A method for producing a polyacrylate rubber

Abstract

The application discloses a preparation method of polyacrylate rubber, which is based on FOX equation, and through a large number of deduction and simulation, the glass transition temperature simulation value of part of monomers is obtained, and then a modified equation is obtained; through verification, the simulation calculation value is quite close to the measured value, and the glass transition temperature is designed by using the method to synthesize the polyacrylate rubber; the synthesis steps include eight steps of raw material selection, raw material proportioning, emulsification, emulsion polymerization, demulsification and coagulation, cleaning, drying and packaging; the composition ratio of acrylate monomers can be designed according to the low-temperature requirement of the product, the glass transition temperature of the product is predicted by means of simulation calculation, and the limitation that the low-temperature data can only be obtained by measuring the product by means of instruments at present is overcome; and the application has an important role in research and development and production of domestic acrylate low-temperature rubber.

Description

Technical Field

[0001] This invention relates to the field of acrylate rubber production technology, and in particular to a method for preparing polyacrylate rubber. Background Technology

[0002] Acrylic rubber is a synthetic rubber copolymerized from acrylate as the main monomer. It has special properties such as high temperature resistance, oil resistance, ozone resistance and ultraviolet resistance. It is a heat-resistant and oil-resistant special rubber, mainly used as various heat-resistant and oil-resistant seals, gaskets and oil seals for automobiles and locomotives.

[0003] In recent years, with the development of the times, downstream industrial chains such as OEMs have increasingly higher requirements for the low temperature of rubber products. Previously, the requirements could be met at around -20℃, but now many applications require -30℃ or even -40℃.

[0004] The glass transition temperature (Tg) of a polymer is an important parameter characterizing its low-temperature performance, and the glass transition temperature of a polymer can be determined by... The formula is used to calculate (W) X This indicates the mass fraction of the component in the total monomers, but this requires knowing the Tg of each component.

[0005] Commonly used monomers for acrylic rubbers include: methyl acrylate, ethyl acrylate, butyl acrylate, n-octyl acrylate, isooctyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, and monomers with high vulcanization points.

[0006] Acrylic rubbers possess high-temperature and oil-resistant properties. Low-temperature acrylic rubbers, in particular, rely heavily on low-temperature oil-resistant monomers (such as methoxyethyl acrylate and ethoxyethyl acrylate), but relevant Tg data for these monomers is unavailable. Monomers with high vulcanization points include: active chlorine monomers, carboxyl monomers, epoxy monomers, and double-bond monomers. While used in very small quantities, they play a crucial role in the product's vulcanization rate, tensile strength, elongation at break, and permanent compression set; similarly, Tg data for these monomers is almost entirely unavailable.

[0007] Furthermore, Tg data for products is typically obtained through analytical instrument testing (such as DSC, DMA, etc.). On one hand, instrument testing corresponds to the backend, providing data on product results and lacking data from the early design and development stages; on the other hand, these devices are expensive to operate and maintain, so companies usually outsource testing to third parties. While outsourcing testing saves costs, it is time-consuming and hinders timely understanding by technical development personnel. Summary of the Invention

[0008] The purpose of the present application is to solve the above problems, a preparation method of polyacrylate rubber is invented, the composition ratio of acrylate monomers can be designed according to the low temperature demand of the product, the Tg of the product is predicted according to the simulation calculation, which breaks through the limitation that only the measured product can obtain low temperature data at present, and helps the development and production of domestic low temperature type and ultralow temperature type acrylate rubber.

[0009] The specific technical solutions are as follows

[0010] Based on Through a large number of deduction and simulation, the simulated values of the glass transition temperature of some monomers (not found in the manual) are obtained, and then the corrected equation is obtained: Then, the equation is used to design Tg to synthesize polyacrylate rubber. The specific operation steps of synthesizing polyacrylate rubber are: selection of raw materials, ratio of raw materials, emulsification, emulsion polymerization, demulsification and coagulation, cleaning, drying and packaging.

