A butyl rubber product having high elongation at break and a method for producing the same

Abstract

The application relates to the technical field of rubber processing, and discloses a butyl rubber product with high breaking elongation and a preparation method thereof, the preparation method comprises the following steps: using an aqueous solution of a metal salt as a coagulant to coagulate unvulcanized butyl latex, and after coagulation, the butyl latex is dried and vulcanized to obtain the butyl rubber product; the metal salt comprises at least one of copper chloride, copper sulfate, copper acetate and aluminum chloride. In the application, the aqueous solution of at least one of copper chloride, copper sulfate, copper acetate and aluminum chloride is used as the coagulant, and a butyl rubber product with super-high breaking elongation is unexpectedly obtained, the breaking elongation can reach more than 1500%, even more than 2000%, the elasticity is excellent, and the tensile strength and tear strength of the material are maintained well.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rubber processing, in particular to a butyl rubber product with high elongation at break and a preparation method thereof. BACKGROUND

[0002] Butyl rubber is a kind of synthetic rubber, which is polymerized by isobutylene and a small amount of isoprene, and has good chemical stability, thermal stability, air tightness, etc. Butyl rubber latex can be prepared by emulsifying butyl rubber, which can expand the application field of butyl rubber. Butyl rubber latex can be processed by subsequent vulcanization after breaking emulsion by coagulant. Traditional coagulant is mainly calcium salt, but coagulant has an impact on the subsequent vulcanization of rubber and the performance of vulcanized rubber.

[0003] Patent CN110358172A proposes a high-rebound, low-specific-gravity butyl reclaimed rubber composite rubber-plastic material and a preparation method thereof. The formula components are 100-120 parts of low-density polyethylene, 80-90 parts of butyl reclaimed rubber, 6-10 parts of macromolecular plasticizer, 10-15 parts of polyurethane, 3-4 parts of lubricant, and 20-30 parts of auxiliary agent. The tensile elongation at break of the prepared butyl rubber is about 450%.

[0004] Patent CN109320861A proposes a wide-temperature-range high-damping halogenated butyl rubber material and a preparation method thereof. The raw material composition includes 4-6% of solid butyl rubber, 33-36% of saturated alkane, 0.1-0.2% of main emulsifier, 0.1-0.2% of auxiliary emulsifier, 0.05-0.15% of stabilizer, 58-62% of deionized water, 0.01-0.02% of defoamer, 0.01-0.02% of pH regulator, and 0.15-0.25% of complex additive. The tensile elongation at break of the prepared butyl rubber is up to 685%.

[0005] Patent CN111363259A proposes a butyl rubber latex, a preparation method and application thereof. The average tensile elongation at break of the latex gloves prepared by the butyl rubber latex is 894%. Patent CN109503963A proposes a butyl rubber latex, a preparation method thereof and a preparation method of gloves prepared by the butyl rubber latex. The tensile elongation at break of the butyl rubber latex gloves prepared by the invention is greater than or equal to 850%.

[0006] It can be seen that the tensile elongation at break of the butyl rubber prepared by the currently published patents is mostly between 400% and 900%. The preparation method of butyl rubber with very high tensile elongation at break (greater than 2000%) has not been reported. SUMMARY

[0007] The present application provides a high elongation at break butyl rubber with a non-traditional calcium salt demulsification method, which has an elongation at break of more than 2000%, excellent elasticity, and good tensile strength and tear strength.

[0008] To achieve the above object, the present application adopts the technical scheme of:

[0009] A preparation method of high elongation at break butyl rubber product, comprising the steps of: using a metal salt aqueous solution as a coagulant to coagulate unvulcanized butyl latex, and drying and vulcanizing the coagulated butyl latex to obtain the butyl rubber product.

[0010] The metal salt includes at least one of copper chloride, copper sulfate, copper acetate, and aluminum chloride.

