Chlorosulfonated polyethylene aqueous emulsion and method for preparing the same

Abstract

The present application relates to a kind of chlorosulfonated polyethylene aqueous emulsion, the particle size of chlorosulfonated polyethylene in the aqueous emulsion is 200-500nm, solid content is 40-60%, emulsion potential is-37mV~ -60mV, 0-8% synthetic latex is also contained in emulsion and does not contain organic solvent;The synthetic latex is chloroprene latex emulsion, natural latex emulsion, nitrile latex emulsion, butyl latex emulsion, and butadiene-styrene latex emulsion one or several kinds.The present application also relates to the preparation method of the chlorosulfonated polyethylene aqueous emulsion, which can achieve the purpose of mixing chlorosulfonated polyethylene rubber liquid with water without hydrophilic modification of chlorosulfonated polyethylene resin, simplify the process flow, save the material cost of using modifier, and the prepared emulsion does not contain organic solvent, environmental protection is pollution-free, emulsion stability is high, storage period can reach 24-100 days, film-forming property (dense film) is good, after preparing glove and other dipping coating products, the density of glue layer is high, can guarantee that glove has good anti-permeation and anti-chemical performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rubber composite material preparation, and particularly relates to a chlorosulfonated polyethylene water-based emulsion and a preparation method thereof. BACKGROUND

[0002] Chlorosulfonated polyethylene rubber (CSM) is a special synthetic rubber made of high-density polyethylene by chlorination and chlorosulfonation. According to the differences in molecular weight, chlorine mass fraction and sulfur mass fraction, it can be divided into many varieties. As a kind of polar saturated rubber, chlorosulfonated polyethylene rubber has no double bond, and the chlorine atoms and sulfur atoms in the molecular chain are arranged randomly. The product has excellent weather resistance, ozone resistance, heat aging resistance, flame resistance, chemical medium resistance, wear resistance, oil resistance, good coloring performance, biological resistance, surface adhesion and electrical properties. CSM is widely used in building materials, outdoor products, green tires, coating industry, automobile parts, adhesive tape, rubber pipe, rubber roller and other industrial products and blending modification materials. For example, CN107383447A and CN102993585B are both to send CSM and other synthetic rubbers such as chloroprene rubber and styrene-butadiene rubber directly into a rubber mixing machine for rubber mixing and vulcanization to prepare products. However, this method can only be used to produce relatively thick composite rubber products. Since the emulsion is not prepared, it is impossible to produce light and thin coating products such as CSM impregnated coating gloves.

[0003] Chlorosulfonated polyethylene has a molecular weight of 3-12 million, a relatively small molecular weight, a certain crystallinity of molecular chain and poor flexibility of molecular chain. The film forming temperature is relatively high, which leads to poor film forming property and spreading property of the latex under natural conditions. In order to be widely used in various industries, chlorosulfonated polyethylene rubber should first be prepared into an emulsion with good film forming property and stability. This requires that the particle size of the emulsion should not be too large. If the particle size is too large, the stability is poor, easy to agglomerate and difficult to form a film, and it is impossible to produce light and thin impregnated products. In addition, the environmental protection of the product is also the primary consideration of each production enterprise.

[0004] At present, most of the CSM emulsions are oil-based CSM emulsions, and the volatilization of the oil agent brings great environmental pollution and production safety problems. There are relatively few reports on CSM water-based emulsions. The CSM emulsion reported in CN113861349A is modified for CSM rubber, the process is complex, the production cycle is long, and the prepared CSM particle size is relatively large, all above 640 nm, and the emulsion film forming property and stability are poor. The CSM emulsion reported in CN113388070A has low polarity due to the chlorosulfonated polyethylene resin itself. This scheme mainly uses acrylic acid, maleic anhydride, hydroxyethyl acrylate or hydroxypropyl acrylate as a hydrophilic grafting modifier, in the presence of a catalyst such as benzoyl peroxide or azobisisobutyronitrile, the hydrophilic grafting modifier is used to graft modify the chlorosulfonated polyethylene resin to overcome the problem of large particle size caused by the low polarity of chlorosulfonated polyethylene during the preparation of the chlorosulfonated polyethylene emulsion. Then, emulsifiers and dispersants are compounded to improve the dispersion and suspension of the latex particles in water and the stability of the emulsion. This modification process not only introduces new reagent raw materials and costs, but also involves energy consumption such as heating during the reaction process. Moreover, the modified chlorosulfonated polyethylene resin molecules will further undergo crosslinking reaction, resulting in larger molecular weight, which makes it difficult to further reduce the particle size of the emulsion, and the stability of the emulsion is poor, and the difficulty of forming a dense film is also increased.

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, it is necessary to improve the prior art. SUMMARY

[0006] (1) Technical problems to be solved

[0007] In view of the above-mentioned shortcomings and deficiencies of the prior art, it is necessary to improve the prior art.