[0011] S1. Select the main monomers of the raw materials as one or more acrylates selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, n-octyl acrylate, isooctyl acrylate, methoxyethyl acrylate, methoxymethyl acrylate, ethoxyethyl acrylate and modified monomers thereof; the curing point monomer is selected as one or more of active chlorine type curing point monomer, carboxyl type curing point monomer, epoxy type curing point monomer and double bond type curing point monomer;

[0012] S2. In the monomers of S1, the monomers are selected according to the required Tg, and the composition ratio of the selected monomers is determined;

[0013] S3. Add emulsifiers and related water-soluble additives to water, then add the monomers prepared in step S2 to the water, emulsify the raw materials, the emulsification temperature is 30-45℃, and the emulsification time is 30-60 minutes;

[0014] S4. Add initiator to the emulsion obtained in step S3 to carry out emulsion polymerization, initiate polymerization reaction at 15-45℃, the amount of initiator is 0.05%-0.5%, then maintain the reaction temperature at 80±10℃ to carry out polymerization reaction, the reaction time is 1-4 hours, and acrylate emulsion is obtained;

[0015] S5. After adding the terminating agent to the emulsion of S4, add a salt solution with a mass percentage of 5%-7% to carry out demulsification and coagulation at 55-85℃;

[0016] S6. Wash the demulsified gel particles with water, the water washing temperature is 55-85℃, and the cleaning is carried out for 3-6 times;

[0017] S7. The washed rubber particles are placed in an oven at a temperature of 80-120°C for drying, and the dried acrylic rubber is obtained, and then packaged.

[0018] In some embodiments, in step S1, the active chlorine type vulcanization site monomer is one or two of vinyl chloroacetate, 2-chloroethyl vinyl ether, vinyl chloroformate, and vinyl chloroacetate.

[0019] In some embodiments, in step S1, the carboxyl type vulcanization site monomer is one or more of acrylic acid, maleic acid, maleic anhydride, maleic acid monobutyl ester, itaconic acid, itaconic acid monobutyl ester, itaconic acid monoethyl ester, fumaric acid, fumaric acid monobutyl ester, and fumaric acid monoethyl ester.

[0020] In some embodiments, in step S1, the epoxy type vulcanization site monomer is one or two of glycidyl methacrylate and allyl glycidyl ester.

[0021] In some embodiments, in step S1, the double bond type vulcanization site monomer is one or two of 3-methyl-2-butene and ethylene norbornene.

[0022] In some embodiments, in step S3, the emulsifier is sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecyl benzene sulfonate, or a non-ionic compound, and the amount is 1-5% of the total monomers.

[0023] In some embodiments, in step S4, the initiator is prepared from an organic peroxide oxidizing agent and a reducing agent, wherein the organic peroxide oxidizing agent is one or more of tert-butyl hydroperoxide, benzoyl peroxide, and cumene hydroperoxide, the reducing agent is one or more of sodium bisulfite, ferrous sulfate, sodium dithionite, and sodium hydrosulfite, the amount of the initiator is 0.1-0.3% of the total monomers, the oxidizing agent:reducing agent ratio is 1.05:1, and the molecular weight regulator is a mercaptan, and the ratio is 0.01-1‰.

[0024] In some embodiments, in step S5, the terminator is one or more of sodium dimethyl dithiocarbamate, N-isopropyl hydroxylamine, sodium polysulfide, sodium nitrite, hydroquinone, tert-butyl hydroquinone, and wood tar, and the amount is 0.1-1.0% of the main monomers, and the demulsification conditions are a 5-8% sodium chloride / calcium chloride solution at 60-90°C.

[0025] In some embodiments, in steps S6 and S7, the obtained rubber is washed with deionized water and a washing solution, the washing temperature is 60-80°C, the washing is performed 3-5 times, and then dehydration is performed, and the obtained rubber is placed in an oven for drying, the drying temperature is 100-110°C, and the acrylic rubber with a specified glass transition temperature is obtained.

[0026] The present application has advantages

[0027] 1. The present application proposes a method for calculating the glass transition temperature of polyacrylate rubber, which predicts the Tg of the product according to simulation calculation, and then designs the composition ratio of acrylate monomers according to the low temperature requirement of the product, solving the limitation that only the measured product can obtain low temperature data at present.