[0011] The present application unexpectedly found that using an aqueous solution of at least one metal salt of copper chloride, copper sulfate, copper acetate, and aluminum chloride as a coagulant can obtain a butyl rubber product with ultra-high elongation at break, with an elongation at break of more than 1500%, even more than 2000%, excellent elasticity, and good tensile strength and tear strength. This may be due to the formation of a complex of copper ions during the vulcanization of butyl rubber, which can enhance the elasticity of the rubber crosslinked network, but the specific principle cannot be determined.

[0012] In some embodiments, the mass concentration of the metal salt in the metal salt aqueous solution is 5%-25%.

[0013] In some embodiments, the unvulcanized butyl latex comprises, by mass fraction, the following raw material components: 100 parts of butyl rubber, 1-3 parts of sulfur, 2-5 parts of zinc oxide, 1-2 parts of stearic acid, 2-6 parts of a vulcanization accelerator, and 1-3 parts of an antioxidant.

[0014] In some embodiments, the mass fraction of butyl rubber in the butyl latex is 10%-60%. Preferably, the mass fraction of butyl rubber in the butyl latex is 40%-50%.

[0015] In some embodiments, the vulcanization accelerator includes at least one of zinc dibenzyl dithiocarbamate and 2-mercaptobenzothiazole zinc salt. Preferably, the vulcanization accelerator includes 0-6 parts of zinc dibenzyl dithiocarbamate and 0-6 parts of 2-mercaptobenzothiazole zinc salt, and both are not 0 at the same time.

[0016] Further preferably, the vulcanization accelerator comprises 1-3 parts of zinc dibenzyl dithiocarbamate and 1-3 parts of zinc 2-mercaptobenzothiazole. Zinc dibenzyl dithiocarbamate and zinc 2-mercaptobenzothiazole can be used alone, and the two accelerators are used in combination to have a vulcanization synergistic effect, so that the comprehensive mechanical properties of the product are better.

[0017] In some embodiments, the antioxidant comprises at least one of N-(1,3-dimethyl)butyl-N'-phenyl-p-phenylenediamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, and 4,4'-dioctyl diphenylamine.

[0018] In some embodiments, the antioxidant comprises 1-2 parts of N-(1,3-dimethyl)butyl-N'-phenyl-p-phenylenediamine.

[0019] In some embodiments, the antioxidant comprises 0-3 parts of N-(1,3-dimethyl)butyl-N'-phenyl-p-phenylenediamine, 0-3 parts of 2,2,4-trimethyl-1,2-dihydroquinoline polymer, and 0-3 parts of 4,4'-dioctyl diphenylamine, and the three are not zero at the same time.

[0020] In some embodiments, the method for preparing the high-elongation-butyl-rubber product further comprises the following steps:

[0021] Step 1: mixing the butyl latex with zinc oxide, stearic acid, and a vulcanization accelerator to obtain an unvulcanized butyl latex;

[0022] Step 2: adding an aqueous solution of a coagulant to the unvulcanized butyl latex to obtain a latex film, and vulcanizing the latex film after drying to obtain the butyl rubber product;

[0023] The coagulant comprises at least one of copper chloride, copper sulfate, copper acetate, and aluminum chloride.

[0024] In some embodiments, the zinc oxide is added in the form of a zinc oxide aqueous dispersion; the mass concentration of the zinc oxide in the zinc oxide aqueous dispersion is 10%-60%; since the particle size of the zinc oxide is generally large, adding the zinc oxide in the form of an aqueous dispersion is conducive to uniform dispersion of the zinc oxide in the latex.

[0025] In some embodiments, the raw materials are mixed for 2-5 minutes in step 1 to ensure uniform mixing of the raw materials.

[0026] Preferably, the latex film obtained by adding the aqueous solution of the coagulant in step 2 is kneaded before drying to facilitate more uniform mixing of the components and better vulcanization. In some embodiments, the kneading is performed 5-20 times.

[0027] In some embodiments, the drying in step 2 is at 5-80℃ for 1-12h; and the vulcanization is at 120-180℃ for 15-45min under 1-10MPa.

[0028] In some embodiments, the vulcanization is first at 120-180℃ for 15-45min under the same pressure, then cooling water is introduced to reduce the pressure to room temperature for 2-5min.