[0008] (2) Technical solutions

[0009] In order to achieve the above-mentioned purposes, the main technical solutions adopted by the present application include:

[0010] In the first aspect, the present application provides a chlorosulfonated polyethylene water-based emulsion, wherein the particle size of chlorosulfonated polyethylene in the water-based emulsion is 200-500 nm, the solid content is 40-60%, the emulsion potential is between-37 mV and-60 mV, the emulsion further contains 0-8% of synthetic latex and does not contain organic solvents; the synthetic latex is one or more of chlorobutyl latex emulsion, natural latex emulsion, nitrile rubber latex emulsion, butyl latex emulsion, and styrene-butadiene latex emulsion.

[0011] The water-based emulsion of the chlorosulfonated polyethylene has a particle size of 200-500 nm and an emulsion potential of 35-60 mV, is high in stability and good in film forming property; in addition, the emulsion does not contain organic solvents, is beneficial to environmental protection and the health of users, and can replace the current oily chlorosulfonated polyethylene glue solution in the use of building materials, outdoor products, the paint industry, automobile parts, adhesive tape, rubber pipe, rubber roller, coating gloves and other industries. When the particle size of the chlorosulfonated polyethylene in the water-based emulsion is less than 200 nm, the emulsion is too stable and it is difficult to produce a dipping coating product. In the preparation of a dipping coating glove, the glove core is dipped in a coagulant and then dipped in the emulsion, and the coagulation of the coagulant is used to realize rapid and uniform dipping. If the particle size of the emulsion is too small, the emulsion is not easy to dip. On the contrary, if the particle size is greater than 500 nm, the emulsion is unstable, easy to break and coagulate, has a short storage period, and it is difficult for the dipping product to form a glue layer with uniform thickness and a dense film surface.

[0012] In a second aspect, the application provides a preparation method of a water-based emulsion of chlorosulfonated polyethylene, comprising,

[0013] S1, preparing a glue solution: 100 parts of chlorosulfonated polyethylene rubber and 600-1000 parts of an organic solvent are dissolved and stirred at 40-65°C to prepare a glue solution according to the mass fraction;

[0014] S2, preparing an emulsified mixed solution: 9-15 parts of an anionic emulsifier is dissolved in 400-800 parts of water to prepare an emulsified mixed solution;

[0015] S3, emulsifying the glue solution: the glue solution in S1 is gradually added to the emulsified mixed solution in S2, and a high-speed homogenizer is used to homogenize at a speed greater than 1500 rpm to prepare an oil-in-water type chlorosulfonated polyethylene rubber emulsion;

[0016] S4, removing the organic solvent: the oil-in-water type chlorosulfonated polyethylene rubber emulsion in S3 is evaporated under negative pressure to remove all the organic solvents and part of the water to prepare a water-based emulsion of chlorosulfonated polyethylene.

[0017] As a preferred embodiment of the application, in S1, the organic solvent is one or more of toluene, xylene, ethyl acetate, cyclohexane, chloroform and trichlorotrifluoroethane.

[0018] When the glue solution is prepared, the chlorosulfonated polyethylene rubber is completely dissolved and uniform in the organic solvent at 40-65°C, and then stirring is stopped.

[0019] The organic solvent is preferably a single agent, which is convenient for rotary evaporation to remove the organic solvent, and the organic solvent can be recycled under a certain temperature range and negative pressure conditions, and the recycled organic solvent can be reused to save production costs.

[0020] In S2, a large amount of water and emulsifier are used to prepare an emulsified mixture, the emulsifier is dispersed very uniformly in the emulsified mixture, then the chlorosulfonated polyethylene rubber solution prepared in S1 (containing only organic solvents) is added to the emulsified mixture in S2, a large amount of water is introduced during emulsification, and an oil-in-water type chlorosulfonated polyethylene rubber emulsion is formed. This method can achieve the purpose of fully mixing chlorosulfonated polyethylene rubber solution and water without modifying the hydrophilicity of chlorosulfonated polyethylene rubber, simplifies the preparation process, and saves the reagent cost and energy consumption cost caused by modifying chlorosulfonated polyethylene rubber using a modifier and a catalyst.

[0021] In S2, the amount of water is 400-800 parts, and the more water, the more conducive to forming chlorosulfonated polyethylene emulsion with smaller particle size and improving the stability of the emulsion, but at the same time, the evaporation and concentration cost will increase, so the amount of water is preferably controlled in the range of 400-800 parts.

[0022] The present application mainly uses an emulsifier and a large amount of water to prepare an emulsified mixture for emulsifying the chlorosulfonated polyethylene rubber solution, reduces the particle size of chlorosulfonated polyethylene in the emulsion, maintains the particle size in the range of 200-500 nm, or even maintains the particle size in the range of 200-350 nm, so that the emulsion has good mechanical stability, spreading property and film-forming property, and can ensure the compactness, anti-permeability and anti-chemical property of the rubber film when preparing a rubber impregnated product.

[0023] In S3, the homogenization treatment is: using a high-speed homogenizer to perform emulsification reaction at high speed at room temperature; in S4, the removal of organic solvents is: in a closed environment, under negative pressure, using heating evaporation method to remove all organic solvents and part of water, to prepare a predetermined solid content chlorosulfonated polyethylene water-based emulsion containing only water, and the recovered solvent can be reused, which is safe and environmentally friendly.

