Preparation method of acrylate rubber, acrylate rubber and application of acrylate rubber

Abstract

The invention relates to the field of preparation of acrylate rubber, and discloses a preparation method of acrylate rubber, the acrylate rubber and application of the acrylate rubber. The preparation method comprises the following steps: S1, contacting a polymeric monomer and an aqueous solution of an emulsifier in a loop reactor for emulsification, and then adding an initiator and ethylene for polymerization reaction to obtain an acrylate rubber emulsion; wherein the polymeric monomer is an acrylate monomer and / or a monomer with a crosslinking active group; the temperature of the polymerization reaction is 10 to 90 DEG C, and the pressure of the polymerization reaction is 0.1 to 2.5 MPa; s2, the acrylate rubber emulsion is led out from the top of the loop reactor and then subjected to steam stripping, condensation, demulsification, water washing and drying treatment, and the acrylate rubber is obtained. According to the preparation method of the acrylate rubber, the ethylene unit is introduced into the acrylate rubber on the premise that the temperature and the pressure are not too high, so that the performance of the product is improved, and the production cost is reduced.

Description

Technical Field

[0001] The invention relates to the field of acrylate rubber preparation, and in particular to a method for preparing acrylate rubber, acrylate rubber and applications thereof. Background Art

[0002] Acrylic rubber is an elastomer obtained by copolymerization with acrylic ester as the main monomer. Its main chain is a saturated carbon chain and the side group is a polar ester group. It has excellent properties such as heat resistance, aging resistance, oil resistance, ozone resistance, and UV resistance. It has special advantages in making oil-resistant rubber products for use under high temperature conditions. It has now become a cost-effective high-temperature oil-resistant special rubber.

[0003] The emulsion method is currently the main production method for acrylic rubber. It is obtained by polymerization reaction in an emulsifier aqueous solution. The polymerization reaction is a free radical reaction with a fast reaction speed and concentrated heat release. The molecular weight of the polymer decreases with the increase of temperature. If the reaction heat cannot be discharged in time, it is easy to cause poor uniformity and stability of product quality. Generally, large-scale mixed batches are required to reduce quality fluctuations. In addition, continuous operation is required when using a kettle reaction. Theoretically, it should be a fully mixed flow during continuous operation. However, due to the high viscosity of the material, the temperature field and concentration in the polymerization kettle are uneven, and it is difficult to achieve the ideal fully mixed flow state in the polymerization. It is difficult to obtain a polymer with a narrow molecular weight and uniform distribution of copolymer components, and the product quality uniformity and stability are poor. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art in terms of poor quality uniformity and stability of acrylic rubber, and to provide a method for preparing acrylic rubber, acrylic rubber and applications thereof. In the method for preparing acrylic rubber of the present invention, ethylene units are introduced into the acrylic rubber under the premise that the temperature and pressure are not too high, so as to improve the performance of the product and reduce the production cost.

[0005] In order to achieve the above object, the first aspect of the present invention provides a method for preparing an acrylic rubber, wherein the preparation method comprises:

[0006] (S1) contacting a polymerizable monomer and an aqueous solution of an emulsifier in a loop reactor for emulsification, and then adding an initiator and ethylene for polymerization reaction to obtain an acrylic rubber emulsion; wherein the polymerizable monomer is an acrylic ester monomer and / or a monomer having a cross-linking active group; the polymerization reaction temperature is 10-90° C. and the pressure is 0.1-2.5 MPa;

[0007] (S2) The acrylic rubber emulsion is drawn out from the top of the loop reactor, and then subjected to stripping, coagulation, demulsification, water washing and drying treatments to obtain acrylic rubber.

[0008] The second aspect of the present invention provides an acrylic rubber prepared by the above-mentioned preparation method.

[0009] A third aspect of the present invention provides a use of the aforementioned acrylic rubber in a hose component.

[0010] Through the above technical solution, the technical solution of the present invention has the following beneficial effects:

[0011] (1) A loop reactor is used in the polymerization process, the temperature inside the loop is uniform, and the prepared acrylic rubber product has stable performance;

[0012] (2) The loop tube has a high aspect ratio and a large specific heat transfer area. The monomer concentration in the loop tube is constant, and the heat release rate of each section is the same without a heat release peak. The loop tube reactor has a good heat removal capacity and the device is easy to scale up.