[0029] The present application also provides a high-elongation-at-break butyl rubber product prepared according to the above method, which has an elongation at break of 1500% or more and excellent tensile properties. In some embodiments, the elongation at break of the butyl rubber product is 2000% or more, such as 2100% or more, 2200% or more, 2300% or more, 2400% or more, 2500% or more, 2600% or more, 2700% or more, etc.

[0030] Compared with the prior art, the present application has the following advantages:

[0031] The present application uses an aqueous solution of copper chloride, copper sulfate, copper acetate or aluminum chloride as a coagulant, and unexpectedly obtains a butyl rubber product with an ultra-high elongation at break, which has an elongation at break of 1500% or more, much higher than the product of 700-800% in the prior art, and the tensile strength and tear strength of the material are maintained well, and the comprehensive performance is excellent. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 Figure 1 is a schematic diagram of the preparation process of the high-elongation-at-break butyl rubber product in the specific embodiment. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below with examples. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application. Those skilled in the art can modify or replace the equivalent without departing from the spirit and scope of the present application, which should be covered by the protection scope of the present application.

[0034] The raw materials used in the following specific embodiments are all purchased from the market, and the solid content of butyl rubber in the butyl latex is 40-50%.

[0035] As shown in Figure 1 the preparation process of the high-elongation-at-break butyl rubber product includes the following steps:

[0036] Step 1, prepare an aqueous coagulant solution;

[0037] Step 2, mixing butyl latex with sulfur, zinc oxide, stearic acid, vulcanization accelerator and antioxidant to obtain unvulcanized butyl latex;

[0038] Step 3, adding the coagulant aqueous solution into the unvulcanized butyl latex to break the emulsion and obtain latex film, drying and vulcanizing to obtain butyl rubber product with high elongation at break.

[0039] Example 1

[0040] Step 1, mixing 5 parts of copper chloride with 95 parts of deionized water to prepare the coagulant aqueous solution.

[0041] Step 2, preparing 5 parts of zinc oxide into a water dispersion with 40% mass content of zinc oxide, and adding into 100 parts of butyl rubber to prepare 40 wt% butyl latex, stirring and mixing uniformly; then grinding 1.5 parts of sulfur, 1.5 parts of zinc dibenzyl dithiocarbamate, 1.5 parts of 2-mercaptobenzothiazole zinc salt, 2 parts of stearic acid, and 1.5 parts of N-(1,3-dimethyl)butyl-N'-phenyl-p-phenylenediamine into fine powder, and adding into the above butyl latex, stirring and mixing for 2 min to prepare unvulcanized butyl latex.

[0042] Step 3, adding the coagulant aqueous solution of copper chloride in Step 1 into the stirring unvulcanized butyl latex to break the emulsion into latex film, kneading repeatedly for 20 times, wiping the surface moisture, drying in the vacuum oven at 80°C for 1 h to obtain dried latex film. Hot pressing the dried latex film at 180°C and 1 MPa for 45 min, and then cold pressing for 2 min, releasing the pressure to take out the vulcanized film to obtain butyl rubber product, and testing the mechanical properties.

[0043] Example 2

[0044] Step 1, preparing 25 parts of copper sulfate and 75 parts of deionized water into coagulant aqueous solution.

[0045] Step 2, preparing 2 parts of zinc oxide into a water dispersion with 10% mass content of zinc oxide, and adding into 100 parts of butyl rubber to prepare 60 wt% butyl latex, stirring and mixing uniformly; then grinding 3 parts of sulfur, 1.5 parts of zinc dibenzyl dithiocarbamate, 1.5 parts of 2-mercaptobenzothiazole zinc salt, 1 part of stearic acid, and 1.5 parts of N-(1,3-dimethyl)butyl-N'-phenyl-p-phenylenediamine into fine powder, and adding into the above butyl latex, stirring and mixing for 5 min to prepare unvulcanized butyl latex.