[0024] As a preferred embodiment of the present application, in S2, the anionic emulsifier is one or more of sodium dodecyl benzene sulfonate, sodium stearate, potassium oleate, potassium disulfide rosin acid, sodium carboxymethyl cellulose, sodium dodecyl alcohol ether sulfate, potassium dodecyl phosphate, ammonium dodecyl sulfate and potassium hydroxide.

[0025] As a preferred embodiment of the present application, in S2, the emulsified mixture further contains 0-2 parts of non-ionic emulsifier; the mass ratio of anionic emulsifier to non-ionic emulsifier is 10:0-1, i.e. 10 parts of anionic emulsifier corresponds to 0-1 parts of non-ionic emulsifier; and the non-ionic emulsifier is one or more of polyvinyl alcohol with an alcoholysis degree of 75%-99%, Tween-20, Tween-80 and sorbitan monooleate.

[0026] The non-ionic emulsifier is added in the emulsified mixture, and is used in combination with the anionic emulsifier, so that the emulsification effect can be further improved, the glue solution emulsification is promoted, the particle size of chlorosulfonated polyethylene in the emulsion can be reduced, and the emulsion stability and film forming property can be improved. In addition, in order to avoid the problem that the amount of the non-ionic emulsifier is too large, the chlorosulfonated polyethylene glue solution cannot be converted from the oil phase to the water phase after being added into the emulsified mixture, and the water-based emulsion cannot be completed, it is limited in the application that the anionic emulsifier: non-ionic emulsifier is 10:0-1.

[0027] The anionic emulsifier is used as the main emulsifier of the chlorosulfonated polyethylene emulsion, but the anionic emulsifier is not resistant to acid. In the emulsion state, chlorosulfonated polyethylene is easy to dechlorinate and acidize, so that the pH value of the emulsion system decreases, the properties of the anionic emulsifier are affected, the stability of the emulsion is reduced, the emulsion storage time is shortened, and usually only a few days. As an auxiliary emulsifier, it is preferred to add some non-ionic emulsifiers, which are good in acid resistance and are not affected by acid precipitation. Therefore, the anionic emulsifier and the non-ionic emulsifier are used in combination, so that the stability of the chlorosulfonated polyethylene emulsion can be improved, and the emulsion stability time can be prolonged. However, the non-ionic emulsifier cannot be used as the main emulsifier, because with the increase of the amount of the non-ionic emulsifier, the HLB value of the emulsifier combination decreases, the hydrophilic ability decreases, and the emulsion cannot form an oil-in-water emulsion. Therefore, it can only be used as an auxiliary emulsifier, and is combined with the preferred anionic emulsifier to play a synergistic effect, and the proportion cannot be too high.

[0028] As a preferred embodiment of the application, in S1, 0-20 parts of the first film forming aid dispersed in the organic solvent are added in combination with every 100 parts of chlorosulfonated polyethylene rubber to prepare the glue solution; or,

[0029] In S3, 0-20 parts of the second film forming aid are added in combination with every 100 parts of chlorosulfonated polyethylene rubber emulsion; wherein the first film forming aid is one or more of chlorobutyl rubber, natural rubber, nitrile rubber, butyl rubber, and styrene-butadiene rubber;

[0030] The second film forming aid is one or more of chlorobutyl latex emulsion, natural rubber latex emulsion, nitrile rubber latex emulsion, butyl rubber latex emulsion, and styrene-butadiene rubber latex emulsion.

[0031] By compounding one or more of neoprene, natural rubber, nitrile rubber, butyl rubber, and styrene-butadiene rubber in the process of preparing the glue solution in step S1, or by compounding one or more of neoprene latex emulsion, natural rubber latex emulsion, nitrile rubber latex emulsion, butyl rubber latex emulsion, and styrene-butadiene rubber latex emulsion in the emulsion in step S3, the latex itself has good adhesion and film-forming property, and can bond the particles of chlorosulfonated polyethylene emulsion to each other to form a film, thus improving the film-forming property of the chlorosulfonated polyethylene emulsion and the compactness of the impregnated coating, and expanding the application range of the chlorosulfonated polyethylene aqueous emulsion. In addition, the addition of neoprene / rubber latex can further reduce the particle size of the chlorosulfonated polyethylene emulsion and improve the stability of the chlorosulfonated polyethylene aqueous emulsion.

[0032] As a preferred embodiment of the present application, in S3, the emulsification of the glue solution includes two stages: the first stage is a feeding stage, the speed of the high-speed homogenizer is set to 500-1500 rpm, and the glue solution prepared in step S1 is gradually added to the emulsified mixed solution prepared in S2 while stirring, and mixed and homogenized for 3-5 min;

[0033] The second stage is a homogenization treatment stage, the speed of the high-speed homogenizer is increased to 2200-4200 rpm, and then dispersed for 10-25 min. The greater the stirring speed, the better the homogenization effect, and the more conducive to reducing the particle size of the chlorosulfonated polyethylene emulsion; the dispersion time of 10-25 min has met the dispersion requirement, and a too long dispersion time not only increases energy consumption, but also is not conducive to obtaining the most suitable emulsion in a stable state.

