05:00 1 Example 3 95:10:00 1.5 Comparative Example 4 100:00:00 1.2 Comparative Example 5 85:15:00 1.2 Comparative Example 6 98:02:00 1.2 Comparative Example 7 90:10:00 0.5 Comparative Example 8 90:10:00 2

[0057] Experimental Example 1: Performance Determination of Chloroprene Rubber Antioxidant

[0058] The properties of the chloroprene rubber produced by using the chloroprene rubber antioxidants in Examples 1 to 3 and Comparative Examples 1 to 3 and the chloroprene rubber produced by Comparative Examples 4 to 8 were tested with reference to the following standards. The experimental data are shown in Table 3:

[0059] (1) Determination of Mooney viscosity: Determined according to GB / T 21462-2008 Chloroprene Rubber (CR) Evaluation Method and with reference to the method described in GB / T14647-93CR121 Chloroprene Rubber Inspection Standard and GB / T15257-94CR322 Chloroprene Rubber Inspection Standard;

[0060] (2) Determination of Mooney scorch: Determined according to GB / T 21462-2008 Chloroprene Rubber (CR) Evaluation Method and with reference to the methods described in GB / T14647-93CR121 Chloroprene Rubber Test Standard and GB / T15257-94CR322 Chloroprene Rubber Test Standard;

[0061] (3) Determination of tensile strength: Determined according to GB / T 21462-2008 Chloroprene Rubber (CR) Evaluation Method and with reference to the methods described in GB / T14647-93CR121 Chloroprene Rubber Test Standard and GB / T15257-94CR322 Chloroprene Rubber Test Standard;

[0062] (4) Determination of elongation at break: Determined according to GB / T 21462-2008 Chloroprene rubber (CR) evaluation method and with reference to the method described in GB / T14647-93CR121 Chloroprene rubber test standard and GB / T15257-94CR322 Chloroprene rubber test standard;

[0063] (5) Determination of volatile matter: Determined according to GB / T 21462-2008 Chloroprene Rubber (CR) Evaluation Method and with reference to the methods described in GB / T14647-93CR121 Chloroprene Rubber Test Standard and GB / T15257-94CR322 Chloroprene Rubber Test Standard;

[0064] (6) Ash content determination: Measured according to GB / T 21462-2008 Chloroprene Rubber (CR) Evaluation Method and with reference to the methods described in GB / T14647-93CR121 Chloroprene Rubber Inspection Standard and GB / T15257-94CR322 Chloroprene Rubber Inspection Standard;

[0065] (7) Low temperature performance: Determined according to the method described in GB / T 1682-2008 "General principles for low temperature test methods for rubber and plastic products" and GB / T1683-2008 "Low temperature test for rubber products" product quality inspection standards.

[0066] Table 2 Differences in properties of chloroprene rubber prepared using antioxidants in Examples 1 to 3 and Comparative Examples 1 to 8

[0067]

[0068] Experimental data show that the low-temperature performance of chloroprene rubber produced by the antioxidant prepared in Example 1 is the best. The chloroprene rubber produced by the antioxidant can withstand an extreme low temperature as low as -55°C, which significantly improves the low-temperature performance of chloroprene rubber and fully meets the performance index requirements of chloroprene rubber products under low temperature conditions.

[0069] The applicant found in the research and development process that the combination of antioxidants and raw material monomers significantly affects the low-temperature performance of the produced chloroprene rubber. Specifically, when the antioxidant N-butyl (chemical name N-phenyl-2-naphthylamine) is added as an antioxidant after the polymerization reaction, the chloroprene rubber produced not only has low low-temperature resistance and cannot meet the performance index requirements under low-temperature conditions, but also N-phenyl-2-naphthylamine is on the list of Class 3 carcinogens, and excessive use will increase safety hazards, which is significantly lower than the low-temperature performance of the chloroprene rubber produced by using the hindered phenol AX-503 antioxidant produced by this solution. In the process of producing hindered phenol AX-503 antioxidant by oneself, the dosage ratio of main antioxidant and auxiliary antioxidant, the dosage ratio of main emulsifier, auxiliary emulsifier I and auxiliary emulsifier II, etc. will also affect the antioxidant ability of the produced antioxidant on chloroprene rubber. For example, if the dosage of main antioxidant is too little (such as comparative example 1), the dosage of auxiliary antioxidant is too little (such as comparative example 2), the dosage of auxiliary antioxidant is too much (such as comparative example 3), etc., the antioxidant ability of the prepared antioxidant on the polymerized chloroprene rubber will be reduced, thereby reducing the low temperature resistance of the prepared chloroprene rubber, and further affecting its normal use under extremely low temperature conditions.

[0070] In the process of polymerizing chloroprene rubber, whether the ratio of the two monomers is inappropriate, or the dosage of various reagents is too much or too little (represented by the dosage of antioxidants being too much or too little), the low-temperature performance of the prepared chloroprene rubber will be reduced. Specifically, if the raw material only uses the first monomer chloroprene (such as Comparative Example 4), the first monomer chloroprene is added in too little amount (such as Comparative Example 5) or the second monomer dichloroprene is added in too little amount (such as Comparative Example 6), the hardness and tensile stress of the chloroprene rubber at low temperatures will be reduced, and its elasticity will be reduced, thereby affecting the service performance of the chloroprene rubber at low temperatures and significantly reducing its low-temperature resistance effect.