[0028] 2. The present application provides a set of mature preparation method of polyacrylate rubber, which optimizes the preparation process of polyacrylate rubber, and helps the development and production of domestic low temperature type and ultralow temperature type acrylate rubber. DETAILED DESCRIPTION

[0029] In order to facilitate the understanding of the technical implementation method of the present application, the technical process steps, specific implementation conditions and materials in the embodiments of the present application will be combined below to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0030] In the early stage, the glass transition temperature of the related raw materials is obtained through a large number of experimental deduction and verification, and the value condition will be explained in the embodiments (the value condition of the vulcanization point monomer is obtained according to a large number of data deduction, and is not completely the glass transition temperature of the monomer itself, and some are based on the calculation results); when the corrected calculation formula is used, the simulation calculation value of Tg can be directly obtained after the amount of each monomer is input in the EXCEL table.

[0031] Example 1

[0032] Design and development of heat-resistant active chlorine type acrylate rubber with Tg about-18℃

[0033] According to simulation calculation: select ethyl acrylate as the main monomer, and ethylene chloroformate as the vulcanization point monomer, and the amount is 2.5% of the main monomer; the polymerization process also includes sodium dodecyl sulfate as an emulsifier, and the amount is 2.5% of the main monomer; thiol as a molecular weight regulator, and the ratio is 1.5‰; emulsification at 30℃ for 60min; benzoyl peroxide and safety powder as initiators, and the amount is 0.2%; initiation reaction at 35℃, and after 85℃, keep warm for 2.0h; add 1.0% of sodium dimethyl dithiocarbamate; add 55℃ sodium chloride solution with a concentration of 7.0% to carry out coagulation demulsification; after washing with 55℃ deionized water for 6 times, dry in an oven at 110℃ to obtain active chlorine heat-resistant acrylate rubber.

[0034] The vinyl chloroformate in this example is valued at 1000, and the simulated value Tg calculated according to the formula is 模拟 -17.45°C. The subsequently measured Tg 实测 -17.21°C, the tensile strength of the acrylate rubber is 12 MPa, the elongation at break is 280%, and the permanent compression set is 32%.

[0035] Example 2

[0036] Design and development of cold-resistant double bond type acrylate rubber with Tg of about -28°C

[0037] Simulation calculation: select ethyl acrylate and butyl acrylate as the main monomers, the ratio is 7:3, the curing point monomer is 3-methyl-2-butene ester, the amount is 2.5% of the main monomers; the polymerization process also includes sodium dodecyl sulfonate as an emulsifier, the amount is 3.0% of the main monomers; thiol as a molecular weight regulator, the ratio is 1.5‰; emulsification at 35°C for 30 min; cumene hydroperoxide and hydrogen peroxide as initiators, the amount is 0.15%; initiate the reaction at 25°C, and keep the temperature at 75°C for 4.0 h; add 1.0% of N-isopropyl hydroxylamine; add 60°C sodium chloride solution with a concentration of 6.0% to coagulate and demulsify; wash with 65°C deionized water for 4 times, and then dry in an oven at 105°C to obtain the cold-resistant double bond type acrylate rubber.

[0038] The 3-methyl-2-butene ester in this example is valued at 800, and the simulated value Tg calculated according to the formula is 模拟 -28.35°C. The subsequently measured Tg 实测 -28.15°C, the tensile strength of the acrylate rubber is 11 MPa, the elongation at break is 220%, and the permanent compression set is 28.4%.

[0039] Example 3

[0040] Design and development of super cold-resistant epoxy type acrylate rubber with Tg of about -35°C

[0041] Simulation calculation: select ethyl acrylate, butyl acrylate, methoxy ethyl acrylate as the main monomer, the ratio is 5:4:1; the vulcanization point monomer is glycidyl methacrylate, the amount is 1.5% of the main monomer; the polymerization process also includes sodium dodecyl benzene sulfonate as the emulsifier, the amount is 4.0% of the main monomer; thiol as the molecular weight regulator, the ratio is 1.0‰; emulsification at 35℃ for 45min; t-butyl hydroperoxide and sodium bisulfite as the initiator, the amount is 0.1%; initiation reaction at 30℃, after 80℃, keep for 3.0h; add 1.0% of t-butyl hydroquinone; add 70℃ calcium chloride solution with the concentration of 6.0% to carry out coagulation demulsification; after washing with 70℃ deionized water for 4 times, dry in the oven at 105℃ to obtain the super cold-resistant epoxy acrylate rubber.