[0034] As a preferred embodiment of the present application, in S4, the process of evaporating to remove the organic solvent is to heat to 30-75℃, maintain a negative pressure value of 40-100 kPa, and evaporate to remove all the organic solvent; or / and,

[0035] Remove part of the water: heat to 65-80℃, maintain a negative pressure value of 85-100 kPa, and remove part of the water by rotary evaporation to prepare a chlorosulfonated polyethylene aqueous emulsion with a preset solid content. Generally, in order to prepare an impregnated coating product and maintain the stability of the emulsion, the solid content of the emulsion should be controlled to 40-60%.

[0036] (Three) beneficial effects

[0037] The beneficial effects of the present application are:

[0038] The preparation method of the chlorosulfonated polyethylene water-based emulsion of the present application mainly comprises the following steps: firstly, an emulsifier mixed solution is prepared by using an anionic emulsifier and a large amount of water; secondly, chlorosulfonated polyethylene rubber liquid prepared by using an organic solvent is gradually added into the emulsifier mixed solution; and thirdly, the chlorosulfonated polyethylene rubber liquid is emulsified by homogenization treatment to obtain an oil-in-water type chlorosulfonated polyethylene rubber emulsion, and then all the organic solvents are removed by negative pressure evaporation to obtain an environmentally friendly chlorosulfonated polyethylene water-based emulsion.

[0039] Compared with the prior art, the method does not need to graft modify the chlorosulfonated polyethylene resin by using a hydrophilic modifier and a catalyst, can reduce the modification process and the cost of reagents, does not need to consider the graft modification conversion rate, and also avoids the problem that the modified chlorosulfonated polyethylene resin molecules continue to crosslink to cause the problem of too large particle size of the chlorosulfonated polyethylene emulsion. The present application adopts a pure physical method, does not need to go through a chemical reaction process, can effectively reduce the particle size of the emulsion, improve the mechanical stability and film forming property of the emulsion, and also can prepare an environmentally friendly chlorosulfonated polyethylene water-based emulsion which does not contain organic solvents at all. The emulsion has an extremely low potential (-37mV to -60mV), the particle size of the emulsion is only 200-500nm, and even can reach 200-350nm, the stability of the emulsion is high, the storage period can reach 24-100 days, the film forming property (dense film) is good, and after the glove dipping coating product is prepared, the glue layer has high density, so that the glove has good anti-permeation and anti-chemical properties.

[0040] In the method, a large amount of water and emulsifiers (anionic emulsifiers and / or non-ionic emulsifiers) are directly used to prepare an emulsifier mixed solution. The emulsifier mixed solution has been fully mixed with the anionic emulsifiers and / or non-ionic emulsifiers in advance, and the water in the emulsifier mixed solution has good lipophilicity at this time. Then, the chlorosulfonated polyethylene rubber liquid (dispersed by an organic solvent) is added into the emulsifier mixed solution, and a large amount of water is introduced at the same time of emulsification, so that the chlorosulfonated polyethylene rubber liquid is mixed with water (oil-water mixture) without hydrophilic modification of the chlorosulfonated polyethylene resin, the process flow is simplified, and the use of the modifier is saved.

[0041] In the present application, other synthetic rubbers (such as one or more of chlorobutyl rubber, natural rubber, nitrile rubber, butyl rubber and styrene-butadiene rubber) are added as film forming aids in the preparation of the sulfonated polyethylene rubber water-based emulsion, so as to further improve the stability and film forming property of the chlorosulfonated polyethylene latex and expand the application range of the emulsion.

[0042] The organic solvents used in the preparation method of the present application are all recycled and utilized in the process, the preparation process almost does not involve chemical reactions, no pollution is generated, the production process is simple, the raw material cost is low, and the present application can replace the current oil-based chlorosulfonated polyethylene emulsion. DETAILED DESCRIPTION

[0043] In order to better explain the present application, so as to be understood, the present application is described in detail below through specific embodiments. In the present application specification, "parts" refers to mass parts in the absence of explicit statement.

[0044] Example 1

[0045] The chlorosulfonated polyethylene aqueous emulsion of the present embodiment is prepared by the following method:

[0046] (1) 100 parts of chlorosulfonated polyethylene rubber and 600 parts of toluene are placed in a dispersion tank and stirred, and heated to 60°C for dissolution to prepare a chlorosulfonated polyethylene glue solution.

[0047] (2) 11.66 parts of anionic emulsifier A (5.28 parts of potassium oleate + 5.28 parts of sodium dodecyl alcohol ether sulfate + 1.1 parts of potassium hydroxide) and 1.11 parts of non-ionic emulsifier B (0.55 parts of sorbitan monooleate + 0.55 parts of Tween-80) are placed in an emulsifying kettle, and 444.44 parts of deionized water is added to the emulsifying kettle, and stirred uniformly to prepare an emulsifier mixture.