[0013] (3) The temperature and concentration in the loop reactor are uniform, and the flow boundary layer is divided into discontinuous short segments, which effectively avoids the formation of gel on the reactor wall;

[0014] (4) To obtain an acrylic rubber emulsion product with the same ethylene content, the loop reactor requires a lower operating pressure or a shorter reaction time than the tank reactor, and the copolymer components in the polymer are more evenly distributed. DETAILED DESCRIPTION

[0015] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0016] As mentioned above, the first aspect of the present invention provides a method for preparing an acrylic rubber, wherein the preparation method comprises:

[0017] (S1) contacting a polymerizable monomer and an aqueous solution of an emulsifier in a loop reactor for emulsification, and then adding an initiator and ethylene for polymerization reaction to obtain an acrylic rubber emulsion; wherein the polymerizable monomer is an acrylic ester monomer and / or a monomer having a cross-linking active group; the polymerization reaction temperature is 10-90° C. and the pressure is 0.1-2.5 MPa;

[0018] (S2) The acrylic rubber emulsion is drawn out from the top of the loop reactor, and then subjected to stripping, coagulation, demulsification, water washing and drying treatments to obtain acrylic rubber.

[0019] The inventors of the present invention have found that when the acrylic rubber contains ethylene structural units, the cold resistance and strength of the crosslinked product of the acrylic rubber are improved. In addition, when the acrylic rubber contains ethylene structural units, for example, when the crosslinked product of the acrylic rubber is used as a hose component, the appearance of the hose component becomes smooth, thereby improving the aesthetics of the hose component. In addition, when the acrylic rubber introduces ethylene structural units, a higher operating pressure or a longer reaction time must be used with a conventional kettle reactor. The inventors of the present invention have found that when an annular tube reactor is used for emulsion polymerization to produce acrylic rubber, the material circulation pump in the annular tube reactor has a strong shear force, which can disperse the polymerized monomer droplets more finely, increase its specific surface area, facilitate the diffusion of ethylene into the monomer droplets, facilitate the increase of the ethylene content in the polymer, and reduce the reaction pressure; in addition, the heat exchange is sufficient, the polymerization temperature is uniform, the reaction time is short, the product quality is stable, the processing performance is good, the glue is less, the operation cycle is long, the process is simple, and it is easy to industrialize large-scale production at a low cost.

[0020] According to the present invention, in step S1, monomers for preparing acrylic rubber are mixed to obtain a monomer stream; an emulsifier and deionized water are mixed to obtain an emulsified aqueous solution stream, and an initiator and deionized water are mixed to obtain an initiator stream; the emulsifier aqueous solution and the monomer stream are added to a loop reactor, a circulating pump of the loop reactor is started for emulsification, an initiator aqueous solution is added, ethylene is added to a desired pressure, ethylene is stopped, the polymerization temperature is controlled, an acrylic rubber emulsion is obtained, and the emulsified solution is drawn out from the top of the loop reactor.

[0021] In the present invention, it should be noted that: by controlling the reaction pressure, ethylene slowly enters the reaction system as the reaction proceeds and participates in the reaction; that is, the amount of ethylene used is limited by controlling the reaction pressure.

[0022] In the present invention, the temperature and pressure of the polymerization reaction are controlled, wherein the temperature of the polymerization reaction is 10-90°C, preferably 20-80°C, more preferably 50-60°C, and further preferably 55-56°C. In the present invention, since the reaction process releases heat and needs heat exchange to remove heat, it is better to control the initiation temperature of the polymerization reaction within a range; the pressure of the polymerization reaction is 0.1-2.5MPa, preferably 0.1-2MPa, more preferably 0.3-1MPa; the reaction time of the polymerization reaction is 1-3h, preferably 1-2h, and more preferably 1.2-1.5h; in the present invention, a loop reactor is used for emulsion polymerization to produce acrylic rubber, and the reaction pressure is low and the reaction time is short. In addition, in the present invention, a dynamic mixer can be added, and the dynamic mixer is placed in front of the inlet of the circulating pump, and the raw materials or supplementary materials are quickly mixed, and the raw materials can be added or supplemented at one time.