[0046] Step 3, the copper sulfate coagulant aqueous solution of step 1 was added dropwise into the stirred unvulcanized butyl latex, broken into latex film, kneaded repeatedly 5 times, wiped dry the surface moisture, dried in a vacuum oven at 5℃ for 12h, obtained dried latex film. The dried latex film was hot pressed at 120℃, 10MPa for 15min, then cold pressed for 5min, released pressure to take out the vulcanized film, obtained butyl rubber product, tested mechanical properties.

[0047] Example 3

[0048] Step 1, copper acetate 15 parts, deionized water 85 parts to prepare coagulant aqueous solution.

[0049] Step 2, 5 parts of zinc oxide was prepared into a water dispersion with mass content of 40% zinc oxide, added into 10wt% butyl latex containing 100 parts of butyl rubber, stirred and mixed uniformly; 1 part of sulfur, 6 parts of zinc dibenzyl dithiocarbamate, 1.5 parts of stearic acid, 1.5 parts of N-(1,3-dimethyl)butyl-N'-phenyl-p-phenylenediamine, 1 part of 2,2,4-trimethyl-1,2-dihydroquinoline polymer, 0.5 parts of 4,4'-dioctyl diphenylamine were ground into fine powder, added into the above butyl latex, stirred and mixed for 3min, prepared unvulcanized butyl latex.

[0050] Step 3, the copper acetate coagulant aqueous solution of step 1 was added dropwise into the stirred unvulcanized butyl latex, broken into latex film, kneaded repeatedly 10 times, wiped dry the surface moisture, dried in a vacuum oven at 50℃ for 8h, obtained dried latex film. The dried latex film was hot pressed at 160℃, 5MPa for 26min, then cold pressed for 3min, released pressure to take out the vulcanized film, obtained butyl rubber product, tested mechanical properties.

[0051] Example 4

[0052] Step 1, copper chloride 4 parts, copper acetate 1 part, deionized water 95 parts to prepare mixed coagulant aqueous solution.

[0053] Step 2, 3 parts of zinc oxide was prepared into a water dispersion with mass content of 40% zinc oxide, added into 40wt% butyl latex containing 100 parts of butyl rubber, stirred and mixed uniformly; 1.5 parts of sulfur, 4 parts of 2-mercaptobenzothiazole zinc salt, 2 parts of stearic acid, 1.5 parts of 2,2,4-trimethyl-1,2-dihydroquinoline polymer were ground into fine powder, added into the above butyl latex, stirred and mixed for 3min, prepared unvulcanized butyl latex.

[0054] Step 3, the copper chloride of step 1 was added dropwise into the stirred unvulcanized butyl latex with mixed coagulant aqueous solution, broken into latex film, kneaded repeatedly for 20 times, wiped dry the surface moisture, dried in vacuum oven at 80℃ for 4h, obtained dried latex film. The dried latex film was hot pressed at 160℃, 2MPa for 30min, then cold pressed for 2min, released pressure to take out the vulcanized film, obtained butyl rubber product, tested mechanical properties.

[0055] Example 5

[0056] Step 1, aluminum chloride 5 parts, deionized water 95 parts to configure coagulant aqueous solution.

[0057] Step 2, 5 parts of zinc oxide was prepared into a water dispersion with mass content of 40% zinc oxide, added into 40wt% butyl latex containing 100 parts of butyl rubber, stirred and mixed uniformly; sulfur 1.5 parts, zinc dibenzyl dithiocarbamate 1.5 parts, 2-mercapto benzothiazole zinc salt 1.5 parts, stearic acid 2 parts, 4,4'-dioctyl diphenylamine 3 parts were ground into fine powder, added into the above butyl latex, stirred and mixed for 3min, prepared unvulcanized butyl latex.

[0058] Step 3, the aluminum chloride coagulant aqueous solution of step 1 was added dropwise into the stirred unvulcanized butyl latex, broken into latex film, kneaded repeatedly for 20 times, wiped dry the surface moisture, dried in vacuum oven at 80℃ for 4h, obtained dried latex film. The dried latex film was hot pressed at 160℃, 2MPa for 21min, then cold pressed for 2min, released pressure to take out the vulcanized film, obtained butyl rubber product, tested mechanical properties.