[0048] (3) The emulsifying kettle in (2) is used at room temperature with a high-speed homogenizer, and the rotation speed is set to 500 rpm. The chlorosulfonated polyethylene glue solution in step (1) is slowly added to the emulsifier mixture, and after mixing and homogenizing for 5 min, 10 parts by weight of chlorobutyl latex (latex solid content is 10 parts by weight) is added, and then the rotation speed is increased to 3000 rpm. After 25 min, the homogenizer is turned off to obtain an oil-in-water type chlorosulfonated polyethylene rubber emulsion.

[0049] (4) The oil-in-water type chlorosulfonated polyethylene rubber emulsion in the emulsifying kettle in (3) is placed on a rotary evaporator, heated in a water bath at 75°C, and the pressure is set to -85 kPa. The organic solvent is removed by rotary evaporation to prepare a chlorosulfonated polyethylene aqueous emulsion.

[0050] Example 2

[0051] The chlorosulfonated polyethylene aqueous emulsion of the present embodiment is different from that of Example 1 only in that:

[0052] In step (1), when preparing the glue solution, 90 parts of chlorosulfonated polyethylene rubber and 10 parts of chlorobutyl rubber are dissolved in 600 parts of toluene, heated to 60°C for dissolution to prepare a chlorosulfonated polyethylene glue solution. At the same time, chlorobutyl latex is no longer added in step (3).

[0053] Other steps and conditions are the same as Example 1.

[0054] Example 3

[0055] The chlorosulfonated polyethylene aqueous emulsion of this example only differs from Example 1 in that:

[0056] In step (2), when preparing the emulsifier mixture, 12.4 parts of anionic emulsifier A (5.7 parts of potassium oleate + 5.7 parts of sodium dodecyl alcohol ether sulfate + 1 part of potassium hydroxide) and 0.6 parts of non-ionic emulsifier B (0.3 parts of sorbitan monooleate + 0.3 parts of Tween-80) are placed in the emulsification kettle, and then 444.44 parts of deionized water is added to the emulsification kettle, stirred uniformly to prepare the emulsifier mixture. At the same time, no chlorobutyl latex is added in step (3). Other steps and conditions are the same as Example 1.

[0057] Example 4

[0058] The chlorosulfonated polyethylene aqueous emulsion of this example only differs from Example 1 in that:

[0059] In step (2), when preparing the emulsifier mixture, 11 parts of anionic emulsifier A (5 parts of potassium oleate + 5 parts of sodium dodecyl alcohol ether sulfate + 1 part of potassium hydroxide) and 1 part of non-ionic emulsifier B (0.5 parts of sorbitan monooleate + 0.5 parts of Tween-80) are placed in the emulsification kettle, and then 400 parts of deionized water is added to the emulsification kettle, stirred uniformly to prepare the emulsifier mixture. At the same time, no chlorobutyl latex is added in step (3). Other steps and conditions are the same as Example 1.

[0060] Example 5

[0061] The chlorosulfonated polyethylene aqueous emulsion of this example only differs from Example 1 in that:

[0062] In step (2), when preparing the emulsifier mixture, 10.5 parts of anionic emulsifier A (4.75 parts of potassium oleate + 4.75 parts of sodium dodecyl alcohol ether sulfate + 1 part of potassium hydroxide) and 0.5 parts of non-ionic emulsifier B (0.25 parts of sorbitan monooleate + 0.25 parts of Tween-80) are placed in the emulsification kettle, and then 400 parts of deionized water is added to the emulsification kettle, stirred uniformly to prepare the emulsifier mixture. At the same time, no chlorobutyl latex is added in step (3). Other steps and conditions are the same as Example 1.

[0063] Example 6

[0064] The chlorosulfonated polyethylene aqueous emulsion of this example only differs from Example 1 in that:

[0065] In step (2), when preparing the emulsifier mixture, 10 parts of anionic emulsifier A (9 parts of potassium disulfide rosin acid + 1 part of potassium hydroxide) and 1 part of non-ionic emulsifier B (0.5 parts of sorbitan monooleate + 0.5 parts of Tween-80) were placed in the emulsification kettle, 400 parts of deionized water was added into the emulsification kettle, and stirred uniformly to prepare the emulsifier mixture. Meanwhile, no chlorobutyl latex was added in step (3). The other steps and conditions were the same as those in Example 1.

[0066] Example 7

[0067] The chlorosulfonated polyethylene aqueous emulsion of the present example only includes the following differences compared with Example 6:

[0068] The "0.5 parts of sorbitan monooleate + 0.5 parts of Tween-80" in Example 6 was adjusted to 0.4 parts of sorbitan monooleate + 0.6 parts of Tween-80. The other steps and conditions were the same as those in Example 6.

[0069] Example 8

[0070] The chlorosulfonated polyethylene aqueous emulsion of the present example only includes the following differences compared with Example 6:

[0071] The "0.5 parts of sorbitan monooleate + 0.5 parts of Tween-80" in Example 6 was adjusted to 0.3 parts of sorbitan monooleate + 0.7 parts of Tween-80. The other steps and conditions were the same as those in Example 6.