[0023] According to the present invention, the loop reactor can be a single-stage loop or two-stage or multi-stage loops connected in series. The diameter and length of the front and rear loops can be the same or different. When the multi-stage loops are connected in series, the comonomer and (or) initiator and (or) emulsifier can be added to the rear loop. In addition, in the present invention, the inner diameter of the loop reactor is 100-400mm, the circumference is 20-140m, and the aspect ratio is 200-350.

[0024] According to the present invention, the polymerizable monomers include acrylate monomers and / or monomers having cross-linking active groups; the acrylate monomers are selected from one or more of butyl acrylate (BA), ethyl acrylate (EA), methoxyethyl acrylate (MOEA), ethoxyethyl acrylate (EEA), alkyl acrylates, alkyl methacrylates, alkoxyalkyl (meth)acrylates, fluorine-containing (meth)acrylates, hydroxyl-containing (meth)acrylates, tertiary amino-containing (meth)acrylates and alkyl methacrylates; preferably, the acrylate monomers are selected from one or more of butyl acrylate (BA), ethyl acrylate (EA), methoxyethyl acrylate (MOEA) and ethoxyethyl acrylate (EEA); more preferably, the acrylate monomers are butyl acrylate (BA) and ethyl acrylate (EA).

[0025] According to the present invention, the monomer having a cross-linking active group may be one or more of acrylonitrile (AN), acrylic acid (AA), itaconic acid (IA), monobutyl itaconate (IBA), vinyl chloroacetate (VCA), glycidyl acrylate (GA), diallyl phthalate and ethylidene norbornene (ENB). Preferably, the monomer having a cross-linking active group is vinyl chloroacetate (VCA) or diallyl phthalate.

[0026] According to the present invention, the monomers for preparing the acrylic rubber may further contain other monomers other than the above monomers as monomer units. As other monomers, for example, one or more of C1-C6 alkyl vinyl ketone, vinyl ether, allyl ether, aromatic vinyl compound, vinyl nitrile, vinyl halide and vinylidene halide can be cited. Preferably, the aromatic vinyl compound is styrene.

[0027] According to the present invention, the emulsifier is selected from one or more of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium diddecylphenyl ether disulfonate, sodium rosin acid, polyvinyl alcohol and alkylphenol polyoxyethylene ether OP-10, preferably one or more of sodium dodecylbenzene sulfonate, alkylphenol polyoxyethylene ether OP-10 and polyvinyl alcohol. In the present invention, when the emulsifier is selected from two or more, the ratio of each emulsifier is not particularly limited, and can be 1: (1-2), preferably 1: 1.

[0028] According to the present invention, the initiator is selected from one or more of tert-butyl hydroperoxide, cumene hydroperoxide, cumene hydroperoxide / ferrous chloride, ammonium persulfate / sodium bisulfite, potassium persulfate / sodium bisulfite and tert-butyl hydroperoxide / rongalite.

[0029] According to the present invention, the weight ratio of the acrylic acid ester monomer to the monomer having a cross-linking active group may be (90-99):(1-10).

[0030] According to the present invention, the weight ratio of any two of the acrylic ester monomers is (55-60):(35-40).

[0031] According to the present invention, based on the total weight of the mixed feed of the polymerization monomer, the aqueous solution of the emulsifier and the initiator, the amount of the polymerization monomer is 30-40wt%, the amount of the initiator is 0.05-3wt%, and the amount of the emulsifier is 0.5-5wt%; preferably, the amount of the polymerization monomer is 35-40wt%, the amount of the initiator is 0.05-2wt%, and the amount of the emulsifier is 0.8-3wt%.

[0032] According to the present invention, in step S1, the emulsification time can be 25-35 minutes. In addition, the flow rate of the material is controlled to be 5-7 m / s, preferably 5-6 m / s.

[0033] According to the present invention, in step S2, the drawn-out acrylic rubber emulsion is introduced into a stripping kettle to remove unreacted monomers; in the present invention, the steam adding pipeline of the stripping kettle is connected to the bottom of the stripping kettle, and the gas phase outlet at the top of the stripping kettle is connected to a condenser and a condensate collecting tank in sequence.

[0034] The emulsion is passed into the stripping kettle, and steam is added through the steam adding pipeline for stripping treatment to remove unreacted small molecules. The generated gas phase is condensed through the condenser, and the condensate enters the condensate collection tank for recovery treatment.