[0059] Example 6

[0060] Step 1, aluminum chloride 5 parts, copper acetate 2 parts, deionized water 93 parts to configure mixed coagulant aqueous solution.

[0061] Step 2, 5 parts of zinc oxide was prepared into a water dispersion with mass content of 40wt% zinc oxide, added into 40wt% butyl latex containing 100 parts of butyl rubber, stirred and mixed uniformly; sulfur 1.5 parts, zinc dibenzyl dithiocarbamate 1.5 parts, 2-mercapto benzothiazole zinc salt 1.5 parts, stearic acid 2 parts, N-(1,3-dimethyl)butyl-N'-phenyl-p-phenylenediamine 1.5 parts were ground into fine powder, added into the above butyl latex, stirred and mixed for 3min, prepared unvulcanized butyl latex.

[0062] Step 3, the aluminum chloride of step 1 was added dropwise into the stirred unvulcanized butyl latex with the mixed coagulant aqueous solution, and the latex film was broken and kneaded repeatedly for 20 times. The surface water was wiped dry, and the dried latex film was dried in a vacuum oven at 80°C for 4h. The dried latex film was hot-pressed at 160°C and 2MPa for 38min, and then cold-pressed for 2min. The vulcanized film was taken out after pressure relief to obtain a butyl rubber product, and the mechanical properties were tested.

[0063] Comparative Example 1

[0064] Step 1, 5 parts of calcium chloride and 95 parts of deionized water were used to prepare a coagulant aqueous solution.

[0065] Step 2, 5 parts of zinc oxide was prepared into a water dispersion with a mass content of 40wt% zinc oxide and added into 40wt% butyl latex containing 100 parts of butyl rubber, and stirred and mixed uniformly. 1.5 parts of sulfur, 1.5 parts of zinc dibenzyl dithiocarbamate, 1.5 parts of 2-mercaptobenzothiazole zinc salt, 2 parts of stearic acid, and 1.5 parts of N-(1,3-dimethyl)butyl-N'-phenyl-p-phenylenediamine were ground into fine powder and added into the above butyl latex, and stirred and mixed for 3min to prepare unvulcanized butyl latex.

[0066] Step 3, the calcium chloride coagulant aqueous solution of step 1 was added dropwise into the stirred unvulcanized butyl latex, and the latex film was broken and kneaded repeatedly for 20 times. The surface water was wiped dry, and the dried latex film was dried in a vacuum oven at 80°C for 4h. The dried latex film was hot-pressed at 160°C and 2MPa for 19min, and then cold-pressed for 2min. The vulcanized film was taken out after pressure relief to obtain a butyl rubber product, and the mechanical properties were tested.

[0067] Comparative Example 2

[0068] Step 1, 15 parts of calcium nitrate and 85 parts of deionized water were used to prepare a coagulant aqueous solution.

[0069] Step 2, 5 parts of zinc oxide was prepared into a water dispersion with a mass content of 40wt% zinc oxide and added into 40wt% butyl latex containing 100 parts of butyl rubber, and stirred and mixed uniformly. 1.5 parts of sulfur, 1.5 parts of zinc dibenzyl dithiocarbamate, 1.5 parts of 2-mercaptobenzothiazole zinc salt, 2 parts of stearic acid, and 1.5 parts of N-(1,3-dimethyl)butyl-N'-phenyl-p-phenylenediamine were ground into fine powder and added into the above butyl latex, and stirred and mixed for 3min to prepare unvulcanized butyl latex.

[0070] Step 3, the aqueous solution of calcium nitrate coagulant of step 1 was added dropwise into the stirred unvulcanized butyl latex, and the latex film was broken and kneaded for 20 times repeatedly, the surface moisture was wiped dry, and the dried latex film was obtained by drying in a vacuum oven at 50℃ for 4h. The dried latex film was hot-pressed at 160℃ and 2MPa for 27min, and then cold-pressed for 2min, and the vulcanized film was taken out after pressure relief, and the mechanical properties were tested.