[0072] Example 9

[0073] The chlorosulfonated polyethylene aqueous emulsion of the present example only includes the following differences compared with Example 6:

[0074] In step (2), when preparing the emulsifier mixture, the total amount of anionic emulsifier A and non-ionic emulsifier B was 13 parts by mass, and the mass ratio of anionic emulsifier A to non-ionic emulsifier B was 10. The other steps and conditions were the same as those in Example 6.

[0075] Example 10

[0076] The chlorosulfonated polyethylene aqueous emulsion of the present example only includes the following differences compared with Example 6:

[0077] In step (2), when preparing the emulsifier mixture, the total amount of anionic emulsifier A and non-ionic emulsifier B was 12 parts by mass, and the mass ratio of anionic emulsifier A to non-ionic emulsifier B was 10. The other steps and conditions were the same as those in Example 6.

[0078] Example 11

[0079] The chlorosulfonated polyethylene aqueous emulsion of the present example only differs from example 1 in that:

[0080] In step (2), when preparing the emulsifier mixture, the total amount of anionic emulsifier A and nonionic emulsifier B is 9.6 parts by mass, and the mass ratio of anionic emulsifier A to nonionic emulsifier B is 10. Other steps and conditions remain the same as in example 6.

[0081] Example 12

[0082] The chlorosulfonated polyethylene aqueous emulsion of the present example only differs from example 1 in that:

[0083] In step (2), when preparing the emulsifier mixture, no nonionic emulsifier B is added, only 11 parts of anionic emulsifier A (5 parts of potassium oleate + 5 parts of sodium dodecyl alcohol ether sulfate + 1 part of potassium hydroxide) is added to 400 parts of deionized water, stirred uniformly to prepare the emulsifier mixture. At the same time, 10 parts of chlorobutyl latex is not added in step (3). Other steps and conditions remain the same as in example 1.

[0084] Example 13

[0085] The chlorosulfonated polyethylene aqueous emulsion of the present example only differs from example 12 in that: in step (1), when preparing the chlorosulfonated polyethylene glue solution, the organic solvent is replaced by an equal amount of chloroform. Other steps and conditions remain the same as in example 12.

[0086] Example 14

[0087] The chlorosulfonated polyethylene aqueous emulsion of the present example only differs from example 12 in that: in step (1), when preparing the chlorosulfonated polyethylene glue solution, the amount of toluene is increased from 600 parts to 700 parts. Other steps and conditions remain the same as in example 12.

[0088] Example 15

[0089] The chlorosulfonated polyethylene aqueous emulsion of the present example only differs from example 12 in that: in step (3), a high-speed homogenizer is used, the rotation speed is first set to 500 rpm, the chlorosulfonated polyethylene glue solution in step (1) is gradually added to the emulsifier mixture, after mixing and homogenizing for 5 min, the rotation speed is increased to 4000 rpm, and after 25 min the homogenizer is turned off to obtain an oil-in-water type chlorosulfonated polyethylene rubber emulsion. Other steps and conditions remain the same as in example 12.

[0090] Example 16

[0091] The chlorosulfonated polyethylene aqueous emulsion of the present example is different from that of Example 1 only in that in step (2), when preparing the emulsifier mixture, only one anionic emulsifier A (11.5 parts of sodium dodecyl alcohol ether sulfate, without adding potassium hydroxide) is used, and no non-ionic emulsifier B is used. That is, 11.5 parts of sodium dodecyl alcohol ether sulfate is placed in the emulsification kettle, and then 400 parts of deionized water is added to the emulsification kettle, and stirred uniformly to prepare the emulsifier mixture. The other steps and conditions are the same as those of Example 1.

[0092] By changing some conditions of the above examples, the following comparative examples are obtained as references.

[0093] Comparative Example 1

[0094] The present comparative example is based on Example 12, and in step (1), when preparing the chlorosulfonated polyethylene glue solution, the amount of toluene is reduced from 600 parts by weight to 400 parts by weight.

[0095] Comparative Example 2

[0096] The present comparative example is based on Example 12, and in step (1), when preparing the chlorosulfonated polyethylene glue solution, the amount of toluene is reduced from 600 parts by weight to 500 parts by weight.

[0097] Comparative Example 3

[0098] The present comparative example is based on Example 12, and in step (1), when preparing the chlorosulfonated polyethylene glue solution, 600 parts by weight of toluene is replaced by an equal amount of trichlorotrifluoroethane.

[0099] Comparative Example 4

[0100] The present comparative example is based on Example 6, and in step (2), when preparing the emulsifier mixture, the total amount of anionic emulsifier A and non-ionic emulsifier B is 9 parts by mass, and the mass ratio of anionic emulsifier A to non-ionic emulsifier B is 10. The other steps and conditions are the same as those of Example 6.

[0101] Comparative Example 5

[0102] The present comparative example is based on Example 12, and in step (3), a high-speed homogenizer is used, the rotational speed is set to 500 rpm, the chlorosulfonated polyethylene glue solution prepared in step (1) is gradually added to the emulsifier mixture, and after mixing and homogenizing for 5 minutes, the rotational speed is increased to 1500 rpm, and after 25 minutes, the homogenizer is turned off to obtain an oil-in-water type chlorosulfonated polyethylene rubber emulsion. The other steps and conditions are the same as those of Example 12.