[0035] The emulsion comes out from the bottom of the stripping kettle and enters the coagulation kettle from the top of the kettle. The demulsifier (electrolyte calcium chloride, sodium chloride, hydrochloric acid) and deionized water enter the coagulation kettle from the top of the kettle respectively. After stirring and washing, the washed raw rubber particles are filtered through a filter tank, and the washing water enters the sewage treatment system. The raw rubber particles are dried or vibrated to obtain acrylic rubber.

[0036] The second aspect of the present invention provides an acrylic rubber prepared by the above-mentioned preparation method.

[0037] According to the present invention, the acrylic rubber comprises a structural unit A provided by an acrylic ester monomer, a structural unit B provided by a monomer having a cross-linking active group, an ethylene structural unit provided by ethylene, and a structural unit C provided by other monomers; wherein, based on the total weight of the acrylic rubber structural unit, the content of the structural unit A is 21.06-99.1wt%, the content of the structural unit B is 0.8-9.99wt%, the content of the ethylene structural unit is 0.1-20wt%, and the content of the structural unit C is 0-48.95wt%; preferably, based on the total weight of the acrylic rubber structural unit Based on weight, the content of the structural unit A is 26.29-98.65wt%, the content of the structural unit B is 0.85-9.95wt%, the content of the ethylene structural unit is 0.5-15wt%, and the content of the structural unit C is 4.9-48.76wt%; more preferably, based on the total weight of the acrylic rubber structural unit, the content of the structural unit A is 77.6-94.0wt%; the content of the ethylene structural unit is 0.5-12.5wt%, the content of the structural unit B is 4.4-5wt%, and the content of the structural unit C is 1.1-4.9wt%.

[0038] According to the present invention, the number average molecular weight of the acrylic rubber is 220,000-1,000,000, and the molecular weight distribution is 1.5-6; preferably, the number average molecular weight of the acrylic rubber is 270,000-800,000, and the molecular weight distribution is 1.5-4; more preferably, the number average molecular weight of the acrylic rubber is 270,000-780,000, and the molecular weight distribution is 2.1-2.8.

[0039] According to the present invention, the content of ethylene units in the acrylic rubber is 0.1-20 wt %, preferably 0.5-15 wt %, and more preferably 2.1-4.2 wt %.

[0040] According to the present invention, the acrylic rubber prepared by the present invention has the above performance parameters, and the cross-linked product of the acrylic rubber has further improved cold resistance and strength.

[0041] A third aspect of the present invention provides a use of the aforementioned acrylic rubber in a hose component.

[0042] The present invention will be described in detail below through examples.

[0043] In the following examples and comparative examples:

[0044] (1) Molecular weight and distribution test

[0045] A gel permeation chromatograph (Waters 1515) produced by Water Company of the United States was used. Tetrahydrofuran was used as the mobile phase and a polystyrene standard molecular weight sample was used as the standard sample to determine the relative molecular weight and molecular weight distribution of the rubber compound.

[0046] (2) The structural unit content of the acrylic rubber was measured by H-NMR spectroscopy. The ethylene content was measured by H-NMR spectroscopy. The H-NMR spectroscopy model was AVANCE NEO 400M, purchased from Bruker, Germany.

[0047] Example 1

[0048] This embodiment is intended to illustrate the acrylic rubber prepared by the method of the present invention.

[0049] (S1) A loop reactor with a diameter of 100 mm and a circumference of 30 m is heated to 55° C. by water vapor in the jacket. Sodium dodecylbenzene sulfonate, OP-10, polyvinyl alcohol emulsifier aqueous solution, polymerization monomers ethyl acrylate, butyl acrylate and vinyl chloroacetate with cross-linking active groups are added to the reactor, the axial flow pump of the loop reactor is turned on, the flow rate of the material is controlled to be 5 m / s, emulsification is carried out for 30 minutes, ethylene is added, and when the reactor pressure is 0.3 MPa, the addition of ethylene is stopped and tert-butyl hydroperoxide is added; wherein, the mass concentration of the emulsifier in the mixed feed is 3%, wherein the mass ratio of sodium dodecylbenzene sulfonate, OP-10 and polyvinyl alcohol is 1:1:1, the mass concentration of the polymerization monomer in the mixed feed is 35%, and the mass concentration of the initiator in the mixed feed is 0.15%; the mass ratio of ethyl acrylate, butyl acrylate and vinyl chloroacetate is 55:40:5. The polymerization temperature is controlled to be 55° C. to 56° C. by water vapor in the jacket of the loop reactor. After the material has been in the reactor for 1.5 hours, the acrylic rubber latex obtained by polymerization overflows from the top of the loop reactor into the stripping kettle;