[0071] The tensile properties of the vulcanized rubber were tested according to the national standard GB / T 528-2009 "Determination of Tensile Stress-Strain Properties of Vulcanized or Thermoplastic Rubber", and the test results are shown in Table 1.

[0072] Table 1 Comparison table of tensile properties test of vulcanized rubber

[0073]

[0074] As shown in Table 1, the elongation at break of the vulcanized rubber of the butyl latex coagulated by copper chloride, copper sulfate, copper acetate, aluminum chloride and other coagulants in the examples is higher than that of the vulcanized rubber of the butyl latex coagulated by traditional calcium salt coagulant in the comparative examples; the elongation at break of the butyl vulcanized rubber coagulated by copper chloride is the highest; the elongation at break of the butyl vulcanized rubber coagulated by copper sulfate, copper acetate and aluminum chloride is greater than 2000% while maintaining the tensile strength and tear strength.

Claims

1. A process for producing a butyl rubber product having a high elongation at break, characterized by, The method comprises the steps of: coagulating the unvulcanized butyl latex with a metal salt aqueous solution as a coagulant, and drying and vulcanizing the coagulated butyl latex to obtain the butyl rubber product. The metal salt is at least one of copper chloride, copper sulfate and copper acetate.

2. The process for producing a high elongation at break butyl rubber article according to claim 1, characterized by, The mass concentration of the metal salt in the metal salt aqueous solution is 5%-25%.

3. The method of producing a high elongation at break butyl rubber article according to claim 1, characterized by, The unvulcanized butyl latex comprises the following raw material components in parts by mass: 100 parts of butyl latex containing butyl rubber, 1-3 parts of sulfur, 2-5 parts of zinc oxide, 1-2 parts of stearic acid, 2-6 parts of a vulcanization accelerator and 1-3 parts of an antioxidant.

4. The method of producing a high elongation at break butyl rubber product according to claim 3, characterized by, The mass fraction of butyl rubber in the butyl latex is 10%-60%.

5. The method of producing a high elongation at break butyl rubber article according to claim 3, characterized by, The vulcanization accelerator comprises at least one of zinc dibenzyl dithiocarbamate and 2-mercaptobenzothiazole zinc salt. The antioxidant comprises at least one of N-(1,3-dimethyl)butyl-N'-phenyl-p-phenylenediamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymer and 4,4'-dioctyl diphenylamine.

6. The method of producing a high elongation at break butyl rubber article according to claim 3, characterized by, The vulcanization accelerator comprises 0-6 parts of zinc dibenzyl dithiocarbamate and 0-6 parts of 2-mercaptobenzothiazole zinc salt, and the two are not zero at the same time. The antioxidant comprises 0-3 parts of N-(1,3-dimethyl)butyl-N'-phenyl-p-phenylenediamine, 0-3 parts of 2,2,4-trimethyl-1,2-dihydroquinoline polymer and 0-3 parts of 4,4'-dioctyl diphenylamine, and the three are not zero at the same time.

7. The method of producing a high elongation at break butyl rubber article according to claim 1, characterized by, The method comprises the steps of: Step 1, mixing the butyl latex with zinc oxide, stearic acid, a vulcanization accelerator and an antioxidant to obtain unvulcanized butyl latex; Step 2, adding the coagulant aqueous solution dropwise to the unvulcanized butyl latex to obtain a latex film, and vulcanizing the dried latex film to obtain the butyl rubber product.

8. The method of producing a high elongation at break butyl rubber article according to claim 7, characterized by, The zinc oxide is added in the form of a zinc oxide aqueous dispersion, and the mass concentration of zinc oxide in the zinc oxide aqueous dispersion is 10%-60%.

9. The method of producing a high elongation at break butyl rubber article according to claim 7, characterized by, The drying in step 2 is performed at 5°C-80°C for 1h-12h. The vulcanization in step 2 is performed at a hot pressing temperature of 120°C-180°C, a hot pressing pressure of 1MPa-10MPa and for 15min-45min.

10. A high elongation butyl rubber article prepared according to the process of any one of claims 1-9, characterized by, The butyl rubber product has an elongation at break of 1500% or more.

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