[0103] Comparative Example 6

[0104] The comparative example is based on example 12, changing the preparation step as follows:

[0105] Step (1) is the same as example 12: take 100 parts by weight of chlorosulfonated polyethylene rubber, 600 parts by weight of toluene, stir in a dispersion tank, heat to 60°C until the rubber is completely dissolved, and obtain a chlorosulfonated polyethylene glue solution.

[0106] (2) Add 11 parts of anionic emulsifier A (5 parts of potassium oleate + 5 parts of sodium dodecyl alcohol ether sulfate + 1 part of potassium hydroxide) to the glue solution prepared in (1), stir for 30 min, mix evenly, and prepare a mixture.

[0107] (3) In an emulsifying kettle, use a high-speed homogenizer at room temperature, set the speed to 500 rpm, gradually add 400 parts of distilled water to the mixture in (2) while stirring, mix and homogenize for 5 minutes, then increase the speed to 3000 rpm, and homogenize for another 25 minutes.

[0108] (4) Under the same evaporation conditions as in example 1, heat in a water bath, set the temperature to 75°C, and set the pressure to -85 kPa. Remove the solvent by rotary evaporation. After the solvent is completely removed, set the rotary evaporation instrument temperature to 65°C and the pressure to -100 kPa to remove water. Concentrate the latex to the desired solid content and discharge.

[0109] The properties of the chlorosulfonated polyethylene water-based emulsion prepared in each example are tested, and the test method is as follows:

[0110] Stability test: take 50g of emulsion in a sealed plastic sample bottle, and observe whether precipitation or stratification occurs.

[0111] Zeta potential, particle size and particle size distribution PDI index test: detected by Malvern particle size analyzer.

[0112] Film formation state test: observe and evaluate the natural film formation on a glass plate.

[0113] Solvent content is detected by gas chromatography.

[0114] The properties of the chlorosulfonated polyethylene water-based emulsion are summarized in Table 1:

[0115] Table 1

[0116]

[0117]

[0118] From the data comparison of Table 1, it can be seen that Examples 1-5 are preferred embodiments of the present application, the prepared chlorosulfonated polyethylene aqueous emulsion has excellent performance and a long stable period of more than 3 months, and the emulsion particle size is less than 350 nm; among them, Example 1 is the best. Comparing Example 1 with Example 2, it can be seen that the effect of adding the film forming aid in the emulsification stage (step 3) is better than that of adding the film forming aid in the preparation stage of the chlorosulfonated polyethylene glue solution (step 1). Comparing Examples 1-2 with Examples 3-5, it can be seen that in the presence of the film forming aid neoprene (or neoprene latex), the emulsion particle size is smaller, the particle size distribution PDI index is smaller, and the film forming property and stability of the emulsion reach a better state.

[0119] From the comparison of Examples 3, 5, 6 and Example 12, it can be seen that the co-action of the anionic emulsifier A and the non-ionic emulsifier B can significantly reduce the emulsion particle size and significantly change the film forming property and stability.

[0120] From the comparison of Examples 6-8, it can be seen that the component ratio in the non-ionic emulsifier B also has a certain influence on the emulsion particle size and stability, and the preferred ratio of sorbitan monooleate and Tween-80 is 1:1.

[0121] From the comparison of Examples 6, 9, 10, 11 and Comparative Example 4, it can be seen that the larger the total amount of the anionic emulsifier A and the non-ionic emulsifier B, the higher the stability of the prepared chlorosulfonated polyethylene aqueous emulsion and the smaller the emulsion particle size, and preferably, when the total amount of the emulsifier is 11 parts, the particle size distribution PDI index is the smallest, and too low total amount of the emulsifier is not conducive to the improvement of the stability of the chlorosulfonated polyethylene aqueous emulsion. From Comparative Example 4, it can be seen that for 100 parts of chlorosulfonated polyethylene rubber, the total amount of the emulsifier is not less than 9 parts.

[0122] From Examples 13 and Comparative Example 3, it can be seen that among the effects of using single solvent to prepare the chlorosulfonated polyethylene glue solution for emulsification, the effect of chloroform is the best, followed by toluene, but chloroform has a lower boiling point and is easy to volatilize at room temperature, and it is difficult to control and has a low recovery rate in the recovery process; therefore, the optimal choice of single solvent is toluene, and the recovery rate can reach more than 90%, which not only can be recycled and save costs, but also has a smaller impact on the surrounding working environment.

[0123] From the comparison of Example 14 with Example 12, Comparative Example 1 and Comparative Example 2, it can be seen that the emulsion particle size decreases and the stability increases with the increase of the amount of solvent, but the increase of the amount of solvent will lead to an increase in the difficulty of the subsequent rotary evaporation process; therefore, the amount of organic solvent is preferably 700 parts.

[0124] From the comparison of Examples 12, 15 and Comparative Example 5, it can be seen that increasing the homogenization speed in the emulsification stage can reduce the emulsion particle size, and too low homogenization speed will affect the emulsification effect and lead to the failure of film forming. Therefore, the homogenization speed of the glue solution emulsification should be greater than 1500 rpm.