[0050] (S2) Unreacted small molecules are removed through a stripping kettle, and then the mixture enters a gel kettle, and electrolyte calcium chloride is added into the gel kettle to demulsify the emulsion, and raw rubber particles are obtained by condensation. Clean water is then added into the condensation kettle through a washing water pipeline to wash the raw rubber particles to remove residual emulsifiers, electrolytes and other impurities. The washed raw rubber particles are filtered through a filter tank, and the washing water enters a sewage treatment system. The raw rubber particles are dried to obtain a product.

[0051] After testing, the number average molecular weight of the product acrylic rubber is 670,000, and the molecular weight distribution is 2.1. In the acrylic rubber, the content of structural unit A is 93.6wt%, the content of structural unit B is 4.9wt%, the content of ethylene structural unit is 1.5wt%, and the content of structural unit C is 0wt%.

[0052] Example 2

[0053] This embodiment is intended to illustrate the acrylic rubber prepared by the method of the present invention.

[0054] (S1) A loop reactor with a diameter of 100 mm and a circumference of 30 m is heated to 55° C. by water vapor in the jacket. Sodium dodecylbenzene sulfonate, OP-10, polyvinyl alcohol emulsifier aqueous solution, polymerization monomers ethyl acrylate, butyl acrylate and vinyl chloroacetate are added to the reactor, the axial flow pump of the loop reactor is turned on, the flow rate of the material is controlled to be 5 m / s, emulsification is carried out for 30 minutes, ethylene is added, and when the reactor pressure is 0.3 MPa, the addition of ethylene is stopped, and initiator sodium persulfate / sodium bisulfite is added; wherein, the mass concentration of the emulsifier in the mixed feed is 3%, wherein the mass ratio of sodium dodecylbenzene sulfonate, OP-10 and polyvinyl alcohol is 1:1:1, the mass concentration of the polymerization monomer in the mixed feed is 35%, the mass concentration of the initiator in the mixed feed is 0.15%, and the mass ratio of ethyl acrylate, butyl acrylate and vinyl chloroacetate is 60:35:5. The polymerization temperature is controlled to be 55° C. to 56° C. by water vapor in the jacket of the loop reactor. After the material has been in the reactor for 1.5 hours, the acrylic rubber latex obtained by polymerization overflows from the top of the loop reactor into the stripping kettle;

[0055] (S2) Unreacted small molecules are removed through a stripping kettle, and then the mixture enters a gel kettle, and electrolyte calcium chloride is added into the gel kettle to demulsify the emulsion, and raw rubber particles are obtained by condensation. Clean water is then added into the condensation kettle through a washing water pipeline to wash the raw rubber particles to remove residual emulsifiers, electrolytes and other impurities. The washed raw rubber particles are filtered through a filter tank, and the washing water enters a sewage treatment system. The raw rubber particles are dried to obtain a product.

[0056] After testing, the number average molecular weight of the product acrylic rubber is 650,000, and the molecular weight distribution is 2.2. In the acrylic rubber, the content of structural unit A is 93.6wt%, the content of structural unit B is 4.9wt%, the content of ethylene structural unit is 1.5wt%, and the content of structural unit C is 0wt%.

[0057] Example 3

[0058] This embodiment is intended to illustrate the acrylic rubber prepared by the method of the present invention.

[0059] (S1) A loop reactor with a diameter of 100 mm and a circumference of 30 m is heated to 55° C. by water vapor in the jacket. Sodium dodecylbenzene sulfonate, OP-10, polyvinyl alcohol emulsifier aqueous solution, polymerization monomers ethyl acrylate, butyl acrylate and vinyl chloroacetate are added to the reactor, and the axial flow pump of the loop reactor is turned on to control the flow rate of the material to 5 m / s. Emulsification is carried out for 30 minutes, and ethylene is added. When the reactor pressure is 1 MPa, the addition of ethylene is stopped and tert-butyl hydroperoxide is added: wherein the mass concentration of the emulsifier in the mixed feed is 3%, wherein the mass ratio of sodium dodecylbenzene sulfonate, OP-10 and polyvinyl alcohol is 1:1:1, the mass concentration of the polymerization monomer in the mixed feed is 35%, the mass concentration of the initiator in the mixed feed is 0.15%, and the mass ratio of ethyl acrylate, butyl acrylate and vinyl chloroacetate is 55:40:5. The polymerization temperature is controlled to be 55° C. to 56° C. by water vapor in the jacket of the loop reactor. After the material has been in the reactor for 1.5 hours, the acrylic rubber latex obtained by polymerization overflows from the top of the loop reactor into the stripping kettle;