[0042] The simulation value Tg calculated by the formula is -34.59℃. The subsequently measured Tg is -34.26℃, the tensile strength of the acrylate rubber is 10MPa, the elongation at break is 200%, and the permanent compression set is 35%. 模拟 实测 The simulation value Tg calculated by the formula is -43.40℃. The subsequently measured Tg is -43.34℃, the tensile strength of the acrylate rubber is 9MPa, the elongation at break is 150%, and the permanent compression set is 25%.

[0043] Example 4

[0044] Design and development of extremely cold-resistant carboxyl acrylate rubber with Tg about -42℃

[0045] Simulation calculation: select ethyl acrylate, butyl acrylate, methoxy ethyl acrylate as the main monomer, the ratio is 1:6:3; the vulcanization point monomer is maleic acid monobutyl ester, the amount is 1.5% of the main monomer; the polymerization process also includes the emulsifier compounded by sodium dodecyl sulfate and non-ionic (the ratio is 5:1), the amount is 6.0% of the main monomer; thiol as the molecular weight regulator, the ratio is 1.0‰; emulsification at 35℃ for 60min; the oxidant compounded by cumene hydroperoxide and ammonium persulfate (4:1), the amount is 0.1% of the total monomer; initiation reaction at 35℃, keep for 3.0h after 75℃; add dimethyl dithiocarbamic acid sodium and hydroquinone (the ratio is 1:1), the amount is 2.0% of the total monomer; add 65℃ calcium chloride solution with the concentration of 7.0% to carry out coagulation demulsification; after washing with 75℃ deionized water for 4 times, dry in the oven at 100℃ to obtain the extremely cold-resistant carboxyl acrylate rubber.

[0046] The simulation value Tg calculated by the formula is -43.40℃. The subsequently measured Tg is -43.34℃, the tensile strength of the acrylate rubber is 9MPa, the elongation at break is 150%, and the permanent compression set is 25%. 模拟 实测 The simulation value Tg calculated by the formula is -43.40℃. The subsequently measured Tg is -43.34℃, the tensile strength of the acrylate rubber is 9MPa, the elongation at break is 150%, and the permanent compression set is 25%.​​

[0047] As can be seen from the formula The simulation value Tg is greatly related to the amount of the vulcanization point monomer. When the amount of the vulcanization point monomer is increased, the simulation value Tg is increased. Conversely, the simulation value Tg is decreased. When the amount of the vulcanization point monomer is unchanged, the ratio of the monomers of the components is adjusted, and the simulation value Tg is adjusted (at the same time, the oil resistance is changed).

[0048] As can be seen from the examples, the error between the measured value and the design value is basically within 2℃, and most of them are within 1℃, which shows that the accuracy of the simulation calculation is relatively high.

[0049] In addition, the error between the simulation value calculated by the formula and the measured value is very small, so it can be used as an effective means for indirectly representing Tg without instrument testing when the product is developed.

[0050] Those skilled in the art should know that although the present application has been described according to the above specific embodiments, the inventive idea of the present application is not limited to this application, and any modification using the inventive idea will be included in the scope of protection of the present patent.