[0125] From the comparison of Example 16 with Example 1 and Example 12, it can be seen that, since Example 16 only uses one anionic emulsifier A, although the addition amount reaches 11.5 parts, no small amount of potassium hydroxide is added, and no non-ionic emulsifier B is used, the chlorosulfonated polyethylene is dechlorinated and acid is precipitated in the emulsion state, and without the addition of potassium hydroxide to neutralize the precipitated acid, the pH drops rapidly, reducing the stability of the emulsion and shortening the storage time of the emulsion. Therefore, when only anionic emulsifier A is used, it is preferred to use a plurality of anionic emulsifiers in combination to improve the stability of the emulsion by the different acid resistance of different anionic emulsifiers; more preferably, a small amount of alkali is added to neutralize the acid precipitation, further improving the stability of the emulsion.

[0126] From the comparison of Example 12 and Comparative Example 6, it can be seen that changing the feeding method, i.e. mixing and emulsifying the organic solvent, chlorosulfonated polyethylene rubber and anionic emulsifier A first, and then adding a large amount of distilled water for homogenization, i.e. using the "agent (emulsifier) in oil method", will make the emulsion particle size larger and the stability worse, ultimately affecting the film forming performance of the emulsion.

[0127] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A chlorosulfonated polyethylene aqueous emulsion for dipping gloves, characterized by: The chlorosulfonated polyethylene in the aqueous emulsion has a particle size of 200-500 nm, a solid content of 40-60%, and an emulsion potential between -37 mV and -60 mV. The emulsion also contains 0-8% synthetic latex and does not contain an organic solvent. The synthetic latex is one or more of chloroprene latex, natural rubber latex, nitrile latex, butyl latex, and styrene-butadiene latex. The preparation method of the chlorosulfonated polyethylene aqueous emulsion is as follows: S1. Prepare glue solution: according to the weight ratio, stir and dissolve 100 parts of chlorosulfonated polyethylene rubber and 600-1000 parts of organic solvent at 40-65°C to prepare glue solution; S2. preparing an emulsified mixture: dissolving 9-15 parts by mass of an anionic emulsifier in 400-800 parts by mass of water to prepare an emulsified mixture; the emulsified mixture further contains 0-2 parts by mass of a nonionic emulsifier; the ratio of anionic emulsifier to nonionic emulsifier is 10:0-1 by mass, i.e., 0-1 parts by mass of nonionic emulsifier are added for every 10 parts by mass of anionic emulsifier; the amount of nonionic emulsifier added is not zero; wherein the nonionic emulsifier is one or more of polyvinyl alcohol having a degree of alcoholysis of 75%-99%, Tween-20, Tween-80, and sorbitan monooleate; and the anionic emulsifier contains 1 part of potassium hydroxide; S3, emulsifying the rubber solution: gradually adding the rubber solution in S1 to the emulsified mixture in S2, and homogenizing the mixture using a high-speed homogenizer at a speed of >1500 rpm to obtain an oil-in-water chlorosulfonated polyethylene rubber emulsion; The emulsification of the glue solution includes two stages: the first stage is the feeding stage, setting the speed of the high-speed homogenizer to 500-1500 rpm, gradually adding the glue solution prepared in step S1 to the emulsified mixture prepared in step S2 while stirring, and mixing and homogenizing for 3-5 minutes; the second stage is the homogenization treatment stage, increasing the speed of the high-speed homogenizer to 2200-4200 rpm, and dispersing for another 10-25 minutes; S4, removing the organic solvent: evaporating the oil-in-water chlorosulfonated polyethylene rubber emulsion in S3 under negative pressure to remove all organic solvent and part of the water therein to obtain a chlorosulfonated polyethylene aqueous emulsion; the method for evaporating all organic solvent is as follows: heating to 30-75° C., maintaining a negative pressure of 40-100 kPa, and evaporating to remove all organic solvent; the method for removing part of the water is as follows: heating to 65-80° C., maintaining a negative pressure of 85-100 kPa, and rotary evaporating to remove part of the water to obtain a chlorosulfonated polyethylene aqueous emulsion with a predetermined solid content; In S1, 0-20 parts of a first film-forming aid are added to every 100 parts by mass of chlorosulfonated polyethylene rubber and dispersed in an organic solvent to prepare the adhesive solution; The first film-forming aid is one or more of chloroprene rubber, natural rubber, nitrile rubber, butyl rubber, and styrene-butadiene rubber.

2. The chlorosulfonated polyethylene aqueous emulsion according to claim 1, characterized in that In S1, the organic solvent is one or more of toluene, xylene, ethyl acetate, cyclohexane, chloroform, and trichlorotrifluoroethane.

3. The chlorosulfonated polyethylene aqueous emulsion according to claim 1, characterized in that In S2, the anionic emulsifier is sodium dodecylbenzenesulfonate, sodium stearate, potassium oleate, potassium disproportionate rosin acid, sodium carboxymethyl cellulose, sodium lauryl alcohol ether sulfate, potassium lauryl phosphate or ammonium lauryl sulfate.

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