[0060] (S2) Unreacted small molecules are removed through a stripping kettle, and then the mixture enters a gel kettle, and electrolyte calcium chloride is added into the gel kettle to demulsify the emulsion, and raw rubber particles are obtained by condensation. Clean water is then added into the condensation kettle through a washing water pipeline to wash the raw rubber particles to remove residual emulsifiers, electrolytes and other impurities. The washed raw rubber particles are filtered through a filter tank, and the washing water enters a sewage treatment system. The raw rubber particles are dried to obtain a product.

[0061] Since the reaction pressure is generated by ethylene, the reaction pressure is different, and the amount of ethylene involved in the reaction is different, resulting in differences in the polymerization products. After testing, the number average molecular weight of the product acrylic rubber is 780,000, and the molecular weight distribution is 2.3. In the acrylic rubber, the content of structural unit A is 83.1wt%, the content of structural unit B is 4.4wt%, the content of ethylene structural unit is 12.5wt%, and the content of structural unit C is 0wt%.

[0062] Example 4

[0063] This embodiment is intended to illustrate the acrylic rubber prepared by the method of the present invention.

[0064] (S1) A loop reactor with a diameter of 100 mm and a circumference of 30 m is heated to 55° C. by water vapor in the jacket. Sodium dodecylbenzene sulfonate, OP-10, polyvinyl alcohol emulsifier aqueous solution, polymerization monomers ethyl acrylate, butyl acrylate and vinyl chloroacetate are added to the reactor, the axial flow pump of the loop reactor is turned on, the flow rate of the material is controlled to be 5 m / s, emulsification is carried out for 30 minutes, ethylene is added, and when the reactor pressure is 0.3 MPa, the addition of ethylene is stopped, and tert-butyl hydroperoxide is added; wherein, the mass concentration of the emulsifier in the mixed feed is 3%, wherein the mass ratio of sodium dodecylbenzene sulfonate, OP-10 and polyvinyl alcohol is 1:1:1, the mass concentration of the polymerization monomer in the mixed feed is 40%, the mass concentration of the initiator in the mixed feed is 0.15%, and the mass ratio of ethyl acrylate, butyl acrylate and vinyl chloroacetate is 55:40:5. The polymerization temperature is controlled to be 55° C. to 56° C. by water vapor in the jacket of the loop reactor. After the material has been in the reactor for 1.5 hours, the acrylic rubber latex obtained by polymerization overflows from the top of the loop reactor into the stripping kettle;

[0065] (S2) Unreacted small molecules are removed through a stripping kettle, and then the mixture enters a gel kettle, and electrolyte calcium chloride is added into the gel kettle to demulsify the emulsion, and raw rubber particles are obtained by condensation. Clean water is then added into the condensation kettle through a washing water pipeline to wash the raw rubber particles to remove residual emulsifiers, electrolytes and other impurities. The washed raw rubber particles are filtered through a filter tank, and the washing water enters a sewage treatment system. The raw rubber particles are dried to obtain a product.

[0066] After testing, the number average molecular weight of the product acrylic rubber is 730,000, and the molecular weight distribution is 2.1. In the acrylic rubber, the content of structural unit A is 93.6wt%, the content of structural unit B is 4.9wt%, the content of ethylene structural unit is 1.5wt%, and the content of structural unit C is 0wt%.

[0067] Example 5

[0068] Acrylic rubber was prepared in the same manner as in Example 1, except that the polymerization temperature was controlled to be 70° C. to 71° C. by using water vapor in the jacket of the loop reactor, and the reaction time was 1.2 hours.

[0069] The number average molecular weight of the product acrylic rubber is 510,000, and the molecular weight distribution is 2.8. In the acrylic rubber, the content of structural unit A is 93.6wt%, the content of structural unit B is 4.9wt%, the content of ethylene structural unit is 1.5wt%, and the content of structural unit C is 0wt%.