Claims

1. A method for producing a polyacrylate rubber, characterized by, The preparation method of the polyacrylate rubber comprises the following operation steps: S1. Selecting raw material main monomers as one or more of methyl acrylate, ethyl acrylate, butyl acrylate, n-octyl acrylate, isooctyl acrylate, methoxyethyl acrylate, methoxy methyl acrylate, ethoxyethyl acrylate and ethoxymethyl acrylate; and selecting vulcanization point monomers as one or more of active chlorine type vulcanization point monomers, carboxyl type vulcanization point monomers, epoxy type vulcanization point monomers and double bond type vulcanization point monomers; S2. In the monomers of S1, the monomers are selected according to the required glass transition temperature, and the composition ratio of the selected monomers is determined to design the glass transition temperature and synthesize the polyacrylate rubber: wherein the glass transition temperature is determined by the equation: were designed; S3. Adding an emulsifier and a water-soluble additive into water, and then adding the monomers prepared in step S2 into the water, to emulsify the raw materials, the emulsification temperature is 30-45℃, and the emulsification time is 30-60 minutes; S4. Adding an initiator into the emulsion obtained in step S3 to perform emulsion polymerization, the polymerization reaction is initiated at 15-45℃, the initiator is used in an amount of 0.05%-0.5%, and then the polymerization reaction is performed at a reaction temperature of 80±10℃ for 1-4 hours to obtain an acrylate emulsion; S5. After adding a terminating agent into the emulsion of S4, adding a salt solution with a mass percentage of 5%-7% to perform demulsification and coagulation at 55-85℃; S6. Washing the gel particles after demulsification, the washing temperature is 55-85℃, and the washing is performed for 3-6 times; S7. Placing the washed gel particles at a temperature of 80-120℃ to perform drying, obtaining the polyacrylate rubber after drying, and then performing packaging.

2. The method for preparing polyacrylate rubber according to claim 1, characterized in that, In step S1: the active chlorine type vulcanization point monomers are one or two of vinyl chloroacetate, 2-chloroethyl vinyl ether, vinyl chloroformate and propyl chloroacetate.

3. The method for preparing polyacrylate rubber according to claim 1, characterized in that, In step S1: the carboxyl type vulcanization point monomers are one or several of acrylic acid, maleic acid, maleic anhydride, maleic acid monobutyl ester, itaconic acid, itaconic acid monobutyl ester, itaconic acid monoethyl ester, fumaric acid, fumaric acid monobutyl ester and fumaric acid monoethyl ester.

4. The method for preparing polyacrylate rubber according to claim 1, characterized in that, In step S1: the epoxy type vulcanization point monomers are one or two of glycidyl methacrylate and allyl glycidyl ether.

5. The method for preparing a polyacrylate rubber according to claim 1, characterized in that, In step S1: the double bond type vulcanization point monomers are one or two of 3-methyl-2-butene and ethylene norbornene.

6. The method for preparing a polyacrylate rubber according to claim 1, characterized in that, In step S3: the emulsifier is prepared from sodium dodecyl sulfate, sodium dodecyl sulfonate and sodium dodecyl benzene sulfonate or is compounded with non-ionic, and is used in an amount of 1%-5% of the total monomers.

7. The method for preparing a polyacrylate rubber according to claim 1, characterized in that, In step S4: the initiator is prepared from organic peroxide oxidants and reducing agents, wherein the organic peroxide oxidants are one or several of tert-butyl hydroperoxide, benzoyl peroxide and cumene hydroperoxide, the reducing agents are one or several of sodium bisulfite, ferrous sulfate, sodium sulfite and sodium dithionite, the initiator is used in an amount of 0.1%-0.3% of the total monomers, the oxidant:reducing agent ratio is 1.05:1, and the molecular weight regulator is mercaptan, and the compounding ratio is 0.01‰-1‰.

8. The method for preparing a polyacrylate rubber according to claim 1, characterized in that, The step S5: the terminator is one or several of dimethyl dithiocarbamic acid sodium, N-isopropyl hydroxylamine, sodium polysulfide, sodium nitrite, hydroquinone, tert-butyl hydroquinone, wood tar, the amount is 0.1% to 1.0% of the main monomer, the demulsification condition is that the mass percentage of sodium chloride / calcium chloride solution is 5-8%, and the demulsification is carried out at 60-90 ℃.

9. The method for preparing a polyacrylate rubber according to claim 1, characterized in that, In the steps S6 and S7, the obtained rubber compound is washed with deionized water and a washing solution, the washing temperature is 60-80 ℃, the washing is carried out for 3-5 times, after completion, dehydration is carried out, and drying is carried out in an oven, the drying temperature is 100-110 ℃, and the polyacrylate rubber with a specified glass transition temperature is prepared.

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