[0071] If too little antioxidant is added (such as in Comparative Example 7), the chloroprene rubber obtained by polymerization will have a poor termination effect, resulting in a too low scorch time of the product, and aging will reduce its low-temperature performance; if too much antioxidant is added (such as in Comparative Example 8), not only will its low-temperature performance not be further improved, but the excessive amount will cause the product appearance to be darker, affecting its use.

[0072] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A high performance chloroprene rubber, characterized in that: The invention is prepared by copolymerizing the following raw materials in parts by weight: 90 to 95 parts of a first monomer chloroprene and 5 to 10 parts of a second monomer dichloroprene.

2. A high performance chloroprene rubber according to claim 1, characterized in that: The invention also includes the following raw materials in parts by weight: based on the total amount of monomers, 0.2 to 0.5 parts of a regulator, 0.3 to 0.6 parts of an emulsifier, 0.3 to 0.5 parts of a dispersant, 0.2 to 0.5 parts of an initiator, 0.03 to 0.04 parts of a reducing agent, 1 to 1.5 parts of an antioxidant, and 98 to 100 parts of water.

3. A high performance chloroprene rubber according to claim 2, characterized in that: The regulator is one or more combinations of regulator 4, n-dodecyl mercaptan, and tert-dodecyl mercaptan.

4. A high performance chloroprene rubber according to claim 2, characterized in that: The emulsifier is one or more combinations of rosin, sodium petroleum sulfonate, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate.

5. The high performance chloroprene rubber according to claim 2, characterized in that: The initiator is formed by thermal decomposition of one or more combinations of potassium persulfate, ammonium persulfate and sodium persulfate.

6. The high performance chloroprene rubber according to claim 2, characterized in that: The reducing agent is one or more combinations of bleaching powder and methyl ether sulfinic acid.

7. The high performance chloroprene rubber according to claim 2, characterized in that: The antioxidant is a hindered phenol AX-503 antioxidant, and the preparation method is as follows: 450-500 parts of the main antioxidant are heated to 105-110°C to melt, 45-55 parts of the auxiliary antioxidant are added to melt, the temperature is lowered to 90-100°C, and the mixture is stirred at 500-600rps, and the melted materials are all put into an emulsifying kettle; when the temperature drops to 95-98°C, 28-50 parts of the main emulsifier are added, and the mixture is mixed at 1500-3000rps for 5-10 minutes. min later, when the temperature is lower than 95°C, add 19.5-30 parts of auxiliary emulsifier I, 10-20 parts of auxiliary emulsifier II and 1-5 parts of defoamer; then, add 24-30 parts of 20% potassium hydroxide aqueous solution under stirring, and add 1-2 parts of auxiliary emulsifier II after saponification reaction; when it is impossible to stir, add 500-520 parts of 90°C hot water, and add 1-2 parts of defoamer in small amounts and multiple times as needed, adjust the pH value to 10-11, cool down, and set aside; The main antioxidant is the antioxidant Wingstay L, and the auxiliary antioxidant is a carbon radical scavenger, which is selected from any one or more of hindered amine stabilizer (HAS), hydroxylamine, bisphenol monoacrylate, LT251, benzofuranone and ortho-allyl substituted phenol in any proportion; the main emulsifier is emulsifier TX-10; the auxiliary emulsifier I and auxiliary emulsifier II are both one or more combinations of oleic acid, rosin, sodium petroleum sulfonate, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate.

8. A method for preparing high-performance chloroprene rubber according to any one of claims 1 to 7, characterized in that: The steps include: Step 1, oil phase preparation: melt and mix the raw materials chloroprene, dispersant, reducing agent, regulator butyl, emulsifier rosin and dichloroprene in steps to obtain an oil phase; Step 2, water phase preparation: dispersing the emulsifiers sodium petroleum sulfonate and sodium hydroxide into water, and heating to obtain a water phase; Step 3, emulsification: mixing the oil phase and the water phase, emulsifying for 10 to 15 minutes to obtain an emulsion; Step 4, polymerization: After heating the emulsion to 38-42°C, add initiator in batches, polymerize at 40±2°C for 2-3h, and obtain high-performance chloroprene rubber material.

9. The method for preparing a high-performance chloroprene rubber according to claim 8, characterized in that: In step 4, the temperature is monitored during the reaction and the reaction temperature is controlled to be 40±2° C. by adding an inhibitor or an initiator, wherein the inhibitor is any one of phenothiazine, amine inhibitors, nitroxide free radical compounds and their derivative inhibitors.

10. The method for preparing a high-performance chloroprene rubber according to claim 9, characterized in that: In step 4, the specific gravity of the polymer solution is measured after the polymerization reaction for 1.5 hours. After the specific gravity of the latex reaches 1.080-1.082, the latex is placed in a termination kettle, and 0.1-0.5 parts of a terminator and 3-5 parts of an antioxidant AX-503 are added under stirring. The mixture is stirred for 15 minutes, and the stirring is stopped. The mixture is sent for post-processing to obtain the cold-resistant chloroprene rubber. The terminator is one or a combination of antioxidant B and phenothiazine.

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