[0070] Example 6

[0071] Acrylic rubber was prepared in the same manner as in Example 1, except that ethylene was added and the addition of ethylene was stopped when the reactor pressure reached 0.2 MPa; and the polymerization temperature was controlled to be 70°C to 71°C using water vapor in the jacket of the annular reactor.

[0072] After testing, the number average molecular weight of the product acrylic rubber is 480,000, and the molecular weight distribution is 2.7. In the acrylic rubber, the content of structural unit A is 94.1wt%, the content of structural unit B is 5.0wt%, the content of ethylene structural unit is 0.9wt%, and the content of structural unit C is 0wt%.

[0073] Example 7

[0074] Acrylic rubber was prepared in the same manner as in Example 1, except that the polymerization temperature was controlled to be 85° C. to 86° C. by using water vapor in the jacket of the loop reactor.

[0075] After testing, the number average molecular weight of the product acrylic rubber is 320,000, and the molecular weight distribution is 4.2. In the acrylic rubber, the content of structural unit A is 93.6wt%, the content of structural unit B is 4.9wt%, the content of ethylene structural unit is 1.5wt%, and the content of structural unit C is 0wt%.

[0076] Example 8

[0077] Acrylic rubber was prepared in the same manner as in Example 1, except that ethylene was added and the addition of ethylene was stopped when the reactor pressure reached 0.1 MPa; and the polymerization temperature was controlled to be 80°C to 81°C using water vapor in the jacket of the annular reactor.

[0078] After testing, the number average molecular weight of the product acrylic rubber is 270,000, and the molecular weight distribution is 4.1. In the acrylic rubber, the content of structural unit A is 94.5wt%, the content of structural unit B is 5wt%, the content of ethylene structural unit is 0.5wt%, and the content of structural unit C is 0wt%.

[0079] Example 9

[0080] Acrylic rubber was prepared in the same manner as in Example 1, except that sodium dodecylbenzene sulfonate, OP-10, and polyvinyl alcohol emulsifier aqueous solution were added to the reactor, and the polymerized monomers ethyl acrylate, butyl acrylate, diallyl phthalate, and styrene were added. The mass ratio of ethyl acrylate, butyl acrylate, diallyl phthalate, and styrene was 40:50:5:5.

[0081] After testing, the number average molecular weight of the product acrylic rubber is 480,000, and the molecular weight distribution is 3.7. In the acrylic rubber, the content of structural unit A is 88.7wt%, the content of structural unit B is 4.9wt%, the content of ethylene structural unit is 1.5wt%, and the content of structural unit C is 4.9wt%.

[0082] Comparative Example 1

[0083] Acrylic rubber was prepared in the same manner as in Example 1, except that a kettle reactor was used for polymerization instead of a loop reactor; specifically, the aqueous phase, emulsifier, and initiator were all added to a high reactor and stirred thoroughly, the air in the reactor was first replaced with nitrogen and then with ethylene, and then pressurized to 3 MPa with ethylene, and the reaction temperature in the reactor was set at 55°C.

[0084] Comparative Example 1 uses a polymerization kettle to prepare acrylic rubber. Similarly, the ethylene pressure required for preparing 1.5% ethylene structure is very high, and it is difficult to remove heat from a single reactor (polymerization kettle), and the molecular weight is low. After testing, the number average molecular weight of the product acrylic rubber is 180,000, and the molecular weight distribution is 4.6. In the acrylic rubber, the content of structural unit A is 93.6wt%, the content of structural unit B is 4.9wt%, the content of ethylene structural unit is 1.5wt%, and the content of structural unit C is 0wt%.

[0085] Comparative Example 2

[0086] Acrylic rubber was prepared in the same manner as in Example 1, except that the polymerization temperature was controlled to be 95° C. to 96° C. by using water vapor in the jacket of the loop reactor.

[0087] After testing, the number average molecular weight of the product acrylic rubber is 76,000, and the molecular weight distribution is 7.1. In the acrylic rubber, the content of structural unit A is 93.6wt%, the content of structural unit B is 4.9wt%, the content of ethylene structural unit is 1.5wt%, and the content of structural unit C is 0wt%.

[0088] In summary, in the method for preparing the acrylic rubber of the present invention, the ethylene unit is introduced into the acrylic rubber under the premise that the temperature and pressure are not too high, so as to improve the performance of the product and thus reduce the production cost.

[0089] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing acrylic rubber, characterized in that: The preparation method comprises: (S1) contacting a polymerizable monomer and an aqueous solution of an emulsifier in a loop reactor for emulsification, and then adding an initiator and ethylene for polymerization reaction to obtain an acrylic rubber emulsion; wherein the polymerizable monomer is an acrylic ester monomer and / or a monomer having a cross-linking active group; the polymerization reaction temperature is 10-90° C. and the pressure is 0.1-2.5 MPa; (S2) The acrylic rubber emulsion is drawn out from the top of the loop reactor, and then subjected to stripping, coagulation, demulsification, water washing and drying treatments to obtain acrylic rubber.

2. The preparation method according to claim 1, wherein The polymerization reaction temperature is 20-80°C, preferably 50-60°C; And / or, the polymerization reaction pressure is 0.1-2 MPa, preferably 0.3-1 MPa; And / or, the reaction time of the polymerization reaction is 1-3 hours, preferably 1-2 hours.

3. The preparation method according to claim 1, wherein The acrylic acid ester monomer is selected from one or more of butyl acrylate, ethyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, alkyl acrylate, alkyl methacrylate, alkoxyalkyl (meth)acrylate, fluorine-containing (meth)acrylate, hydroxyl-containing (meth)acrylate, tertiary amino group-containing (meth)acrylate and alkyl methacrylate; Preferably, the acrylic acid ester monomer is selected from one or more of butyl acrylate, ethyl acrylate, methoxyethyl acrylate and ethoxyethyl acrylate.

4. The preparation method according to claim 1, wherein The monomer having a cross-linking active group is selected from one or more of acrylonitrile, acrylic acid, itaconic acid, monobutyl itaconate, vinyl chloroacetate, glycidyl acrylate, diallyl phthalate and ethylidene norbornene; And / or, the emulsifier is selected from one or more of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium didodecylphenyl ether disulfonate, sodium rosin acid, polyvinyl alcohol and alkylphenol polyoxyethylene ether OP-10.

5. The preparation method according to any one of claims 1 to 4, wherein: The polymerizable monomers further include other monomers, and the other monomers are selected from one or more of C1-C6 alkyl vinyl ketone, vinyl ether, allyl ether, aromatic vinyl compound, vinyl nitrile, vinyl halide and vinylidene halide.

6. The preparation method according to any one of claims 1 to 5, wherein: The weight ratio of the acrylic acid ester monomer to the monomer having a cross-linking active group may be (90-99): (1-10); Preferably, the weight ratio of any two of the acrylic ester monomers is (55-60): (35-40); And / or, based on the total weight of the mixed feed of the polymerization monomer, the aqueous solution of the emulsifier and the initiator, the amount of the polymerization monomer is 30-40wt%, the amount of the initiator is 0.05-3wt%, and the amount of the emulsifier is 0.5-5wt%.

7. An acrylic rubber prepared by the preparation method according to any one of claims 1 to 6.

8. The acrylic rubber according to claim 7, wherein The acrylic rubber comprises a structural unit A provided by an acrylic ester monomer, a structural unit B provided by a monomer having a cross-linking active group, an ethylene structural unit provided by ethylene, and a structural unit C provided by other optional monomers; Wherein, based on the total weight of the acrylic rubber structural unit, the content of the structural unit A is 21.06-99.1wt%, the content of the structural unit B is 0.8-9.99wt%, the content of the ethylene structural unit is 0.1-20wt%, and the content of the structural unit C is 0-48.95wt%; Preferably, based on the total weight of the acrylic rubber structural unit, the content of the structural unit A is 26.29-98.65wt%, the content of the structural unit B is 0.85-9.95wt%, the content of the ethylene structural unit is 0.5-15wt%, and the content of the structural unit C is 4.9-48.76wt%.

9. The acrylic rubber according to claim 7 or 8, wherein The number average molecular weight of the acrylic rubber is 220,000-1,000,000, and the molecular weight distribution is 1.5-6; Preferably, the number average molecular weight of the acrylic rubber is 270,000-800,000, and the molecular weight distribution is 1.5-4.

10. Use of the acrylic rubber according to any one of claims 7 to 9 in a hose component.